Identification and Expression Analysis of Genes in Tea Plant Reveal Their Complex Regulatory Role in Stress Responses.

Calmodulin-binding transcription activators (CAMTAs) are evolutionarily conserved transcription factors and have multi-functions in plant development and stress response. However, identification and functional analysis of tea plant () genes () are still lacking. Here, five were identified from tea plant genomic database. Their gene structures were similar except , and protein domains were conserved. Phylogenetic relationship classified the CsCAMTAs into three groups, CsCAMTA2 was in group I, and CsCAMTA1, 3 and CsCAMTA4, 5 were, respectively, in groups II and III. Analysis showed that stress and phytohormone response-related -elements were distributed in the promoters of genes. Expression analysis showed that were differentially expressed in different organs and under various stress treatments of tea plants. Three-hundred and four hundred-one positive co-expressed genes of were identified under cold and drought, respectively. and their co-expressed genes constituted five independent co-expression networks. KEGG enrichment analysis of and the co-expressed genes revealed that hormone regulation, transcriptional regulation, and protein processing-related pathways were enriched under cold treatment, while pathways like hormone metabolism, lipid metabolism, and carbon metabolism were enriched under drought treatment. Protein interaction network analysis suggested that CsCAMTAs could bind (G/A/C)CGCG(C/G/T) or (A/C)CGTGT element in the target gene promoters, and transcriptional regulation might be the main way of -mediated functional regulation. The study establishes a foundation for further function studies of genes in stress response.