SB202190调节蚕豆保卫细胞中SA诱导H2O2产生

运用激光共聚焦扫描技术，在p38MAP激酶专一抑制剂SB202190处理下，探索植物促分裂原活化蛋白激酶（mitogen-activated protein kinase，MAP激酶）介导蚕豆（Vicia faba）保卫细胞中H2O2为代表的活性氧（reactive oxygen species，ROS）信号机制，发现：p38MAP激酶专一抑制剂SB202190处理没有导致蚕豆保卫细胞中H2O2和Ca^2＋探针荧光强度增强，与水杨酸（salicylic acid，SA）或脱落酸（abscisic acid，ABA）迅速加强2种探针荧光强度形成鲜明对比；而该抑制剂分别与SA和ABA共同处理，前者H2O2探针荧光强度没有增加，而后者荧光强度仍然能够增加；而进一步使用Ca^2＋螯合剂BAPTA和SB202190＋SA共同处理，H2O2探针荧光强度没有增加。这些结果初步表明：无论胞质Ca^2＋浓度高低，SB202190调节蚕豆保卫细胞中SA诱导H2O2产生，但是不调节植物逆境信使分子ABA此类的反应。因此推测，植物细胞中可能有类似动物和酵母细胞中的p38MAP激酶类，并可能专一调节植物保卫细胞中H2O2信号通路。据我们所知，这是首次报道SB202190和SA共同调节植物保卫细胞中ROS信号过程。

SB202190 Modulate Salicylic Acid-induced H2O2 Generation in Vicia Guard Cells

Using laser scanning confocal microscopy, we tested the mechanism of mitogen-activated protein kinase (MAPK) regulation of salicylic acid (SA)-or abscisic acid (ABA)-induced reactive oxygen species H2O2 elevation in Vicia guard cells. SB202190, a special inhibitor of p38 MAPK, blocked the elevation of H2O2 by SA but not ABA, whereas SB202190 alone could not increase H2O2 or Ca2+ level in guard cells. The combination of BAPTA, the chelator of Ca2+, and SA+SB202190 could not increase H2O2 level, which suggests that activation of p38 MAPK-like especially modulates H2O2 signaling in plant cells, regardless of Ca2+ level, similar to the mechanism in mammalian or yeast cells. To our knowledge, this is the first report that SB202190 regulates SA-induced ROS signaling in plant cells.