Salicylic Acid Induces Vanadium Stress Tolerance in Rice by Regulating the AsA-GSH Cycle and Glyoxalase System

Salicylic acid (SA) is a signaling molecule and behaves as an antioxidant that induces stress tolerance in plants against abiotic stress. The present study explored the rice seedling response to V stress and the role of SA in improving the V stress tolerance of rice seedlings. The rice seedlings were sown in Petri dishes and incubated in a climate-controlled chamber for 4 days without light for germination. After that, the rice seedlings were shifted into hydroponic solution and allowed to grow for 18 days in hydroponic solution. The roots of 21-day-old rice seedlings were pretreated with SA (200 μM) for 3 days, and exposed to V (35 mg L −1 ) stress for 7 days. After 7 days of V stress, rice seedlings were harvested to determine the root attributes, photosynthetic assimilation, reactive oxygen species (ROS), ascorbate-glutathione (AsA-GSH) pathway enzymes, antioxidant and glyoxalase enzyme activities, and plant growth parameters. The findings disclosed that pretreatment of rice seedlings with SA had a high SPAD index, chlorophyll pigment content, and photosynthetic assimilation resulted in better growth compared to non-SA-pretreated rice seedlings. Strikingly, SA sustains the V homeostasis by inhibiting the accumulation of V from rice root to shoot. Besides this, pretreatment of SA increased the superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione S-transferase (GST), and ascorbate-glutathione (AsA-GSH) pathway enzymes, and also enhanced the ascorbate (AsA) and glutathione (GSH) level, and minimized the hydrogen peroxide (H 2 O 2 ) and superoxide anion ( O_2^-∙ ) of rice seedlings, by regulating the gene expression of antioxidant enzymes ( OsCuZnSOD1 , OsCaTB , OsGPX1 , OsAPX1 , OsGR2 , and OsGSTU37 ). Furthermore, SA reduced methylglyoxal toxicity and enhanced glyoxalase enzyme activity by upregulating the genes expression of glyoxalase genes ( OsGLYI-1 and OsGLYII-2 ) under V stress condition. Considering these findings demonstrated that SA may be utilized to reduce V availability to rice seedlings while also improving rice seedling growth and V stress resistance. Graphical abstract