OsbZIP72 Is Involved in Transcriptional Gene-Regulation Pathway of Abscisic Acid Signal Transduction by Activating Rice High-Affinity Potassium Transporter OsHKT1;1

摘要

We created CRISPR-Cas9 knock-out and overexpressingOsbZIP72transgenic rice plants to gain a better understanding of the role and molecular mechanism ofOsbZIP72gene in stress tolerance, which has remained largely elusive.OsbZIP72was expressed and integrated into rice transgenic plant genomes, and theOsbZIP72transcript in overexpression lines was elicited by salinity, abscisic acid (ABA) and drought stresses.OsbZIP72overexpressing plants showed higher tolerance to drought and salinity stresses, while knock-out transgenic lines showed higher sensitivity to these stresses. The differentially expressed genes (DEGs) from RNA-sequencing data encompassed several abiotic stress genes, and the functional classification of these DEGs demonstrated the robust transcriptome diversity inOsbZIP72. Yeast one-hybrid, along with luciferase assay, indicated thatOsbZIP72acted as a transcriptional initiator. Remarkably, electrophoresis mobility assay revealed thatOsbZIP72bound directly to the ABA- responsive element in theOsHKT1;1promoter region and activated its transcription. Overall, our findings revealed thatOsbZIP72can act as a transcriptional modulator with the ability to induce the expression ofOsHKT1;1in response to environmental stress through an ABA-dependent regulatory pathway, indicating thatOsbZIP72can play a crucial role in the ABA-mediated salt and drought tolerance pathway in rice.