Calcium channels activated by hydrogen peroxide mediate abscisic acid signalling in guard cells
Calcium channels activated by hydrogen peroxide mediate abscisic acid signalling in guard cells
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DOI：
10.1038/35021067
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发表时间：
2000-08-17
期刊：
影响因子：
64.8
通讯作者：
Schroeder, JI
中科院分区：
文献类型：
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作者：
Pei, ZM;Murata, Y;Schroeder, JI
干旱是农业生产的主要威胁。植物在干旱时合成激素脱落酸(ABA)，触发保卫细胞中的信号级联，导致气孔关闭，从而减少水分损失[1]。ABA可引起保卫细胞胞浆内钙离子浓度的增加(2-6)，包括钙离子跨膜内流(3，5，7-9)。然而，对钙电流的直接记录一直是有限的(3)，质膜钙通道的上游激活机制尚不清楚。在这里，我们报道了过氧化氢激活拟南芥保卫细胞质膜上的钙离子通透通道。H_2O_2激活的Ca~(2+)通道既介导了原生质体中Ca~(2+)的内流，又介导了完整保卫细胞内[Ca~(2+)](Cyt)的升高。ABA诱导保卫细胞产生过氧化氢。如果H_2O_2的产生被阻断，ABA诱导的气孔关闭就会被抑制。此外，在隐性ABA不敏感突变体gca2中，H_2O_2以及ABA-和H_2O_2诱导的气孔关闭导致的Ca~(2+)通道的激活被破坏。这些数据表明，ABA诱导的H_2O_2产生和H_2O_2激活的钙通道是ABA诱导气孔关闭的重要机制。
Drought is a major threat to agricultural production. Plants synthesize the hormone abscisic acid (ABA) in response to drought, triggering a signalling cascade in guard cells that results in stomatal closure, thus reducing water loss(1). ABA triggers an increase in cytosolic calcium in guard cells ([Ca2+](cyt))(2-6) that has been proposed to include Ca2+ influx across the plasma membrane(3,5,7-9). However, direct recordings of Ca2+ currents have been limited(3) and the upstream activation mechanisms of plasma membrane Ca2+ channels remain unknown. Here we report activation of Ca2+-permeable channels in the plasma membrane of Arabidopsis guard cells by hydrogen peroxide. The H2O2-activated Ca2+ channels mediate both influx of Ca2+ in protoplasts and increases in [Ca2+](cyt) in intact guard cells. ABA induces the production of H2O2 in guard cells. If H2O2 production is blocked, ABA-induced closure of stomata is inhibited. Moreover, activation of Ca2+ channels by H2O2 and ABA- and H2O2-induced stomatal closing are disrupted in the recessive ABA-insensitive mutant gca2. These data indicate that ABA-induced H2O2 production and the H2O2-activated Ca2+ channels are important mechanisms for ABA-induced stomatal closing.