Mycorrhizal or not mycorrhizal? Assessing the role of root-associated fungi in plant nutrition
Microbial Ecology and Applied Microbiology
Final Report Abstract
Plant roots provide niches for species-rich assemblages of fungi, which play important roles in plant health and productivity. Multiple studies show that root-associated fungal communities are pervasive across plant hosts and habitats, and that overall they influence plant processes like growth, responses to environmental cues, and competition. However, little is yet known about the implication of particular fungi in specific processes, and whether the fungal effects on host plants are phylogenetically conserved. The project focused on the implication of root-associated fungi in a single process: the host plant’s uptake of soil nutrients. This is an important process for plant performance and ecosystem functioning, and fungi have repeatedly shown to affect the hosts’ ability to capture mineral nutrients, either directly or indirectly. The aim was to map across fungal phylogeny the capability to assist plant hosts in obtaining soil nutrients, and to search for ecological and evolutionary patterns indicative of such a fungal trait. The results show that the assembly of root-associated fungal communities in natural habitats does not importantly depend on the specific conditions of nutrients limitation, nor on the phylogeny or ecology of the plant hosts. Instead, other environmental and geographic factors were determinant in defining fungal communities, suggesting that no specific assemblages of fungi are associated with either particular soil nutrient availabilities, or plant needs for assistance in nutrients uptake by microbial symbionts. This result was confirmed in in vitro assays, in which model plants failed to recruit specific fungal communities in their roots when subject to different conditions of nutrient starvation. However, inoculation bioassays of Arabidopsis thaliana plants with individual fungal isolates showed a widespread ability of phylogenetically diverse fungi to improve plant growth in the presence of organic nutrients, readily usable by fungi but not by plants. Analyses still ongoing are directed to link the differences in plant growth observed with the nutritional status of the host plants, as well as to search for genomic signatures in fungi for the ability to translocate soil nutrients to plants. Altogether, the results from this project suggest that root-associated fungi have a generalized ability to sustain plant growth under nutrient starvation, irrespective of fungal phylogeny and of the extant environmental context where the symbioses take place. I expect that the results will provide new insights on the role of fungal diversity in important ecosystem processes and services, as well as inform future implementations of plant-associated fungi in conservation and applied ecology.
Publications
- (2019). (±) Alternarlactones A and B, two antiparasitic alternariol-like dimers from the fungus Alternaria alternata P1210 isolated from the halophyte Salicornia sp. Journal of Organic Chemistry, 17, 11203–11209
Shi, Y.-N., Pusch, S., Shi, Y.-M., Richter, C., Maciá-Vicente, J.G., Schwalbe, H., et al.
(See online at https://doi.org/10.1021/acs.joc.9b01229) - (2019). Orchard conditions and fruiting body characteristics drive the microbiome of the black truffle Tuber aestivum. Frontiers in Microbiology, 10
Splivallo, R., Vahdatzadeh, M., Maciá-Vicente, J.G., Molinier, V., Peter, M., Egli, S., et al.
(See online at https://doi.org/10.3389/fmicb.2019.01437) - (2019). Root endophytic fungi show low levels of interspecific competition in planta. Fungal Ecology, 39, 184–191
Kia, S.H., Pallesch, S., Piepenbring, M. & Maciá-Vicente, J.G.
(See online at https://doi.org/10.1016/j.funeco.2019.02.009) - (2020) Brassicaceous roots as an unexpected diversity hot-spot of helotialean endophytes. IMA Fungus, 11, 16
Maciá-Vicente, J.G., Piepenbring, M., Koukol, O.
(See online at https://doi.org/10.1186/s43008-020-00036-w) - (2020) Multilocus phylogeny- and fruiting feature-assisted delimitation of European Cyclocybe aegerita from a new Asian species complex and related species. Mycological Progress
Frings, R.A., Maciá-Vicente, J.G., Buße, S., Čmoková, A., Kellner, H., Hofrichter, M. & Hennicke, F.
(See online at https://doi.org/10.1007/s11557-020-01599-z) - (2020). Fungal Planet description sheets: 1042-1111. Persoonia - Molecular Phylogeny and Evolution of Fungi, 44, 301–459
Crous, P.W., Wingfield, M.J., Chooi, Y.-H., Gilchrist, C.L.M., Lacey, E., Pitt, J.I, …, Maciá- Vicente, J.G., et al.
(See online at https://doi.org/10.3767/persoonia.2020.44.11) - (2020). Mapping mycological ignorance – checklists and diversity patterns of fungi known for West Africa. IMA Fungus, 11, 13
Piepenbring, M., Maciá-Vicente, J.G., Codjia, J.E.I., Glatthorn, C., Kirk, P., Meswaet, Y., et al.
(See online at https://doi.org/10.1186/s43008-020-00034-y) - (2020). Root filtering, rather than host identity or age, determines the composition of root-associated fungi and oomycetes in three naturally co-occurring Brassicaceae. Soil Biology and Biochemistry, 146, 107806
Maciá-Vicente, J.G., Nam, B. & Thines, M.
(See online at https://doi.org/10.1016/j.soilbio.2020.107806)
