Iuchi S, Kobayashi M, Taji T, Naramoto M, Seki M, Kato T, Tabata S, Kakubari Y, Yamaguchi-Shinozaki K, Shinozaki K
Laboratory of Plant Molecular Biology, RIKEN Tsukuba Institute, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan.
Plant J. 2001 Aug;27(4):325-33. doi: 10.1046/j.1365-313x.2001.01096.x.
Abscisic acid (ABA), a plant hormone, is involved in responses to environmental stresses such as drought and high salinity, and is required for stress tolerance. ABA is synthesized de novo in response to dehydration. 9-cis-epoxycarotenoid dioxygenase (NCED) is thought to be a key enzyme in ABA biosynthesis. Here we demonstrate that the expression of an NCED gene of Arabidopsis, AtNCED3, is induced by drought stress and controls the level of endogenous ABA under drought-stressed conditions. Overexpression of AtNCED3 in transgenic Arabidopsis caused an increase in endogenous ABA level, and promoted transcription of drought- and ABA-inducible genes. Plants overexpressing AtNCED3 showed a reduction in transpiration rate from leaves and an improvement in drought tolerance. By contrast, antisense suppression and disruption of AtNCED3 gave a drought-sensitive phenotype. These results indicate that the expression of AtNCED3 plays a key role in ABA biosynthesis under drought-stressed conditions in Arabidopsis. We improved drought tolerance by gene manipulation of AtNCED3 causing the accumulation of endogenous ABA.
脱落酸（ABA）是一种植物激素，参与植物对干旱和高盐等环境胁迫的响应，是植物耐受胁迫所必需的。ABA在脱水条件下从头合成。9-顺式环氧类胡萝卜素双加氧酶（NCED）被认为是ABA生物合成中的关键酶。在此，我们证明拟南芥NCED基因AtNCED3的表达受干旱胁迫诱导，并在干旱胁迫条件下控制内源ABA水平。在转基因拟南芥中过表达AtNCED3导致内源ABA水平升高，并促进干旱和ABA诱导基因的转录。过表达AtNCED3的植株叶片蒸腾速率降低，耐旱性提高。相反，反义抑制和破坏AtNCED3则产生干旱敏感表型。这些结果表明，AtNCED3的表达在拟南芥干旱胁迫条件下的ABA生物合成中起关键作用。我们通过对AtNCED3进行基因操作使内源ABA积累，从而提高了耐旱性。
