Fungal community assembly in soils and roots under plant invasion and nitrogen deposition

Abstract

Fungal community composition in the Anthropocene is driven by rapid changes in environmental conditions caused by human activities. This study examines the relative importance of two global change drivers -atmospheric nitrogen (N) deposition and annual grass invasion -on structuring fungal communities in a California chaparral ecosystem, with emphasis on arbuscular mycorrhizal fungi. We used molecular markers, functional groupings, generalized linear statistics and joint distribution modeling, to examine how environmental variables structure taxonomic and functional composition of fungal communities. Invasion of a chaparral ecosystem decreased richness and relative abundance of non-AMF symbionts and rhizophilic AMF (e.g. Glomeraceae) as well as the proportion of edaphophilic AMF (e.g. Gigasporaceae). We found increased richness and the proportion of rhizophilic and edaphophilic AMF with increasing soil NO 3 . Our findings suggest that invasive persistence may decrease the presence of multiple soil symbionts that native species depend on for pathogen protection and increased access to soil resources.

Persistence of plant-mediated microbial soil legacy effects in soil and inside roots

“…This is potentially due to faster turnover times of soil bacterial communities 36 . Furthermore, due to their hyphal growth form, many fungi can simultaneously grow inside the roots and in the rhizosphere environment 38 , and soils could therefore potentially predict intimate active fungal-plant relationships better than bacterial-plant relationships. Another possible option is that not all organisms detected with DNA-based methods are active and thus part of the signal we are detecting originates from dead cells or inactive organisms 39 .…”

Root traits explain rhizosphere fungal community composition among temperate grassland plant species

“…Given the importance of AMF to trait–fungal relationships, methods using AMF‐specific primers should be used to establish whether the patterns reported here are consistent across AMF clades. Furthermore, as studies are increasingly using molecular data to infer fungal functional data (Semchenko et al ., 2018; Che et al ., 2019; Phillips et al ., 2019), future studies are needed to assess how well molecular‐derived relative abundances and richness estimates relate to functional data, such as percentage root colonisation by AMF.…”

Persistence of plant-mediated microbial soil legacy effects in soil and inside roots

“…This is potentially due to faster turnover times of soil bacterial communities (34). Furthermore, due to their hyphal growth form, many fungi can simultaneously grow inside the roots and in the rhizosphere environment (37), and soils could therefore potentially predict intimate active fungal-plant relationships better than bacterial-plant relationships. Another possible option is that not all organisms detected with DNA based methods are active and thus part of the signal we are detecting originates from dead cells or inactive organisms (38).…”

“…This may be important, as endophytic bacterial communities were more tightly linked to plant performance than soil bacterial communities, while for fungi both soil and endophytic communities influenced plant performance to a similar extent. This is probably due to the ability of fungi to grow as hyphae and thus bridging endophytic and soil environments (37). Previously, it has been shown that endophytic microbes are especially beneficial for plant growth through effects on plant nutrition, plant defense and interactions with the phytobiome, the response to abiotic constraints such as drought and on development (8)(9)(10)24).…”