Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
Microbial Processes and Interactions Unit, Faculty of Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium.
Plant Cell Rep. 2017 Nov;36(11):1731-1746. doi: 10.1007/s00299-017-2187-z. Epub 2017 Aug 11.
The Pseudomonas- derived cyclic lipopeptide orfamide can induce resistance to Cochliobolus miyabeanus but not to Magnaporthe oryzae in rice. Abscisic acid signaling is involved in the induced systemic resistance response triggered by orfamide. Diverse natural products produced by beneficial Pseudomonas species have the potential to trigger induced systemic resistance (ISR) in plants, and thus may contribute to control of diseases in crops. Some beneficial Pseudomonas spp. can produce cyclic lipopeptides (CLPs), amphiphilic molecules composed of a fatty acid tail linked to an oligopeptide which is cyclized. CLPs can have versatile biological functions, but the capacity of Pseudomonas-derived CLPs in triggering ISR responses has barely been studied. Pseudomonas protegens and related species can produce orfamide-type CLPs. Here we show that in rice, orfamides can act as ISR elicitors against the necrotrophic fungus Cochliobolus miyabeanus, the causal agent of brown spot disease, but are not active against the blast fungus Magnaporthe oryzae. Orfamide A can trigger early defensive events and activate transcripts of defense-related genes in rice cell suspension cultures, but does not cause cell death. Further testing in rice cell suspension cultures and rice plants showed that abscisic acid signaling, the transcriptional activator OsWRKY4 and pathogenesis-related protein PR1b are triggered by orfamide A and may play a role in the ISR response against C. miyabeanus.
来源于假单胞菌的环状脂肽类化合物orfamide 可诱导水稻对禾谷镰孢菌产生抗性，但不能诱导对稻瘟病菌产生抗性。脱落酸信号参与了 orfamide 触发的系统诱导抗性反应。有益假单胞菌产生的多种天然产物具有在植物中引发诱导系统抗性（ISR）的潜力，因此可能有助于控制作物病害。一些有益的假单胞菌可以产生环状脂肽（CLP），这是一种由脂肪酸尾巴与寡肽连接并环化的两亲分子。CLP 可以具有多种生物学功能，但假单胞菌衍生的 CLP 触发 ISR 反应的能力几乎没有被研究过。假单胞菌保护菌和相关物种可以产生 orfamide 型 CLP。在这里，我们表明在水稻中，orfamides 可以作为 ISR 诱导剂，对抗坏死性真菌禾谷镰孢菌，即褐斑病的病原体，但对稻瘟病菌没有活性。orfamide A 可以触发水稻悬浮细胞培养物中的早期防御事件并激活防御相关基因的转录，但不会引起细胞死亡。在水稻悬浮细胞培养物和水稻植株中的进一步测试表明，脱落酸信号、转录激活因子 OsWRKY4 和病程相关蛋白 PR1b 被 orfamide A 触发，可能在对 C. miyabeanus 的 ISR 反应中发挥作用。
