发芽
植物激素
突变体
赤霉素
转录因子
胚胎
调节器
作者
Christophe Belin,Christian Megies,Eva Hauserová,Luis Lopez-Molina
出处
期刊:The Plant Cell
[Oxford University Press]
日期:2009-08-01
卷期号:21 (8): 2253-2268
被引量:110
标识
DOI:10.1105/tpc.109.067702
摘要
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.
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