PLANTS HAVING INCREASED TOLERANCE TO HERBICIDES (2024)

This application is a continuation of U.S. patent application Ser. No. 16/468,036, which is a U.S. National Stage application of International Application No. PCT/EP2017/083244, filed Dec. 18, 2017, which claims priority to European Patent Application No. 16205383.9, filed on Dec. 20, 2016. The entire contents of the aforementioned applications are hereby incorporated herein by reference in their entirety.

The Sequence Listing, which is a part of the present disclosure, is submitted concurrently with the specification as an XML file. The name of the file containing the Sequence Listing is “78939A_Seqlisting.xml”, which was created on Dec. 8, 2023 and is 202,681 bytes in size. The subject matter of the Sequence Listing is incorporated herein in its entirety by reference.

The present invention relates in general to methods for conferring on plants agricultural level tolerance to a herbicide. Particularly, the invention refers to plants having an increased tolerance to PPO-inhibiting herbicides. More specifically, the present invention relates to methods and plants obtained by mutagenesis and cross-breeding and transformation that have an increased tolerance to PPO-inhibiting herbicides.

Herbicides that inhibit protoporphyrinogen oxidase (hereinafter referred to as Protox or PPO; EC:1.3.3.4), a key enzyme in the biosynthesis of protoporphyrin IX, have been used for selective weed control since the 1960s. PPO catalyzes the last common step in chlorophyll and heme biosynthesis which is the oxidation of protoporphyrinogen IX to protoporphyrin IX. (Matringe et al. 1989. Biochem. 1. 260: 231). PPO-inhibiting herbicides include many different structural classes of molecules (Duke et al. 1991. Weed Sci. 39: 465; Nandihalli et al. 1992. Pesticide Biochem. Physiol. 43: 193; Matringe et al. 1989. FEBS Lett. 245: 35; Yanase and Andoh. 1989. Pesticide Biochem. Physiol. 35: 70). These herbicidal compounds include the diphenylethers (e.g. lactofen, (+−)-2-ethoxy-1-methyl-2-oxoethyl 5-{2-chloro-4-(trifluoromethyl)phenoxy}-2-nitrobenzoate; acifluorfen, 5-{2-chloro-4-(trifluoromethyl)phenoxy}-2-nitrobenzoic acid; its methyl ester; or oxyfluorfen, 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluorobenzene)}, oxidiazoles, (e.g. oxidiazon, 3-{2,4-dichloro-5-(1-methylethoxy)phenyl}-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2-(3H)-one), cyclic imides (e.g. S-23142, N-(4-chloro-2-fluoro-5-propargyloxyphenyl)-3,4,5,6-tetrahydrophthalimide; chlorophthalim, N-(4-chlorophenyl)-3,4,5,6-tetrahydrophthalimide), phenyl pyrazoles (e.g. TNPP-ethyl, ethyl 2-{1-(2,3,4-trichlorophenyl)-4-nitropyrazolyl-5-oxy}propionate; M&B 39279), pyridine derivatives (e.g. LS 82-556), and phenopylate and its O-phenylpyrrolidino- and piperidinocarbamate analogs. Many of these compounds competitively inhibit the normal reaction catalyzed by the enzyme, apparently acting as substrate analogs.

Application of PPO-inhibiting herbicides results in the accumulation of protoporphyrinogen IX in the chloroplast and mitochondria, which is believed to leak into the cytosol where it is oxidized by a peroxidase. When exposed to light, protoporphyrin IX causes formation of singlet oxygen in the cytosol and the formation of other reactive oxygen species, which can cause lipid peroxidation and membrane disruption leading to rapid cell death (Lee et al. 1993. Plant Physiol. 102: 881).

Not all PPO enzymes are sensitive to herbicides which inhibit plant PPO enzymes. Both the Escherichia coli and Bacillus subtilis PPO enzymes (Sasarmen et al. 1993. Can. J. Microbiol. 39: 1155; Dailey et al. 1994. J. Biol. Chem. 269: 813) are resistant to these herbicidal inhibitors. Mutants of the unicellular alga Chlamydomonas reinhardtii resistant to the phenylimide herbicide S-23142 have been reported (Kataoka et al. 1990. J. Pesticide Sci. 15: 449; Shibata et al. 1992. In Research in Photosynthesis, Vol. III, N. Murata, ed. Kluwer:Netherlands. pp. 567-70). At least one of these mutants appears to have an altered PPO activity that is resistant not only to the herbicidal inhibitor on which the mutant was selected, but also to other classes of protox inhibitors (Oshio et al. 1993. Z. Naturforsch. 48c: 339; Sato et al. 1994. In ACS Symposium on Porphyric Pesticides, S. Duke, ed. ACS Press: Washington, D.C.). A mutant tobacco cell line has also been reported that is resistant to the inhibitor S-21432 (Che et al. 1993. Z. Naturforsch. 48c: 350). Auxotrophic E. coli mutants have been used to confirm the herbicide resistance of cloned plant PPO-inhibting herbicides.

Three main strategies are available for making plants tolerant to herbicides, i.e. (1) detoxifying the herbicide with an enzyme which transforms the herbicide, or its active metabolite, into non-toxic products, such as, for example, the enzymes for tolerance to bromoxynil or to basta (EP242236, EP337899); (2) mutating the target enzyme into a functional enzyme which is less sensitive to the herbicide, or to its active metabolite, such as, for example, the enzymes for tolerance to glyphosate (EP293356, Padgette S. R. et al., J. Biol. Chem., 266, 33, 1991); or (3) overexpressing the sensitive enzyme so as to produce quantities of the target enzyme in the plant which are sufficient in relation to the herbicide, in view of the kinetic constants of this enzyme, so as to have enough of the functional enzyme available despite the presence of its inhibitor. The third strategy was described for successfully obtaining plants which were tolerant to PPO inhibitors (see e.g. U.S. Pat. No. 5,767,373 or U.S. Pat. No. 5,939,602, and patent family members thereof.). In addition, US 2010/0100988 and WO 2007/024739 discloses nucleotide sequences encoding amino acid sequences having enzymatic activity such that the amino acid sequences are resistant to PPO inhibitor herbicidal chemicals, in particular 3-phenyluracil inhibitor specific PPO mutants.

WO 2012/080975 discloses plants the tolerance of which to a PPO-inhibiting herbicide. In particular, WO 2012/080975 discloses that the introduction of nucleic acids which code for a mutated PPO of an Amaranthus type II PPO in which the Arginine at position 128 had been replaced by a leucine, alanine, or valine, and the phenylalanine at position 420 had been replaced by a methionine, cysteine, isoleucine, leucine, or threonine, confers increased tolerance/resistance to a benzoxazinone-derivative herbicide. WO 2013/189984 describes that the introduction of nucleic acids which code for a mutated PPO in which the leucine corresponding to position 397, and the phenylalanine corresponding to position 420 of an Amaranthus type II PPO are replaced confers increased tolerance/resistance to PPO inhibiting herbicides. WO2015/022636 describes novel PPO mutants in which which the arginine corresponding to position 128, and the phenylalanine corresponding to position 420 of an Amaranthus type II PPO are replaced by amino acids which are different from those disclosed by WO 2012/080975.

WO2015/022640 discloses novel PPO enzymes and mutants thereof derived from Alopecurus myosuroides. WO2015/092706 decribes that the transfer of mutations from Amaranthus (as decribed above) into crop PPO sequences show an increased tolerance effect in plant. U.S. Pat. No. 7,671,254 describes mutated PPO of an Amaranthus type II PPO in which the glycine at positions 210 and/or 211 are deleted. In contrast to positions corresponding to 128, 397, and 420, said positions 210 and/or 211 are known to lie outside the catalytic site of PPO (“non-active sites”). The inventors of the present invention have now surprisingly found out that a substitution of amino acids at Gly210/211, or at other non-active sites, in particular when combined with a substitution at positions at active sites, i.e. corresponding to positions 128, 397, and/or 420 of the Amaranthus type II PPO increase herbicide tolerance.

Accordingly, in one aspect, the present invention provides a plant or plant part comprising a polynucleotide encoding a mutated PPO polypeptide, the expression of said polynucleotide confers to the plant or plant part tolerance to herbicides.

In a preferred embodiment, said mutated PPO polypeptide comprises one or more of the following motifs.

In some aspects, the present invention provides a seed capable of germination into a plant comprising in at least some of its cells a polynucleotide operably linked to a promoter operable in plant cells, the promoter capable of expressing a mutated PPO polypeptide encoded by the polynucleotide of the present invention, the expression of the mutated PPO polypeptide conferring to the plant tolerance to herbicides.

In one aspect, the present invention provides a plant cell capable of regenerating a plant comprising in at least some of its cells a polynucleotide operably linked to a promoter operable in plant cells, the promoter capable of expressing a mutated PPO polypeptide encoded by the polynucleotide of the present invention, the expression of the mutated PPO polypeptide conferring to the plant tolerance to herbicides, wherein the plant cell comprises the polynucleotide operably linked to a promoter.

