Fungal communities in sediments of subtropical Chinese seas as estimated by DNA metabarcoding

Ribosomal RNA internal transcribed spacer-1 (ITS1) metabarcoding was used to investigate the distribution patterns of fungal communities and the factors influencing these patterns in subtropical Chinese seas, including the southern and northern Yellow Sea and the Bohai Sea. These seas were found to harbor high levels of fungal diversity, with 816 operational taxonomic units (OTUs) that span 130 known genera, 36 orders, 14 classes and 5 phyla. Ascomycota was the most abundant phylum, containing 72.18% and 79.61% of all OTUs and sequences, respectively, followed by Basidiomycota (19.98%, 18.64%), Zygomycota (1.10%, 0.11%), Chytridiomycota (0.25%, 0.04%) and Rozellomycota (0.12%, 0.006%). The compositions of fungal communities across these three sea regions were found to be vary, which may be attributed to sediment source, geographical distance, latitude and some environmental factors such as the temperature and salinity of bottom water, water depth, total nitrogen, and the ratio of total organic carbon to nitrogen. Among these environmental factors, the temperature of bottom water is the most important driver that governs the distribution patterns of fungal communities across the sampled seas. Our data also suggest that the cold-water mass of the Yellow Sea likely balances competitive relationships between fungal taxa rather than increasing species richness levels.