Poster Session 6, 4:15 PM - 5:00 PM: Room 163 [C16]
Mycorrhizal Functional Diversity Drives Divergent Growth Responses in the Grass Brachypodium distachyon
Presenter: Samantha Reisner
Faculty Sponsor: Rachel Hestrin
School: UMass Amherst
Research Area: Biology
ABSTRACT
Arbuscular mycorrhizal fungi (AMF) form obligate symbioses with approximately 80% of terrestrial plant species, exchanging soil-derived nutrients for photosynthetically fixed carbon from their hosts. We hypothesize that differences in AMF life history strategy and morphology lead to distinct plant growth and resource allocation outcomes. To test this, we conducted a 15-week greenhouse experiment using the model grass Brachypodium distachyon, grown either without AMF or inoculated with one of two functionally distinct species: Rhizophagus irregularis or Gigaspora rosea. Plants were harvested at 9, 12, and 15 weeks to quantify above- and below-ground biomass and fungal colonization. Plants inoculated with R. irregularis developed significantly larger root systems than those inoculated with G. rosea, suggesting that there are species-specific effects on host growth. Preliminary microscopy indicates that R. irregularis also achieved higher root colonization levels. Ongoing analyses will quantify total colonization and the abundance of key fungal structures—including arbuscules, vesicles, spores, and hyphae—at each time point. Additional work examines whether morphological differences among AMF species are linked to patterns of plant carbon allocation and soil carbon dynamics. Collectively, this research advances our understanding of how functional diversity among AMF species shapes plant performance and ecosystem resource distribution.