title: Rice OsACDR1 (Oryza sativa accelerated cell death and resistance 1) is a potential positive regulator of fungal disease resistance.
abstract: Rice Oryza sativa accelerated cell death and resistance 1 (OsACDR1) encodes a putative Raf-like mitogen-activated protein kinase kinase kinase (MAPKKK). We had previously reported upregulation of the OsACDR1 transcript by a range of environmental stimuli involved in eliciting defense-related pathways. Here we apply biochemical, gain and loss-of-function approaches to characterize OsACDR1 function in rice. The OsACDR1 protein showed autophosphorylation and possessed kinase activity. Rice plants overexpressing OsACDR1 exhibited spontaneous hypersensitive response (HR)-like lesions on leaves, upregulation of defense-related marker genes and accumulation of phenolic compounds and secondary metabolites (phytoalexins). These transgenic plants also acquired enhanced resistance to a fungal pathogen (Magnaporthe grisea) and showed inhibition of appressorial penetration on the leaf surface. In contrast, loss-offunction and RNA silenced OsACDR1 rice mutant plants showed downregulation of defense-related marker genes expressions and susceptibility to M. grisea. Furthermore, transient expression of an OsACDR1:GFP fusion protein in rice protoplast and onion epidermal cells revealed its localization to the nucleus. These results indicate that OsACDR1 plays an important role in the positive regulation of disease resistance in rice.
authors.affiliation: Department of Molecular Biology, College of Natural Science, Sejong University, Seoul 143-747, Korea.
authors.forename: Jung-A
authors.initials: JA
authors.lastname: Kim
authors.forename: Kyoungwon
authors.initials: K
authors.lastname: Cho
authors.forename: Raksha
authors.initials: R
authors.lastname: Singh
authors.forename: Young-Ho
authors.initials: YH
authors.lastname: Jung
authors.forename: Seung-Hee
authors.initials: SH
authors.lastname: Jeong
authors.forename: So-Hee
authors.initials: SH
authors.lastname: Kim
authors.forename: Jae-Eun
authors.initials: JE
authors.lastname: Lee
authors.forename: Yoon-Seong
authors.initials: YS
authors.lastname: Cho
authors.forename: Ganesh K
authors.initials: GK
authors.lastname: Agrawal
authors.forename: Randeep
authors.initials: R
authors.lastname: Rakwal
authors.forename: Shigeru
authors.initials: S
authors.lastname: Tamogami
authors.forename: Birgit
authors.initials: B
authors.lastname: Kersten
authors.forename: Jong-Seong
authors.initials: JS
authors.lastname: Jeon
authors.forename: Gynheung
authors.initials: G
authors.lastname: An
authors.forename: Nam-Soo
authors.initials: NS
authors.lastname: Jwa
mesh_terms: D002467:Cell Nucleus / Q000201:enzymology; D015169:Colony Count, Microbial; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D055786:Gene Knockout Techniques; D007113:Immunity, Innate / Q000235:genetics / Q000276:immunology*; D020930:MAP Kinase Kinase Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020082:Magnaporthe / Q000472:pathogenicity / Q000502:physiology*; D009154:Mutation / Q000235:genetics; D012275:Oryza / Q000201:enzymology* / Q000235:genetics / Q000276:immunology / Q000382:microbiology*; D010636:Phenols / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology*; D018515:Plant Leaves / Q000201:enzymology / Q000382:microbiology; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D034622:RNA Interference
chemical_list: D010636:Phenols; D010940:Plant Proteins; D020930:MAP Kinase Kinase Kinases