Alleviation of Drought Stress in Arabidopsis thaliana by 17β-Estradiol Application

Animal steroidal hormones, including estrogens, arebeing introduced into the agricultural soil and water supply from increasedpharmaceutical and farm waste. Considering the current levels of xenoestrogencontamination of plant environments in view of the climate change induceddrought conditions, this study was designed to understand the effect ofestradiol (ES) application on Arabidopsis drought stress responses. Estradiol treatment (10 nM, 100 nM) of plantssubjected to drought stress conditions by withholding water for 7 days resultedin increased tolerance to drought stress reflected in the significantly higherplant survival rates of 74% and 78%, respectively compared to control plants’survival rates of 36% (no treatment) and 40% (mock treatment). Estradiol applicationsignificantly increased the content of glutathione, proline and H2O2 and significantly enhanced the transcription of the stress responsive genes GSTU3, GER5, HSP101, and HSP70b. A high concentration of ES (10 μM)did not protect plants against drought stress and proved to be toxic. Theseresults provide new insight into the effect of ES on drought-stress responsesin Arabidopsis with possiblepractical agricultural applications regarding the effect of environmentalestrogens on crop plants.