In another aspect, the present invention provides a plant cell comprising a polynucleotide operably linked to a promoter operable in a cell, the promoter capable of expressing a mutated PPO polypeptide encoded by the polynucleotide of the present invention, the expression of the mutated PPO polypeptide conferring to the plant tolerance to herbicides.

In other aspects, the present invention provides a plant product prepared from a plant or plant part comprising in at least some of its cells a polynucleotide operably linked to a promoter operable in plant cells, the promoter capable of expressing a mutated PPO polypeptide encoded by the polynucleotide of the present invention, the expression of the mutated PPO polypeptide conferring to the plant tolerance to herbicides.

In some aspects, the present invention provides a progeny or descendant plant derived from a plant comprising in at least some of its cells a polynucleotide operably linked to a promoter operable in plant cells, the promoter capable of expressing a mutated PPO polypeptide encoded by the polynucleotide of the present invention, wherein the progeny or descendant plant comprises in at least some of its cells the recombinant polynucleotide operably linked to the promoter, the expression of the mutated PPO polypeptide conferring to the progeny or descendant plant tolerance to the herbicides.

In other aspects, the present invention provides a method for controlling weeds at a locus for growth of a plant, the method comprising: (a) applying an herbicide composition comprising herbicides to the locus; and (b) planting a seed at the locus, wherein the seed is capable of producing a plant that comprises in at least some of its cells a polynucleotide operably linked to a promoter operable in plant cells, the promoter capable of expressing a mutated PPO polypeptide encoded by the polynucleotide of the present invention, the expression of the mutated PPO polypeptide conferring to the plant tolerance to herbicides.

In some aspects, the present invention provides a method for controlling weeds at a locus for growth of a plant, the method comprising: applying an herbicidal composition comprising herbicides to the locus; wherein said locus is: (a) a locus that contains: a plant or a seed capable of producing said plant; or (b) a locus that is to be after said applying is made to contain the plant or the seed; wherein the plant or the seed comprises in at least some of its cells a polynucleotide operably linked to a promoter operable in plant cells, the promoter capable of expressing a mutated PPO polypeptide encoded by the polynucleotide of the present invention, the expression of the mutated PPO polypeptide conferring to the plant tolerance to herbicides.

In one aspect, step (a) occurs before, after, or concurrently with step (b).

In other aspects, the present invention provides a method of producing a plant having tolerance to herbicides, the method comprising regenerating a plant from a plant cell transformed with a polynucleotide operably linked to a promoter operable in plant cells, the promoter capable of expressing a mutated PPO polypeptide encoded by the polynucleotide of the present invention, the expression of the mutated PPO polypeptide conferring to the plant tolerance to herbicides.

In one aspect, the present invention provides a method of producing a progeny plant having tolerance to herbicides, the method comprising: crossing a first herbicide-tolerant plant with a second plant to produce a herbicide-tolerant progeny plant, wherein the first plant and the progeny plant comprise in at least some of their cells a polynucleotide operably linked to a promoter operable in plant cells, the promoter capable of expressing a mutated PPO polypeptide encoded by the polynucleotide of the present invention, the expression of the mutated PPO polypeptide conferring to the plant tolerance to herbicides.

In addition, the present invention refers to a method for identifying a herbicide by using a mutated PPO of the present invention.

In a preferred embodiment, the mutated PPO-encoding nucleic acid selected in step d) provides at least 2-fold as much tolerance to a herbicide as compared to that provided by the control PPO-encoding nucleic acid.

The resistance or tolerance can be determined by generating a transgenic plant comprising a nucleic acid sequence of the library of step a) and comparing said transgenic plant with a control plant.

Preferably, the difference corresponding to position 391 of SEQ ID NO:1 referes to an insertion, and the difference corresponding to positions 40, 250, 520, 521, 522, 523, 524, 525, 526, 527, 528, 529, 530, 531, 532, 533, 534 of SEQ ID NO: 1 or 2 refers to a deletion.

Another object refers to an expression cassette comprising the nucleic acid molecule of the present invention and a promoter operable in plant cells.

Another object refers to an isolated, recombinant and/or chemically synthesized mutated PPO polypeptide encoded by the nucleic acid molecule as claimed in any of claims 17 to 25 or a polypeptide having at least 80%, 90%, 95%, 98%, 99% identity to the sequence of SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129, or a variant, paralogue, orthologue or hom*olog thereof, wherein the amino acid sequence of the mutated PPO polypeptide differs from the wildtype amino acid sequence of a PPO polypeptide at one or more positions corresponding to positions 32, 53, 57, 61, 63, 64, 65, 67, 71, 76, 82, 83, 85, 86, 87, 88, 91, 103, 104, 106, 108, 116, 119, 126, 127, 129, 139, 159, 210, 211, 224, 245, 246, 248, 249, 252, 253, 254, 255, 257, 259, 260, 262, 264, 286, 291, 305, 308, 309, 323, 335, 343, 345, 358, 372, 373, 387, 391, 392, 400, 412, 414, 415, 425, 428, 431, 433, 434, 435, 436, 447, 451, 453, 464, 466, 482 of SEQ ID NO: 1 or 2, wherein said difference refers to a substitution of the amino acid at that positions by any other amino acid.

Another object refers to an isolated, recombinant and/or chemically synthesized mutated PPO polypeptide encoded by the nucleic acid molecule as claimed in any of claims 17 to 25 or a polypeptide having at least 80%, 90%, 95%, 98%, 99% identity to the sequence of SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129, or a variant, paralogue, orthologue or hom*olog thereof, wherein the amino acid sequence of the mutated PPO polypeptide differs from the wildtype amino acid sequence of a PPO polypeptide at one or more positions corresponding to positions 40, 250, 391, 520, 521, 522, 523, 524, 525, 526, 527, 528, 529, 530, 531, 532, 533, 534 of SEQ ID NO: 1 or 2, wherein said difference refers to a deletion or an insertion of the amino acid at that positions.

In still further aspects, the present invention provides a plant or plant part comprising in at least some of its cells a polynucleotide operably linked to a promoter operable in plant cells, the promoter capable of expressing a mutated PPO polypeptide encoded by the polynucleotide, the expression of the mutated PPO polypeptide conferring to the plant tolerance to herbicides, wherein the plant or plant part further exhibits a second or third herbicide-tolerant trait.

In another embodiment, the invention refers to a plant cell transformed by and expressing a mutated PPO nucleic acid according to the present invention or a plant which has been mutated to obtain a plant expressing, preferably over-expressing a mutated PPO nucleic acid according to the present invention, wherein expression of said nucleic acid in the plant cell results in increased resistance or tolerance to a herbicide as compared to a wild type variety of the plant cell In another embodiment, the invention refers to a plant comprising a plant cell according to the present invention, wherein expression of the nucleic acid in the plant results in the plant's increased resistance to herbicide as compared to a wild type variety of the plant.

The plants of the present invention can be transgenic or non-transgenic.

Preferably, the expression of the nucleic acid of the invention in the plant results in the plant's increased resistance to herbicides as compared to a wild type variety of the plant.

In another embodiment, the invention refers to a seed produced by a transgenic plant comprising a plant cell of the present invention, wherein the seed is true breeding for an increased resistance to a herbicide as compared to a wild type variety of the seed.

In another embodiment, the invention refers to a method of producing a transgenic plant cell with an increased resistance to a herbicide as compared to a wild type variety of the plant cell comprising, transforming the plant cell with an expression cassette comprising a polynucleotide operably linked to a promoter operable in plant cells, the promoter capable of expressing a mutated PPO polypeptide encoded by the polynucleotide.

In another embodiment, the invention refers to a method of producing a transgenic plant comprising, (a) transforming a plant cell with an expression cassette comprising a polynucleotide operably linked to a promoter operable in plant cells, the promoter capable of expressing a mutated PPO polypeptide encoded by the polynucleotide, and (b) generating a plant with an increased resistance to herbicide from the plant cell.

Preferably, the expression cassette further comprises a transcription initiation regulatory region and a translation initiation regulatory region that are functional in the plant.

FIG. 1 shows a germination assay using transgenic Arabidopsis plants (SEQ ID NO:1 mutated AMATU_PPO2_G211A_F420M). Plants were treated with the indicated concentrations of Saflufenacil. Pictures were taken 14 days after treatment.

FIG. 2 shows T1 Tolerance Spray using transgenic Arabidopsis plants (SEQ ID NO:1 mutated AMATU_PPO2_G211A_F420M). Pictures were taken 8 days after treatment (days after spraying). Top at bottom contain 2 wild type plants, upper 5 pots contain independent transgenic events (T1 plants, selected by confirming presence of resistance gene AHAS).

