Key Laboratory for Subtropical Wetland Ecosystem Research of MOE, School of Life Sciences, Xiamen University, Xiamen, Fujian 361005, PR China.
J Exp Bot. 2011 Aug;62(13):4481-93. doi: 10.1093/jxb/err145. Epub 2011 May 30.
Hydrogen sulphide (H(2)S) is emerging as a potential messenger molecule involved in modulation of physiological processes in animals and plants. In this report, the role of H(2)S in modulating photosynthesis of Spinacia oleracea seedlings was investigated. The main results are as follows. (i) NaHS, a donor of H(2)S, was found to increase the chlorophyll content in leaves. (ii) Seedlings treated with different concentrations of NaHS for 30 d exhibited a significant increase in seedling growth, soluble protein content, and photosynthesis in a dose-dependent manner, with 100 μM NaHS being the optimal concentration. (iii) The number of grana lamellae stacking into the functional chloroplasts was also markedly increased by treatment with the optimal NaHS concentration. (iv) The light saturation point (Lsp), maximum net photosynthetic rate (Pmax), carboxylation efficiency (CE), and maximal photochemical efficiency of photosystem II (F(v)/F(m)) reached their maximal values, whereas the light compensation point (Lcp) and dark respiration (Rd) decreased significantly under the optimal NaHS concentration. (v) The activity of ribulose-1,5-bisphosphate carboxylase (RuBISCO) and the protein expression of the RuBISCO large subunit (RuBISCO LSU) were also significantly enhanced by NaHS. (vi) The total thiol content, glutathione and cysteine levels, internal concentration of H(2)S, and O-acetylserine(thiol)lyase and L-cysteine desulphydrase activities were increased to some extent, suggesting that NaHS also induced the activity of thiol redox modification. (vii) Further studies using quantitative real-time PCR showed that the gene encoding the RuBISCO large subunit (RBCL), small subunit (RBCS), ferredoxin thioredoxin reductase (FTR), ferredoxin (FRX), thioredoxin m (TRX-m), thioredoxin f (TRX-f), NADP-malate dehydrogenase (NADP-MDH), and O-acetylserine(thiol)lyase (OAS) were up-regulated, but genes encoding serine acetyltransferase (SERAT), glycolate oxidase (GYX), and cytochrome oxidase (CCO) were down-regulated after exposure to the optimal concentration of H(2)S. These findings suggest that increases in RuBISCO activity and the function of thiol redox modification may underlie the amelioration of photosynthesis and that H(2)S plays an important role in plant photosynthesis regulation by modulating the expression of genes involved in photosynthesis and thiol redox modification.
硫化氢 (H₂S) 作为一种潜在的信使分子，正在成为参与动植物生理过程调节的研究热点。本研究报告探讨了 H₂S 对菠菜幼苗光合作用的调节作用。主要结果如下：(i) 供氢体 NaHS 可增加叶片叶绿素含量。(ii) 经不同浓度 NaHS 处理 30 d 的幼苗，其生长、可溶性蛋白含量和光合作用均呈剂量依赖性显著增加，以 100 μM NaHS 为最佳浓度。(iii) 最佳 NaHS 浓度处理后，功能叶绿体中类囊体片层的数量也明显增加。(iv) 光饱和点 (Lsp)、最大净光合速率 (Pmax)、羧化效率 (CE) 和最大光化学效率的 PSⅡ(Fv/Fm) 达到最大值，而光补偿点 (Lcp) 和暗呼吸速率 (Rd) 则显著降低。(v) NaHS 还显著增强了核酮糖-1,5-二磷酸羧化酶 (RuBISCO) 的活性和 RuBISCO 大亚基 (RuBISCO LSU) 的蛋白表达。(vi) 总巯基含量、谷胱甘肽和半胱氨酸水平、内源性 H₂S 浓度以及 O-乙酰丝氨酸 (硫醇) 裂解酶和 L-半胱氨酸脱硫酶的活性均有一定程度的增加，表明 NaHS 还诱导了巯基氧化还原修饰的活性。(vii) 进一步的实时定量 PCR 研究表明，编码 RuBISCO 大亚基 (RBCL)、小亚基 (RBCS)、铁氧还蛋白-硫氧还蛋白还原酶 (FTR)、铁氧还蛋白 (FRX)、硫氧还蛋白 m (TRX-m)、硫氧还蛋白 f (TRX-f)、NADP-苹果酸脱氢酶 (NADP-MDH) 和 O-乙酰丝氨酸 (硫醇) 裂解酶 (OAS) 的基因被上调，但编码丝氨酸乙酰转移酶 (SERAT)、乙醇酸氧化酶 (GYX) 和细胞色素氧化酶 (CCO) 的基因被下调。这些发现表明，RuBISCO 活性的增加和巯基氧化还原修饰功能的增强可能是光合作用改善的基础，而 H₂S 通过调节参与光合作用和巯基氧化还原修饰的基因的表达，在植物光合作用调节中发挥重要作用。
