Ecological succession of fungal and bacterial communities in Antarctic mosses affected by a fairy ring disease

We evaluated fungal and bacterial diversity in an established moss carpet on King George Island, Antarctica, affected by ‘fairy ring’ disease using metabarcoding. These microbial communities were assessed through the main stages of the disease. A total of 127 fungal and 706 bacterial taxa were assigned. The phylum Ascomycota dominated the fungal assemblages, followed by Basidiomycota, Rozellomycota, Chytridiomycota, Mortierellomycota and Monoblepharomycota. The fungal community displayed high indices of diversity, richness and dominance, which increased from healthy through infected to dead moss samples. Bacterial diversity and richness were greatest in healthy moss and least within the infected fairy ring. Chalara sp. 1, Alpinaria sp., Helotiaceae sp. 2, Chaetothyriales sp. 1, Ascomycota sp. 1, Rozellomycota sp. and Fungi sp. were most abundant within the fairy ring samples. A range of fungal taxa were more abundant in dead rather than healthy or fairy ring moss samples. The dominant prokaryotic phyla were Actinobacteriota, Proteobacteria, Bacteroidota and Cyanobacteria. The taxon Cyanobacteriia sp., whilst consistently dominant, were less abundant in fairy ring samples. Microbacteriaceae sp. and Chloroflexi sp. were the most abundant taxa within the fairy rings. Our data confirmed the presence and abundance of a range of plant pathogenic fungi, supporting the hypothesis that the disease is linked with multiple fungal taxas. Further studies are required to characterise the interactions between plant pathogenic fungi and their host Antarctic mosses. Monitoring the dynamics of mutualist, phytopathogenic and decomposer microorganisms associated with moss carpets may provide bioindicators of moss health.

Chemical studies on bioactive compounds related to higher fungi

Hericium erinaceus (Yamabushitake in Japan) is a well-known edible and medicinal mushroom. We discovered antidementia compounds, hericenones C to H, from the fruiting bodies and erinacine A to I from the cultured mycelia of the fungus. Based on the data of the compounds, several clinical experiments were performed using the fungus. “Fairy rings” is a phenomenon that turfgrass grows more prolific or inhibited than the surrounding area as a ring and then occasionally mushrooms develop on the ring. We found fairy-ring causing principles “fairy chemicals” and the biosynthetic routes of the compounds on the purine metabolic pathway in plants and mushrooms.

Isolation and Characterization of the Mycorrhiza Helper Bacteria from the Fairy Rings of Floccularia Luteovirens

Floccularia luteovirens is an edible ectomycorrhizal fungus which forms fairy rings (FRs) distributed on the Qinghai-Tibet Plateau. Our previous study found four isolates of potential mycorrhiza helper bacteria (MHB), but they were only isolated from a single FR and their mycorrhizal promoting ability was not tested. Thus, it was necessary to collect samples from a larger area and measure the mycorrhizal promoting ability of the potential candidates. Of 184 bacterial isolates from five fairy rings located in Qinghai-Tibet Plateau belonging to 12 species, and 7 of them (58.3%) significantly promoting the growth of F. luteovirens. We also tested the symbiosis-promoting ability of the isolates, and the results showed that only four of them stimulated the formation of mycorrhizal symbiosis. This is the first report of the construction of mycorrhizal symbiosis between F. luteovirens and its host plant in greenhouse conditions. Our results showed that the strain A89 (Achromobacter marplatensis) could produce antifungal properties but nonetheless stimulated the fungal growth. This may due to the nutrient condition of medium and the genotype specificity of MHBs. The results suggest that the promotion of significant growth is not a good predictor for mycorrhiza formation promotion ability of MHB.