Sessile organism, plants constitutively challenged with pathogens have been developed various strategies for protection, such as preformed and inducible defense mechanisms. Receptor-like Proteins(RLPs) play critical roles in defense response as well as in plant development and growth. The domain structure of RLPs consists of extracellular leucine–rich repeats, a transmembrane domain, and a short cytoplasmic tail. Here, we identified putative 170 RLP genes from pepper genome using in-house bioinformatics pipeline. The distribution of RLPs on pepper pseudomolecule showed uneven spread and a number of RLPs were physically clustered by tandem array in the specific chromosome. Motifs analysis of pepper RLPs showed conserved LRR sequences (LxxLxxLDLxxNxxxGxIP). To understand further functional and evolutionary characteristics, evolutional relationship and gene profiling analysis are on progress.

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.