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

Luiz Henrique Rosa,Otávio Henrique Bezerra Pinto,Peter Convey,Carlos Augusto Rosa,Lívia Da Costa Coelho,Micheline Carvalho-Silva,Paulo E A S Câmara

doi:10.1007/s00792-021-01240-1

Abstract

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.

Highlights

Antarctic vegetation is dominated by bryophytes, with 116 species currently recognised representing cosmopolitan, endemic and bipolar taxa[1,2]
The moss carpet was formed by the species Sanionia uncinata (Hedw.) Loeske identified by the Dr Paulo EAS Câmara from University of Brasília based on macro- and micromorphological characteristics with reference to Ochyra et al.[1]
The use of a metabarcoding approach to assess the diversity of microbial communities associated with different stages of the disease in a carpet of the moss S. antarctica revealed, based on sequence assignment, a greater diversity of associated mutualistics, phytopathogens and decomposer fungi than previously recognised, with clear community differences as the disease progressed

Summary

Introduction

Antarctic vegetation is dominated by bryophytes, with 116 species currently recognised representing cosmopolitan, endemic and bipolar taxa[1,2]. Antarctic mosses may form extensive carpets in some parts of Antarctica, in the maritime Antarctic, contributing to the greatest development of ‘fellfield’ communities globally, and providing habitats and ameliorating Antarctica’s extreme environmental conditions for contained microbial and invertebrate communities[3,4,5]). Well established Antarctic moss carpets may act as "sentinels" sensitive to environmental changes, in temperature and hydration, across the Antarctic Peninsula region[5]. Moss carpet health has been a subject of research attention since the early years of Antarctic terrestrial research[6]. Rosa et al.[14] recorded the development of fairy rings on previously unreported moss species from new locations in the western Antarctic Peninsula region, suggesting that the disease is more widespread in maritime Antarctica than previously believed and may be increasing in prevalence

Methods

Results

Discussion

Conclusion