Ectopic Expression of OsSta2 Enhances Salt Stress Tolerance in Rice.

Manu Kumar,Seong-Ryong Kim,Juyoung Choi,Gynheung An

doi:10.3389/fpls.2017.00316

Manu Kumar, Seong-Ryong Kim + Show 2 more

Open Access

https://doi.org/10.3389/fpls.2017.00316

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Abstract

Salt stress can severely reduce crop yields. To understand how rice (Oryza sativa) plants respond to this environmental challenge, we investigated the genes involved in conferring salt tolerance by screening T-DNA tagging lines and identified OsSta2-D (Oryza sativa Salt tolerance activation 2-Dominant). In that line, expression of OsSta2 was enhanced by approximately eightfold when compared with the non-transformed wild type (WT). This gene was highly expressed in the callus, roots, and panicles. To confirm its role in stress tolerance, we generated transgenic rice that over-expresses OsSta2 under a maize ubiquitin promoter. The OsSta2-Ox plants were salt-tolerant at the vegetative stage, based on our calculations of chlorophyll fluorescence (Fv/Fm), fresh and dry weights, chlorophyll concentrations, and survival rates. Under normal paddy field conditions, the Ox plants were somewhat shorter than the WT control but had improved agronomic traits such as higher total grain yield. They were also more tolerant to osmotic stress and hypersensitive to abscisic acid. Based on all of these results, we suggest that OsSta2 has important roles in determining yields as well as in conferring tolerance to salt stresses.

Highlights

For more than half of the world’s people, rice (Oryza sativa) is a major food crop
Molecular analysis by inverse PCR revealed that the T-DNA was tagged between LOC_Os02g43820 and LOC_Os02g43830 (Figure 1B)
Rice is a salt-sensitive crop at the germination stage, but becomes more tolerant as plants progress from young seedlings to the vegetative stage (Heenan et al, 1988; Lutts et al, 1995)

Summary

Introduction

For more than half of the world’s people, rice (Oryza sativa) is a major food crop. Global demand for this grain will rise as populations continue to grow. Drought and salt stresses are common environmental factors that restrict rice productivity (Yeo and Flowers, 1984; Xoconostle-Cázares et al, 2010; Das et al, 2015; Fita et al, 2015). Significant progress has been made in understanding the mechanism(s) for salt tolerance in many plant species, including rice (Kumar et al, 2013; Deinlein et al, 2014; Parihar et al, 2015). Cells can be protected and normal plant growth maintained through cellular responses such as cytosolic calcium release, ionic imbalances

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