Abstract：
Competition for iron is an important factor for microbial niche establishment in the rhizosphere. Pathogenic and beneficial symbiotic bacteria use various secretion systems to interact with their hosts and acquire limited resources from the environment. Bacillus spp. are important plant commensals that encode a type VII secretion system (T7SS). However, the function of this secretion system in rhizobacteria-plant interactions is unclear. Here we use the beneficial rhizobacterium Bacillus velezensis SQR9 to show that the T7SS and the major secreted protein YukE are critical for root colonization. In planta experiments and liposome-based experiments demonstrate that secreted YukE inserts into the plant plasma membrane and causes root iron leakage in the early stage of inoculation. The increased availability of iron promotes root colonization by SQR9. Overall, our work reveals a previously undescribed role of the T7SS in a beneficial rhizobacterium to promote colonization and thus plant-microbe interactions.
摘要：
铁的竞争是根际微生物生态位建立的重要因素。致病性和有益的共生细菌使用各种分泌系统与其宿主相互作用并从环境中获得有限的资源。芽孢杆菌。是编码VII型分泌系统(T7SS)的重要植物共生体。然而,该分泌系统在根际细菌-植物相互作用中的功能尚不清楚。在这里，我们使用有益的根瘤菌芽孢杆菌SQR9来表明T7SS和主要的分泌蛋白YukE对于根定植至关重要。在植物实验和基于脂质体的实验中表明，分泌的YukE插入植物质膜并在接种的早期引起根铁泄漏。铁的可用性增加促进了SQR9的根定植。总的来说,我们的工作揭示了T7SS在有益根瘤菌中的先前未描述的作用，以促进定植，从而促进植物-微生物相互作用。
