Phylogenetic analyses of peanut resistance gene candidates and screening of different genotypes for polymorphic markers

The nucleotide-binding-site-leucine-rich-repeat (NBS–LRR)-encoding gene family has attracted much research interest because approximately 75% of the plant disease resistance genes that have been cloned to date are from this gene family. Here, we describe a collection of peanut NBS–LRR resistance gene candidates (RGCs) isolated from peanut (Arachis) species by mining Gene Bank data base. NBS–LRR sequences assembled into TIR-NBS-LRR (75.4%) and non-TIR-NBS-LRR (24.6%) subfamilies. Total of 20 distinct clades were identified and showed a high level of sequence divergence within TIR-NBS and non-TIR-NBS subfamilies. Thirty-four primer pairs were designed from these RGC sequences and used for screening different genotypes belonging to wild and cultivated peanuts. Therefore, peanut RGC identified in this study will provide useful tools for developing DNA markers and cloning the genes for resistance to different pathogens in peanut.