H2S信号通过调节RuBisCo增强植物抗旱性

Hydrogen Sulfide Signal Enhances Drought Resistance by Regulating RuBisCo in Arabidopsis thaliana

气体信号分子硫化氢(H2S)同时参与"诱导气孔关闭"和"增强光合作用"两个看似矛盾的生理过程。为了探究这一现象可能的机制,该文以模式植物拟南芥野生型(WT)与内源H2S生成酶缺失突变体(lcd/des1)为实验材料,研究干旱胁迫下H2S信号对植物非气孔因素的影响。结果表明,lcd/des1经外源生理浓度H2S熏蒸后,气孔导度(Gs)下降,胞间二氧化碳浓度(Ci)显著降低,净光合速率(Pn)显著升高;干旱胁迫下的lcd/des1与WT相比,Gs增加,Pn显著降低。特别地,干旱条件下对lcd/des1外源施加H2S,显著上调光合作用关键酶RuBisCo编码基因的表达量与酶活性。综上所述,H2S可通过调节非气孔因素RuBisCo酶的转录表达及其羧化活性,以增加叶片Pn,使干旱胁迫下的植株在气孔关闭时仍维持较高效率的光合作用。

Hydrogen sulfide(H2S),as a gasotransmitter,was reported to be involved in the induced stomatal closure and enhanced photosynthesis,which were contradictory physiological processes in plants.In order to explore the potential mechanism underlying this process,the model plant Arabidopsis thaliana wild type(WT)and mutant defective in the gene encoding H2S-producing enzyme(lcd/des1)were used as experimental materials to study the effect of H2S signal on non-stomatal factors under drought stress.The results showed that in the presence of exogenous physiological concentrations of H2S,stomatal conductance(Gs)decreased,intercellular carbon dioxide concentration(Ci)decreased significantly,while net photosynthetic rate(Pn)increased significantly in lcd/des1 mutant.Under drought stress,compared with WT,Gs in lcd/des1 increased and Pn decreased significantly.In particular,after the treatment of exogenous H2S under drought conditions,the expression levels of RuBisCo(the key enzyme in the calvin cycle of photosynthesis)coding genes in lcd/des1 were up-regulated and the activity of RuBisCo was significantly improved.In summary,H2S can increase Pn by regulating the transcriptional expression of RuBisCo,which is one of the non-stomatal factors,and increasing its carboxylation activity,so that the plants under drought stress maintain high-efficiency photosynthesis during the stomatal closure.