title: A Role for Reactive Oxygen Species Produced by NADPH Oxidases in the Embryo and Aleurone Cells in Barley Seed Germination.
abstract: Reactive oxygen species (ROS) promote the germination of several seeds, and antioxidants suppress it. However, questions remain regarding the role and production mechanism of ROS in seed germination. Here, we focused on NADPH oxidases, which produce ROS. After imbibition, NADPH oxidase mRNAs were expressed in the embryo and in aleurone cells of barley seed; these expression sites were consistent with the sites of ROS production in the seed after imbibition. To clarify the role of NADPH oxidases in barley seed germination, we examined gibberellic acid (GA) / abscisic acid (ABA) metabolism and signaling in barley seeds treated with diphenylene iodonium chloride (DPI), an NADPH oxidase inhibitor. DPI significantly suppressed germination, and suppressed GA biosynthesis and ABA catabolism in embryos. GA, but not ABA, induced NADPH oxidase activity in aleurone cells. Additionally, DPI suppressed the early induction of α-amylase by GA in aleurone cells. These results suggest that ROS produced by NADPH oxidases promote GA biosynthesis in embryos, that GA induces and activates NADPH oxidases in aleurone cells, and that ROS produced by NADPH oxidases induce α-amylase in aleurone cells. We conclude that the ROS generated by NADPH oxidases regulate barley seed germination through GA / ABA metabolism and signaling in embryo and aleurone cells.
authors.affiliation: Crop Science Laboratory, Faculty of Agriculture, Kyushu University, Hakozaki, Higashi-ku, Fukuoka, Japan.
authors.forename: Yushi
authors.initials: Y
authors.lastname: Ishibashi
authors.affiliation: Crop Science Laboratory, Faculty of Agriculture, Kyushu University, Hakozaki, Higashi-ku, Fukuoka, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Kasa
authors.affiliation: Crop Science Laboratory, Faculty of Agriculture, Kyushu University, Hakozaki, Higashi-ku, Fukuoka, Japan.
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Sakamoto
authors.affiliation: Crop Science Laboratory, Faculty of Agriculture, Kyushu University, Hakozaki, Higashi-ku, Fukuoka, Japan.
authors.forename: Nozomi
authors.initials: N
authors.lastname: Aoki
authors.affiliation: Crop Science Laboratory, Faculty of Agriculture, Kyushu University, Hakozaki, Higashi-ku, Fukuoka, Japan.
authors.forename: Kyohei
authors.initials: K
authors.lastname: Kai
authors.affiliation: Crop Science Laboratory, Faculty of Agriculture, Kyushu University, Hakozaki, Higashi-ku, Fukuoka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yuasa
authors.affiliation: RIKEN Plant Science Center, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hanada
authors.affiliation: RIKEN Plant Science Center, Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, Japan.
authors.forename: Shinjiro
authors.initials: S
authors.lastname: Yamaguchi
authors.affiliation: Crop Science Laboratory, Faculty of Agriculture, Kyushu University, Hakozaki, Higashi-ku, Fukuoka, Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Iwaya-Inoue
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018525:Germination / Q000187:drug effects; D005875:Gibberellins / Q000096:biosynthesis; D001467:Hordeum / Q000166:cytology* / Q000196:embryology* / Q000201:enzymology / Q000235:genetics; D006861:Hydrogen Peroxide / Q000378:metabolism; D007477:Ions; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012639:Seeds / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D013481:Superoxides / Q000378:metabolism; D000516:alpha-Amylases / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D005875:Gibberellins; D007477:Ions; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D013481:Superoxides; D000040:Abscisic Acid; D006861:Hydrogen Peroxide; D019255:NADPH Oxidases; D000516:alpha-Amylases; D002118:Calcium