Induced defence in tobacco by Pseudomonas chlororaphis strain O6 involves at least the ethylene pathway

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• 作者：Spencer ; Matthew ; Ryu ; Choong-Min ; Yang ; Kwang-Yeol ; Kim ; Young Cheol ; Kloepper ; Joseph W. ; et. al.
• 关键词：Erwinia carotovora subsp. carotovora ; Ethylene ; GacS ; Induced resistance ; Phenazines ; Plant defense signaling ; Pseudomonas chlororaphis O6 ; Pseudomonas syringae pv. tabaci
• 刊名：Physiological and Molecular Plant Pathology
• 出版年：2003
• 出版时间：July, 2003
• 年：2003
• 卷：63
• 期：1
• 页码：27-34
• 全文大小：241 K

文摘

The antifungal phenazines produced by certain root colonizing pseudomonads are credited with contributing to the biocontrol activity of these isolates. However, the phenazine producer Pseudomonas chlororaphis O6 also induces systemic resistance in tobacco. Protection against two foliar bacterial pathogens, the wild fire pathogen, Pseudomonas syringae pv. tabaci, and Erwinia carotovora subsp. carotovora that causes a soft rot, was observed. A mutation in the bacterial global regulator gacS gene eliminated certain secondary traits, including phenazine production, but did not prevent induction of resistance in tobacco to P. syringae pv. tabaci. However, induction of resistance to E. carotovora subsp. carotovora was impaired in plants colonized by the GacS mutant compared to the level of protection in plants colonized by wild-type P. chlororaphis O6. Colonization by both the wild-type and the GacS mutant caused increased accumulation for transcripts of plant defense genes regulated by ethylene. Tobacco transformed with a mutant etr1 gene to reduce ethylene sensitivity did not display induced resistance to E. carotovora when colonized by P. chlororaphis O6. We conclude that inducers other than phenazines appear to initiate the pathways for systemic resistance induced by P. chlororaphis O6.