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Mol Plant. 2014 Oct;7(10):1522-32. doi: 10.1093/mp/ssu063. Epub 2014 May 22.

A DTX/MATE-type transporter facilitates abscisic acid efflux and modulates ABA sensitivity and drought tolerance in Arabidopsis.

Author information

1
a College of Life Sciences, Capital Normal University, Beijing, 100048, China.
2
b Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA c Institute of Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing, 210093, China sluan@berkeley.edu lgli@mail.cnu.edu.cn.
3
a College of Life Sciences, Capital Normal University, Beijing, 100048, China sluan@berkeley.edu lgli@mail.cnu.edu.cn.

Abstract

Abscisic acid (ABA) regulates numerous physiological and developmental processes in plants. Recent studies identify intracellular ABA receptors, implicating the transport of ABA across cell membranes as crucial for ABA sensing and response. Here, we report that a DTX/Multidrug and Toxic Compound Extrusion (MATE) family member in Arabidopsis thaliana, AtDTX50, functions as an ABA efflux transporter. When expressed heterologously in both an Escherichia coli strain and Xenopus oocyte cells, AtDTX50 was found to facilitate ABA efflux. Furthermore, dtx50 mutant mesophyll cells preloaded with ABA released less ABA compared with the wild-type (WT). The AtDTX50 gene was expressed mainly in the vascular tissues and guard cells and its expression was strongly up-regulated by exogenous ABA. The AtDTX50::GFP fusion protein was localized predominantly to the plasma membrane. The dtx50 mutant plants were observed to be more sensitive to ABA in growth inhibition. In addition, compared with the WT, dtx50 mutant plants were more tolerant to drought with lower stomatal conductance, consistent with its function as an ABA efflux carrier in guard cells.

KEYWORDS:

Arabidopsis; hormone biology; molecular transport

PMID:
24851876
DOI:
10.1093/mp/ssu063
[Indexed for MEDLINE]
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