FIG. 3 shows Transgenic Arabidopsis plants sprayed post in the greenhouse with the indicated amount of Saflufenacil+1% (v/v) MSO. Plants harbor the SEQ ID NO:1 mutated traits: A) AMATU_PPO2_R128A_G210S_F420M, B) AMATU_PPO2_R128A_S387L_F420M, C) AMATU_PPO2_G211A_L397Q_F420M, D) AMATU_PPO2_R128A_F420M E) AMATU_PPO2_F420V F) AMATU_PP02_L397Q_F420M G) Wild-type (non-transgenic). Evaluation performed 6 Days After Treatment (DAT).

FIG. 4 shows transgenic Arabidopsis plants sprayed post in the greenhouse with the indicated amount of Trifludimoxazine+1% (v/v) MSO. Plants harbor the SEQ ID NO:1 mutated traits: A) AMATU_PPO2_R128A_G210S_F420M, B) AMATU_PPO2_R128A_S387L_F420M, C) AMATU_PPO2_G211A_F420V, D) AMATU_PPO2_G211A_L397Q_F420M, E) AMATU_PPO2_R128A_F420M F) AMATU_PPO2_F420V G) AMATU_PPO2_L397Q_F420M H) Wild-type (non-transgenic). Evaluation performed 6 Days After Treatment (DAT).

FIG. 5 shows transgenic Arabidopsis plants sprayed post in the greenhouse with the indicated amount of Saflufenacil+Trifludimoxazine+1% (v/v) MSO. Plants harbor the SEQ ID NO:1 mutated traits: A) AMATU_PPO2_R128A_G210S_F420M, B) AMATU_PPO2_R128A_S387L_F420M, C) AMATU_PPO2_G211A_F420V, D) AMATU_PPO2_G211A_L397Q_F420M, E) AMATU_PPO2_R128A_F420M F) AMATU_PPO2_F420V G) AMATU_PPO2_L397Q_F420M H) Wild-type (non-transgenic). Evaluation performed 6 Days After Treatment (DAT).

FIG. 6 shows transgenic Arabidopsis plants sprayed post in the greenhouse with the indicated amount of Uracilpyridine 2+1% (v/v) MSO. Plants harbor the SEQ ID NO:1 mutated traits: A) AMATU_PPO2_R128A_G210S_F420M, B) AMATU_PPO2_R128A_S387L_F420M, C) AMATU_PPO2_G211A_F420V, D) AMATU_PPO2_G211A_L397Q_F420M, E) AMATU_PPO2_R128A_F420M F) AMATU_PPO2_F420V G) AMATU_PPO2_L397Q_F420M H) Wild-type (non-transgenic). Evaluation performed 6 Days After Treatment (DAT).

FIG. 7 shows transgenic Arabidopsis plants sprayed post in the greenhouse with the indicated amount of Uracilpyridine 4+1% (v/v) MSO. Plants harbor the SEQ ID NO:1 mutated traits: A) AMATU_PPO2_R128A_G210S_F420M, B) AMATU_PPO2_R128A_S387L_F420M, C) AMATU_PPO2_G211A_F420V, D) AMATU_PPO2_G211A_L397Q_F420M, E) AMATU_PPO2_R128A_F420M F) AMATU_PPO2_F420V G) AMATU_PPO2_L397Q_F420M H) Wild-type (non-transgenic). Evaluation performed 6 Days After Treatment (DAT).

FIG. 8 shows transgenic Arabidopsis plants sprayed post in the greenhouse with the indicated amount of Uracilpyridine 1+1% (v/v) MSO. Plants harbor the SEQ ID NO:1 mutated traits: A) AMATU_PPO2_R128A_G210S_F420M, B) AMATU_PPO2_R128A_S387L_F420M, C) AMATU_PPO2_G211A_L397Q_F420M, D) AMATU_PPO2_R128A_F420M E) AMATU_PPO2_F420V F) AMATU_PP02_L397Q_F420M G) Wild-type (non-transgenic). Evaluation performed 6 Days After Treatment (DAT).

FIG. 9 shows transgenic Arabidopsis plants sprayed post in the greenhouse with the indicated amount of Sulfentrazone+1% (v/v) MSO. Plants harbor the SEQ ID NO:1 mutated traits: A) AMATU_PPO2_R128A_G210S_F420M, B) AMATU_PPO2_R128A_S387L_F420M, C) AMATU_PPO2_G211A_L397Q_F420M, D) AMATU_PPO2_R128A_F420M E) AMATU_PPO2_F420V F) AMATU_PP02_L397Q_F420M G) Wild-type (non-transgenic). Evaluation performed 6 Days After Treatment (DAT).

FIG. 10 shows transgenic Arabidopsis plants sprayed post in the greenhouse with the indicated amount of Flumioxazin+1% (v/v) MSO. Plants harbor the SEQ ID NO:1 mutated traits: A) AMATU_PPO2_R128A_G210S_F420M, B) AMATU_PPO2_R128A_S387L_F420M, C) AMATU_PPO2_R128A_F420M D) AMATU_PPO2_F420V E) AMATU_PPO2_L397Q_F420M F) Wild-type (non-transgenic). Evaluation performed 6 Days After Treatment (DAT).

FIG. 11 shows transgenic Arabidopsis plants harboring SEQ ID NO:1 mutated AMATU_PPO2_G211A_F420M construct, sprayed post in the greenhouse with the indicated amount of A) Saflufenacil+Trifludimoxazine, B) Tiafenacil, C) Uracilpyridine 6, D) Pyraflufen-ethyl, E) Uracilpyridine 7, with +1% (v/v) MSO. Evaluation performed 14 Days After Treatment (DAT) and is shown as injury (%) relative to non-transgenic treated plants.

FIG. 12 shows examples of transgenic Zea mays harboring AmtuPPX2L variants after pre-emergent treatment with Saflufenacil.

FIG. 13 shows tolerance of transgenic Glycine max harboring AmtuPPX2L variants after treatment with a mixture of Saflufenacil and Trifludimoxazine. 0/0 denotes no active ingredient, 50/25 denotes 50 grams of active ingredient per hectare (AI/Ha) of Saflufenacil and 25 grams AI/Ha of Trifludimoxazine, 100/50 denotes 100 g AI/Ha Saflufenacil and 50 g AI/Ha Trifludimoxazine and 200/100 denotes 200 g AI/Ha Saflufenacil and 100 g AI/Ha Trifludimoxazine. Wild type untransformed is represented by the soy (Glycine max) cultivar Jake (cv. Jake).

FIG. 14 shows examples of herbicide tolerance of transgenic Glycine max harboring AmtuPPX2L variants after treatment with a mixture of Saflufenacil and Trifludimoxazine. 0/0 denotes no active ingredient, 25/50 denotes 50 grams of active ingredient per hectare (AI/Ha) of Saflufenacil and 25 grams AI/Ha of Trifludimoxazine, 50/100 denotes 100 g AI/Ha Saflufenacil and 50 g AI/Ha Trifludimoxazine and 100/200 denotes 200 g AI/Ha Saflufenacil and 100 g AI/Ha Trifludimoxazine. Wild type untransformed is represented by the soy (Glycine max) cultivar Jake (cv. Jake).

The articles “a” and “an” are used herein to refer to one or more than one (i.e., to at least one) of the grammatical object of the article. By way of example, “an element” means one or more elements.

As used herein, the word “comprising,” or variations such as “comprises” or “comprising,” will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

The term “control of undesired vegetation or weeds” is to be understood as meaning the killing of weeds and/or otherwise retarding or inhibiting the normal growth of the weeds. Weeds, in the broadest sense, are understood as meaning all those plants which grow in locations where they are undesired. The weeds of the present invention include, for example, dicotyledonous and monocotyledonous weeds. Dicotyledonous weeds include, but are not limited to, weeds of the genera: Sinapis, Lepidium, Galium, Stellaria, Matricaria, Anthemis, Galinsoga, Chenopodium, Urtica, Senecio, Amaranthus, Portulaca, Xanthium, Convolvulus, Ipomoea, Polygonum, Sesbania, Ambrosia, Cirsium, Carduus, Sonchus, Solanum, Rorippa, Rotala, Lindernia, Lamium, Veronica, Abutilon, Emex, Datura, Viola, Galeopsis, Papaver, Centaurea, Trifolium, Ranunculus, and Taraxacum. Monocotyledonous weeds include, but are not limited to, weeds of of the genera: Echinochloa, Setaria, Panicum, Digitaria, Phleum, Poa, Festuca, Eleusine, Brachiaria, Lolium, Bromus, Avena, Cyperus, Sorghum, Agropyron, Cynodon, Monochoria, Fimbristyslis, Sagittaria, Eleocharis, Scirpus, Paspalum, Ischaemum, Sphenoclea, Dactyloctenium, Agrostis, Alopecurus, and Apera. In addition, the weeds of the present invention can include, for example, crop plants that are growing in an undesired location. For example, a volunteer maize plant that is in a field that predominantly comprises soybean plants can be considered a weed, if the maize plant is undesired in the field of soybean plants.

