Altered disease development in the eui mutants and Eui overexpressors indicates that gibberellins negatively regulate rice basal disease resistance.
Gibberellins (GAs) form a group of important plant tetracyclic diterpenoid hormones that are involved in many aspects of plant growth and development. Emerging evidence implicates that GAs also play roles in stress responses. However, the role of GAs in biotic stress is largely unknown. Here, we report that knockout or overexpression of the Elongated uppermost internode (Eui) gene encoding a GA deactivating enzyme compromises or increases, respectively, disease resistance to bacterial blight (Xanthomonas oryzae pv. oyrzae) and rice blast (Magnaporthe oryzae). Exogenous application of GA(3) and the inhibitor of GA synthesis (uniconazol) could increase disease susceptibility and resistance, respectively, to bacterial blight. Similarly, uniconazol restored disease resistance of the eui mutant and GA(3) decreased disease resistance of the Eui overexpressors to bacterial blight. Therefore, the change of resistance attributes to GA levels. In consistency with this, the GA metabolism genes OsGA20ox2 and OsGA2ox1 were down-regulated during pathogen challenge. We also found that PR1a induction was enhanced but the SA level was decreased in the Eui overexpressor, while the JA level was reduced in the eui mutant. Together, our current study indicates that GAs play a negative role in rice basal disease resistance, with EUI as a positive modulator through regulating the level of bioactive GAs.
Yang
Dong-Lei
DL
National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
Li
Qun
Q
Deng
Yi-Wen
YW
Lou
Yong-Gen
YG
Wang
Mu-Yang
MY
Zhou
Guo-Xing
GX
Zhang
Ying-Ying
YY
He
Zu-Hua
ZH
D003517:Cyclopentanes / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005875:Gibberellins / Q000494:pharmacology*; D007113:Immunity, Innate / Q000187:drug effects*; D020082:Magnaporthe / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity; D009154:Mutation; D012275:Oryza / Q000187:drug effects / Q000276:immunology / Q000382:microbiology / Q000502:physiology*; D054883:Oxylipins / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D010937:Plant Growth Regulators / Q000378:metabolism; D018515:Plant Leaves / Q000382:microbiology; D020156:Salicylic Acid / Q000378:metabolism; D036226:Seedlings / Q000378:metabolism; D014230:Triazoles / Q000494:pharmacology; D014974:Xanthomonas / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity*
D003517:Cyclopentanes; D005875:Gibberellins; D054883:Oxylipins; D010937:Plant Growth Regulators; D014230:Triazoles; C011006:jasmonic acid; D020156:Salicylic Acid; C092705:uniconazole