基于转录组学的'龙井43'及其变异品种低温抗性差异形成机制研究OA

Low temperature is one of the major environmental factors limiting tea production.Elucidating the regulatory network underlying cold tolerance in tea plants and identifying key functional genes provide a theoretical basis for cold-resistant cultivar breeding through molecular approaches.In this study,'Longjing 43'(LJ43)and its closely related variants'Zhongcha Huangya 5'(ZH5)and'Zhongcha 108'(ZC108),which share highly similar genetic backgrounds,were used as materials.Based on phenotypic observations and measurements of relative electrolyte leakage(REL),maximum photochemical efficiency of PSII(Fv/Fm),and malondialdehyde(MDA)content,the cold tolerance of the three cultivars was found to be in the following order:ZH5>ZC108>LJ43.Transcriptome sequencing identified 2 384,4 186,and 4 434 differentially expressed genes(DEGs).Among these DEGs,999 were shared by all three cultivars.Pathway enrichment analysis reveals that these common DEGs were significantly enriched in early cold-responsive biological processes,including plant hormone signal transduction,MAPK signaling cascade and transcriptional regulation,which constituted the core factors underlying the divergent cold resistance of the three tea cultivars.Further analysis identifies cultivar-specific DEGs in LJ43(899),ZC108(1 722)and ZH5(1 504),which were separately enriched in distinct substance metabolism pathways.Weighted gene co-expression network analysis(WGCNA)further demonstrates that modules significantly correlated with cold treatment exhibited obvious disparities among the three cultivars.In summary,these results indicate that tea cultivars adopt genotype-specific strategies to cope with cold stress,and such differential responses serve as a critical contributor to the inter-cultivar variation in cold tolerance.This study clarified the molecular basis underlying the differences in cold tolerance between LJ43 and its variants,expanded the current understanding of cold tolerance regulation in tea plants,and provided a theoretical foundation for cold-resistance breeding.