Effects of other microbes and the host on the interaction and ecological function of Pseudomonas and Sphingomonas isolates with plants

德国西南部野生拟南芥植物叶片中最常见的细菌属为假单胞菌和鞘氨醇单胞菌。虽然有许多致病假单胞菌，但鞘氨醇单胞菌即使有，也很少，但这两个分类群都包括能够保护植物免受病原体影响的菌株。尽管这两个属普遍存在，但它们在野生柳杉属植物中呈现出截然不同的分布模式：鞘氨醇单胞菌在单个植物中的丰度非常一致，而假单胞菌的丰度差异很大，只有假单胞菌才能很好地预测这些植物中的总微生物负荷。我们将对简化的假单胞菌和鞘氨醇单胞菌群落进行调查，以了解假单胞菌和鞘氨醇单胞菌在植物体内的相互作用及其对宿主的影响。我们将问的具体问题是：(I)共生假单胞菌菌株保护植物的生态相关基因是什么？(2)特征、生态位和功能，包括与假单胞菌和简化微生物群落的相互作用，在不同的鞘氨醇单胞菌菌株之间有何不同？(3)神经鞘氨醇单胞菌群落是如何建立的，它们的多样性和组成如何影响植物健康，它们如何与其他微生物相互作用？

The most common bacterial genera in leaves of wild Arabidopsis thaliana plants in Southwest Germany are Pseudomonas and Sphingomonas. While there are many pathogenic Pseudomonas, there are few, if any, Sphingomonas pathogens, but both taxa include strains that can protect plants from the effects of pathogens. Despite the ubiquity of both genera, they exhibit contrasting distribution patterns across wild A. thaliana plants: The abundances of Sphingomonas populations in individual plants are very uniform, whereas those of Pseudomonas greatly vary, and only Pseudomonas is a strong predictor of overall microbial load in these plants. We will investigate simplified Pseudomonas and Sphingomonas communities to learn about interactions between Pseudomonas and Sphingomonas strains inside plants and their effects on the host. Specific questions that we will ask are: (i) What ecologically relevant genes underlie plant protection by commensal Pseudomonas strains? (ii) How do traits, niches and functions, including interaction with Pseudomonas and a simplified microbial community, differ among individual Sphingomonas strains? (iii) How are Sphingomonas communities established, how do their diversity and composition affect plant health, and how do they interact with other microbes?