Persiani, A. M. | bioRxiv Science

bioRxiv2023

The rapid diversification of Boletales is linked to Early Eocene and Mid-Miocene Climatic Optima

O_LIInvestigating the mechanisms that underpin the diversity and distribution patterns of species is fundamental in ecology and evolution. However, the study of fungi, particularly the ectomycorrhizal group, has been relatively constrained in this field. C_LIO_LIWe conducted a high-resolution phylogenomic analysis of Boletales, an ecologically and economically significant group of fungi, covering 83 genera across 15 families. We subsequently investigated its evolutionary history using sequences at four genes obtained from 984 species across 121 genera within 15 families. C_LIO_LIThe findings unveiled that Boletales likely originated in Early Jurassic and underwent two remarkable episodes of rapid diversification, commencing in early Eocene ([~]54 Mya) and early Miocene ([~]17 Mya) epochs. The notable surges were predominantly driven by ectomycorrhizal clades, with a specific emphasis on East Asia and North America. These expansions were strongly correlated with the warm-humid paleoclimates during the Early Eocene Climatic Optimum and Mid-Miocene Climatic Optimum, as well as the rapid expansion of Fagales and Pinaceae hosts. C_LIO_LIThis study provides novel insights into the spatiotemporal evolution of fungi, highlighting the synergistic impact of abiotic factors, such as warm and humid paleoclimates, and the biotic factor of rapid diversification of host plants on the fungal diversification. C_LI

evolutionary biology↗

bioRxiv2022

ANTARCTIC FUNGI: A BIO-SOURCE ALTERNATIVE TO PRODUCE POLYUNSATURATED FATTY ACIDS (PUFAs)

The Antarctic ecosystem is a combination of conditions including extremely low values of temperature. The environmental temperature is one of the parameters thoroughly affecting the structure and composition of fungal membranes lipids. The psychrophilic fungi generally increase the disorder within macromolecules to maintain membrane fluidity at low temperatures. The strategy adopted by Antarctic fungi is to increase the proportion of unsaturated fatty acid that allows maintaining a semi-fluid state of the membranes. This ecological feature might be exploited for using Antarctic fungi as potential alternative source of polyunsaturated fatty acids (PUFAs) for human diet. This study provides both the characterization of fungal strains isolated from Antarctica by lipidomic analysis and the laboratory/large-scale production of fungal biomass with high content of beneficial PUFAs. In detail, three fungal species isolated from environmental matrices from Antarctica were tested and identified at genome level. Growth experiments to evaluate the influence of temperature and substrate in the yield in biomass and unsaturated fatty acid (UFA) were conducted. The results showed that the selected fungi have a high percentage of UFA compared to saturated ones; low growth temperatures increase the yield in linolenic fatty acid (C18:3); the biomass yield depends on the composition of the growth substrate and a satisfying qualitative-quantitative yield has also been obtained by using an agri-food chain waste product as growth substrate. IMPORTANCEThe presence of polyunsaturated fatty acids (PUFAs) in human and animal diet is gaining attention because PUFAs have several recognized functional properties: they modulate immune response, have anti-allergic and anti-inflammatory activity, cardio-protective effect and reduce blood LDL cholesterol levels. Human diets typically do not contain sufficient PUFAs because foods rich in PUFAs are few and it is therefore necessary to supplement this diet. Food supplements with these types of fatty acid currently commercially available come from marine fish oils and this source is no longer sustainable. It is necessary to develop efficient industrial processes capable of producing good quality PUFAs and in quantity, even using as carbon and nitrogen sources agro-industrial chains (in our case spent yeast from brewing and whey waste) waste products. Like microorganisms we used Antarctic fungi because they are adapted at very low temperature increasing the proportion of unsaturated fatty acid that allows maintaining a semi-fluid state of the membranes.

ecology↗