脱落酸
拟南芥
胚乳
生物
发芽
突变体
分解代谢
拟南芥
休眠
种子休眠
胚胎
基因
细胞生物学
生物化学
植物
酶
作者
Masanori Okamoto,Ayuko Kuwahara,Mitsunori Seo,Tetsuo Kushiro,Tadao Asami,Nobuhiro Hirai,Yuji Kamiya,Tomokazu Koshiba,Eiji Nambara
出处
期刊:Plant Physiology
[Oxford University Press]
日期:2006-03-16
卷期号:141 (1): 97-107
被引量:555
标识
DOI:10.1104/pp.106.079475
摘要
Abstract Endogenous abscisic acid (ABA) levels are regulated by both biosynthesis and catabolism of the hormone. ABA 8′-hydroxylase is considered to be the key catabolic enzyme in many physiological processes. We have previously identified that four members of the Arabidopsis (Arabidopsis thaliana) CYP707A gene family (CYP707A1 to CYP707A4) encode ABA 8′-hydroxylases, and that the cyp707a2 mutants showed an increase in ABA levels in dry and imbibed seeds. In this study, we showed that the cyp707a1 mutant accumulated ABA to higher levels in dry seeds than the cyp707a2 mutant. Expression analysis showed that the CYP707A1 was expressed predominantly during mid-maturation and was down-regulated during late-maturation. Concomitantly, the CYP707A2 transcript levels increased from late-maturation to mature dry seed. Phenotypic analysis of single and double cyp707a mutants indicates that the CYP707A1 is important for reducing ABA levels during mid-maturation. On the other hand, CYP707A2 is responsible for the regulation of ABA levels from late-maturation to germination. Moreover, CYP707A1 and CYP707A3 were also shown to be involved in postgermination growth. Spatial expression analysis suggests that CYP707A1 was expressed predominantly in embryo during mid-maturation, whereas CYP707A2 expression was detected in both embryo and endosperm from late-maturation to germination. Our results demonstrate that each CYP707A gene plays a distinct role during seed development and postgermination growth.
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