Defensin variants and methods of use

摘要

Compositions and methods for protecting a plant from a pathogen, particularly a fungal pathogen, are provided. Compositions include amino acid sequences, and variants and fragments thereof, for novel variants of antipathogenic polypeptides generated through DNA shuffling that exhibit improved antipathogenic activity. Polynucleotides that encode the antipathogenic polypeptides are also provided. A method for inducing pathogen resistance in a plant using the polynucleotides disclosed herein is further provided. Compositions comprising an antipathogenic polypeptide or a microorganism comprising an antipathogenic polynucleotide of the invention in combination with a carrier and methods of using these compositions to protect a plant from a pathogen are further provided. Plants, plant cells, seeds, and microorganisms comprising an antipathogenic polynucleotide or polypeptide of the invention are also disclosed.

主权项

1. An isolated polynucleotide comprising a nucleotide sequence selected from the group consisting of:
(a) the nucleotide sequence set forth in SEQ ID NO: 5, 7, 9 or 11; (b) a nucleotide sequence encoding an amino acid sequence comprising SEQ ID NO: 6, 8, 10, or 12; (c) a nucleotide sequence encoding an amino acid sequence having at least 85% sequence identity to SEQ ID NO: 6, 8, 10, or 12; wherein said polynucleotide encodes a polypeptide having antifungal activity against Colletotrichum graminocola; and wherein said polypeptide has the amino acid residues selected from the group consisting of: (a) the arginine (Arg) residue at the position corresponding to residue 1 of SEQ ID NO: 6, 8, 10, or 12; (b) the serine (Ser) residue at the position corresponding to residue 16 of SEQ ID NO: 6, 8, 10, or 12; (c) the arginine (Arg) residue at the position corresponding to residue 25 of SEQ ID NO: 6, 8, 10, or 12; (d) the serine (Ser) residue at the position corresponding to residue 36 of SEQ ID NO: 6, 8, 10, or 12; and (e) the serine (Ser) residue at the position corresponding to residue 42 of SEQ ID NO: 6, 8, 10, or 12.