The Soybean bZIP Transcription Factor Gene GmbZIP2 Confers Drought and Salt Resistances in Transgenic Plants

Abstract

Abiotic stresses, such as drought and salt, are major environmental stresses, affecting plant growth and crop productivity. Plant bZIP transcription factors (bZIPs) confer stress resistances in harsh environments and play important roles in each phase of plant growth processes. In this research, 15 soybean bZIP family members were identified from drought-induced de novo transcriptomic sequences of soybean, which were unevenly distributed across 12 soybean chromosomes. Promoter analysis showed that these 15 genes were rich in ABRE, MYB and MYC <i>cis</i>-acting elements which were reported to be involved in abiotic stress responses. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated that 15 <i>GmbZIP</i> genes could be induced by drought and salt stress. <i>GmbZIP2</i> was significantly upregulated under stress conditions and thus was selected for further study. Subcellular localization analysis revealed that the GmbZIP2 protein was located in the cell nucleus. qRT-PCR results show that <i>GmbZIP2</i> can be induced by multiple stresses. The overexpression of <i>GmbZIP2</i> in <i>Arabidopsis</i> and soybean hairy roots could improve plant resistance to drought and salt stresses. The result of differential expression gene analysis shows that the overexpression of <i>GmbZIP2</i> in soybean hairy roots could enhance the expression of the stress responsive genes <i>GmMYB48</i>, <i>GmWD40</i>, <i>GmDHN15</i>, <i>GmGST1</i> and <i>GmLEA</i>. These results indicate that soybean <i>bZIP</i>s played pivotal roles in plant resistance to abiotic stresses.