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ARS Home » Southeast Area » Fort Lauderdale, Florida » Invasive Plant Research Laboratory » Research » Publications at this Location » Publication #362497

Research Project: Identification, Evaluation, and Implementation of Biological Control Agents for Invasive Weeds of Southeastern Ecosystems

Location: Invasive Plant Research Laboratory

Title: Testing for loss of Epichloë and non-epichloid symbionts under altered rainfall regimes

item David, Aaron
item BELL-DERESKE, LUKAS - Michigan State University
item EMERY, SARAH - University Of Louisville
item MCCORMICK, BRANDON - University Of New Mexico
item SEABLOOM, ERIC - University Of Minnesota
item RUDGERS, JENNIFER - University Of New Mexico

Submitted to: American Journal of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2019
Publication Date: 8/6/2019
Citation: David, A.S., Bell-Dereske, L., Emery, S., Mccormick, B., Seabloom, E., Rudgers, J. 2019. Testing for loss of Epichloë and non-epichloid symbionts under altered rainfall regimes. American Journal of Botany. 106(8):1081-1089.

Interpretive Summary: Global change has the potential to alter plant associations with its microbial symbionts, yet it is unclear what types of symbionts will be affected and at what stage in the host lifecycle these associations might be altered. Here, we demonstrate that reduced precipitation can lead to a loss of a systemic symbiont, but not localized symbionts, with important implications for how plants and their symbionts cope with a changing climate.

Technical Abstract: Understanding how global change factors alter the associations between hosts and their microbial symbionts may improve predictions of future changes in host population dynamics and microbial diversity. Here, we investigated how one global change factor, precipitation, affected the maintenance or loss of symbionts by considering 1) how precipitation altered associations with systemic and localized fungal symbionts across host ontogeny, and (2) interactive effects of water availability and symbionts on early seedling life history stages. We manipulated the presence of the systemic endophyte Epichloë amarillans in American beachgrass (Ammophila breviligulata) within a multiyear field experiment that imposed three precipitation regimes (ambient or ±30% rainfall). Reduced precipitation decreased the incidence of the systemic symbiont Epichloë, but had no effect on associations with localized fungal symbionts. Additional laboratory seed viability and germination assays suggested that association with Epichloë is likely maintained, in part, due to protective benefits against localized seed pathogens and to enhanced seed germination regardless of water availability. Our study empirically demonstrates a diversity of pathways for symbionts to be lost or maintained across host ontogeny, and suggests that reductions in precipitation can drive the loss of a plant’s microbial symbionts.