TCP family genes control leaf development and its responses to hormonal stimuli in tea plant [Camellia sinensis (L.) O. Kuntze]

Tea plant [Camellia sinensis (L.) O. Kuntze] is a perennial evergreen woody crop that is cultivated worldwide. Tea leaf is an important resource for producing natural non-alcoholic beverages. TCP (TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTORS) is a transcription factor family that controls the cell growth and proliferation of leaf tissues. In this study, 17 homologous TCP family transcription factors were identified and characterized in the leaf transcriptome of C. sinensis. The structural features, phylogenetic tree, and interaction networks of C. sinensis TCP (CsTCP) proteins were analyzed. Prediction of miRNA target sites suggests that miR319 may be involved in the post-transcriptional regulation of the CsTCP15 transcript. The expression profiles of all identified CsTCP genes were investigated in five tea leaf developmental stages (i.e., 1st, 2nd, 3rd, 4th, and older leaves) and normal growth tea leaves subjected to five hormonal stimuli (i.e., ABA, GA(3), IAA, MeJA, and SA). Several CsTCP genes presented functional redundancies in leaf development and response to hormones. This study establishes an extensive overview of the TCP family genes and provides insights into the molecular mechanism of leaf development and hormonal stimuli in C. sinensis.