MAPK Kinase and CDP Kinase Modulate Hydrogen Peroxide Levels during dark-induced Stomatal Closure in Guard Cells of Vicia faba

黑暗引起的蠶豆氣孔關閉與MEK和CDPK調節保衛細胞中的過氧化氫的水準有關

宋喜貴(Xi-Gui Song) ； 佘小平(Xiao-Ping She) ； 郭林英(Lin-Ying Guo) ； 孟昭妮(Zhao-Ni Meng) ； 黃愛霞(Ai-Xia Huang)

《Botanical Studies》 49卷4期 (2008/10) Pp. 323-334

摘要

本實驗應用促細胞分裂原蛋白激酶激酶(MEK)的抑制劑2'-氨基－3'-甲氧基黃酮(PD98059)和鈣依賴的蛋白激酶(CDPK)的特效抑制劑三氟啦嗪(TFP)探究了MEK和CDPK在黑暗引起的蠶豆氣孔關閉中的作用和二者對該過程中保衛細胞中過氧化氫(H2O2)水準的影響。我們的結果證實PD98059和TFP在黑暗條件下都能降低保衛細胞H2O2水準並能促進氣孔開放，暗示了MEK和CDPK介導的黑暗引起的氣孔關閉是通過影響保衛細胞中H2O2的水準來實現的。另外，和H2O2的產生有關的NADPH氧化酶的抑制劑二苯基碘(DPI)的作用效果不同，而和H2O2的清除劑抗壞血酸(ASA)的作用效果類似，PD98059和TFP不僅能夠降低光下保衛細胞的外加的H2O2水準，而且還能清除由黑暗條件誘導的已經產生的H2O2，並能引起氣孔開放。這些結果暗示MEK和CDPK介導的黑暗引起的氣孔關閉可能通過遏制保衛細胞的與H2O2的清除體系相關的酶來實現的，當然也不排除MEK/CDPK在保衛細胞信號傳導鏈中作為H2O2的下游信號影響氣孔運動的可能性。

關鍵字

黑暗 ； 過氧化氫 ； MEK ； CDPK ； 氣孔關閉 ； 蠶豆

並列摘要

We used 2'-amino-3'-methoxyflavone (PD98059) (an inhibitor of mitogen-activated protein kinase kinase, MEK) and Trifluoperazine (TFP) (a specific inhibitor of calcium-dependent protein kinase, CDPK) to investigate the role of MEK/CDPK and its effects on H2O2 levels of guard cells in the dark-induced stomatal closure in Vicia faba. We provide evidence that both PD98059 and TFP reduced H2O2 levels in guard cells and promoted stomatal opening significantly in the dark, implying that MEK/CDPK mediated darkinduced stomatal closure by influencing H2O2 levels of guard cells. In addition, like ascorbic acid (ASA), an important reducing substrate for H2O2 removal, but unlike diphenylene iodonium (DPI), an inhibitor of the H2O2-generating enzyme NADPH oxidase, PD98059 and TFP not only reduced exogenous H2O2 levels in guard cells in light, but also eliminated the H2O2 that had been generated during a dark period and promoted stomatal opening. The results suggest MEK and CDPK are probably involved in restraining the H2O2 scavenging enzyme and elevating H2O2 levels in guard cells during dark-induced stomatal closure. Of course, the probability of MEK and CDPK acting as the target downstream of H2O2 in the signaling transduction chain is not excluded.

並列關鍵字

Dark ； Hydrogen peroxide ； MAPK kinase and CDP kinase ； Stomatal closure ； Vicia faba