Open Stomata 1 (OST1) is limiting in abscisic acid responses of Arabidopsis guard cells
Open Stomata 1 (OST1) is limiting in abscisic acid responses of Arabidopsis guard cells
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DOI：
10.1111/nph.12469
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发表时间：
2013-12-01
期刊：
影响因子：
9.4
通讯作者：
Assmann, Sarah M.
中科院分区：
文献类型：
--
作者：
Acharya, Biswa R.;Jeon, Byeong Wook;Assmann, Sarah M.
开放气孔1 （Open Stomata 1, SnRK2.6或SRK2E）是一种丝氨酸/苏氨酸蛋白激酶，在脱落酸（ABA）介导的气孔反应中是一个正调节因子，但OST1对K+和Ca2+电流的调节尚未在保护细胞中直接研究，也不清楚OST1的活性是否限制了ABA介导的气孔反应。我们采用功能丧失和功能获得的方法研究了拟南芥保护细胞对天然ABA的反应。我们进行了气孔孔径生物测定、膜片钳分析和活性氧（ROS）测量。在ost1突变体中，ABA对内向K+通道和光诱导的气孔打开的抑制作用减弱，而过表达ost1的转基因植株在这些反应中表现出ABA超敏。ost1突变体对ABA诱导的气孔关闭、缓慢阴离子电流的调节、Ca2+可渗透通道的激活和ROS的产生不敏感，而ost1过表达系对这些反应敏感，导致对ABA的气孔关闭加速。在没有外源ABA的情况下，植物中OST1的过表达不影响基孔或离子电流。此外，我们还证明了OST1与内向K+通道KAT1、阴离子通道sla1以及NADPH氧化酶AtrbohD和AtrbohF的物理相互作用。我们的研究结果支持OST1是ABA调控拟南芥保护细胞气孔开度、离子通道和NADPH氧化酶的关键限制性成分。
Open Stomata 1 (OST1) (SnRK2.6 or SRK2E), a serine/threonine protein kinase, is a positive regulator in abscisic acid (ABA)-mediated stomatal response, but OST1-regulation of K+ and Ca2+ currents has not been studied directly in guard cells and it is unknown whether OST1 activity is limiting in ABA-mediated stomatal responses.We employed loss-of-function and gain-of-function approaches to study native ABA responses of Arabidopsis guard cells. We performed stomatal aperture bioassays, patch clamp analyses and reactive oxygen species (ROS) measurements.ABA inhibition of inward K+ channels and light-induced stomatal opening are reduced in ost1 mutants while transgenic plants overexpressing OST1 show ABA hypersensitivity in these responses. ost1 mutants are insensitive to ABA-induced stomatal closure, regulation of slow anion currents, Ca2+-permeable channel activation and ROS production while OST1 overexpressing lines are hypersensitive for these responses, resulting in accelerated stomatal closure in response to ABA. Overexpression of OST1 in planta in the absence of ABA application does not affect basal apertures or ion currents. Moreover, we demonstrate the physical interaction of OST1 with the inward K+ channel KAT1, the anion channel SLAC1, and the NADPH oxidases AtrbohD and AtrbohF.Our findings support OST1 as a critical limiting component in ABA regulation of stomatal apertures, ion channels and NADPH oxidases in Arabidopsis guard cells.