Honda Kenji, Yamada Naotake, Yoshida Riichiro, Ihara Hideshi, Sawa Tomohiro, Akaike Takaaki, Iwai Sumio
Department of Horticultural Science, Faculty of Agriculture, Kagoshima University, Kagoshima, 890-0065 Japan.
Department of Bioscience & Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, 812-8581 Japan.
Plant Cell Physiol. 2015 Aug;56(8):1481-9. doi: 10.1093/pcp/pcv069. Epub 2015 May 14.
Plants are exposed to hydrogen sulfide (H2S) both exogenously, as it exists as a pollutant gas in the environment, and endogenously, as it is synthesized in cells. H2S has recently been found to function as a gaseous signaling molecule, but its signaling cascade remains unknown. Here, we examined H2S-mediated guard cell signaling in Arabidopsis. The H2S donor GYY4137 (morpholin-4-ium-4-methoxyphenyl [morpholino] phosphinodithioate) induced stomatal closure, which peaked after 150 min at 1 µM or after 90 min at 10 and 100 µM. After reaching maximal closure, stomatal apertures gradually increased in size in response to further exposure to GYY4137. GYY4137 induced nitric oxide (NO) generation in guard cells, and GYY4137-induced stomatal closure was reduced by an NO scavenger and inhibitors of NO-producing enzymes. Mass spectrometry analyses showed that GYY4137 induces the synthesis of 8-nitro-cGMP and 8-mercapto-cGMP and that this synthesis is mediated by NO. In addition, 8-mercapto-cGMP triggered stomatal closure. Moreover, inhibitor and genetic studies showed that calcium, cADP ribose and slow anion channel 1 act downstream of 8-mercapto-cGMP. This study therefore demonstrates that 8-mercapto-cGMP mediates the H2S signaling cascade in guard cells.
植物会外源性地接触到硫化氢（H₂S），因为它作为一种污染性气体存在于环境中；同时也会内源性地接触到硫化氢，因为它在细胞中合成。最近发现H₂S作为一种气体信号分子发挥作用，但其信号传导途径仍不清楚。在这里，我们研究了拟南芥中H₂S介导的保卫细胞信号传导。H₂S供体GYY4137（吗啉-4-鎓-4-甲氧基苯基[吗啉代]次膦酸二硫酯）诱导气孔关闭，在1μM时150分钟后达到峰值，在10和100μM时90分钟后达到峰值。达到最大关闭状态后，气孔孔径会随着进一步暴露于GYY4137而逐渐增大。GYY4137诱导保卫细胞中一氧化氮（NO）的生成，并且NO清除剂和NO生成酶抑制剂会减少GYY4137诱导的气孔关闭。质谱分析表明，GYY4137诱导8-硝基-cGMP和8-巯基-cGMP的合成，并且这种合成是由NO介导的。此外，8-巯基-cGMP引发气孔关闭。此外，抑制剂和遗传学研究表明，钙、环ADP核糖和慢阴离子通道1在8-巯基-cGMP的下游起作用。因此，这项研究表明8-巯基-cGMP介导保卫细胞中的H₂S信号传导级联反应。
