Genome-wide characterization of the basic leucine zipper transcription factors in Camellia sinensis

The basic leucine zipper (bZIP) transcription factor family contains a large number of genes and has been found in many plant species. Previous studies have reported that bZIP family genes play important roles in the regulation of plant development and biotic/abiotic stress responses. However, a comprehensive investigation of this transcription factor family in tea plant (Camellia sinensis) has been lacking. In this study, a total of 61 bZIP genes were identified from the tea plant whole genome. The phylogenetic analysis classified these bZIP genes into 11 groups. The gene structures and composition patterns of the conserved motifs of bZIP genes were also characterized, which was consistent with the phylogenetic result. The gene expression analysis revealed that multiple bZIPs could be involved in response to drought, cold, or tea geometrid (Ectropis oblique) feeding. Our expression profile also indicated that many identified bZIPs were possibly involved in different developmental stages in tea plant. This study has provided an extensive overview of the tea plant bZIP transcription factor family and their possible roles in stress-responses.