Cloning and characterization of BES1/BZR1 transcription factor genes in maize

BES1/BZR1 transcription factors regulate the expression of brassinosteroid-responsive genes and play vital roles in plant growth and response to environmental stimuli. Their regulation mechanism has been well elucidated in genetic model plants. The complexity of the maize genome might lead to evolutional and functional diversification among the members of the ZmBES1/BZR1 gene family. In the present study, eleven members of the ZmBES1/BZR1 gene family were identified by genome-wide analysis, and ten of their open reading frames were successfully amplified. Bioinformatics analysis showed that these genes unevenly distributed on seven of the ten maize chromosomes, with three pairs of segmental duplication genes, and their encoding proteins shared similar motif composition and conserved domains. The expression of the ZmBES1/BZR1 genes displayed much differential in different organs and developmental stages, as well as in response to abscisic acid and light signal. Subcellular localization confirmed that most of them localized in nucleus. More attention should be paid to ZmBES1/BZR1-4 and -5, which were clustered into a distinguished phylogenetic Glade, and ZmBES1/BZR1-2 and -7, which localized in chloroplast. The results indicated their similar but not identical functions in brassinosteroid-mediated signaling pathway and would be helpful in further functional study of the ZmBES1/BZR1s in maize.