JcDREB2, a Physic Nut AP2/ERF Gene, Alters Plant Growth and Salinity Stress Responses in Transgenic Rice.

Yuehui Tang,Kun Liu,Kedong Xu,Xiaoli Li,Ju Zhang,Deshui Yu,Chengwei Li,Jian Wang,Yi Zhang,Jing Qi

doi:10.3389/fpls.2017.00306

Abstract

Transcription factors of the AP2/ERF family play important roles in plant growth, development, and responses to biotic and abiotic stresses. In this study, a physic nut AP2/ERF gene, JcDREB2, was functionally characterized. Real-time PCR analysis revealed that JcDREB2 was expressed mainly in the leaf and could be induced by abscisic acid but suppressed by gibberellin (GA) and salt. Transient expression of a JcDREB2-YFP fusion protein in Arabidopsis protoplasts cells suggested that JcDREB2 is localized in the nucleus. Rice plants overexpressing JcDREB2 exhibited dwarf and GA-deficient phenotypes with shorter shoots and roots than those of wild-type plants. The dwarfism phenotype could be rescued by the application of exogenous GA3. The expression levels of GA biosynthetic genes including OsGA20ox1, OsGA20ox2, OsGA20ox4, OsGA3ox2, OsCPS1, OsKO2, and OsKAO were significantly reduced in plants overexpressing JcDREB2. Overexpression of JcDREB2 in rice increased sensitivity to salt stress. Increases in the expression levels of several salt-tolerance-related genes in response to salt stress were impaired in JcDREB2-overexpressing plants. These results demonstrated not only that JcDREB2 influences GA metabolism, but also that it can participate in the regulation of the salt stress response in rice.

Highlights

Abiotic stresses, such as high salinity and drought, adversely affect plant growth and agricultural productivity, resulting in serious losses in yield
We demonstrate that JcDREB2 encodes a transcription factor whose expression is regulated by salinity, gibberellic acid (GA3) and abscisic acid (ABA) treatments
Our results indicated that overexpression of JcDREB2 in rice resulted in both a dwarf phenotype, via downregulation of key genes involved in GA biosynthesis, and increased sensitivity to salinity stress

Summary

Introduction

Abiotic stresses, such as high salinity and drought, adversely affect plant growth and agricultural productivity, resulting in serious losses in yield. To cope with these adverse conditions, plants have evolved various defense mechanisms enabling them to tolerate environmental stresses. DREB-encoding genes in several other species, genes which include VvDREB2A, SsDREB, and GmDREB1, have been identified as playing significant parts in salinity tolerance through regulating the expression of stress-responsive genes and physiological processes (Jin et al, 2010; Zhang et al, 2014; Chen H. et al, 2015). Many DREB transcription factors have been extensively studied in various plants, further efforts are still needed to identify other novel DREB genes that are involved in plant development and stress responses

Methods

Results

Conclusion