Microelement Research Center, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China; Hubei Collaborative Innovation Center for Grain Industry, Jingzhou, 434023, China.
Department of Biochemistry and Molecular Biology, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, 1706, Bangladesh.
Plant Physiol Biochem. 2019 May;138:100-111. doi: 10.1016/j.plaphy.2019.02.023. Epub 2019 Mar 2.
Hydrogen sulfide (HS) modulates plant tolerance to abiotic stresses, but its regulatory effects on nitrogen metabolism and chloroplast protection under nickel (Ni) stress in crop plants remain elusive. Taking this into account, we investigated the potential roles of sodium hydrosulfide (NaHS), a HS generator, in the improvement of growth performance of rice plants under Ni stress. Results showed that NaHS successfully reversed the adverse effects of Ni, as reflected in plant growth and biomass, and photosynthesis attributes including photosynthetic rates, stomatal conductance, transpiration rate, internal CO concentration and photosynthetic pigment contents. NaHS generated HS plays a crucial role in controlling the photosynthetic machinery of rice as evidenced by the ultrastructure of chloroplast viewed under transmission electron microscope (TEM). The reduced content of Ni in roots and leaves of NaHS-supplemented Ni-stressed plants has revealed the restricted uptake and accumulation of Ni. A rescue of NaHS to the Ni-induced decline in nitrate (NO) content and the activities NO biosynthesizing enzymes nitrate reductase, nitrite reductase, glutamate synthase, glutamate oxaloacetate transaminase, glutamine synthetase, and glutamate pyruvate transaminase in leaves indicated a positive role of HS on NO metabolism in rice under Ni stress. NaHS application also reverted Ni-mediated increases in ammonium (NH) content and glutamate dehydrogenase activity, implying HS-induced alleviation of NH toxicity. The regulatory effects of HS on nitrogen metabolism was further confirmed by increased and decreased transcript abundance of NO and NH metabolism associated genes, respectively. Our study suggests a decisive role of HS in controlling Ni toxicity as elucidated by the novel findings such as enhanced gas exchanged parameters, Ni homeostasis and chloroplast protection. Moreover, this article highlights the significance of HS in controlling chloroplast biogenesis and nitrogen metabolism in rice crop under Ni stress.
硫化氢 (HS) 调节植物对非生物胁迫的耐受性，但它在镍 (Ni) 胁迫下对作物氮代谢和叶绿体保护的调节作用仍不清楚。考虑到这一点，我们研究了氢硫化钠 (NaHS)，一种 HS 生成剂，在提高水稻植物在 Ni 胁迫下生长性能方面的潜在作用。结果表明，NaHS 成功地逆转了 Ni 的不利影响，表现在植物生长和生物量，以及光合作用属性，包括光合速率、气孔导度、蒸腾速率、内部 CO 浓度和光合色素含量。NaHS 生成的 HS 在控制水稻光合作用机制方面起着至关重要的作用，这可以从透射电子显微镜 (TEM) 下观察到的叶绿体超微结构中得到证明。补充 NaHS 的 Ni 胁迫植物的根和叶中 Ni 含量减少，表明 Ni 的吸收和积累受到限制。NaHS 对 Ni 诱导的硝酸盐 (NO) 含量下降和叶片中硝酸合成酶硝酸还原酶、亚硝酸还原酶、谷氨酸合酶、谷氨酸草酰乙酸转氨酶、谷氨酰胺合成酶和谷氨酸丙酮酸转氨酶活性的恢复，表明 HS 在 Ni 胁迫下对水稻中 NO 代谢的积极作用。NaHS 的应用也使 Ni 介导的铵 (NH) 含量增加和谷氨酸脱氢酶活性恢复正常，表明 HS 诱导减轻了 NH 的毒性。HS 对氮代谢的调节作用还通过增加和减少与 NO 和 NH 代谢相关的基因的转录丰度得到进一步证实。我们的研究表明，HS 在控制 Ni 毒性方面起着决定性的作用，这可以从增强的气体交换参数、Ni 稳态和叶绿体保护等新发现中得到证明。此外，本文强调了 HS 在控制 Ni 胁迫下水稻作物叶绿体生物发生和氮代谢中的重要性。
