eATP位于H2S下游参与乙烯诱导的拟南芥气孔关闭过程

以拟南芥(Arabidopsis thaliana)野生型、H₂S合成突变体(Atl-cdes和Atd-cdes)和ABC转运体突变体(Atmrp4、Atmrp5 和Atmrp4/5)为材料, 探讨乙烯诱导气孔关闭过程中eATP与H₂S之间的关系。结果显示, ABC转运体阻断剂格列本脲(Gli)、P2受体抑制剂磷酸吡哆醛-6-偶氮苯基-2',4'-二硫酸(PPADS)和三磷酸腺苷双磷酸酶(Apyrase)可抑制乙烯诱导的气孔关闭乙烯可提高拟南芥幼苗叶片eATP含量及AtMRP4和AtMRP5相对表达量, 但对Atmrp4、Atmrp5和Atmrp4/5突变体幼苗叶片eATP含量和气孔运动没有显著作用。实验结果表明, eATP是乙烯诱导拟南芥气孔关闭过程的重要信号分子, AtMRP4和AtMRP5参与胞内ATP的分泌H₂S清除剂次牛磺酸(HT)能阻遏乙烯诱导的拟南芥幼苗叶片eATP含量的升高乙烯对Atl-cdes、Atd-cdes幼苗叶片eATP含量及AtMRP4和AtMRP5相对表达量无显著影响。据此推测eATP位于H₂S下游参与乙烯诱导的拟南芥气孔关闭过程。

Extracellular Adenosine Triphosphate Functions Downstream of Hydrogen Sulfide in Ethylene-induced Stomatal Closure in Arabidopsis thaliana

Using wild-type Arabidopsis, hydrogen sulfide (H₂S)-synthesis mutants (Atl-cdes and Atd-cdes) and ABC- transporter mutants (Atmrp4, Atmrp5 and Atmrp4/5), we examined the effect of extracellular adenosine triphosphate (eATP) on ethylene-induced stomatal closure and its relationship with H₂S. The ABC transporter blocker glibenclamide, P2 receptor inhibiter pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid and apyrase inhibited the inducing effects of ethylene on stomatal closure in Arabidopsis and ethylene-enhanced eATP content and upregulated relative expression of AtMRP4 and AtMRP5 in leaves of wild-type Arabidopsis but had no effect on eATP content or stomatal movement in Atmrp4, Atmrp5 and Atmrp4/5 mutants. Thus, eATP is involved in ethylene-induced stomatal closure, and AtMRP4 and AtMRP5 proteins take part in the secretion of intracellular ATP. The H₂S scavenger hypotaurine inhibited the improving effect of ethylene on eATP content in leaves of wild-type Arabidopsis but had no effect on eATP content or relative expression of AtMRP4 and AtMRP5 in Atl-cdes and Atd-cdes mutants. eATP may be located downstream of H₂S in ethylene-induced stomatal closure in Arabidopsis thaliana.