Maize ZmbZIP92 transcription factor positively regulates drought tolerance in Arabidopsis

Plants are susceptible to various environmental stresses, but basic leucine zipper (bZIP) transcription factors play a key role in regulating stress responses. In this study, a drought response-related candidate gene (ZmbZIP92) was cloned from maize (Zea mays L.) following a comparative genomic analysis. This gene is highly homologous to the rice (Oryza sativa L.) gene OsbZIP62, exhibits tissue-specific expression patterns, and is significantly induced by drought, high salinity, and abscisic acid (ABA) treatments. Subcellular localization revealed that ZmbZIP92 is a nuclear protein. Additionally, yeast-based assays of ZmbZIP92 detected a lack of transcriptional self-activation. Dual-luciferase reporter assays demonstrated that ZmbZIP92 binds specifically to the G-box (CACGTG) cis-element. Overexpressing ZmbZIP92 in Arabidopsis thaliana significantly promoted root elongation, enhanced drought tolerance, and increased sensitivity to ABA, which was reflected by markedly inhibited seed germination. RNA sequencing and differential expression analyses indicated that multiple stress response-related pathways were enriched in ZmbZIP92-overexpressing plants, including ABA signaling, antioxidant response, transmembrane transport, and general plant signal transduction pathways. In summary, ZmbZIP92 positively regulates drought tolerance through its effects on the ABA signaling pathway and other stress response-related signaling networks.