Heterologous Expression of AtWRKY57 Confers Drought Tolerance in Oryza sativa

Yanjuan Jiang,Yuping Qiu,Diqiu Yu,Yanru Hu

doi:10.3389/fpls.2016.00145

Abstract

Drought stress is a severe environmental factor that greatly restricts plant distribution and crop production. Recently, we have found that overexpressing AtWRKY57 enhanced drought tolerance in Arabidopsis thaliana. In this study, we further reported that the Arabidopsis WRKY57 transcription factor was able to confer drought tolerance to transgenic rice (Oryza sativa) plants. The enhanced drought tolerance of transgenic rice was resulted from the lower water loss rates, cell death, malondialdehyde contents and relative electrolyte leakage while a higher proline content and reactive oxygen species-scavenging enzyme activities was observed during stress conditions. Moreover, further investigation revealed that the expression levels of several stress-responsive genes were up-regulated in drought-tolerant transgenic rice plants, compared with those in wild-type plants. In addition to the drought tolerance, the AtWRKY57 over-expressing plants also had enhanced salt and PEG stress tolerances. Taken together, our study indicates that over-expressing AtWRKY57 in rice improved not only drought tolerance but also salt and PEG tolerance, demonstrating its potential role in crop improvement.

Highlights

Drought is a critical abiotic stress that severely restricts crop production (Zhu, 2002)
To explore whether AtWRKY57 plays an important role in improving the agronomic traits through gene manipulation approaches, we introduced this gene to rice
POD, superoxide dismutase (SOD), and CAT activity levels were not different; after 14 days of drought stress, the activities of the antioxidative enzymes were all significantly enhanced in the AtWRKY57overexpressing plants compared with those in the control plants (Figures 3A–C). These results suggested that over-expression of after 14 days drought stress. (E) MDA content in the leaves of control and transgenic plants after 0, 14, and 20 days drought stress

Summary

Introduction

Drought is a critical abiotic stress that severely restricts crop production (Zhu, 2002). With the process of evolution, plants have gained a variety of strategies with the purpose of avoiding drought stress by reducing water loss or increasing water uptake. Other strategies need to protect plant cells from damage when water is exhausted and tissue dehydration unavoidable (Verslues et al, 2006). The molecular, cellular, and whole-plant levels strategies should be coordinated to adapt to drought stress (Yu et al, 2008). Under drought- or salt-stress conditions, plants accumulate reactive oxygen species (ROS) (Verslues et al, 2006). A master level of ROS gives rise to the oxidation of biomolecules, such as lipids, nucleic acids and proteins, which caused cellular damage. When CO2 fixation is restricted under environmental stress conditions, the photosynthetic electron transport system generates ROS (Asada, 1999).

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Results

Conclusion