title: Gibberellin 20-oxidase gene OsGA20ox3 regulates plant stature and disease development in rice.
abstract: Gibberellin (GA) 20-oxidase (GA20ox) catalyses consecutive steps of oxidation in the late part of the GA biosynthetic pathway. A T-DNA insertion mutant (17S-14) in rice, with an elongated phenotype, was isolated. Analysis of the flanking sequences of the T-DNA insertion site revealed that an incomplete T-DNA integration resulted in enhanced constitutively expression of downstream OsGA20ox3 in the mutant. The accumulation of bioactive GA(1) and GA(4) were increased in the mutant in comparison with the wild-type plant. Transgenic plants overexpressing OsGA20ox3 showed phenotypes similar to those of the 17S-14 mutant, and the RNA interference (RNAi) lines that had decreased OsGA20ox3 expression exhibited a semidwarf phenotype. Expression of OsGA20ox3 was detected in the leaves and roots of young seedlings, immature panicles, anthers, and pollens, based on β-glucuronidase (GUS) activity staining in transgenic plants expressing the OsGA20ox3 promoter fused to the GUS gene. The OsGA20ox3 RNAi lines showed enhanced resistance against rice pathogens Magnaporthe oryzae (causing rice blast) and Xanthomonas oryzae pv. oryzae (causing bacterial blight) and increased expression of defense-related genes. Conversely, OsGA20ox3-overexpressing plants were more susceptible to these pathogens comparing with the wild-type plants. The susceptibility of wild-type plants to X. oryzae pv. oryzae was increased by exogenous application of GA(3) and decreased by S-3307 treatment. Together, the results provide direct evidence for a critical role of OsGA20ox3 in regulating not only plant stature but also disease resistance in rice.
authors.affiliation: State Key Laboratory of Agrobiotechnology, China Agricultural University, Yuanmingyan West Road 2, Beijing 100193, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Qin
authors.forename: Jun Hua
authors.initials: JH
authors.lastname: Liu
authors.forename: Wen Sheng
authors.initials: WS
authors.lastname: Zhao
authors.forename: Xu Jun
authors.initials: XJ
authors.lastname: Chen
authors.forename: Ze Jian
authors.initials: ZJ
authors.lastname: Guo
authors.forename: You Liang
authors.initials: YL
authors.lastname: Peng
mesh_terms: D004269:DNA, Bacterial; D060467:Disease Resistance; D035264:Flowers; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000032:analysis / Q000378:metabolism*; D020082:Magnaporthe / Q000472:pathogenicity*; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism*; D016254:Mutagenesis, Insertional; D012275:Oryza / Q000201:enzymology* / Q000235:genetics / Q000276:immunology / Q000502:physiology; D010641:Phenotype; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D018515:Plant Leaves / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots; D030821:Plants, Genetically Modified / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D034622:RNA Interference; D020156:Salicylic Acid / Q000378:metabolism; D036226:Seedlings / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D014974:Xanthomonas / Q000472:pathogenicity*
chemical_list: D004269:DNA, Bacterial; D005875:Gibberellins; D010940:Plant Proteins; C036483:T-DNA; D006899:Mixed Function Oxygenases; C089210:gibberellin, 2-oxoglutarate-oxygen oxidoreductase (20-hydroxylating, oxidizing); D020156:Salicylic Acid