Abscisic Acid Represses Growth of the Arabidopsis Embryonic Axis after Germination by Enhancing Auxin Signaling
Abscisic Acid Represses Growth of the Arabidopsis Embryonic Axis after Germination by Enhancing Auxin Signaling
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DOI：
10.1105/tpc.109.067702
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发表时间：
2009-08-01
期刊：
影响因子：
11.6
通讯作者：
Lopez-Molina, Luis
中科院分区：
文献类型：
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作者：
Belin, Christophe;Megies, Christian;Lopez-Molina, Luis
在不利的环境条件下，胁迫植物激素ABA抑制了干种子胚向幼苗的发育转变。我们开发了一种基因筛选，分离出早期幼苗发育对ABA具有抗性的拟南芥突变体。在这里，我们报道了生长素抗性1 （AUX1）的隐性突变，编码细胞生长素内流载体。虽然生长素是植物的一种主要形态发生激素，但人们对aba -生长素在幼苗早期生长过程中的相互作用知之甚少。我们发现aux1和pin2突变体对aba依赖性的胚胎轴（下胚轴和胚根）伸长抑制不敏感。遗传和生理实验表明，这涉及到生长素运输到胚胎轴伸长区，在那里ABA增强了生长素响应启动子的活性。我们认为ABA通过增强胚胎轴伸长区生长素信号来抑制胚胎轴伸长。这涉及生长素诱导（Aux/IAA）基因AXR2/IAA7的抑制，该基因编码萌发后生长过程中ABA和生长素依赖反应的关键组成部分。
Under unfavorable environmental conditions, the stress phytohormone ABA inhibits the developmental transition from an embryo in a dry seed into a young seedling. We developed a genetic screen to isolate Arabidopsis thaliana mutants whose early seedling development is resistant to ABA. Here, we report the identification of a recessive mutation in AUXIN RESISTANT1 (AUX1), encoding a cellular auxin influx carrier. Although auxin is a major morphogenesis hormone in plants, little is known about ABA-auxin interactions during early seedling growth. We show that aux1 and pin2 mutants are insensitive to ABA-dependent repression of embryonic axis (hypocotyl and radicle) elongation. Genetic and physiological experiments show that this involves auxin transport to the embryonic axis elongation zone, where ABA enhances the activity of an auxin-responsive promoter. We propose that ABA represses embryonic axis elongation by potentiating auxin signaling in its elongation zone. This involves repression of the AUXIN INDUCIBLE (Aux/IAA) gene AXR2/IAA7, encoding a key component of ABA- and auxin-dependent responses during postgerminative growth.