@article { , title = {Elevated CO2-Induced Responses in Stomata Require ABA and ABA Signaling}, 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.}, doi = {10.1016/j.cub.2015.09.013}, issn = {0960-9822}, issue = {20}, journal = {Current Biology}, pages = {2709-2716}, publicationstatus = {Published}, publisher = {Elsevier (Cell Press)}, url = {https://uwe-repository.worktribe.com/output/804515}, volume = {25}, keyword = {Centre for Research in Biosciences, guard cells, stomata, ABA receptors, [CO2] signaling, ABA signaling, NADPH oxidases, Rboh genes, signaling convergence, ROS, stomatal closure, stomatal density}, year = {2015}, author = {Chater, Caspar and Peng, Kai and Movahedi, Mahsa and Dunn, Jessica A. and Walker, Heather J. and Liang, Yun-Kuan and McLachlan, Deirdre H. and Casson, Stuart and Isner, Jean Charles and Wilson, Ian and Neill, Steven J. and Hedrich, Rainer and Gray, Julie E. and Hetherington, Alistair M.} }