Genome-wide systematic characterization and its regulatory expression reprogramming process of the bZIP transcription factors during trauma response in Camellia sinensis

Abstract

Basic leucine zipper (bZIP) transcription factor (TF) genes regulate numerous biological processes, as well as biotic and abiotic responses. Although the genome of the tea tree (Camellia sinensis (L.) Kuntze) has been released, knowledge regarding the bZIP TF family in C. sinensis, e.g., phylogenetic relationship and transcriptional gene expression profiles, remains limited. In this study, we characterized 77 bZIP genes in C. sinensis based on transcriptomic and genomic data and divided them into 11 groups according to their phylogenetic relationship with those in Arabidopsis, which allowed us to identify 14 pairs of orthologous proteins shared by Arabidopsis and C. sinensis and 19 pairs of paralogous proteins in C. sinensis. Conserved motif analysis of CsbZIP proteins showed high group specificity. Our classification was supported by the predicted specificities based on DNA-binding domains, as well as the dimerization property based on characteristic features in the basic and hinge regions and the leucine zipper. Specifically, they indicated that some highly conserved amino acid residues exist across each major group in the tree of land plant life. Expression profiling analyses indicate that the CsbZIP genes are likely involved in response to trauma, and a model was established to display the unique expression of each group during different time intervals after wounding. This work provides useful clues for further functional characterization of the CsbZIP TFs.