The calmodulin-binding transcription factor OsCBT suppresses defense responses to pathogens in rice.
We previously isolated the OsCBT gene, which encodes a calmodulin (CaM)-binding protein, from a rice expression library constructed from fungal elicitor-treated rice suspension cells. In order to understand the function of OsCBT in rice, we isolated and characterized a T-DNA insertion mutant allele named oscbt-1. The oscbt-1 mutant exhibits reduced levels of OsCBT transcripts and no significant morphological changes compared to wild-type plant although the growth of the mutant is stunted. However, oscbt-1 mutants showed significant resistance to two major rice pathogens. The growth of the rice blast fungus Magnaporthe grisea, as well as the bacterial pathogen Xanthomonas oryzae pv. oryzae was significantly suppressed in oscbt-1 plants. Histochemical analysis indicated that the hypersensitive-response was induced in the oscbt-1 mutant in response to compatible strains of fungal pathogens. OsCBT expression was induced upon challenge with fungal elicitor. We also observed significant increase in the level of pathogenesis-related genes in the oscbt-1 mutant even under pathogen-free condition. Taken together, the results support an idea that OsCBT might act as a negative regulator on plant defense.
Koo
Sung Cheol
SC
Division of Applied Life Science (Brain Korea 21 program), Plant Molecular Biology and Biotechnology Research Center and Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Korea.
Choi
Man Soo
MS
Chun
Hyun Jin
HJ
Shin
Dong Bum
DB
Park
Bong Soo
BS
Kim
Yul Ho
YH
Park
Hyang-Mi
HM
Seo
Hak Soo
HS
Song
Jong Tae
JT
Kang
Kyu Young
KY
Yun
Dae-Jin
DJ
Chung
Woo Sik
WS
Cho
Moo Je
MJ
Kim
Min Chul
MC
D002148:Calmodulin-Binding Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D048708:Cell Growth Processes / Q000235:genetics; D004269:DNA, Bacterial; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D007108:Immune Tolerance; D007109:Immunity / Q000235:genetics; D020082:Magnaporthe / Q000254:growth & development / Q000276:immunology / Q000472:pathogenicity; D050505:Mutant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D012275:Oryza / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D014974:Xanthomonas / Q000254:growth & development / Q000276:immunology* / Q000472:pathogenicity
D002148:Calmodulin-Binding Proteins; D004269:DNA, Bacterial; D050505:Mutant Proteins; D010940:Plant Proteins; C036483:T-DNA; D014157:Transcription Factors