The Stomatal Response to Reduced Relative Humidity Requires Guard Cell-Autonomous ABA Synthesis
The Stomatal Response to Reduced Relative Humidity Requires Guard Cell-Autonomous ABA Synthesis
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DOI：
10.1016/j.cub.2012.11.022
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发表时间：
2013-01-07
期刊：
影响因子：
9.2
通讯作者：
Hedrich, Rainer
中科院分区：
文献类型：
--
作者：
Bauer, Hubert;Ache, Peter;Hedrich, Rainer
气孔是叶片表面的孔，由两个保卫细胞包围，控制光合作用的CO2吸收和伴随的水蒸气损失。在1898年，弗朗西斯达尔文[1]表明，气孔关闭响应降低大气相对湿度（rh），然而，我们的理解的信号通路负责耦合变化的rh气孔开度的变化是零碎的。这里提出的结果突出了脱落酸（阿坝）在气孔响应干燥空气的首要地位。我们表明，保卫细胞拥有整个阿坝生物合成途径，它出现上调阿坝的正反馈。当野生型拟南芥和ABA缺陷突变体aba 3 -1暴露于rh减少，aba 3 -1突变体枯萎，而野生型没有。然而，当aba 3 -1植物，其中阿坝合成已被专门拯救保卫细胞，受到挑战与干燥的空气，他们没有枯萎。这些数据表明，保卫细胞自主阿坝的合成是必需的，是足够的气孔关闭响应低RH。保卫细胞自主阿坝合成允许植物精细地定制叶片气体交换以适应当时的环境条件。
Stomata are pores on the leaf surface, bounded by two guard cells, which control the uptake of CO2 for photosynthesis and the concomitant loss of water vapor. In 1898, Francis Darwin [1] showed that stomata close in response to reduced atmospheric relative humidity (rh); however, our understanding of the signaling pathway responsible for coupling changes in rh to alterations in stomatal aperture is fragmentary. The results presented here highlight the primacy of abscisic acid (ABA) in the stomatal response to drying air. We show that guard cells possess the entire ABA biosynthesis pathway and that it appears upregulated by positive feedback by ABA. When wild-type Arabidopsis and the ABA-deficient mutant aba3-1 were exposed to reductions in rh, the aba3-1 mutant wilted, whereas the wild-type did not. However, when aba3-1 plants, in which ABA synthesis had been specifically rescued in guard cells, were challenged with dry air, they did not wilt. These data indicate that guard cell-autonomous ABA synthesis is required for and is sufficient for stomatal closure in response to low rh. Guard cell-autonomous ABA synthesis allows the plant to tailor leaf gas exchange exquisitely to suit the prevailing environmental conditions.