Fig. 10

Working model of pepper defense signal network in response to P. capsica. When plant membrane receptors sense P. capsici infection, genes such as CDPK, FLS2, CML, MAPK, WRYK, PR1, and ERF are expressed, inducing the first layer immunity (PTI) in pepper plants. When the pathogen effector protein breaks through the PTI response, it is bound by NLR-like receptors to stimulate the ETI immune response. Meanwhile, the synthesis of various metabolites such as plant hormone, phenylpropane, fatty acids, sesquiterpenoid, triterpenoid, starch, and sucrose may increase to synergistically protect plants from further pathogen attacks. In addition, the differential expression of some immune-related genes such as RPP13, MYB, RLP, RLK, bHLH, STPK, GsSRK, LRR-RLK, and CRK may play important roles in PTI and ETI. Abbreviations: PRRs, pattern recognition receptors; PTI, pattern-triggered immunity; NLR, nucleotide-binding domain and leucine-rich repeat protein; ETI, effector-triggered immunity