Front Plant Sci. 2017 Mar 10;8:316. doi: 10.3389/fpls.2017.00316. eCollection 2017.
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.
Figure 1: Identification of salt-tolerant activation tagging line (ATL) OsSta2-D. (A) Visual phenotypes of salt response by ATL and WT after 8 DAG seedlings were exposed to either 100 mM NaCl for 7 days or 250 mM NaCl for 48 h. All seedlings were returned to normal conditions for 6 days of recovery. (B) Schematic diagram of ATL of OsSta2 and RT-PCR of LOC_Os02g43830 (OsSta2) and LOC_Os02g43830. (C) qRT-PCR of ATL showing OsSta2 mRNA levels isolated from young seedlings. Error bars represent standard error of three replicates.