Engineered pesticidal proteins and methods of controlling plant pests
The invention provides nucleic acids, polypeptides, transgenic plants, compositions and methods for conferring pesticidal activity (e.g., insecticidal activity) to bacteria, plants, plant cells, tissues and seeds. Nucleic acids encoding the insecticidal proteins can be used to transform prokaryotic and eukaryotic organisms, including plants, to express the insecticidal proteins. The recombinant organisms and compositions containing the recombinant organisms or insecticidal proteins can be used to control a pest (e.g., an insect).
1. A modified Axmi205 toxin, wherein said modified Axmi205 toxin comprises an amino acid sequence having at least 99% identity to the polypeptide of SEQ ID NO: 1 and comprises a substitution of a serine, leucine, alanine, phenylalanine, aspartic acid or arginine at positions M422 and M423 in the polypeptide of SEQ ID NO: 1, and wherein the substitution results in enhanced digestion of the modified Axmi205 toxin by pepsin as compared with the Axmi205 toxin that does not comprise the substitution.
2. The modified Axmi205 toxin of claim 1 , wherein said toxin is active against an insect pest selected from the group consisting of Western corn rootworm (Diabrotica virgifera virgifera), Northern Corn Rootworm (Diabrotica barberi), Southern Corn Rootworm (Diabrotica undecimpunctata howardi) and Mexican Corn Rootworm (Diabrotica virgifera zeae).
3. The modified Axmi205 toxin of claim 1 , wherein the modified Axmi205 toxin comprises an amino acid substitution of M422S and M423L in the polypeptide of SEQ ID NO: 1 or the corresponding methionine residues in the amino acid sequence having at least 99% identity to SEQ ID NO:1.
4. The modified Axmi205 toxin of claim 1 , wherein the modified Axmi205 toxin comprises the amino acid sequence of SEQ ID NO: 57.
5. A polynucleotide comprising a nucleotide sequence encoding the modified Axmi205 toxin according to claim 1 .
6. The polynucleotide according to claim 5 , wherein the polynucleotide comprises the nucleotide sequence of SEQ ID NO: 58 or 76.
7. A nucleic acid molecule comprising the polynucleotide according to claim 5 operably associated with a heterologous promoter.
8. A vector comprising the nucleic acid molecule according to claim 7 .
9. A transgenic plant comprising the nucleic acid molecule of claim 7 .
10. The transgenic plant according to claim 9 , wherein the transgenic plant is a maize plant.
11. A transgenic seed of the transgenic plant according to claim 9 , wherein the seed comprises the nucleic acid molecule.
12. A transgenic seed of the transgenic plant according to claim 10 , wherein the seed comprises the nucleic acid molecule.
13. A method of producing a transgenic plant with increased resistance to a coleopteran insect pest, the method comprising introducing into a plant the polynucleotide of claim 5 , wherein the modified Axmi205 toxin is expressed in the plant, thereby producing a transgenic plant with increased resistance to a coleopteran insect pest.
14. The method according to claim 13 , wherein the introducing step comprises:
i. transforming a plant cell with the polynucleotide and regenerating a transgenic plant from said plant cell;
ii. crossing a first plant comprising the polynucleotide with a second plant; or
iii. genome editing a polynucleotide sequence encoding an Axmi205 toxin in a transgenic plant.
15. The method according to claim 14 , wherein the method further comprises obtaining a transgenic progeny plant for one or more generations from the transgenic plant, wherein the progeny plant comprises the polynucleotide and has increased resistance to a coleopteran insect pest.
16. A polynucleotide comprising a nucleotide sequence encoding the modified Axmi205 toxin according to claim 4 .
17. A nucleic acid molecule comprising the polynucleotide according to claim 16 operably associated with a heterologous promoter.
18. A transgenic plant comprising the nucleic acid molecule of claim 17 .
19. The transgenic plant according to claim 18 , wherein the transgenic plant is a maize plant.
20. A transgenic seed of the transgenic plant according to claim 19 , wherein the seed comprises the nucleic acid molecule.