The term “plant” is used in its broadest sense as it pertains to organic material and is intended to encompass eukaryotic organisms that are members of the Kingdom Plantae, examples of which include but are not limited to vascular plants, vegetables, grains, flowers, trees, herbs, bushes, grasses, vines, ferns, mosses, fungi and algae, etc, as well as clones, offsets, and parts of plants used for asexual propagation (e.g. cuttings, pipings, shoots, rhizomes, underground stems, clumps, crowns, bulbs, corms, tubers, rhizomes, plants/tissues produced in tissue culture, etc.). The term “plant” further encompasses whole plants, ancestors and progeny of the plants and plant parts, including seeds, shoots, stems, leaves, roots (including tubers), flowers, florets, fruits, pedicles, peduncles, stamen, anther, stigma, style, ovary, petal, sepal, carpel, root tip, root cap, root hair, leaf hair, seed hair, pollen grain, microspore, cotyledon, hypocotyl, epicotyl, xylem, phloem, parenchyma, endosperm, a companion cell, a guard cell, and any other known organs, tissues, and cells of a plant, and tissues and organs, wherein each of the aforementioned comprise the gene/nucleic acid of interest. The term “plant” also encompasses plant cells, suspension cultures, callus tissue, embryos, meristematic regions, gametophytes, sporophytes, pollen and microspores, again wherein each of the aforementioned comprises the gene/nucleic acid of interest.

Plants that are particularly useful in the methods of the invention include all plants which belong to the superfamily Viridiplantae, in particular monocotyledonous and dicotyledonous plants including fodder or forage legumes, ornamental plants, food crops, trees or shrubs selected from the list comprising Acer spp., Actinidia spp., Abelmoschus spp., Agave sisalana, Agropyron spp., Agrostis stolonifera, Allium spp., Amaranthus spp., Ammophila arenaria, Ananas comosus, Annona spp., Apium graveolens, Arachis spp, Artocarpus spp., Asparagus officinalis, Avena spp. (e.g. Avena sativa, Avena fatua, Avena byzantina, Avena fatua var. sativa, Avena hybrida), Averrhoa carambola, Bambusa sp., Benincasa hispida, Bertholletia excelsea, Beta vulgaris, Brassica spp. (e.g. Brassica napus, Brassica rapa ssp. [canola, oilseed rape, turnip rape]), Cadaba farinosa, Camellia sinensis, Canna indica, Cannabis sativa, Capsicum spp., Carex elata, Carica papaya, Carissa macrocarpa, Carya spp., Carthamus tinctorius, Castanea spp., Ceiba pentandra, Cichorium endivia, Cinnamomum spp., Citrullus lanatus, Citrus spp., Cocos spp., Coffea spp., Colocasia esculenta, Cola spp., Corchorus sp., Coriandrum sativum, Corylus spp., Crataegus spp., Crocus sativus, Cucurbita spp., Cucumis spp., Cynara spp., Daucus carota, Desmodium spp., Dimocarpus longan, Dioscorea spp., Diospyros spp., Echinochloa spp., Elaeis (e.g. Elaeis guineensis, Elaeis oleifera), Eleusine coracana, Eragrostis tef, Erianthus sp., Eriobotrya japonica, Eucalyptus sp., Eugenia uniflora, fa*gopyrum spp., fa*gus spp., Festuca arundinacea, Ficus carica, Fortunella spp., Fragaria spp., Ginkgo biloba, Glycine spp. (e.g. Glycine max, Soja hispida or Soja max), Gossypium hirsutum, Helianthus spp. (e.g. Helianthus annuus), Hemerocallis fulva, Hibiscus spp., Hordeum spp. (e.g. Hordeum vulgare), Ipomoea batatas, Juglans spp., Lactuca sativa, Lathyrus spp., Lens culinaris, Linum usitatissimum, Litchi chinensis, Lotus spp., Luffa acutangula, Lupinus spp., Luzula sylvatica, Lycopersicon spp. (e.g. Lycopersicon esculentum, Lycopersicon lycopersicum, Lycopersicon pyriforme), Macrotyloma spp., Malus spp., Malpighia emarginata, Mammea americana, Mangifera indica, Manihot spp., Manilkara zapota, Medicago sativa, Melilotus spp., Mentha spp., Miscanthus sinensis, Momordica spp., Morus nigra, Musa spp., Nicotiana spp., Olea spp., Opuntia spp., Ornithopus spp., Oryza spp. (e.g. Oryza sativa, Oryza latifolia), Panicum miliaceum, Panicum virgatum, Passiflora edulis, Pastinaca sativa, Pennisetum sp., Persea spp., Petroselinum crispum, Phalaris arundinacea, Phaseolus spp., Phleum pratense, Phoenix spp., Phragmites australis, Physalis spp., Pinus spp., Pistacia vera, Pisum spp., Poa spp., Populus spp., Prosopis spp., Prunus spp., Psidium spp., Punica granatum, Pyrus communis, Quercus spp., Raphanus sativus, Rheum rhabarbarum, Ribes spp., Ricinus communis, Rubus spp., Saccharum spp., Salix sp., Sambucus spp., Secale cereale, Sesamum spp., Sinapis sp., Solanum spp. (e.g. Solanum tuberosum, Solanum integrifolium or Solanum lycopersicum), Sorghum bicolor, Spinacia spp., Syzygium spp., Tagetes spp., Tamarindus indica, Theobroma cacao, Trifolium spp., Tripsacum dactyloides, Triticosecale rimpaui, Triticum spp. (e.g. Triticum aestivum, Triticum durum, Triticum turgidum, Triticum hybernum, Triticum macha, Triticum sativum, Triticum monococcum or Triticum vulgare), Tropaeolum minus, Tropaeolum majus, Vaccinium spp., Vicia spp., Vigna spp., Viola odorata, Vitis spp., Zea mays, Zizania palustris, Ziziphus spp., amaranth, artichoke, asparagus, broccoli, Brussels sprouts, cabbage, canola, carrot, cauliflower, celery, collard greens, flax, kale, lentil, oilseed rape, okra, onion, potato, rice, soybean, strawberry, sugar beet, sugar cane, sunflower, tomato, squash, tea and algae, amongst others. According to a preferred embodiment of the present invention, the plant is a crop plant. Examples of crop plants include inter alia soybean, sunflower, canola, alfalfa, rapeseed, cotton, tomato, potato or tobacco. Further preferebly, the plant is a monocotyledonous plant, such as sugarcane. Further preferably, the plant is a cereal, such as rice, maize, wheat, barley, millet, rye, sorghum or oats.

Generally, the term “herbicide” is used herein to mean an active ingredient that kills, controls or otherwise adversely modifies the growth of plants. The preferred amount or concentration of the herbicide is an “effective amount” or “effective concentration.” By “effective amount” and “effective concentration” is intended an amount and concentration, respectively, that is sufficient to kill or inhibit the growth of a similar, wild-type, plant, plant tissue, plant cell, or host cell, but that said amount does not kill or inhibit as severely the growth of the herbicide-resistant plants, plant tissues, plant cells, and host cells of the present invention. Typically, the effective amount of a herbicide is an amount that is routinely used in agricultural production systems to kill weeds of interest. Such an amount is known to those of ordinary skill in the art. Herbicidal activity is exhibited by herbicides useful for the the present invention when they are applied directly to the plant or to the locus of the plant at any stage of growth or before planting or emergence. The effect observed depends upon the plant species to be controlled, the stage of growth of the plant, the application parameters of dilution and spray drop size, the particle size of solid components, the environmental conditions at the time of use, the specific compound employed, the specific adjuvants and carriers employed, the soil type, and the like, as well as the amount of chemical applied. These and other factors can be adjusted as is known in the art to promote non-selective or selective herbicidal action. Generally, the herbicide treatments can be applied PPI (Pre Plant Incorporated), PPSA (Post plarIt surface applied), PRE- or POST-emergent. Postemergent treatment typically occurs to relatively immature undesirable vegetation to achieve the maximum control of weeds.

By a “herbicide-tolerant” or “herbicide-resistant” plant, it is intended that a plant that is tolerant or resistant to at least one herbicide at a level that would normally kill, or inhibit the growth of, a normal or wildtype plant. Levels of herbicide that normally inhibit growth of a non-tolerant plant are known and readily determined by those skilled in the art. Examples include the amounts recommended by manufacturers for application. The maximum rate is an example of an amount of herbicide that would normally inhibit growth of a non-tolerant plant. For the present invention, the terms “herbicide-tolerant” and “herbicide-resistant” are used interchangeably and are intended to have an equivalent meaning and an equivalent scope. Similarly, the terms “herbicide-tolerance” and “herbicide-resistance” are used interchangeably and are intended to have an equivalent meaning and an equivalent scope. Similarly, the terms “tolerant” and “resistant” are used interchangeably and are intended to have an equivalent meaning and an equivalent scope. As used herein, in regard to an herbicidal composition useful in various embodiments hereof, terms such as herbicides, and the like, refer to those agronomically acceptable herbicide active ingredients (A.I.) recognized in the art. Similarly, terms such as fungicide, nematicide, pesticide, and the like, refer to other agronomically acceptable active ingredients recognized in the art.

