MAP kinase specifically mediates the ABA-induced H_2O_2 generation in guard cells of Vicia faba L.  

作　　者：JIANG Jing1,2, AN Guoyong1, WANG Pengcheng1, WANG Pengtao1, HAN Jinfeng2, JIA Yanbin1 & SONG Chunpeng1 1. College of Life Sciences, Henan University, Kaifeng 475001, China 2. College of Agriculture Science, Henan Agriculture University, Zheng-zhou 450001, China Correspondence should be addressed to Song Chunpeng (e-mail: songcp @henu. edu.cn) 

出　　处：《Chinese Science Bulletin》2003年第18期1919-1926,共8页

摘　　要：Mitogen-activated protein (MAP) kinase is involved in ABA- or H2O2-signaling, and H2O2 acts as inter-mediate in the downstream of ABA signal transduction pathway, which has recently emerged as a secondary mes-senger of ABA signaling. Using an epidermal strip bioassay and laser scanning confocal microscope, we provided the first evidence that MAP kinase plays an important role in H2O2 signal initial, amplification and specific targeting in response to stimuli in guard cells. ABA- or H2O2-induced Vicia faba stomatal closure was inhibited or reversed by the specific inhibitor PD98059 of MEK1/2; the guard cells were pre-incubated or -microinjected by 10 mmol·L-1 PD98059, ABA could not enhance the fluorescence intensity of H2O2 probe dichlorofluorescein (DCF). Meanwhile, after ABA induced the H2O2 accumulation in guard cells, the exogenous or intracellular PD98059 could reduce the DCF fluorescence intensity. Most interestingly, on the contrary to ABA, the DCF fluorescence intensity of guard cells treated by 100 mmol·L-1 salicylic acid (SA) was not down-regulated by PD98059, yet PD98059 did not regulate the stomatal move-ment being induced by light, dark or salicylic acid. These results suggest that MEK1/2 could mediate stomatal closure by abolishing the ABA-induced H2O2 generation/accumula- tion in the specific manner.Mitogen-activated protein (MAP) kinase is involved in ABA- or H2O2-signaling, and H2O2 acts as inter-mediate in the downstream of ABA signal transduction pathway, which has recently emerged as a secondary mes-senger of ABA signaling. Using an epidermal strip bioassay and laser scanning confocal microscope, we provided the first evidence that MAP kinase plays an important role in H2O2 signal initial, amplification and specific targeting in response to stimuli in guard cells. ABA- or H2O2-induced Vicia faba stomatal closure was inhibited or reversed by the specific inhibitor PD98059 of MEK1/2; the guard cells were pre-incubated or -microinjected by 10 mmol·L-1 PD98059, ABA could not enhance the fluorescence intensity of H2O2 probe dichlorofluorescein (DCF). Meanwhile, after ABA induced the H2O2 accumulation in guard cells, the exogenous or intracellular PD98059 could reduce the DCF fluorescence intensity. Most interestingly, on the contrary to ABA, the DCF fluorescence intensity of guard cells treated by 100 mmol·L-1 salicylic acid (SA) was not down-regulated by PD98059, yet PD98059 did not regulate the stomatal move-ment being induced by light, dark or salicylic acid. These results suggest that MEK1/2 could mediate stomatal closure by abolishing the ABA-induced H2O2 generation/accumula- tion in the specific manner.

关 键 词：MAP KINASE PD98059 ABA H2O2 GUARD cells. 

分 类 号：Q26[生物学—细胞生物学]