Elevated CO2-Induced Responses in Stomata Require ABA and ABA Signaling

Chater, Caspar; Peng, Kai; Movahedi, Mahsa; Dunn, Jessica A.; Walker, Heather J.; Liang, Yun-Kuan; McLachlan, Deirdre H.; Casson, Stuart; Isner, Jean Charles; Wilson, Ian; Neill, Steven J.; Hedrich, Rainer; Gray, Julie E.; Hetherington, Alistair M.

Abstract

© 2015 The Authors. An integral part of global environment change is an increase in the atmospheric concentration of CO2 ([CO2]) [1]. Increased [CO2] reduces leaf stomatal apertures and density of stomata that plays out as reductions in evapotranspiration [2-4]. Surprisingly, given the importance of transpiration to the control of terrestrial water fluxes [5] and plant nutrient acquisition [6], we know comparatively little about the molecular components involved in the intracellular signaling pathways by which [CO2] controls stomatal development and function [7]. Here, we report that elevated [CO2]-induced closure and reductions in stomatal density require the generation of reactive oxygen species (ROS), thereby adding a new common element to these signaling pathways. We also show that the PYR/RCAR family of ABA receptors [8, 9] and ABA itself are required in both responses. Using genetic approaches, we show that ABA in guard cells or their precursors is sufficient to mediate the [CO2]-induced stomatal density response. Taken together, our results suggest that stomatal responses to increased [CO2] operate through the intermediacy of ABA. In the case of [CO2]-induced reductions in stomatal aperture, this occurs by accessing the guard cell ABA signaling pathway. In both [CO2]-mediated responses, our data are consistent with a mechanism in which ABA increases the sensitivity of the system to [CO2] but could also be explained by requirement for a CO2-induced increase in ABA biosynthesis specifically in the guard cell lineage. Furthermore, the dependency of stomatal [CO2] signaling on ABA suggests that the ABA pathway is, in evolutionary terms, likely to be ancestral.

• Journal Article Type: Article
• Acceptance Date: Sep 2, 2015
• Online Publication Date: Oct 8, 2015
• Publication Date: Oct 19, 2015
• Deposit Date: Dec 2, 2015
• Publicly Available Date: Feb 25, 2016
• Journal: Current Biology
• Print ISSN: 0960-9822
• Publisher: Elsevier (Cell Press)
• Peer Reviewed: Peer Reviewed
• Volume: 25
• Issue: 20
• Pages: 2709-2716
• DOI: https://doi.org/10.1016/j.cub.2015.09.013
• Keywords: guard cells; stomata; ABA receptors; [CO2] signaling; ABA signaling; NADPH oxidases; Rboh genes; signaling convergence; ROS; stomatal closure; stomatal density
• Public URL: https://uwe-repository.worktribe.com/output/804515
• Publisher URL: http://dx.doi.org/10.1016/j.cub.2015.09.013
• Contract Date: Feb 25, 2016