When used in reference to a particular mutant enzyme or polypeptide, terms such as herbicide-tolerant and herbicide-tolerance refer to the ability of such enzyme or polypeptide to perform its physiological activity in the presence of an amount of an herbicide A.I. that would normally inactivate or inhibit the activity of the wild-type (non-mutant) version of said enzyme or polypeptide. Furthermore, the PPO activity of such a herbicide-tolerant or herbicide-resistant mutated PPO protein may be referred to herein as “herbicide-tolerant” or “herbicide-resistant” PPO activity.

As used herein, “recombinant,” when referring to nucleic acid or polypeptide, indicates that such material has been altered as a result of human application of a recombinant technique, such as by polynucleotide restriction and ligation, by polynucleotide overlap-extension, or by genomic insertion or transformation. A gene sequence open reading frame is recombinant if that nucleotide sequence has been removed from its natural context and cloned into any type of artificial nucleic acid vector. The term recombinant also can refer to an organism having a recombinant material, e.g., a plant that comprises a recombinant nucleic acid can be considered a recombinant plant.

The term “transgenic plant” refers to a plant that comprises a heterologous polynucleotide. Preferably, the heterologous polynucleotide is stably integrated within the genome such that the polynucleotide is passed on to successive generations. The heterologous polynucleotide may be integrated into the genome alone or as part of a recombinant expression cassette. “Transgenic” is used herein to refer to any cell, cell line, callus, tissue, plant part or plant, the genotype of which has been so altered by the presence of heterologous nucleic acid including those transgenic organisms or cells initially so altered, as well as those created by crosses or asexual propagation from the initial transgenic organism or cell. In some embodiments, a “recombinant” organism is a “transgenic” organism. The term “transgenic” as used herein is not intended to encompass the alteration of the genome (chromosomal or extra-chromosomal) by conventional plant breeding methods (e.g., crosses) or by naturally occurring events such as, e.g., self-fertilization, random cross-fertilization, non-recombinant viral infection, non-recombinant bacterial transformation, non-recombinant transposition, or spontaneous mutation.

As used herein, “mutagenized” refers to an organism or DNA thereof having alteration(s) in the biomolecular sequence of its native genetic material as compared to the sequence of the genetic material of a corresponding wild-type organism or DNA, wherein the alteration(s) in genetic material were induced and/or selected by human action. Examples of human action that can be used to produce a mutagenized organism or DNA include, but are not limited to, treatment with a chemical mutagen such as EMS and subsequent selection with herbicide(s); or by treatment of plant cells with x-rays and subsequent selection with herbicide(s). Any method known in the art can be used to induce mutations. Methods of inducing mutations can induce mutations in random positions in the genetic material or can induce mutations in specific locations in the genetic material (i.e., can be directed mutagenesis techniques), such as by use of a genoplasty technique.

As used herein, a “genetically modified organism” (GMO) is an organism whose genetic characteristics contain alteration(s) that were produced by human effort causing transfection that results in transformation of a target organism with genetic material from another or “source” organism, or with synthetic or modified-native genetic material, or an organism that is a descendant thereof that retains the inserted genetic material. The source organism can be of a different type of organism (e.g., a GMO plant can contain bacterial genetic material) or from the same type of organism (e.g., a GMO plant can contain genetic material from another plant). As used herein in regard to plants and other organisms, “recombinant,” “transgenic,” and “GMO” are considered synonyms and indicate the presence of genetic material from a different source; in contrast, “mutagenized” is used to refer to a plant or other organism, or the DNA thereof, in which no such transgenic material is present, but in which the native genetic material has become mutated so as to differ from a corresponding wild-type organism or DNA.

As used herein, “wild-type” or “corresponding wild-type plant” means the typical form of an organism or its genetic material, as it normally occurs, as distinguished from, e.g., mutagenized and/or recombinant forms. Similarly, by “control cell” or “similar, wild-type, plant, plant tissue, plant cell or host cell” is intended a plant, plant tissue, plant cell, or host cell, respectively, that lacks the herbicide-resistance characteristics and/or particular polynucleotide of the invention that are disclosed herein. The use of the term “wild-type” is not, therefore, intended to imply that a plant, plant tissue, plant cell, or other host cell lacks recombinant DNA in its genome, and/or does not possess herbicide-resistant characteristics that are different from those disclosed herein.

As used herein, “descendant” refers to any generation plant. In some embodiments, a descendant is a first, second, third, fourth, fifth, sixth, seventh, eight, ninth, or tenth generation plant.

As used herein, “progeny” refers to a first generation plant.

The term “seed” comprises seeds of all types, such as, for example, true seeds, caryopses, achenes, fruits, tubers, seedlings and similar forms. In the context of Brassica and Sinapis species, “seed” refers to true seed(s) unless otherwise specified. For example, the seed can be seed of transgenic plants or plants obtained by traditional breeding methods. Examples of traditional breeding methods can include cross-breeding, selfing, back-crossing, embryo rescue, in-crossing, out-crossing, inbreeding, selection, asexual propagation, and other traditional techniques as are known in the art.

Although exemplified with reference to specific plants or plant varieties and their hybrids, in various embodiments, the presently described methods using herbicides can be employed with a variety of commercially valuable plants. Herbicide-tolerant plant lines described as useful herein can be employed in weed control methods either directly or indirectly, i. e. either as crops for herbicide treatment or as herbicide-tolerance trait donor lines for development, to produce other varietal and/or hybrid crops containing such trait or traits. All such resulting variety or hybrids crops, containing the ancestral herbicide-tolerance trait or traits can be referred to herein as progeny or descendant of the ancestral, herbicide-tolerant line(s). Such resulting plants can be said to retain the “herbicide tolerance characteristic(s)” of the ancestral plant, i.e. meaning that they possess and express the ancestral genetic molecular components responsible for the trait.

In one aspect, the present invention provides a plant or plant part comprising a polynucleotide encoding a mutated PPO polypeptide, the expression of said polynucleotide confers to the plant or plant part tolerance to herbicides.

In a preferred embodiment, the plant has been previously produced by a process comprising recombinantly preparing a plant by introducing and over-expressing a mutated PPO transgene according to the present invention, as described in greater detail hereinfter.

In another embodiment, the polynucleotide encoding the mutated PPO polypeptide polypeptide comprises the nucleic acid sequence set forth in SEQ ID NO: 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, or 130, or a variant or derivative thereof.

In other embodiments, the mutated PPO polypeptide according to the present invention is a functional variant having, over the full-length of the variant, at least about 80%, illustratively, at least about 80%, 90%, 95%, 98%, 99% or more amino acid sequence identity to SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129.

In another embodiment, the mutated PPO polypeptide for use according to the present invention is a functional fragment of a polypeptide having the amino acid sequence set forth in SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129.

It is recognized that the PPO polynucleotide molecules and PPO polypeptides of the invention encompass polynucleotide molecules and polypeptides comprising a nucleotide or an amino acid sequence that is sufficiently identical to nucleotide sequence set forth in SEQ ID NOs: 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, or 130, or to the amino acid sequence set forth in SEQ ID Nos: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129. The term “sufficiently identical” is used herein to refer to a first amino acid or nucleotide sequence that contains a sufficient or minimum number of identical or equivalent (e.g., with a similar side chain) amino acid residues or nucleotides to a second amino acid or nucleotide sequence such that the first and second amino acid or nucleotide sequences have a common structural domain and/or common functional activity.

Generally, “sequence identity” refers to the extent to which two optimally aligned DNA or amino acid sequences are invariant throughout a window of alignment of components, e.g., nucleotides or amino acids. An “identity fraction” for aligned segments of a test sequence and a reference sequence is the number of identical components that are shared by the two aligned sequences divided by the total number of components in reference sequence segment, i.e., the entire reference sequence or a smaller defined part of the reference sequence. “Percent identity” is the identity fraction times 100. Optimal alignment of sequences for aligning a comparison window are well known to those skilled in the art and may be conducted by tools such as the local hom*ology algorithm of Smith and Waterman, the hom*ology alignment algorithm of Needleman and Wunsch, the search for similarity method of Pearson and Lipman, and preferably by computerized implementations of these algorithms such as GAP, BESTFIT, FASTA, and TFASTA available as part of the GCG. Wisconsin Package. (Accelrys Inc. Burlington, Mass.)

By an “isolated polynucleotide”, including DNA, RNA, or a combination of these, single or double stranded, in the sense or antisense orientation or a combination of both, dsRNA or otherwise, we mean a polynucleotide which is at least partially separated from the polynucleotide sequences with which it is associated or linked in its native state. Preferably, the isolated polynucleotide is at least 60% free, preferably at least 75% free, and most preferably at least 90% free from other components with which they are naturally associated. As the skilled addressee would be aware, an isolated polynucleotide can be an exogenous polynucleotide present in, for example, a transgenic organism which does not naturally comprise the polynucleotide. Furthermore, the terms “polynucleotide(s)”, “nucleic acid sequence(s)”, “nucleotide sequence(s)”, “nucleic acid(s)”, “nucleic acid molecule” are used interchangeably herein and refer to nucleotides, either ribonucleotides or deoxyribonucleotides or a combination of both, in a polymeric unbranched form of any length.

