Department of Botany, Aligarh Muslim University, Aligarh, 202002, India.
Physiol Plant. 2014 Oct;152(2):331-44. doi: 10.1111/ppl.12173. Epub 2014 Apr 8.
Sulfur (S) assimilation results in the synthesis of cysteine (Cys), a common metabolite for the formation of both reduced glutathione (GSH) and ethylene. Thus, ethylene may have regulatory interaction with GSH in the alleviation of salt stress. The involvement of ethylene in the alleviation of salt stress by S application was studied in mustard (Brassica juncea cv. Pusa Jai Kisan). First, the effects of 0, 0.5, 1.0 and 2.0 mM SO4 (2) (-) were studied on photosynthetic and growth parameters to ascertain the S requirement as sufficient-S and excess-S for the plant. In further experiments, the effects of sufficient-S (1 mM SO4 (2) (-) ) and excess-S (2 mM SO4 (2) (-) ) were studied on the alleviation of salt stress-induced by 100 mM NaCl, and ethylene involvement in the alleviation of salt stress by S. Under non-saline condition, excess-S increased ethylene with less content of Cys and GSH and adversely affected photosynthesis and growth. In contrast, excess-S maximally alleviated salt stress due to high demand for S and optimal ethylene formation, which maximally increased GSH and promoted photosynthesis and growth. The involvement of ethylene in S-mediated alleviation of salt stress was further substantiated by the reversal of the effects of excess-S on photosynthesis by aminoethoxyvinylglycine (AVG), ethylene biosynthesis inhibitor. The studies suggest that plants respond differentially to the S availability under non-saline and salt stress and excess-S was more potential in the alleviation of salt stress. Further, ethylene regulates plants' response and excess S-induced alleviation of salt stress and promotion of photosynthesis.
硫（S）同化导致半胱氨酸（Cys）的合成，Cys 是形成还原型谷胱甘肽（GSH）和乙烯的常见代谢物。因此，乙烯可能与 GSH 一起参与缓解盐胁迫。本研究以芥菜（Brassica juncea cv. Pusa Jai Kisan）为材料，研究了 S 应用通过乙烯缓解盐胁迫的作用。首先，研究了 0、0.5、1.0 和 2.0mM SO4（2-）对光合和生长参数的影响，以确定 S 对植物的需求是适量 S 和过量 S。在进一步的实验中，研究了适量 S（1mM SO4（2-））和过量 S（2mM SO4（2-））对 100mM NaCl 诱导的盐胁迫缓解的影响，以及 S 通过乙烯缓解盐胁迫的作用。在非盐胁迫条件下，过量 S 增加了乙烯，降低了 Cys 和 GSH 的含量，从而对光合作用和生长产生不利影响。相比之下，过量 S 由于对 S 的高需求和最佳乙烯形成，最大程度地缓解了盐胁迫，这最大程度地增加了 GSH，并促进了光合作用和生长。过量 S 对光合作用的影响可以通过乙烯生物合成抑制剂氨基乙氧基乙烯基甘氨酸（AVG）逆转，进一步证实了乙烯在 S 介导的缓解盐胁迫中的作用。研究表明，植物在非盐胁迫和盐胁迫下对 S 的可利用性有不同的反应，过量 S 在缓解盐胁迫方面更有潜力。此外，乙烯调节植物的反应和过量 S 诱导的缓解盐胁迫以及促进光合作用。
