Exogenous nitric oxide donor and arginine provide protection againstshort-term drought stress in wheat seedlings.

Abstract

Nitric oxide (NO) is an important plant signaling molecule that has a vital role in abiotic stress tolerance. In the present study, we assesseddrought-induced (15 and 30% PEG, polyethylene glycol) damage in wheat (Triticum aestivum L. cv. Prodip) seedlings and mitigation by the synergistic effect of exogenous Arg (0.5mM l-Arginine) and an NO donor (0.5mM sodium nitroprusside, SNP). Drought stress sharply decreased the leaf relative water content (RWC) but markedly increased the proline (Pro) content in wheat seedlings. Drought stress caused overproduction of reactive oxygen species (ROS) and methylglyoxal (MG) due to the inefficiency of antioxidant enzymes, theglyoxalase system, and theascorbate-glutathione pool. However, supplementation with theNO donor and Arg enhanced the antioxidant defense system (both non-enzymatic and enzymatic components) in drought-stressed seedlings. Application of theNO donor and Arg also enhanced the glyoxalase system and reduced the MG content by increasing the activities of the glyoxalase system enzymes (Gly I and Gly II), which restored the leaf RWC and further increased the Pro content under drought stress conditions. Exogenous NO donor and Arg application enhanced the endogenous NO content, which positively regulated the antioxidant system and reduced ROS production. Thus, the present study reveals the crucial roles of Arg and NO in enhancing drought stress tolerance in wheat seedlings by upgrading their water status and reducing oxidative stress and MG toxicity.