Universität zu Köln

Mekonnen, Dereje Worku ORCID: 0000-0003-3167-7412, Fluegge, Ulf-Ingo and Ludewig, Frank (2016). Gamma-aminobutyric acid depletion affects stomata closure and drought tolerance of Arabidopsis thaliana. Plant Sci., 245. S. 25 - 35. CLARE: ELSEVIER IRELAND LTD. ISSN 0168-9452

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Abstract

A rapid accumulation of gamma-aminobutyric acid (GABA) during biotic and abiotic stresses is well documented. However, the specificity of the response and the primary role of GABA under such stress conditions are hardly understood. To address these questions, we investigated the response of the GABA-depleted gad1/2 mutant to drought stress. GABA is primarily synthesized from the decarboxylation of glutamate by glutamate decarboxylase (GAD) which exists in five copies in the genome of Arabidopsis thaliana. However, only GAD1 and GAD2 are abundantly expressed, and knockout of these two copies dramatically reduced the GABA content. Phenotypic analysis revealed a reduced shoot growth of the gad1/2 mutant. Furthermore, the gad1/2 mutant was wilted earlier than the wild type following a prolonged drought stress treatment. The early-wilting phenotype was due to an increase in stomata aperture and a defect in stomata closure. The increase in stomata aperture contributed to higher stomatal conductance. The drought oversensitive phenotype of the gad1/2 mutant was reversed by functional complementation that increases GABA level in leaves. The functionally complemented gad1/2 x pop2, triple mutant contained more GABA than the wild type. Our findings suggest that GABA accumulation during drought is a stress-specific response and its accumulation induces the regulation of stomatal opening thereby prevents loss of water. (C) 2016 Elsevier Ireland Ltd. All rights reserved.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Mekonnen, Dereje Worku UNSPECIFIED orcid.org/0000-0003-3167-7412 UNSPECIFIED Fluegge, Ulf-Ingo UNSPECIFIED UNSPECIFIED UNSPECIFIED Ludewig, Frank UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-280236
DOI:	10.1016/j.plantsci.2016.01.005
Journal or Publication Title:	Plant Sci.
Volume:	245
Page Range:	S. 25 - 35
Date:	2016
Publisher:	ELSEVIER IRELAND LTD
Place of Publication:	CLARE
ISSN:	0168-9452
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SUCCINIC-SEMIALDEHYDE-DEHYDROGENASE; GLUTAMATE-DECARBOXYLASE; GABA TRANSAMINASE; METABOLISM; PLANT; ACCUMULATION; SHUNT; CHANNEL; EXPRESSION; COMPARTMENTATION Multiple languages Biochemistry & Molecular Biology; Plant Sciences Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/28023