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The WRKY family is one of the most important transcription factor families in plants, involved in the regulation of a broad range of biological roles. The recent releases of whole-genome sequences of pepper (Capsicum annuum L.) allow us to perform a genome-wide identification and characterization of the WRKY family. In this study, 61 CaWRKY proteins were identified in the pepper genome. Based on protein structural and phylogenetic analyses, these proteins were classified into four main groups (I, II, III, and NG), and Group II was further divided into five subgroups (IIa to IIe). Chromosome mapping analysis indicated that CaWRKY genes are distributed across all 12 chromosomes, although the location of four CaWRKYs (CaWRKY58-CaWRKY61) could not be identified. Two pairs of CaWRKYs located on chromosome 01 appear to be tandem duplications. Furthermore, the phylogenetic tree showed a close evolutionary relationship of WRKYs in three species from Solanaceae. In conclusion, this comprehensive analysis of CaWRKYs will provide rich resources for further functional studies in pepper.

Tomato yellow leaf curl virus is one of the main diseases affecting tomato production worldwide. Previous studies have shown that Ty-2 is an important resistance gene located between molecular markers C2_At2g28250 (82.3 cM) and T0302 (89.0 cM), and exhibits strong resistance to tomato yellow leaf curl virus in Asia. In this study, Ty-2 candidate genes were subjected to bioinformatic analysis for the sequenced tomato genome. We identified 69 genes between molecular markers C2_At2g28250 and T0302, 22 of which were disease-related resistant genes, including nucleotide binding site-leucine-rich repeat disease resistance genes, protease genes (protein kinase, kinase receptor, and protein isomerase), cytochromes, and transcription factors. Expressed sequence tag analysis revealed that 77.3% (17/22) of candidate disease-resistance genes were expressed, involving 143 expressed sequence tags. Based on full-length cDNA sequence analysis, 7 candidate genes were found, 4 of which were involved in tomato responses to pathogens. Microarray expression analysis also showed that most candidate genes were involved in the tomato responses to multiple pathogens, including fungi, viruses, and bacteria. RNA-seq expression analysis revealed that all candidate genes participated in tomato growth and development.