Dominant Members of the Plant Microbiome: Seed Transmitted Endophytes.

Grasslands are among the largest and widely distributed ecosystems representing 26% of the world land area and 70% of the world agricultural area. C3 grasses from the subfamily Pooideae are often infected with an endophytic Epichloë species. These Epichloë species represent a dominant member of the plant’s microbiome and provide protection to their host from biotic and abiotic stresses. Many of the Epichloë species are seed-transmitted but represent only a single genet within a plant. We have evaluated thousands of PI lines representing members of the Poaceae from the US Department of Agriculture’s National Plant Germplasm System (USDA-NPGS). We determined which host species contain seed transmitted endophytes, the level of infection within an infected line and then we have identified how much diversity exists across the endophytic species contained within a single host species. The contribution an endophyte can have on its host is evaluated by generating clone pairs of endophyte-infected and endophyte-free plants. These clonal populations are grown under different environments such as heat stress, water stress and over-grazing to determine the impact (positive and negative) of the seed-transmitted symbiont.