ABC transporter AtABCG25 is involved in abscisic acid transport and responses
ABC transporter AtABCG25 is involved in abscisic acid transport and responses
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DOI：
10.1073/pnas.0912516107
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发表时间：
2010-02-02
影响因子：
11.1
通讯作者：
Shinozaki, Kazuo
中科院分区：
文献类型：
--
作者：
Kuromori, Takashi;Miyaji, Takaaki;Shinozaki, Kazuo
脱落酸（阿坝）是一种重要的植物激素，与种子的成熟、萌发和衰老有关。阿坝主要在血管组织中产生，并在包括保卫细胞在内的各种细胞中发挥激素反应。虽然阿坝反应需要ABA分泌细胞在细胞间阿坝信号通路中分泌阿坝，但阿坝通过质膜的运输机制仍不清楚。本研究通过阿坝敏感性基因筛选，从拟南芥中分离到一个ATP结合盒（ABC）转运蛋白基因AtABCG 25。AtABCG25主要在血管组织中表达。AtABCG25荧光蛋白融合蛋白定位于植物细胞质膜。在AtABCG25表达昆虫细胞的膜囊泡中，AtABCG25表现出ATP依赖的阿坝转运。AtABCG25过表达的植物表现出较高的叶温，这意味着气孔调节的影响。这些结果强烈表明AtABCG 25是阿坝的输出者，并参与细胞间阿坝信号通路。阿坝运输机制的存在揭示了植物细胞对环境胁迫的多细胞阿坝响应的主动控制。
Abscisic acid (ABA) is one of the most important phytohormones involved in abiotic stress responses, seed maturation, germination, and senescence. ABA is predominantly produced in vascular tissues and exerts hormonal responses in various cells, including guard cells. Although ABA responses require extrusion of ABA from ABA-producing cells in an intercellular ABA signaling pathway, the transport mechanisms of ABA through the plasma membrane remain unknown. Here we isolated an ATP-binding cassette (ABC) transporter gene, AtABCG25, from Arabidopsis by genetically screening for ABA sensitivity. AtABCG25 was expressed mainly in vascular tissues. The fluorescent protein-fused AtABCG25 was localized at the plasma membrane in plant cells. In membrane vesicles derived from AtABCG25-expressing insect cells, AtABCG25 exhibited ATP-dependent ABA transport. The AtABCG25-overexpressing plants showed higher leaf temperatures, implying an influence on stomatal regulation. These results strongly suggest that AtABCG25 is an exporter of ABA and is involved in the intercellular ABA signaling pathway. The presence of the ABA transport mechanism sheds light on the active control of multicellular ABA responses to environmental stresses among plant cells.