Drought stress is a major concern for current agriculture as it limits plant growth and yield. An experiment was conducted with a drought susceptible rice (Oryza sativa L. cv. BRRI dhan29) to explore the potential functions and possible mechanisms of exogenous glutathione (GSH)-induced drought stress tolerance. Fifteen-day-old seedlings, GSH-pretreated or non-pretreated (0.2 mM GSH for 72 h), were subjected to PEG-induced (15% polyethylene glycol 6000) drought stress for 4 days. Rice plants exposed to drought stress displayed reduced growth, which was correlated with reduced chlorophyll content, water balance, antioxidant enzymes activities and mineral contents (K⁺, Ca²⁺ and Mg²⁺), as evidenced by principle component analysis (PCA) and heatmap clustering. The PCA also revealed that hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) accumulations were strongly linked with the declined growth and development of rice plants under drought stress. Importantly, pretreatment with GSH improved the growth responses of rice plants to drought stress. GSH strengthened numerous physio-biochemical processes which were coupled with increased uptake of K⁺, Ca²⁺ and Mg²⁺, enhanced accumulation of soluble sugars, higher activities of enzymatic and non-enzymatic antioxidants. Moreover, GSH-pretreated seedlings under drought stress conditions had lower levels of O^·−₂ , H₂O₂ and MDA which indicates successful adaptation of rice seedlings to drought stress. The results of PCA strongly supported that GSH conferred drought tolerance mostly by enhancing antioxidant activities and mineral homeostasis. Collectively, our findings provide an important prospect for use of GSH in modulating drought tolerance in rice plants. Breeding strategies should therefore be undertaken to increase the GSH content of rice plants as a means to increase drought tolerance.

中文翻译：

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外源谷胱甘肽介导的水稻耐旱性（Oryza sativa L.）与较低的氧化损伤和良好的离子稳态相关。

干旱胁迫是当前农业的主要问题，因为它限制了植物的生长和产量。对易受干旱影响的水稻（Oryza sativa L. cv。BRRI dhan29）进行了一项实验，以探索外源谷胱甘肽（GSH）诱导的干旱胁迫耐受性的潜在功能和可能的机制。将经过GSH预处理或未预处理（0.2 mM GSH持续72 h）的15日龄幼苗置于PEG诱导的（15％聚乙二醇6000）干旱胁迫下4天。受干旱胁迫的水稻植株生长减慢，这与叶绿素含量，水平衡，抗氧化酶活性和矿物质含量（K ⁺，Ca ²⁺和Mg ²⁺），这由主成分分析（PCA）和热图聚类证明。PCA还显示，过氧化氢（H ₂ O ₂）和丙二醛（MDA）的积累与干旱胁迫下水稻植物生长发育的下降密切相关。重要的是，用谷胱甘肽预处理可以改善水稻植物对干旱胁迫的生长反应。GSH增强了许多生理生化过程，同时增加了对K ⁺，Ca ²⁺和Mg ^2+的吸收，增加了可溶性糖的积累，提高了酶促和非酶促抗氧化剂的活性。此外，谷胱甘肽预处理的幼苗在干旱胁迫条件下的O ^· ₋₂水平较低 ，H ₂ O ₂和MDA表示水稻幼苗已成功适应干旱胁迫。PCA的结果强烈支持GSH主要通过增强抗氧化活性和矿物质稳态来赋予抗旱性。总的来说，我们的发现为使用谷胱甘肽调节水稻植株的耐旱性提供了重要的前景。因此，应采取育种策略来增加稻米中谷胱甘肽的含量，以此作为提高抗旱性的手段。