Premium
Arabidopsis mutants of AtABCG22 , an ABC transporter gene, increase water transpiration and drought susceptibility
Author(s) -
Kuromori Takashi,
Sugimoto Eriko,
Shinozaki Kazuo
Publication year - 2011
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2011.04641.x
Subject(s) - guard cell , abscisic acid , mutant , arabidopsis , transpiration , biology , gene , arabidopsis thaliana , microbiology and biotechnology , phenotype , genetics , botany , photosynthesis
Summary In plants, water vapour is released into the atmosphere through stomata in a process called transpiration. Abscisic acid (ABA) is a key phytohormone that facilitates stomatal closure through its action on guard cells. Recently, ATP‐binding cassette (ABC) transporter genes, AtABCG25 and AtABCG40 , were shown to be involved in ABA transport and responses. However, the functions of many other AtABCG family genes are still unknown. Here, we identified another ABCG gene ( AtABCG22 ) that is required for stomatal regulation in Arabidopsis. The atabcg22 mutant plants had lower leaf temperatures and increased water loss, implying elevated transpiration through an influence on stomatal regulation. We also found that atabcg22 plants were more suspectible to drought stress than wild‐type plants. AtABCG22 was expressed in aerial organs, mainly guard cells, in which the gene expression pattern was consistent with the mutant phenotypes. Using double mutants, we investigated the genetic relationships between the mutations. The atabcg22 mutation further increased the water loss of srk2e / ost1 mutants, which were defective in ABA signalling in guard cells. Also, the atabcg22 mutation enhanced the phenotype of nced3 mutants, which were defective in ABA biosynthesis. Accordingly, the additive roles of AtABCG22 functions in ABA signalling and ABA biosynthesis are discussed.