Microbial life in the phyllosphere

Compared with our understanding of the microbial ecology of the rhizosphere (the below-ground parts of plants), our understanding of the microbial ecology of the phyllosphere (the aerial parts of plants) has lagged behind, but this has begun to change in recent years. Here, Julia Vorholt reviews the latest research into the composition of microbial phyllosphere communities, the factors that drive this composition and the adaptation of these communities to the plant environment. Our knowledge of the microbiology of the phyllosphere, or the aerial parts of plants, has historically lagged behind our knowledge of the microbiology of the rhizosphere, or the below-ground habitat of plants, particularly with respect to fundamental questions such as which microorganisms are present and what they do there. In recent years, however, this has begun to change. Cultivation-independent studies have revealed that a few bacterial phyla predominate in the phyllosphere of different plants and that plant factors are involved in shaping these phyllosphere communities, which feature specific adaptations and exhibit multipartite relationships both with host plants and among community members. Insights into the underlying structural principles of indigenous microbial phyllosphere populations will help us to develop a deeper understanding of the phyllosphere microbiota and will have applications in the promotion of plant growth and plant protection.