Challenges in assessing links between root exudates and the structure and function of soil microbial communities

Abstract

Root exudates provide carbon for rhizosphere microbial communities and thus potentially play an important role in regulation of community composition and activity. The rhizosphere is an extremely complex environment with simultaneous spatial and temporal interactions between soil, plants, and microorganisms. There are significant technical challenges associated with the collection and analysis of root exudates and investigation of rhizosphere microbial communities. Design of in vitro and in situ systems to study interactions between root exudates and composition of microbial communities remains an important issue. Various experimental systems under controlled conditions have been described and a range of techniques used to demonstrate links between root exudates and microbial community structure and function. Nonetheless, our understanding of direct links between root exudates and microbial‐mediated rhizosphere processes in “undisturbed” systems still remains somewhat limited. In order to better understand rhizosphere processes, there is need to improve techniques for in situ analysis, which in turn will further our knowledge of how root exudates regulate the structure of rhizosphere microbial communities and contribute to their associated functions.