The term “mutated PPO nucleic acid” refers to a PPO nucleic acid having a sequence that is mutated from a wild-type PPO nucleic acid and that confers increased herbicide tolerance to a plant in which it is expressed. Furthermore, the term “mutated protoporphyrinogen oxidase (mutated PPO)” refers to the replacement of an amino acid of the wild-type primary sequence of SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129, or a variant, a derivative, a hom*ologue, an orthologue, or paralogue thereof, with another amino acid. The expression “mutated amino acid” will be used below to designate the amino acid which is replaced by another amino acid, thereby designating the site of the mutation in the primary sequence of the protein.

In a preferred embodiment, the PPO nucleotide sequence encoding a mutated PPO comprises the sequence of SEQ ID NO: 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, or 130, or a variant or derivative thereof

Furthermore, it will be understood by the person skilled in the art that the PPO nucleotide sequences encompasse hom*ologues, paralogues and and orthologues of SEQ ID NO: 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, or 130, as defined hereinafter.

The term “variant” with respect to a sequence (e.g., a polypeptide or nucleic acid sequence such as—for example—a transcription regulating nucleotide sequence of the invention) is intended to mean substantially similar sequences. For nucleotide sequences comprising an open reading frame, variants include those sequences that, because of the degeneracy of the genetic code, encode the identical amino acid sequence of the native protein. Naturally occurring allelic variants such as these can be identified with the use of well-known molecular biology techniques, as, for example, with polymerase chain reaction (PCR) and hybridization techniques. Variant nucleotide sequences also include synthetically derived nucleotide sequences, such as those generated, for example, by using site-directed mutagenesis and for open reading frames, encode the native protein comprising the sequence of SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129, as well as those that encode a polypeptide having amino acid substitutions relative to the native protein, e.g. the mutated PPO according to the present invention as disclosed herein. Generally, nucleotide sequence variants of the invention will have at least 30, 40, 50, 60, to 70%, e.g., preferably 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, to 79%, generally at least 80%, e.g., 81%-84%, at least 85%, e.g., 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, to 98% and 99% nucleotide “sequence identity” to the nucleotide sequence of SEQ ID NO: 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, or 130. The % identity of a polynucleotide is determined by GAP (Needleman and Wunsch, 1970) analysis (GCG program) with a gap creation penalty=5, and a gap extension penalty=0.3. Unless stated otherwise, the query sequence is at least 45 nucleotides in length, and the GAP analysis aligns the two sequences over a region of at least 45 nucleotides. Preferably, the query sequence is at least 150 nucleotides in length, and the GAP analysis aligns the two sequences over a region of at least 150 nucleotides. More preferably, the query sequence is at least 300 nucleotides in length and the GAP analysis aligns the two sequences over a region of at least 300 nucleotides. Even more preferably, the GAP analysis aligns the two sequences over their entire length.

By “substantially purified polypeptide” or “purified” a polypeptide is meant that has been separated from one or more lipids, nucleic acids, other polypeptides, or other contaminating molecules with which it is associated in its native state. It is preferred that the substantially purified polypeptide is at least 60% free, more preferably at least 75% free, and more preferably at least 90% free from other components with which it is naturally associated. As the skilled addressee will appreciate, the purified polypeptide can be a recombinantly produced polypeptide. The terms “polypeptide” and “protein” are generally used interchangeably and refer to a single polypeptide chain which may or may not be modified by addition of non-amino acid groups. It would be understood that such polypeptide chains may associate with other polypeptides or proteins or other molecules such as co-factors. The terms “proteins” and “polypeptides” as used herein also include variants, mutants, modifications, analogous and/or derivatives of the polypeptides of the invention as described herein.

The % identity of a polypeptide is determined by GAP (Needleman and Wunsch, 1970) analysis (GCG program) with a gap creation penalty=5, and a gap extension penalty=0.3. The query sequence is at least 25 amino acids in length, and the GAP analysis aligns the two sequences over a region of at least 25 amino acids. More preferably, the query sequence is at least 50 amino acids in length, and the GAP analysis aligns the two sequences over a region of at least 50 amino acids. More preferably, the query sequence is at least 100 amino acids in length and the GAP analysis aligns the two sequences over a region of at least 100 amino acids. Even more preferably, the query sequence is at least 250 amino acids in length and the GAP analysis aligns the two sequences over a region of at least 250 amino acids. Even more preferably, the GAP analysis aligns the two sequences over their entire length.

With regard to a defined polypeptide, it will be appreciated that % identity figures higher than those provided above will encompass preferred embodiments. Thus, where applicable, in light of the minimum % identity figures, it is preferred that the PPO polypeptide of the invention comprises an amino acid sequence which is at least 40%, more preferably at least 45%, more preferably at least 50%, more preferably at least 55%, more preferably at least 60%, more preferably at least 65%, more preferably at least 70%, more preferably at least 75%, more preferably at least 80%, more preferably at least 85%, more preferably at least 90%, more preferably at least 91%, more preferably at least 92%, more preferably at least 93%, more preferably at least 94%, more preferably at least 95%, more preferably at least 96%, more preferably at least 97%, more preferably at least 98%, more preferably at least 99%, more preferably at least 99.1%, more preferably at least 99.2%, more preferably at least 99.3%, more preferably at least 99.4%, more preferably at least 99.5%, more preferably at least 99.6%, more preferably at least 99.7%, more preferably at least 99.8%, and even more preferably at least 99.9% identical to SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129.

By “variant” polypeptide is intended a polypeptide derived from the protein of SEQ ID NO: 2, by deletion (so-called truncation) or addition of one or more amino acids to the N-terminal and/or C-terminal end of the native protein; deletion or addition of one or more amino acids at one or more sites in the native protein; or substitution of one or more amino acids at one or more sites in the native protein. Such variants may result from, for example, genetic polymorphism or from human manipulation. Methods for such manipulations are generally known in the art.

“Derivatives” of a protein encompass peptides, oligopeptides, polypeptides, proteins and enzymes having amino acid substitutions, deletions and/or insertions relative to the unmodified protein in question and having similar biological and functional activity as the unmodified protein from which they are derived. Thus, functional variants and fragments of the PPO polypeptides, and nucleic acid molecules encoding them, also are within the scope of the present invention, and unless specifically described otherwise, irrespective of the origin of said polypeptide and irrespective of whether it occurs naturally. Various assays for functionality of a PPO polypeptide can be employed. For example, a functional variant or fragment of the PPO polypeptide can be assayed to determine its ability to confer herbicides detoxification. By way of illustration, a herbicides detoxification rate can be defined as a catalytic rate sufficient to provide a determinable increase in tolerance to herbicides in a plant or plant part comprising a recombinant polynucleotide encoding the variant or fragment of the PPO polypeptide, wherein the plant or plant part expresses the variant or fragment at up to about 0.5%, illustratively, about 0.05 to about 0.5%, about 0.1 to about 0.4%, and about 0.2 to about 0.3%, of the total cellular protein relative to a similarly treated control plant that does not express the variant or fragment.

In a preferred embodiment, the mutated PPO polypeptide is a functional variant or fragment of a protoporphyrinogen oxidase having the amino acid sequence set forth in SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129, wherein the functional variant or fragment has at least about 80% amino acid sequence identity to SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129.

In other embodiments, the functional variant or fragment further has a herbicides detoxification rate defined as a catalytic rate sufficient to provide a determinable increase in tolerance to herbicides in a plant or plant part comprising a recombinant polynucleotide encoding the variant or fragment, wherein the plant or plant part expresses the variant or fragment at up to about 0.5% of the total cellular protein to a similarly treated control plant that does not express the variant or fragment.

“hom*ologues” of a protein encompass peptides, oligopeptides, polypeptides, proteins and enzymes having amino acid substitutions, deletions and/or insertions relative to the unmodified protein in question and having similar biological and functional activity as the unmodified protein from which they are derived.

In addition, one of ordinary skill in the art will further appreciate that changes can be introduced by mutation into the nucleotide sequences of the invention thereby leading to changes in the amino acid sequence of the encoded proteins without altering the biological activity of the proteins.

Thus, for example, an isolated polynucleotide molecule encoding a mutated PPO polypeptide having an amino acid sequence that differs from that of SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129 can be created by introducing one or more nucleotide substitutions, additions, or deletions into the corresponding nucleotide sequence, such that one or more amino acid substitutions, additions or deletions are introduced into the encoded protein. Mutations can be introduced by standard techniques, such as site-directed mutagenesis and PCR-mediated mutagenesis. Such variant nucleotide sequences are also encompassed by the present invention. For example, preferably, conservative amino acid substitutions may be made at one or more predicted preferably nonessential amino acid residues. A “nonessential” amino acid residue is a residue that can be altered from the wild-type sequence of a protein without altering the biological activity, whereas an “essential” amino acid residue is required for biological activity.

