Recent reports have uncovered the multifunctional role of H2S in the physiological response of plants to biotic and abiotic stresses. Here, we studied whether NaHS (an H2S donor) pretreatment could provoke the tolerance of cucumber (Cucumis sativus L.) seedlings subsequently exposed to chilling stress and whether glutathione was involved in this process. Results showed that cucumber seedlings sprayed with NaHS exhibited remarkably increased chilling tolerance, as evidenced by the observed plant tolerant phenotype, as well as the lower levels of electrolyte leakage (EL), malondialdehyde (MDA) content, hydrogen peroxide (H2O2) content and RBOH mRNA abundance, compared with the control plants. In addition, NaHS treatment increased the endogenous content of the reduced glutathione (GSH) and the ratio of reduced/oxidized glutathione (GSH/GSSG), meanwhile, the higher net photosynthetic rate (Anet), the light-saturated CO2 assimilation rate (Asat), the photochemical efficiency (Fv/Fm) and the maximum photochemical efficiency of PSII in darkness (ФPSII) as well as the mRNA levels and activities of the key photosynthetic enzymes (Rubisco, TK, SBPase and FBA) were observed in NaHS-treated seedlings under chilling stress, whereas this effect of NaHS was weakened by buthionine sulfoximine (BSO, an inhibitor of glutathione) or 6-Aminonicotinamide (6-AN, a specific pentose inhibitor and thus inhibits the NADPH production), which preliminarily proved the interaction between H2S and GSH. Moreover, transcription profiling analysis revealed that the GSH-associated genes (GST Tau, MAAI, APX, GR, GS and MDHAR) were significantly up-regulated in NaHS-treated cucumber seedlings, compared to the H2O-treated seedlings under chilling stress. Thus, novel results highlight the importance of glutathione as a downstream signal of H2S-induced plant tolerance to chilling stress.

中文翻译：

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生理反应和转录谱分析揭示了谷胱甘肽在 H2S 诱导的黄瓜幼苗低温胁迫耐受性中的作用

最近的报告揭示了 H2S 在植物对生物和非生物胁迫的生理反应中的多功能作用。在这里，我们研究了 NaHS（H2S 供体）预处理是否可以激发黄瓜（Cucumis sativus L.）幼苗对随后暴露于低温胁迫的耐受性，以及谷胱甘肽是否参与了这一过程。结果表明，喷洒 NaHS 的黄瓜幼苗表现出显着提高的耐寒性，如观察到的植物耐受表型，以及较低水平的电解质泄漏 (EL)、丙二醛 (MDA) 含量、过氧化氢 (H2O2) 含量和 RBOH mRNA 丰度，与对照植物相比。此外，NaHS处理增加了还原型谷胱甘肽（GSH）的内源含量和还原型/氧化型谷胱甘肽的比例（GSH/GSSG），同时，较高的净光合速率 (Anet)、光饱和 CO2 同化速率 (Asat)、光化学效率 (Fv/Fm) 和 PSII 在黑暗中的最大光化学效率 (ФPSII) 以及 mRNA 水平和活性在低温胁迫下，在 NaHS 处理的幼苗中观察到了关键光合酶（Rubisco、TK、SBPase 和 FBA）的这种作用，而丁硫氨酸亚砜亚胺（BSO，一种谷胱甘肽抑制剂）或 6-氨基烟酰胺（6- AN，一种特定的戊糖抑制剂，从而抑制 NADPH 的产生），初步证明了 H2S 和 GSH 之间的相互作用。此外，转录谱分析显示，在 NaHS 处理的黄瓜幼苗中，GSH 相关基因（GST Tau、MAAI、APX、GR、GS 和 MDHAR）显着上调，与低温胁迫下 H2O 处理的幼苗相比。因此，新的结果强调了谷胱甘肽作为 H2S 诱导的植物对低温胁迫的耐受性的下游信号的重要性。