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Stomatal responses to vapour pressure deficit are regulated by high speed gene expression in angiosperms
journal contribution
posted on 2023-05-18, 12:54 authored by McAdam, SAM, Frances SussmilchFrances Sussmilch, Timothy BrodribbTimothy BrodribbPlants dynamically regulate water use by the movement of stomata on the surface of leaves. Stomatal responses to changes in vapour pressure deficit (VPD) are the principal regulator of daytime transpiration and water use efficiency in land plants. In angiosperms, stomatal responses to VPD appear to be regulated by the phytohormone abscisic acid (ABA), yet the origin of this ABA is controversial. After a 20 minute exposure of plants, from three diverse angiosperm species, to a doubling in VPD, stomata closed, foliar ABA levels increased and the expression of the gene encoding the key, rate-limiting carotenoid cleavage enzyme (9-cis-epoxycarotenoid dioxygenase, NCED) in the ABA biosynthetic pathway was significantly upregulated. The NCED gene was the only gene in the ABA biosynthetic pathway to be upregulated over the short time scale corresponding to the response of stomata. The closure of stomata and rapid increase in foliar ABA levels could not be explained by the release of ABA from internal stores in the leaf or the hydrolysis of the conjugate ABA-glucose ester. These results implicate an extremely rapid de novo biosynthesis of ABA, mediated by a single gene, as the means by which angiosperm stomata respond to natural changes in VPD.
Funding
Australian Research Council
History
Publication title
Plant, Cell and EnvironmentVolume
39Pagination
485-491ISSN
0140-7791Department/School
School of Natural SciencesPublisher
Blackwell Publishing LtdPlace of publication
9600 Garsington Rd, Oxford, England, Oxon, Ox4 2DgRights statement
Copyright 2015 John Wiley & Sons LtdRepository Status
- Restricted