Stimulation of Tomato Drought Tolerance by and Mutations.

Drought stress is a severe environmental issue that threatens agriculture at a large scale. PHYTOCHROMES (PHYs) are important photoreceptors in plants that control plant growth and development and are involved in plant stress response. The aim of this study was to identify the role of in the tomato cv. 'Moneymaker' under drought conditions. The tomato genome contains five , among which mutant lines in tomato and ( and ) were used. Compared to the WT, and mutants exhibited drought tolerance and showed inhibition of electrolyte leakage and malondialdehyde accumulation, indicating decreased membrane damage in the leaves. Both mutants also inhibited oxidative damage by enhancing the expression of reactive oxygen species (ROS) scavenger genes, inhibiting hydrogen peroxide (HO) accumulation, and enhancing the percentage of antioxidant activities via DPPH test. Moreover, expression levels of several aquaporins were significantly higher in and , and the relative water content (RWC) in leaves was higher than the RWC in the WT under drought stress, suggesting the enhancement of hydration status in the mutants. Therefore, inhibition of oxidative damage in and mutants may mitigate the harmful effects of drought by preventing membrane damage and conserving the plant hydrostatus.