A deletion refers to removal of one or more amino acids from a protein.

An insertion refers to one or more amino acid residues being introduced into a predetermined site in a protein. Insertions may comprise N-terminal and/or C-terminal fusions as well as intra-sequence insertions of single or multiple amino acids. Generally, insertions within the amino acid sequence will be smaller than N- or C-terminal fusions, of the order of about 1 to 10 residues. Examples of N- or C-terminal fusion proteins or peptides include the binding domain or activation domain of a transcriptional activator as used in the yeast two-hybrid system, phage coat proteins, (histidine)-6-tag, glutathione S-transferase-tag, protein A, maltose-binding protein, dihydrofolate reductase, Tag•100 epitope, c-myc epitope, FLAG®-epitope, lacZ, CMP (calmodulin-binding peptide), HA epitope, protein C epitope and VSV epitope.

A substitution refers to replacement of amino acids of the protein with other amino acids having similar properties (such as similar hydrophobicity, hydrophilicity, antigenicity, propensity to form or break α-helical structures or β-sheet structures). Amino acid substitutions are typically of single residues, but may be clustered depending upon functional constraints placed upon the polypeptide and may range from 1 to 10 amino acids; insertions will usually be of the order of about 1 to 10 amino acid residues. A conservative amino acid substitution is one in which the amino acid residue is replaced with an amino acid residue having a similar side chain. Families of amino acid residues having similar side chains have been defined in the art. These families include amino acids with basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan), beta-branched side chains (e.g., threonine, valine, isoleucine) and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine). Such substitutions would not be made for conserved amino acid residues, or for amino acid residues residing within a conserved motif. Conservative substitution tables are well known in the art (see for example Creighton (1984) Proteins. W.H. Freeman and Company (Eds).

Amino acid substitutions, deletions and/or insertions may readily be made using peptide synthetic techniques well known in the art, such as solid phase peptide synthesis and the like, or by recombinant DNA manipulation. Methods for the manipulation of DNA sequences to produce substitution, insertion or deletion variants of a protein are well known in the art. For example, techniques for making substitution mutations at predetermined sites in DNA are well known to those skilled in the art and include M13 mutagenesis, T7-Gen in vitro mutagenesis (USB, Cleveland, OH), QuickChange Site Directed mutagenesis (Stratagene, San Diego, CA), PCR-mediated site-directed mutagenesis or other site-directed mutagenesis protocols.

“Derivatives” further include peptides, oligopeptides, polypeptides which may, compared to the amino acid sequence of the naturally-occurring form of the protein, such as the protein of interest, comprise substitutions of amino acids with non-naturally occurring amino acid residues, or additions of non-naturally occurring amino acid residues. “Derivatives” of a protein also encompass peptides, oligopeptides, polypeptides which comprise naturally occurring altered (glycosylated, acylated, prenylated, phosphorylated, myristoylated, sulphated etc.) or non-naturally altered amino acid residues compared to the amino acid sequence of a naturally-occurring form of the polypeptide. A derivative may also comprise one or more non-amino acid substituents or additions compared to the amino acid sequence from which it is derived, for example a reporter molecule or other ligand, covalently or non-covalently bound to the amino acid sequence, such as a reporter molecule which is bound to facilitate its detection, and non-naturally occurring amino acid residues relative to the amino acid sequence of a naturally-occurring protein. Furthermore, “derivatives” also include fusions of the naturally-occurring form of the protein with tagging peptides such as FLAG, HIS6 or thioredoxin (for a review of tagging peptides, see Terpe, Appl. Microbiol. Biotechnol. 60, 523-533, 2003).

“Orthologues” and “paralogues” encompass evolutionary concepts used to describe the ancestral relationships of genes. Paralogues are genes within the same species that have originated through duplication of an ancestral gene; orthologues are genes from different organisms that have originated through speciation, and are also derived from a common ancestral gene.

It is well-known in the art that paralogues and orthologues may share distinct domains harboring suitable amino acid residues at given sites, such as binding pockets for particular substrates or binding motifs for interaction with other proteins.

The term “domain” refers to a set of amino acids conserved at specific positions along an alignment of sequences of evolutionarily related proteins. While amino acids at other positions can vary between hom*ologues, amino acids that are highly conserved at specific positions indicate amino acids that are likely essential in the structure, stability or function of a protein. Identified by their high degree of conservation in aligned sequences of a family of protein hom*ologues, they can be used as identifiers to determine if any polypeptide in question belongs to a previously identified polypeptide family.

The term “motif” or “consensus sequence” refers to a short conserved region in the sequence of evolutionarily related proteins. Motifs are frequently highly conserved parts of domains, but may also include only part of the domain, or be located outside of conserved domain (if all of the amino acids of the motif fall outside of a defined domain).

Specialist databases exist for the identification of domains, for example, SMART (Schultz et al. (1998) Proc. Natl. Acad. Sci. USA 95, 5857-5864; Letunic et al. (2002) Nucleic Acids Res 30, 242-244), InterPro (Mulder et al., (2003) Nucl. Acids. Res. 31, 315-318), Prosite (Bucher and Bairoch (1994), A generalized profile syntax for biomolecular sequences motifs and its function in automatic sequence interpretation. (In) ISMB-94; Proceedings 2nd International Conference on Intelligent Systems for Molecular Biology. Altman R., Brutlag D., Karp P., Lathrop R., Searls D., Eds., pp 53-61, AAAI Press, Menlo Park; Hulo et al., Nucl. Acids. Res. 32:D134-D137, (2004)), or Pfam (Bateman et al., Nucleic Acids Research 30(1): 276-280 (2002)). A set of tools for in silico analysis of protein sequences is available on the ExPASy proteomics server (Swiss Institute of Bioinformatics (Gasteiger et al., ExPASy: the proteomics server for in-depth protein knowledge and analysis, Nucleic Acids Res. 31:3784-3788(2003)). Domains or motifs may also be identified using routine techniques, such as by sequence alignment.

Methods for the alignment of sequences for comparison are well known in the art, such methods include GAP, BESTFIT, BLAST, FASTA and TFASTA. GAP uses the algorithm of Needleman and Wunsch ((1970) J Mol Biol 48: 443-453) to find the global (i.e. spanning the complete sequences) alignment of two sequences that maximizes the number of matches and minimizes the number of gaps. The BLAST algorithm (Altschul et al. (1990) J Mol Biol 215: 403-10) calculates percent sequence identity and performs a statistical analysis of the similarity between the two sequences. The software for performing BLAST analysis is publicly available through the National Centre for Biotechnology Information (NCBI). hom*ologues may readily be identified using, for example, the ClustalW multiple sequence alignment algorithm (version 1.83), with the default pairwise alignment parameters, and a scoring method in percentage. Global percentages of similarity and identity may also be determined using one of the methods available in the MatGAT software package (Campanella et al., BMC Bioinformatics. 2003 Jul. 10; 4:29. MatGAT: an application that generates similarity/identity matrices using protein or DNA sequences.). Minor manual editing may be performed to optimise alignment between conserved motifs, as would be apparent to a person skilled in the art. Furthermore, instead of using full-length sequences for the identification of hom*ologues, specific domains may also be used. The sequence identity values may be determined over the entire nucleic acid or amino acid sequence or over selected domains or conserved motif(s), using the programs mentioned above using the default parameters. For local alignments, the Smith-Waterman algorithm is particularly useful (Smith T F, Waterman M S (1981) J. Mol. Biol 147(1); 195-7).

The proteins of the invention may be altered in various ways including amino acid substitutions, deletions, truncations, and insertions. Methods for such manipulations are generally known in the art. For example, amino acid sequence variants can be prepared by mutations in the DNA. Methods for mutagenesis and nucleotide sequence alterations are well known in the art. See, for example, Kunkel (1985) PNAS, 82:488-492; Kunkel et al. (1987) Methods in Enzymol. 154:367-382; U.S. Pat. No. 4,873,192; Walker and Gaastra, eds. (1983) Techniques in Molecular Biology (MacMillan Publishing Company, New York) and the references cited therein. Guidance as to appropriate amino acid substitutions that do not affect biological activity of the protein of interest may be found in the model of Dayhoff et al. (1978) Atlas of Protein Sequence and Structure (Natl. Biomed. Res. Found., Washington, D. C), herein incorporated by reference. Conservative substitutions, such as exchanging one amino acid with another having similar properties, may be preferable.

Alternatively, variant nucleotide sequences can be made by introducing mutations randomly along all or part of a coding sequence, such as by saturation mutagenesis, and the resultant mutants can be screened to identify mutants that encode proteins that retain activity. For example, following mutagenesis, the encoded protein can be expressed recombinantly, and the activity of the protein can be determined using standard assay techniques.

The inventors of the present invention have found that by substituting one or more of the amino acid residues in the non-actives sites of the PPO enzyme of SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129, e.g. by employing one of the above described methods to mutate the PPO encoding nucleic acids, the tolerance or resistance to particular herbicides could be remarkably increased.

