Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Jena, Germany.
Research Group Mass Spectrometry, Max Planck Institute for Chemical Ecology, Jena, Germany.
Mol Ecol. 2019 Mar;28(5):1154-1169. doi: 10.1111/mec.15012.
The beneficial effects of plant--bacterial interactions in controlling plant pests have been extensively studied with single bacterial isolates. However, in nature, bacteria interact with plants in multitaxa consortia, systems which remain poorly understood. Previously, we demonstrated that a consortium of five native bacterial isolates protected their host plant Nicotiana attenuata from a sudden wilt disease. Here we explore the mechanisms behind the protection effect against the native pathosystem. Three members of the consortium, Pseudomonas azotoformans A70, P. frederiksbergensis A176 and Arthrobacter nitroguajacolicus E46, form biofilms when grown individually in vitro, and the amount of biofilm increased synergistically in the five-membered consortium, including two Bacillus species, B. megaterium and B. mojavensis. Fluorescence in situ hybridization and scanning electron microscopy in planta imaging techniques confirmed biofilm formation and revealed locally distinct distributions of the five bacterial strains colonizing different areas on the plant-root surface. One of the five isolates, K1 B. mojavensis produces the antifungal compound surfactin, under in vitro and in vivo conditions, clearly inhibiting fungal growth. Furthermore, isolates A70 and A176 produce siderophores under in vitro conditions. Based on these results we infer that the consortium of five bacterial isolates protects its host against fungal phytopathogens via complementary traits. The study should encourage researchers to create synthetic communities from native strains of different genera to improve bioprotection against wilting diseases.
植物-细菌相互作用在控制植物害虫方面的有益效果已经被广泛研究，其中使用了单一的细菌分离株。然而，在自然界中，细菌与植物以多分类群联合体的形式相互作用，而这些系统仍知之甚少。此前，我们证明了由五个本土细菌分离株组成的联合体可以保护其宿主植物烟草原生萎蔫病。在这里，我们探讨了针对原生体系的保护作用背后的机制。联合体中的三个成员，即产氮假单胞菌 A70、弗雷德里克斯堡假单胞菌 A176 和节杆菌 nitroguajacolicus E46，在体外单独生长时会形成生物膜，并且在包括两种芽孢杆菌（巨大芽孢杆菌和莫哈韦芽孢杆菌）在内的五成员联合体中，生物膜的数量会协同增加。荧光原位杂交和植物体内扫描电子显微镜成像技术证实了生物膜的形成，并揭示了这五种细菌在植物根部表面不同区域的局部分布情况。这五个分离株之一，K1 莫哈韦芽孢杆菌会在体外和体内条件下产生抗真菌化合物表面活性剂，明显抑制真菌生长。此外，A70 和 A176 分离株在体外条件下会产生铁载体。基于这些结果，我们推断这五个细菌分离株联合体通过互补特性来保护其宿主免受真菌病原体的侵害。该研究应鼓励研究人员从不同属的本土菌株中创建合成群落，以提高对萎蔫病的生物保护。
