New research in Plant and Soil shows that a fungus living entirely inside perennial ryegrass leaves can change microbial communities throughout the soil below. Epichloë festucae, a foliar endophyte, altered bacterial and fungal diversity differently across aggregate sizes, from microaggregates under 0.25 mm to macroaggregates above 2 mm. Infected plots had more uniform microbial communities across those fractions and shifted network connections, especially around nitrogen cycling and soil organic carbon.\n\nThese findings matter for soil carbon management because aggregate size controls where decomposition and carbon storage happen. If endophyte-infected forage grasses change those processes, breeding or inoculating grasses with specific endophyte strains could become a practical tool for managing soil carbon and nitrogen in pasture systems. The study is observational after five years in the field, so long-term functional outcomes still need testing.
