Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, France.
De Sangosse, Bonnel, 47480 Pont-Du-Casse, France.
Mol Plant Microbe Interact. 2020 Feb;33(2):223-234. doi: 10.1094/MPMI-05-19-0142-R. Epub 2019 Dec 4.
Streptomycetes are soil-dwelling, filamentous actinobacteria and represent a prominent bacterial clade inside the plant root microbiota. The ability of streptomycetes to produce a broad spectrum of antifungal metabolites suggests that these bacteria could be used to manage plant diseases. Here, we describe the identification of a soil strain named AgN23 which strongly activates a large array of defense responses when applied on leaves. AgN23 increased the biosynthesis of salicylic acid, leading to the development of ()dependent necrotic lesions. Size exclusion fractionation of plant elicitors secreted by AgN23 showed that these signals are tethered into high molecular weight complexes. AgN23 mycelium was able to colonize the leaf surface, leading to plant resistance against infection in wild-type plants. AgN23-induced resistance was found partially compromised in salicylate, jasmonate, and ethylene mutants. Our data show that soil bacteria can develop at the surface of plant leaves to induce defense responses and protection against foliar fungal pathogens, extending their potential use to manage plant diseases.
链霉菌是土壤栖息的丝状放线菌，是植物根际微生物群中一个重要的细菌分支。链霉菌产生广谱抗真菌代谢物的能力表明，这些细菌可用于防治植物疾病。在这里，我们描述了一种名为 AgN23 的土壤菌株的鉴定，该菌株在叶片上应用时强烈激活了大量防御反应。AgN23 增加了水杨酸的生物合成，导致 () 依赖性坏死病变的发展。AgN23 分泌的植物激发子的分子筛分级显示这些信号被束缚在高分子量复合物中。AgN23 菌丝能够在叶片表面定殖，导致野生型 植物对 感染的抗性。在水杨酸、茉莉酸和乙烯突变体中，AgN23 诱导的抗性部分受损。我们的数据表明，土壤细菌可以在植物叶片表面发育，诱导防御反应，防止叶部真菌病原体，从而扩大其在防治植物疾病方面的潜在用途。
