title: The rare sugar D-allose acts as a triggering molecule of rice defence via ROS generation.
abstract: Only D-allose, among various rare monosaccharides tested, induced resistance to Xanthomonas oryzae pv. oryzae in susceptible rice leaves with defence responses: reactive oxygen species, lesion mimic formation, and PR-protein gene expression. These responses were suppressed by ascorbic acid or diphenylene iodonium. Transgenic rice plants overexpressing OsrbohC, encoding NADPH oxidase, were enhanced in sensitivity to D-allose. D-Allose-mediated defence responses were suppressed by the presence of a hexokinase inhibitor. 6-Deoxy-D-allose, a structural derivative of D-allose unable to be phosphorylated, did not confer resistance. Transgenic rice plants expressing Escherichia coli AlsK encoding D-allose kinase to increase D-allose 6-phosphate synthesis were more sensitive to D-allose, but E. coli AlsI encoding D-allose 6-phosphate isomerase expression to decrease D-allose 6-phosphate reduced sensitivity. A D-glucose 6-phosphate dehydrogenase-defective mutant was also less sensitive, and OsG6PDH1 complementation restored full sensitivity. These results reveal that a monosaccharide, D-allose, induces rice resistance to X. oryzae pv. oryzae by activating NADPH oxidase through the activity of D-glucose 6-phosphate dehydrogenase, initiated by hexokinase-mediated conversion of D-allose to D-allose 6-phosphate, and treatment with D-allose might prove to be useful for reducing disease development in rice.
authors.affiliation: Faculty of Agriculture, Rare Sugar Research Center, and Gene Research Center, Kagawa University, Miki, Kagawa 761-0795, Japan.
authors.forename: Akihito
authors.initials: A
authors.lastname: Kano
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fukumoto
authors.forename: Kouhei
authors.initials: K
authors.lastname: Ohtani
authors.forename: Akihide
authors.initials: A
authors.lastname: Yoshihara
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Ohara
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Tajima
authors.forename: Ken
authors.initials: K
authors.lastname: Izumori
authors.forename: Keiji
authors.initials: K
authors.lastname: Tanaka
authors.forename: Takeo
authors.initials: T
authors.lastname: Ohkouchi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ishida
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nishizawa
authors.forename: Kazuya
authors.initials: K
authors.lastname: Ichimura
authors.forename: Yasuomi
authors.initials: Y
authors.lastname: Tada
authors.forename: Kenji
authors.initials: K
authors.lastname: Gomi
authors.forename: Kazuya
authors.initials: K
authors.lastname: Akimitsu
mesh_terms: D018506:Gene Expression Regulation, Plant; D005947:Glucose / Q000276:immunology*; D019255:NADPH Oxidases / Q000235:genetics / Q000276:immunology; D012275:Oryza / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000276:immunology; D017382:Reactive Oxygen Species / Q000276:immunology*; D014974:Xanthomonas / Q000502:physiology
chemical_list: D010940:Plant Proteins; D017382:Reactive Oxygen Species; C002055:allose; D019255:NADPH Oxidases; D005947:Glucose
keywords: NADPH oxidase; Oryza sativa L; d-Allose; d-glucose 6-phosphate dehydrogenase; hexokinase; rare sugar.