title: Identification and characterization of 2'-deoxyuridine from the supernatant of conidial suspensions of rice blast fungus as an infection-promoting factor in rice plants.
abstract: We previously detected infection-promoting activity in the supernatant of the conidial suspension (SCS) of the rice blast fungus. In the present study, a molecule carrying the activity was purified and identified as 2'-deoxyuridine (dU). The infection-promoting activity of dU was strictly dependent on its chemical structure and displayed characteristics consistent with those of the SCS. Notably, the activity of dU was exclusively detected during interactions between rice and virulent isolates of the fungus, the number of susceptible lesions in leaf blades was increased by dU, and nonhost resistance in rice plants was not affected by treatment with dU. In addition, the expression of pathogensis-related genes, accumulation of H(2)O(2), and production of phytoalexins in rice in response to inoculation with virulent fungal isolates was not suppressed by dU. The infection-promoting activity of dU was not accompanied by elevated levels of endogenous abscissic acid, which is known to modify plant-pathogen interactions, and was not detected in interactions between oat plants and a virulent oat blast fungus isolate. Taken together, these results demonstrate that dU is a novel infection-promoting factor that acts specifically during compatible interactions between rice plants and rice blast fungus in a mode distinct from that of toxins and suppressors.
authors.affiliation: Division of Plant Sciences, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
authors.forename: Sugihiro
authors.initials: S
authors.lastname: Ando
authors.forename: Yuko
authors.initials: Y
authors.lastname: Sato
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Shigemori
authors.forename: Takafumi
authors.initials: T
authors.lastname: Shimizu
authors.forename: Kazunori
authors.initials: K
authors.lastname: Okada
authors.forename: Hisakazu
authors.initials: H
authors.lastname: Yamane
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Jikumaru
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kamiya
authors.forename: Kosumi
authors.initials: K
authors.lastname: Yamada
authors.forename: Chiharu
authors.initials: C
authors.lastname: Akimoto-Tomiyama
authors.forename: Shigeru
authors.initials: S
authors.lastname: Tanabe
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nishizawa
authors.forename: Eiichi
authors.initials: E
authors.lastname: Minami
mesh_terms: D018554:Avena / Q000382:microbiology / Q000502:physiology; D003857:Deoxyuridine / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D054884:Host-Pathogen Interactions; D006861:Hydrogen Peroxide / Q000378:metabolism; D020082:Magnaporthe / Q000378:metabolism* / Q000472:pathogenicity* / Q000502:physiology; D012275:Oryza / Q000235:genetics / Q000382:microbiology* / Q000502:physiology; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000378:metabolism / Q000382:microbiology / Q000502:physiology; D018749:RNA, Plant / Q000235:genetics; D012680:Sensitivity and Specificity; D012717:Sesquiterpenes / Q000378:metabolism; D013172:Spores, Fungal / Q000378:metabolism / Q000472:pathogenicity / Q000502:physiology; D014774:Virulence; D000094162:Phytoalexins
chemical_list: D018749:RNA, Plant; D012717:Sesquiterpenes; D006861:Hydrogen Peroxide; D003857:Deoxyuridine; D000094162:Phytoalexins