Location: Soil, Water & Air Resources ResearchTitle: Conserved and reproducible bacterial communities associate with extraradical hyphae of arbuscular mycorrhizal fungi
|LEVESQUE-TREMBLAY, VERONIQUE - Boyce Thompson Institute|
|HARRISON, MARIA - Boyce Thompson Institute|
Submitted to: The ISME Journal: Multidisciplinary Journal of Microbial Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/29/2021
Publication Date: 3/1/2021
Citation: Emmett, B.D., Levesque-Tremblay, V., Harrison, M.J. 2021. Conserved and reproducible bacterial communities associate with extraradical hyphae of arbuscular mycorrhizal fungi. The ISME Journal: Multidisciplinary Journal of Microbial Ecology. 15:2276-2288. https://doi.org/10.1038/s41396-021-00920-2.
Interpretive Summary: Arbuscular mycorrhizal fungi (AMF) form symbioses with roots of most land plants, including major agricultural crops, and provide host plants nutrients in exchange for energy. AMF may be useful to improve nutrient use efficiency of agricultural systems, but constraints on their establishment, activity and interaction with other soil organisms are not fully understood. We identified soil bacteria that preferentially colonize the surface of the AMF hyphae and found that distinct groups repeatedly associate with AMF. This community did change among soil types and between AMF species, but the same related groups of taxa were observed throughout our experiments. These results can be used by researchers seeking to investigate potential positive or negative interactions between AMF and soil bacteria. Biotechnology companies developing AMF inoculants can use these results to guide testing and development of bacterial co-inoculants to improve the success of AMF applications.
Technical Abstract: Extraradical hyphae of arbuscular mycorrhizal fungi are the foraging and exploration organ of the mycorrhizal symbiosis. ERH interact with soil microbial communities with potential for positive, neutral and negative interactions. Existing evidence of association between ERH and soil bacteria suggest the existence of an ERH microbiome with consequences for soil carbon and nutrient cycling. Utilizing an in-growth core system with a sand and live soil mixture that allowed manual extraction of ERH, a series of experiments were undertaken to determine if an ERH associated community was apparent and explore controls on its establishment and composition. 16S rRNA gene amplicon profiling revealed an ERH associated community that was observed across soils and experiments, with conserved selection at the family and order ranks and variation between soils at lower ranks. This ERH associated microbiome was shared between Glomus versiforme and Rhizophagus irregularis, but these species varied in specificity and strength of selection. The ERH associated community was dynamic over time, but did not vary in response to nutrient treatment. Identification of a conserved ERH microbiome can aid efforts to characterize facilitative and antagonistic interactions influencing the function of the plant-fungal symbiosis.