Plants have evolved elaborate innate immune systems against invading pathogens, such as bacteria, fungi, oomycetes, viruses and insects. Among them, intracellular immune receptors known as nucleotide-binding site and leucine-rich repeat (NB-LRR) play critical roles in effector-triggered immunity (ETI) regarding to plant defense. Here, we identified potential NB-LRR coding sequences from pepper genome using bioinformatics analysis and performed comparative analysis with Solanaceae plants. As a result, we identified 267, 443, and 755 NBS-encoding genes in the genome of tomato, potato, and pepper, respectively. These may indicate that the Solanaceae NB-LRRs were evolved through species-specific unequal-duplication event. Further phylogenetic and clustering analyses revealed that Solanaceae NB-LRRs were classified into the 14 subgroups with 1 TNL and 13 CNL types. We found that the genes in CNL-G1 and CNL-G2 subgroup were highly expanded compared to other subgroup showing a large portion of NB-LRR in pepper genome. Among 755 NB-LRRs in pepper genome, 623 were physically mapped on all 12 pepper chromosome pseudomolecules. Furthermore, a number of NB-LRRs in the same group were physically clustered by tandem array in the specific chromosome. Genome-wide identification of pepper NB-LRR family and their evolutionary analysis could provide an important resource for identification and characterization of genes for breeding of disease resistance crops.

Pepper mottle virus (PepMoV) is frequently occurring virus in pepper field. PepMoV infected plants show symptoms including mosaic leaf, distortion of foliage and fruit deformation. The dominant gene Pvr7 from Capsicum annuum ‘9093’ confers resistance to PepMoV. Previous research reveals that Pvr7 is located in 10 chromosome and linked to the dominant potyvirus resistance gene Pvr4 and Tomato spotted wilt virus (TSWV) resistance gene Tsw. To identify the Pvr7 gene, we constructed an intraspecific F2 mapping population from a cross between C. annuum ‘9093’ (PepMov resistant) and C. annuum ‘Jejujaerae’ (PepMoV susceptible). Resistance of F2 plants were screened with green flouorescent protein (GFP) tagged PepMoV. Genomic DNA was extracted from F2 individuals and markers were developed using C.annuum ‘CM334’ whole genome sequence (WGS). Several single nucleotide polymorphism (SNP) markers that were co-segregated with Pvr7 were developed. We are expecting that this Pvr7 SNP marker can be used to breeding PepMoV resistant cultivars and fine mapping of Pvr7.