Plant disease resistance genes

Abstract

Plants defend themselves against pathogens using different mechanisms, some of which rely on the expression of disease resistance genes (R genes). R genes encode proteins (R proteins) that provide resistance to a wide spectrum of pathogens including viruses, bacteria, nematodes and fungi. Most of the isolated R genes code for the protein of NBS-LRR class with characteristic nucleotide binding domain (NBS domain) and leucine-rich domain (LRR domain). Models of defence mechanism initiated by R gene products are proposed, based either on direct or indirect interaction of the plant R protein with the product of avirulence pathogen gene. Most of the R gene and R gene-like sequences are isolated by insertional mutagenesis, map-based cloning and amplification by polymerase chain reaction (PCR).