Preferred substitutions of mutated PPO are those that increase the herbicide tolerance of the plant, but leave the biological activity of the PPO enzymatic activity substantially unaffected.

Accordingly, in another object of the present invention refers to a mutated PPO polypeptide, comprising the sequence of SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129, a variant, derivative, orthologue, paralogue or hom*ologue thereof, the key amino acid residues of which is substituted by any other amino acid.

It will be understood by the person skilled in the art that amino acids located in a close proximity to the positions of amino acids mentioned below may also be substituted.

Thus, in another embodiment the variant of SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129, a variant, derivative, orthologue, paralogue or hom*ologue thereof comprises a mutated PPO, wherein an amino acid ±3, ±2 or ±1 amino acid positions from a key amino acid is substituted by any other amino acid.

Based on techniques well-known in the art, a highly characteristic sequence pattern can be developed, by means of which further of mutated PPO candidates with the desired activity may be searched.

Searching for further mutated PPO candidates by applying a suitable sequence pattern would also be encompassed by the present invention. It will be understood by a skilled reader that the present sequence pattern is not limited by the exact distances between two adjacent amino acid residues of said pattern. Each of the distances between two neighbours in the above patterns may, for example, vary independently of each other by up to ±10, ±5, ±3, ±2 or ±1 amino acid positions without substantially affecting the desired activity.

Furthermore, by applying the method of site directed mutagenesis, e.g. saturation mutagenes (see e.g. Schenk et al., Biospektrum March 2006, pages 277-279), the inventors of the present invention have identified and generated specific amino acid subsitutions and combinations thereof, which—when introduced into a plant by transforming and expressing the respective mutated PPO encoding nucleic acid—confer increased herbicide resistance or tolerance to a herbicide to said plant.

Thus, in a particularly preferred embodiment, the variant or derivative of the mutated PPO refers to a PPO polypeptide comprising SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129, a orthologue, paralogue, or hom*ologue thereof, wherein the amino acid sequence differs from the wildtype amino acid sequence of a PPO polypeptide at one or more positions corresponding to the following positions of SEQ ID NO: 1 or 2: 32, 53, 57, 61, 63, 64, 65, 67, 71, 76, 82, 83, 85, 86, 87, 88, 91, 103, 104, 106, 108, 116, 119, 126, 127, 129, 139, 159, 210, 211, 224, 245, 246, 248, 249, 252, 253, 254, 255, 257, 259, 260, 262, 264, 286, 291, 305, 308, 309, 323, 335, 343, 345, 358, 372, 373, 387, 391, 392, 400, 412, 414, 415, 425, 428, 431, 433, 434, 435, 436, 447, 451, 453, 464, 466, 482 of SEQ ID NO: 1 or 2, wherein said difference refers to a substitution of the amino acid at that positions by any other amino acid.

In a particularly preferred embodiment, the variant or derivative of the mutated PPO refers to a PPO polypeptide comprising SEQ ID NO: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, or 129, a orthologue, paralogue, or hom*ologue thereof, wherein the amino acid sequence differs from the wildtype amino acid sequence of a PPO polypeptide at one or more positions corresponding to the following positions of SEQ ID NO: 1 or 2: 40, 250, 391, 520, 521, 522, 523, 524, 525, 526, 527, 528, 529, 530, 531, 532, 533, 534 of SEQ ID NO: 1 or 2, wherein said difference refers to a deletion or an insertion of the amino acid at that positions.

Preferably, the difference corresponding to position 391 of SEQ ID NO:1 referes to an insertion, and the difference corresponding to positions 40, 250, 520, 521, 522, 523, 524, 525, 526, 527, 528, 529, 530, 531, 532, 533, 534 of SEQ ID NO: 1 or 2 refers to a deletion

Preferably, said differences at these amino acid positions (corresponding to the respective positions in SEQ ID NO: 2 or 4) include, but are not limited to, one or more of the following:

the amino acid corresponding to position G32 is substituted by any other amino acid

the amino acid corresponding to position V53 is substituted by any other amino acid

the amino acid corresponding to position A57 is substituted by any other amino acid

the amino acid corresponding to position K61 is substituted by any other amino acid

the amino acid corresponding to position K63 is substituted by any other amino acid

the amino acid corresponding to position S64 is substituted by any other amino acid

the amino acid corresponding to position H65 is substituted by any other amino acid

the amino acid corresponding to position L67 is substituted by any other amino acid

the amino acid corresponding to position L71 is substituted by any other amino acid

the amino acid corresponding to position S76 is substituted by any other amino acid

the amino acid corresponding to position L82 is substituted by any other amino acid

the amino acid corresponding to position K83 is substituted by any other amino acid

the amino acid corresponding to position V85 is substituted by any other amino acid

the amino acid corresponding to position K86 is substituted by any other amino acid

the amino acid corresponding to position K87 is substituted by any other amino acid

the amino acid corresponding to position D88 is substituted by any other amino acid

the amino acid corresponding to position I91 is substituted by any other amino acid

the amino acid corresponding to position E103 is substituted by any other amino acid

the amino acid corresponding to position A104 is substituted by any other amino acid

the amino acid corresponding to position V106 is substituted by any other amino acid

the amino acid corresponding to position S108 is substituted by any other amino acid

the amino acid corresponding to position R116 is substituted by any other amino acid

the amino acid corresponding to position Q119 is substituted by any other amino acid, preferably Leu

the amino acid corresponding to position K127 is substituted by any other amino acid

the amino acid corresponding to position N126 is substituted by any other amino acid

the amino acid corresponding to position Y129 is substituted by any other amino acid

the amino acid corresponding to position L139 is substituted by any other amino acid

the amino acid corresponding to position Q159 is substituted by any other amino acid

the amino acid corresponding to position G210 is substituted by any other amino acid, preferably by Ser;

the amino acid corresponding to position G211 is substituted by any other amino acid, preferably by Asp, Asn, Thr or Ala;

the amino acid corresponding to position E224 is substituted by any other amino acid

the amino acid corresponding to position L245 is substituted by any other amino acid

the amino acid corresponding to position K248 is substituted by any other amino acid

the amino acid corresponding to position S246 is substituted by any other amino acid

the amino acid corresponding to position E249 is substituted by any other amino acid

the amino acid corresponding to position G252 is substituted by any other amino acid

the amino acid corresponding to position E253 is substituted by any other amino acid

the amino acid corresponding to position N254 is substituted by any other amino acid

the amino acid corresponding to position A255 is substituted by any other amino acid

the amino acid corresponding to position I257 is substituted by any other amino acid

the amino acid corresponding to position K259 is substituted by any other amino acid

the amino acid corresponding to position P260 is substituted by any other amino acid

the amino acid corresponding to position V262 is substituted by any other amino acid

the amino acid corresponding to position G264 is substituted by any other amino acid

the amino acid corresponding to position D286 is substituted by any other amino acid

the amino acid corresponding to position Q291 is substituted by any other amino acid

the amino acid corresponding to position P305 is substituted by any other amino acid

the amino acid corresponding to position G308 is substituted by any other amino acid

the amino acid corresponding to position N309 is substituted by any other amino acid

the amino acid corresponding to position Q323 is substituted by any other amino acid

the amino acid corresponding to position R335 is substituted by any other amino acid

the amino acid corresponding to position M343 is substituted by any other amino acid

the amino acid corresponding to position F345 is substituted by any other amino acid

the amino acid corresponding to position T358 is substituted by any other amino acid

the amino acid corresponding to position D372 is substituted by any other amino acid

the amino acid corresponding to position K373 is substituted by any other amino acid

the amino acid corresponding to position S387 is substituted by any other amino acid, preferably Leu

the amino acid corresponding to position H391 is substituted by any other amino acid

the amino acid corresponding to position N392 is substituted by any other amino acid

the amino acid corresponding to position L400 is substituted by any other amino acid

the amino acid corresponding to position S412 is substituted by any other amino acid, preferably by Asn;

the amino acid corresponding to position M414 is substituted by any other amino acid

the amino acid corresponding to position C415 is substituted by any other amino acid

the amino acid corresponding to position R425 is substituted by any other amino acid

the amino acid corresponding to position K428 is substituted by any other amino acid

the amino acid corresponding to position N431 is substituted by any other amino acid

the amino acid corresponding to position S433 is substituted by any other amino acid

the amino acid corresponding to position M434 is substituted by any other amino acid

the amino acid corresponding to position D435 is substituted by any other amino acid

the amino acid corresponding to position E436 is substituted by any other amino acid

the amino acid corresponding to position Q447 is substituted by any other amino acid

the amino acid corresponding to position T451 is substituted by any other amino acid

the amino acid corresponding to position D453 is substituted by any other amino acid

the amino acid corresponding to position S464 is substituted by any other amino acid

the amino acid corresponding to position Q466 is substituted by any other amino acid

the amino acid corresponding to position D482 is substituted by any other amino acid

The corresponding residues in other species are shown in the following table: