H_2S与Ca^(2+)互作提高黄瓜幼苗耐冷性

Hydrogen Sulfide Interacts with Ca^(2+) to Enhance Chilling Tolerance of Cucumber Seedlings

硫化氢(hydrogen sulfide,H_2S)是一种新型气体信号分子,钙离子(calcium,Ca^(2+))为重要的第二信使,两者在调控植物生长发育及多种逆境胁迫中分别起着重要作用。然而,H_2S和Ca^(2+)信号在调控植物耐冷性中的作用关系并不十分清楚。本研究针对以上问题以‘津优35号’黄瓜为试材进行研究,结果表明,低温胁迫可诱导H_2S信号的产生,且这种信号可被外源Ca^(2+)增强;低温胁迫可诱导Ca^(2+)信号转导相关基因CaM、CIPK5的mRNA表达,且外源H_2S能够上调低温下CaM、CIPK5的表达量;进一步研究发现,外源H_2S和Ca^(2+)可显著增强植株的抗氧化能力,减少活性氧积累,从而降低低温胁迫对黄瓜幼苗的损伤,且加入Ca^(2+)螯合剂乙二醇二乙醚二胺四乙酸(ethylene glycol tetraacetic acid,EGTA)或钙调素拮抗剂氯丙嗪(chlorpromazine,CPZ)后,H_2S对黄瓜幼苗抗氧化能力的促进效应明显减弱,同样的,H_2S清除剂次牛磺酸(hypotaurine,HT)也会降低Ca^(2+)的作用。以上结果表明H_2S与Ca^(2+)信号间存在着复杂的联系,而且他们可以通过相互作用调控黄瓜幼苗的抗氧化系统,从而增强植株耐冷性。

Hydrogen sulfide （H2S） is a new gasotransmitter and calcium （Ca2＋ ） is an important second messenger. Both play important roles in regulating plant growth development and adversity stresses, respectively. Here we used ＇ Jinyou 35 ＇ cucumber plants to study the relationship between H2S and Ca2＋ in regulating chilling resistance. The results showed that chilling stress could induce the generation of H2S signals, which could be enhanced by exogenous Ca2＋. Among the genes involved the Ca2＋ signal transduction pathway, the mRNA abundances of CaM and CIPK5 were stimulated in chilling stress and up-regulated by exogenous H2＋. Our studies also showed that exogenous H2＋ and Ca2＋ could remarkably strengthen the antioxidant ability and reduce accumulation of reactive oxygen species, thereby alleviatingthe damage of chilling stress to cucumber seedlings. Furthermore, the positive effect of H2＋ on the antioxidant ability was removed by adding the Ca2＋ chelating agent ethylene glycol tetraacetic acid （EGTA） or the calmodulin antagonist chlorpromazine （CPZ） , and the function of Ca2＋ was weakened by the H2S scavenger hypotaurine （HT）. We propose that there are complex connections between H2＋and Ca2＋ signaling, and that H2S and Ca2＋ may enhance chilling tolerance by adjusting the antioxidative system in cucumber seedlings.