Effects of Epichloë festucae var. lolii fungal endophyte strains associated with Lolium perenne on root exudate chemistry and microbial communities in the rhizosphere

Identifying key metabolites that are changing in the Lolium perenne - Epichloë festucae var. lolii metabolome will contribute to our understanding of their role in the belowground microfood-web and subsequently in ecosystem level processes. I designed two glasshouse studies to investigate the role of a plant-fungal endophyte symbiosis in shaping the grass-fungal metabolome and the microbial community in the rhizosphere. I tested the influence of several strains of E. festucae var. lolii on L. perenne growth and the composition of root exudate metabolites in hydroponic and soil mediums, and on the composition of microorganisms in a soil medium using metabolomic and next-generation sequencing techniques. I found that plant and endophyte growth, and the metabolomic profiles of root exudate and rhizosphere soils saw significant endophyte strain specific effects. While, compositions of the microbial communities in the rhizosphere had only subtle, and mostly non-significant changes as a result of endophyte soil conditioning treatments. The significant results of the metabolomics analyses provide a strong rational for more targeted investigations of the root exudate grass-fungal endophyte metabolome.