Identification and Expression Regulation Analysis of the CsWCOR413 Gene Family in Camellia sinensis

Low temperature stress significantly impairs the growth and development of tea plants (Camellia sinensis), as well as the yield and quality of tea. The WCOR413 gene family plays an important role in plant cold resistance. However, it has not yet been systematically identified in tea plants. This study employed pan-genome and cold acclimation transcriptome data of tea plants, combined with bioinformatics and RT-qPCR analysis, to identify members of the CsWCOR413 gene family. The results show that the CsWCOR413 family consists of six members (CsWCOR413-1 to CsWCOR413-6), which can be divided into two subclasses based on the conserved domains of the proteins: plasma membrane-localized and internal/thylakoid membrane-localized. Promoter cis-element analysis finds that the CsWCOR413 genes may be regulated by various transcription factors, enabling them to respond to cold, dehydration and ABA signals. RT-qPCR analysis reveals the expression patterns of the CsWCOR413 genes. CsWCOR413-1 was predominantly expressed in leaves, responded to JA and ABA signaling, and was significantly induced by low temperature stress. CsWCOR413-5 responded to short-term cold stress and calcium ion signaling. The transcriptome and Weighted gene co-expression network analysis (WGCNA) indicate that CsWCOR413-1 was significantly upregulated during natural cold acclimation and was strongly co-expressed with CsCBF3, a core transcription factor in cold signaling. Subcellular localization reveals that CsWCOR413-1 was localized in the cell membrane and cytoplasm. Dual-luciferase reporter assay confirms that CsCBF1 and CsCBF3 directly bound to the CsWCOR413-1 promoter and activated its expression. This study systematically elucidated the characteristics and expression profiles of the CsWCOR413 gene family and revealed that CsWCOR413-1 is transcriptionally regulated by CsCBF1 and CsCBF3, suggesting the crucial role of CsWCOR413-1 in tea plant under low temperature stress.