[sdt1, a novel Arabidopsis mutant tolerant to drought and high-salinity stresses].

Among the 20000 independent Arabidopsis activation tagging lines, we screened a novel mutant with high-salinity and drought tolerance, namely sdt1 (high-salinity and drought tolerant 1). sdt1 kept normal growth under drought stress by consecutively withholding water for 26d, while all the wild type wilted to death. Furthermore, the same result was repeated under high-salinity stress when sdtl and wild type were treated with 150 mmol/L NaCl. Seeds germination test on the medium indicated that the response of sdt1 to endogenous or exogenous ABA was reduced as compared with wild type. Under drought stress conditions the rates of water loss of sdt1 rosette leaves were significantly lower than that of wild type. Southern hybridization of sdt1 and the result of high-salinity tolerance genetic analysis showed that two copies of T-DNA were inserted into the two linking sites by shoulder to shoulder.