title: Antagonism between abscisic acid and gibberellins is partially mediated by ascorbic acid during seed germination in rice.
abstract: The antagonism between abscisic acid (ABA) and gibberellin (GA) plays a key role in controlling seed germination, but the mechanism of antagonism during this process is not known. In the associated study, we investigated the relationship among ABA, reactive oxygen species (ROS), ascorbic acid (ASC) and GA during rice seed germination. ROS production is reduced by ABA, which hence results in decreasing ASC accumulation during imbibition. GA accumulation was also suppressed by a reduced ROS and ASC level, whereas application of exogenous ASC can partially rescue seed germination from ABA treatment. Further results show that production of ASC, which acts as a substrate in GA biosynthesis, was significantly inhibited by lycorine which thus suppressed the accumulation of GA. Consequently, expression of GA biosynthesis genes was suppressed by the low levels of ROS and ASC in ABA-treated seeds. These studies reveal a new role for ASC in mediating the antagonism between ABA and GA during seed germination in rice.
authors.affiliation: Department of Biology, Hong Kong Baptist University, Hong Kong, China.
authors.forename: Nenghui
authors.initials: N
authors.lastname: Ye
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D047151:Amaryllidaceae Alkaloids / Q000494:pharmacology; D001205:Ascorbic Acid / Q000378:metabolism* / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018525:Germination / Q000187:drug effects / Q000235:genetics*; D005875:Gibberellins / Q000378:metabolism*; D012275:Oryza / Q000502:physiology*; D010617:Phenanthridines / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012639:Seeds / Q000187:drug effects / Q000502:physiology
chemical_list: D047151:Amaryllidaceae Alkaloids; D005875:Gibberellins; D010617:Phenanthridines; D010937:Plant Growth Regulators; D017382:Reactive Oxygen Species; D000040:Abscisic Acid; C015330:lycorine; D001205:Ascorbic Acid