Bioinformatics analysis of bZIP (basic leucine zipper) transcription factor genes in watermelon and analysis of gene expression profiles under drought stress

The basic leucine zipper (bZIP) transcription factor family has diverse crucial roles in multiple morphological and physiological processes as regulator. Despite of the identification of bZIP genes in several plants, comprehensive investigation of bZIP members in watermelon has not been presented yet. 59 of ClabZIP genes were determined on Citrillus lanatus chromosomes. bZIP protein family members in Citrillus lanatus were phylogenetically grouped into 7 subfamilies. The majority of bZIP proteins in the same subfamily shared similar gene structures and conserved motifs. According to the chromosome distribution and the genetics analysis, 21 ClabZIP genes displayed duplication events. Further, three-dimensional structure and functional annotation of bZIP proteins were predicted. Publicly available RNA-seq data including various fruit development stages and vascular tissues were analyzed to elucidate gene expression profiles of ClabZIP genes in different tissues. In addition, the expression profiles of selected ClabZIP genes were evaluated in root and leaf tissues of watermelon under drought-stress using Real time PCR. As a result, ClabZIP-57 gene exhibited the highest expression levels after drought stress treatment in leaf and root tissues. This kind of gene identification studies open new perspectives to analyze functions of bZIP protein family members in plants.