Role of root exudates in plant-microbe interactions

The interactions in the rhizosphere are leading to a highly structured microbial community which, to a great deal, is influenced by the root exudates of plant origin. In this review, we have included the different types of interaction with special regard to the root exudates' function in Such positive or negative interactions beween plants and both bacterial and fungal partners of the plant in the rhizosphere, including rnycorrhiza, nitrogen-fixing symbionts, plant growth promoting rhizobacteria endophytes and biological control organisms as well as allelopathy, antimicrobial effects and effects on nematodes. The differences in root exudates induced by microbial associations, role of quorum sensing in structuring communitites and effect on biogeochemical cycles are reviewed. The focus is put on agricultural systems and implications for ecosystems on arable land are drawn.