Rice OsACDR1 (Oryza sativa accelerated cell death and resistance 1) is a potential positive regulator of fungal disease resistance.
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.
Kim
Jung-A
JA
Department of Molecular Biology, College of Natural Science, Sejong University, Seoul 143-747, Korea.
Cho
Kyoungwon
K
Singh
Raksha
R
Jung
Young-Ho
YH
Jeong
Seung-Hee
SH
Kim
So-Hee
SH
Lee
Jae-Eun
JE
Cho
Yoon-Seong
YS
Agrawal
Ganesh K
GK
Rakwal
Randeep
R
Tamogami
Shigeru
S
Kersten
Birgit
B
Jeon
Jong-Seong
JS
An
Gynheung
G
Jwa
Nam-Soo
NS
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
D010636:Phenols; D010940:Plant Proteins; D020930:MAP Kinase Kinase Kinases