The role of Arabidopsis ABA receptors from the PYR/PYL/RCAR family in stomatal acclimation and closure signal integration

First author: Marcus Dittrich; Affiliations: University of Würzburg (维尔茨堡大学): Würzburg, Germany

Corresponding author: Alistair M. Hetherington

Stomata are microscopic pores found on the surfaces of leaves that act to control CO2 uptake and water loss. By integrating information derived from endogenous signals with cues from the surrounding environment, the guard cells, which surround the pore, ‘set’ the stomatal aperture to suit the prevailing conditions. Much research has concentrated on understanding the rapid intracellular changes that result in immediate changes to the stomatal aperture. In this study, we look instead at how stomata acclimate to longer timescale variations in their environment. We show that the closure-inducing signals abscisic acid (ABA), increased CO2, decreased relative air humidity and darkness each access a unique gene network made up of clusters (or modules) of common cellular processes. However, within these networks some gene clusters are shared amongst all four stimuli. All stimuli modulate the expression of members of the PYR/PYL/RCAR family of ABA receptors. However, they are modulated differentially in a stimulus-specific manner. Of the six members of the PYR/PYL/RCAR family expressed in guard cells, PYL2 is sufficient for guard cell ABA-induced responses, whereas in the responses to CO2, PYL4 and PYL5 are essential. Overall, our work shows the importance of ABA as a central regulator and integrator of long-term changes in stomatal behaviour, including sensitivity, elicited by external signals. Understanding this architecture may aid in breeding crops with improved water and nutrient efficiency.

植物的气孔是存在于叶片表面上的微孔结构，其功能主要在于控制CO2的吸收和水分的散失。通过整合外界的环境信号和自身内源性信号，气孔两边的保卫细胞控制气孔的开度以适应一般的情况。很多研究重点关注了导致气孔开度即刻变化的细胞内改变。本文中，作者探究了在当前所处的环境下，植物的气孔在长时间变异尺度上的适应。作者发现气孔关闭诱导信号脱落酸ABA、CO2升高，相对空气湿度降低以及黑暗均能够诱导各自特意的基因网络。然而，在这些网络中，某些基因集在四个条件刺激下均能够响应。所有的刺激均能够调节ABA受体PYR/PYL/RCAR家族成员的表达。然而，在不同的条件刺激下，这些基因的调控方式有所差异。PYR/PYL/RCAR家族中有6个基因在保卫细胞中表达，其中PYL2对于保卫细胞由ABA诱导的响应是必须的，而PYL4和PYL5对于保卫细胞响应于CO2是必须的。综上，本文的研究揭示了脱落酸ABA作为气孔行为的长期改变的核心调控因子发挥作用，这种气孔行为包括由外部信号诱导的气孔敏感性。对于植物气孔开度机制的进一步理解可能有助于作物提升水分和营养利用效率的改良育种。

通讯：Alistair M. Hetherington（http://www.bristol.ac.uk/biology/people/alistair-m-hetherington/index.html)

个人简介：1979年，圣安德鲁斯大学，学士；1982年，圣安德鲁斯大学，博士。

研究方向：CO2，ABA和大气相对湿度的变化对于植物节气孔开度和发育的调控。

doi: https://doi.org/10.1038/s41477-019-0490-0

Journal: Nature Plants

Published date: August 26, 2019