Phyllosphere microbiology

The aerial parts of plants create a habitat for microorganisms that is referred to as phyllosphere, in analogy to the term rhizosphere. The major part of the phyllosphere is made up by plant leaves, which provide an estimated global surface of 6.4 x 10^8 km² (i.e., four times the global continental surface). Plant leaves are colonized by diverse bacterial and fungal species (Figure 3). In particular cultivation-independent methods have resulted in deeper insight into the composition of phyllosphere inhabiting bacterial communities during the last years. Proteobacteria appear to be frequently the dominant colonizers of this habitat.

Our research aims at a better understanding of how microbial phyllosphere communities are shaped and how environmental factors influence plant colonization. Moreover, we want to identify specific adaptations of bacterial taxa that are necessary to colonize this habitat successfully. To address these questions, we analyze plant leaf associated microbial communities of naturally grown plants. Further insight is gained from experiments performed under defined conditions in the laboratory using model organisms.

Figure 3: Colonization of the plant phyllosphere by microorganisms, illustrated by leaf imprints. A soybean leaf imprint on a complex medium results in the growth of diverse microorganisms, several of them with yellow pigmentation (upper images). An imprint of a clover leaf on a mineral salt medium plate supplemented with methanol as sole carbon source results in the growth of pink pigmented Methylobacteria (lower images). © Microbiology of the rhizosphere

Selected publications:

Ueda, Y., Frindte, K., Knief, C., Ashrafuzzaman, M., Frei, M. (2016) Effects of elevated tropospheric ozone concentration on the bacterial community in the phyllosphere and rhizosphere of rice. PLoS One 11: e0163178

Knief, C., Delmotte, N., Chaffron, S., Stark, M., Innerebner, G., Wassmann, R., von Mering, C. Vorholt, J. A. (2012) Metaproteomic analysis of microial communities in the phyllosphere and rhizosphere of rice. ISME J. 6: 1378-1390.

Knief, C., Dengler, V., Bodelier, P. L. E., Vorholt, J. A. (2012) Characterization of Methylobacterium strains isolated from the phyllosphere and description of Methylobacterium longum sp. nov. Antonie van Leeuwenhoek 101: 169-183.

Knief, C., Delmotte, N., Vorholt, J. A. (2011) Bacterial adaptation to life in association with plants – A proteomic perspective from culture to in situ conditions. Proteomics 11: 3086-3105.

Innerebner, G., Knief, C., Vorholt, J. A. (2011) Protection of Arabidopsis thaliana against leaf-pathogenic Pseudomonas syringae by Sphingomonasstrains in a controlled model system. Appl. Environ. Microbiol. 77: 3202-3210.

Knief, C., Frances, L., Vorholt, J. A. (2010) Competitiveness of diverse Methylobacterium strains in the phyllosphere of Arabidopsis thaliana and identification of representative models, including M. extorquens PA1. Microb. Ecol. 60: 440-452.

Knief, C., Ramette, A., Frances, L., Alonso-Blanco, C., Vorholt, J. A. (2010) Site and plant species are important determinants of the Methylobacteriumcommunity composition in the phyllosphere. ISME J. 4: 719-728.

Delmotte, N., Knief, C., Chaffron, S., Innerebner, G., Roschitzki, B., Schlapbach, R., von Mering, C. Vorholt, J. A. (2009) Community proteogenomics reveals insights into the physiology of phyllosphere bacteria. Proc. Natl. Acad. Sci. U S A 106: 16428-16433.