Genome-Wide Identification and Male Sterility-Related Expression Analysis of Papain-like Cysteine Protease Gene Family in Capsicum annuum

• Published in: Horticulturae 2024-08, Vol.10 (8), p.892
• Main Authors: Chen, Rong, Wang, Benqi, Huang, Shuping, Chen, Xia, Tan, Jie, Zhang, Hongyuan, Wang, Junliang, Zhang, Min
• Format: Article
• Language: English
• Subjects: Abiotic stress; Amino acids; CaPLCPs; Capsicum annuum; Cell death; Chromosomes; Crop production; Cysteine; Cysteine proteinase; Drought; Functional analysis; gene expression; Genes; Genomes; Genomic analysis; Genomics; Infertility; Localization; Low temperature; male reproductive development; Male sterility; Males; Molecular weight; Papain; pepper; Peppers; Phylogenetics; Phylogeny; Plant immunity; Proteins; Proteolysis; Regulatory sequences; Seeds; Senescence; Thiols; Vegetables
• ISSN: 2311-7524; 2311-7524
• DOI: 10.3390/horticulturae10080892

PLCPs (papain-like cysteine proteases) are one of the most abundant groups of cysteine proteases and play vital roles in multiple processes. The pepper (Capsicum annuum) is an important Solanaceae vegetable crop; its commercial hybrid seeds are widely used in production. Male sterility is a valuable trait for hybrid seed production. However, the function of PLCPs and the underlying mechanisms of male sterility in peppers remain unclear. In this study, we comprehensively identified the PLCP gene family in peppers, identifying 31 CaPLCPs. A phylogenetic analysis classified 31 members into eight clades. These CaPLCPs were unevenly distributed across eight chromosomes, and five segmental duplicated pairs were observed. The promoter cis-acting element analysis indicated that CaPLCP promoters contained abundant hormone-responsive and stress-responsive cis-elements, suggesting that CaPLCPs may play important roles in responding to abiotic stress, such as drought and low temperatures, as well as in plant immunity. The qRT-PCR analysis demonstrated that the expression levels of CaPLCP1, CaPLCP5, CaPLCP11, CaPLCP12, CaPLCP13, CaPLCP17, CaPLCP19, and CaPLCP21 were significantly reduced in the flowers of MS (male sterile pepper) at least at one stage, indicating their potential roles as regulatory factors in pepper male sterility. These findings provide important insights into the functional analysis of the PLCP gene family in peppers and other species, laying a crucial foundation for understanding the mechanisms of male sterility in peppers.