title: Isolation and molecular characterization of a Spotted leaf 18 mutant by modified activation-tagging in rice.
abstract: A lesion mimic mutant that we designated Spotted leaf 18 (Spl18) was isolated from 13,000 activation-tagging lines of rice produced by our modified activation-tagging vector and further characterized. Spl18 was dominant and its phenotype was linked to the T-DNA insertion. An ORF was located about 500 bp downstream of the inserted T-DNA, and the deduced protein, designated OsAT1, showed sequence similarity to an acyltransferase whose expression is induced by hypersensitive reaction in tobacco. The transcriptional level of OsAT1 was very low in the WT leaf blade but high in Spl18 leaf blade. In wild-type rice, OsAT1 was transcribed mainly in the young panicle, in the panicle just after heading, and in the leaf sheath. In addition, transcription of the genes for PR protein was upregulated in Spl18, accumulation of phytoalexins (both momilactone A and sakuranetin) was increased, and resistance to blast disease was improved. We then combined OsAT1 genomic DNA downstream of the modified 35S promoter and re-transformed it into rice. Lesion mimic and blast resistance phenotypes were detected in the transgenic lines produced, clearly indicating that overexpression of OsAT1 caused the Spl18 phenotypes. In addition, plants overexpressing OsAT1 showed resistance to bacterial blight.
authors.affiliation: National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan. morimasa@nias.affrc.go.jp
authors.forename: Masaki
authors.initials: M
authors.lastname: Mori
authors.forename: Chikako
authors.initials: C
authors.lastname: Tomita
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Sugimoto
authors.forename: Morifumi
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Nagao
authors.initials: N
authors.lastname: Hayashi
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Dubouzet
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Ochiai
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sekimoto
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Hirochika
authors.forename: Shoshi
authors.initials: S
authors.lastname: Kikuchi
mesh_terms: D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D015152:Blotting, Northern; D018506:Gene Expression Regulation, Plant; D020082:Magnaporthe / Q000254:growth & development; D008969:Molecular Sequence Data; D009154:Mutation; D016366:Open Reading Frames; D012275:Oryza / Q000235:genetics* / Q000382:microbiology; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D018515:Plant Leaves / Q000235:genetics* / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D012717:Sesquiterpenes; D013729:Terpenes / Q000378:metabolism; D014974:Xanthomonas / Q000254:growth & development; D000094162:Phytoalexins
chemical_list: D010940:Plant Proteins; D012717:Sesquiterpenes; D013729:Terpenes; D000217:Acyltransferases; D000094162:Phytoalexins