50. 種子休眠性が異なるオオムギ系統におけるアブシジン酸の量的制御の解析

概要

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Abscisic acid (ABA) plays an important role in the maintenance of grain dormancy in barley (Hordeum vulgare L.). Previously, we have cloned the barley genes encoding key enzymes in ABA biosynthesis (9-cis-epoxycarotenoid dioxygenase : NCED) and catabolism (ABA 8'-hydroxylase : CYP707A). In this study, we examined the polymorphism of two NCED genes (HvNCED1, 2) and one CYP707A gene (HvCYP707A1) in barley lines with different levels of grain dormancy. Next, we analyzed the expression patterns of these genes during grain development and imbibition of two barley cultivars. One cultivar, "Ishukushirazu", shows a relatively high level of dormancy. The other cultivar, "Nishinochikara", shows a low level of dormancy. HvNCED1 and HvCYP707A1 showed the different expression patterns in Ishukushirazu and Nishinochikara during grain development and imbibition, however, HvNCED2 showed the same expression patterns in these cultivars. Sequence analysis of HvNCEDs and HvCYP707A1 revealed that only HvNCED2 is identical in Ishukushirazu and Nishinochikara. Quantification analysis of endogenous ABA content in embryo revealed that Ishukushirazu contains a higher level of ABA than Nishinochikara during grain development and imbibition. These data indicated that the different levels of grain dormancy in barley lines are likely to reflect the different regulations of ABA content in embryo itself during imbibition.
植物化学調節学会の論文
2005-10-13