Overexpression of the Transcription Factor Gene OsSTAP1 Increases Salt Tolerance in Rice

BACKGROUND: High soil salinity can cause significant losses in rice productivity worldwide, mainly because salt inhibits plant growth and reduces grain yield. To cope with environmental changes, plants have evolved several adaptive mechanisms that involve the regulation of many stress-responsive genes. RESULTS: In this study, we identified OsSTAP1, which encodes an AP2/ERF-type transcription factor, was rapidly induced by ABA, ACC, salt, cold, and PEG treatments. OsSTAP1 is localized to the nucleus and acts as a transcriptional activator in plant cells. Compared with wild type, transgenic lines overexpressing OsSTAP1 exhibited increased tolerance to salt stress with higher SOD, POD, and CAT activities, and lower Na(+)/K(+) ratios in the shoots. In addition, many other stress-responsive genes, including other ERF- and peroxidase-encoding genes, were upregulated in the OsSTAP1-overexpression lines. CONCLUSION: This study suggests that OsSTAP1 functions as an AP2/ERF transcriptional activator, and plays a positive role in salt tolerance by decreasing the Na(+)/K(+) ratio and maintaining cellular redox homeostasis.