Genome-Wide Identification of NLR Gene Family and Expression Patterns in Response to Colletotrichum camelliae Infection in Tea Plant (Camellia sinensis)

Background: Colletotrichum camelliae is an important fungal disease in tea plants (Camellia sinensis), and NLR gene family play a central role in plant disease resistance recognition. Analyzing the expression characteristics and regulatory network of NLR genes in tea plants in response to anthracnose infection can provide a theoretical basis for exploring key genes for tea plant resistance to anthracnose and elucidating the molecular mechanisms of disease resistance. Method: Using the tea tree reference genome Shuchazao 2 as the material, CsNLR genes were identified based on NB-ARC (Pfam ID: PF00931) and LRR (Pfam ID: PF00560) conserved domains; Conduct bioinformatics analysis using TBtools, MEME, and MEGA; Using quantitative real-time PCR (qRT-PCR) to detect the expression changes of CsNLR in the common variety Sucha 120 and the purple variety Ziying 2 after anthracnose infection, and constructing a protein prediction association network. Result: A total of 158 CsNLR genes were identified, and their physicochemical properties, phylogenetics, gene structure, and cis element analysis revealed differentiation among family members. The promoters generally contain stress and hormone response elements; CsNLR is highly expressed in roots, stems, and mature leaves. After 4 days of inoculation with anthracnose infection, the expression trends of CsNLR in the two tea tree varieties were opposite, with Sucha 120 upregulated and Ziying 2 downregulated; The predicted protein association network shows CsNLR as the central node of the network, with 77 CsNLR proteins were included in the predictive functional association network, and there were differences in the connectivity of different members. Conclusions: The CsNLR identified in this study is a potential NLR resistant gene for anthracnose in tea plants, laying the foundation for subsequent functional verification of disease resistant genes and analysis of resistance mechanisms.