Micobioma endolítico de recifes biogênicos na região da Oceaniadesvendado pela metagenômica de amplicon

Abstract

Biogenic reefs form a complex marine ecosystem, their biological, economic and social importance is incalculable. They develop under special natural conditions and very slowly. Its three-dimensional structures are generally bioconstructed by corals secreting calcium carbonate (CaCO3) and by coral algae that are characterized by the presence of calcium carbonate in their cell walls. Reef bioconstructive organisms harbor in their limestone structures an endolytic biological diversity that has not yet been explored. However, fungi comprise a poorly studied reef community. Studies that try to clarify the contribution of these organisms in the reef microbioma are insufficient to understand the interactions between fungi and reefs, as well as their true roles in this ecosystem. In this context, the metagenomics allows us to know which microorganisms are present in the endolithic mycobioma of reefs, to estimate their quantity, and to delineate the taxonomic profile of the community in different hosts and localities. In this work the amplicon (18S rDNA) sequencing was used to investigate the diversity and distribution of endolithic fungi in reef bioconstructive organisms in three countries of Oceania: Australia, Papua New Guinea and New Caledonia. A total of 132 samples collected from 6 localities, Western Australia, Victoria, Queensland, Madang, Kavieng and New Caledonia was sequenced by the Illumina MiSeq platform, v.3 (2 x300bp). As a result, we identified the endolytic reef mycobioma by identifying 165 OTUs, most at the species level, and demonstrated that the taxonomic diversity found indicates a diverse mycological community residing in limestone coral skeletons, coral algae and fragments of sandstone, and still that the fungal component of this endolytic microbiome is diverse among the hosts and between the locations where the samples were collected. The phylogenetic analysis of the mycobioma showed a high diversity of Ascomycetes (69%) Basidiomycetes (28%), Mucoromycetes (2%) and Chytridiomycetes (1%), distributed in 38 genera. In terms of abundance, the genus Lulworthia (26%) was the most representative in this community and is statistically an important taxon, since it was identified in four of the six studied locations, Zalerion (10.30%) was present in five of the six localities, and Oudemansiella (7,30%), Malassezia (6,10%) and Cladosporium (6,10%), in three of the six localities. This mycological representation, though partial, characterizes a powerful interface between bioinformatics, microbiology and ecology, and we deepen our knowledge of endolithic communities associated to reefs and establish the bases for understanding the structure of reef interactions and their mycobioma