We evaluated fungal and bacterial diversity in an established moss carpet on King George Island, Antarctica, affected by ‘fairy ring’ disease using metabarcoding. A total of 127 fungal and 706 bacterial taxa were assigned. 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. A range of fungal taxa were more abundant in dead rather than healthy or fairy ring moss samples. Bacterial diversity and richness were greatest in healthy moss and least within the infected fairy ring. The dominant prokaryotic phyla were Actinobacteriota, Proteobacteria, Bacteroidota and Cyanobacteria. Cyanophyceae sp., whilst consistently dominant, were less abundant in fairy ring samples. 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 taxa. 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.

我们使用元条形码评估了南极乔治王岛已建立的苔藓地毯中真菌和细菌的多样性，该苔藓受到“仙女环”病的影响。总共分配了 127 个真菌和 706 个细菌类群。子囊菌为主的真菌组合，其次是担子，Rozellomycota，壶菌门，Mortierellomycota和Monoblepharomycota. 真菌群落表现出很高的多样性、丰富度和优势指数，从健康的苔藓样品到受感染的苔藓样品再到死亡的苔藓样品。一系列真菌类群在死亡而非健康或仙环苔藓样本中更为丰富。细菌多样性和丰富度在健康苔藓中最大，在受感染的仙女环中最少。优势原核菌门为放线菌门、变形菌门、拟杆菌门和蓝藻门。蓝藻科sp.，虽然一直占主导地位，但在仙女环样本中含量较少。我们的数据证实了一系列植物病原真菌的存在和丰度，支持了该疾病与多种真菌类群有关的假设。需要进一步研究来表征植物病原真菌与其寄主南极苔藓之间的相互作用。监测与苔藓地毯相关的共生微生物、植物病原微生物和分解微生物的动态可以提供苔藓健康的生物指标。