Distribution pattern and antibacterial activity of 548 fungi from offshore and pelagic seawater

Abstract:

[Objective] Marine fungi are ideal producers of novel natural products. This paper aims to deepen the understanding of the diversity of culturable marine fungi and identify potential useful marine fungi.[Methods] Fungi were isolated from offshore and pelagic seawater by membrane filtration. Through the isolation and purification of strains and internal transcribed spacer (ITS) sequencing, the diversity of culturable fungi in neritic water, bathyal water, and abyssal water was analyzed. The solid plate method was used to screen strains with antibacterial activity.[Results] A total of 548 fungi were isolated and they fell into 44 species, 24 genera, 19 families, 11 orders, 6 classes, and 2 phyla, including 15 marine species and 3 novel taxa. At the class level, Dothideomycetes dominated (13 species), followed by Sordariomycetes (11 species) and Eurotiomycetes (11 species). At the genus level, Penicillium, Cladosporium, Exophiala, and Simplicillium were dominant. The 44 species presented 5 geographic distribution pattern:presence in neritic, bathyal, and abyssal areas (15 species), presence only in neritic area (5 species), absence in neritic area (12 species), absence in bathyal area (5 species), and absence in abyssal area (7 species). A total of 12 species had antibacterial activity. Among them, Hortaea werneckii showed the broadest antibacterial spectrum, and Simplicillium cylindrosporum demonstrated the strongest inhibition on Staphylococcus aureus MCCC1A0646.[Conclusion] This study reveals the diversity and distribution pattern of culturable fungi in the offshore and pelagic seawater and enriches the resource of marine fungi.

Key words:marine fungi;diversity;membrane filtration;natural products;antibacterial activity