Due to the specific properties of the marine environment, marine microorganisms have exclusive physicochemical characteristics that are different from those of terrestrial microorganisms, which can produce various secondary metabolites (SMs) with considerable structural diversity and biological activity. In this study, three strains of coepiphytic Aspergillus with potential antibacterial activities, A7 (Aspergillus flavus), B27 (Aspergillus flavipes), and R12 (Aspergillus sydowii), were isolated from the South China Sea. Via the Illumina MiSeq sequencing platform, the genomes of the three strains were sequenced, and genome comparison showed the highest diversity of the biosynthetic gene clusters (BGCs) in A7. In addition, a comparison of physiological and genomic characteristics between A7 and other A. flavus strains demonstrated the superior environmental adaptability of A7, which is apparently consistent with the genetic richness of BGCs. By assigning reads to known BGCs, putative BGCs were allocated in A7 that corresponded to various SMs, including naphthopyrone, pyranonigrin E, and cyclopiazonic acids. Based on gene homology analysis, we surmise that a region is involved in the biosynthesis of ustiloxin-like RiPPs, a less thoroughly studied SM in fungi. Our results provide genetic information for the investigation of marine Aspergillus spp., which may help to elucidate their chemical diversity and adaptive strategies.

As an important saprophytic filamentous fungus, Aspergillus terreus is ubiquitously distributed, including soil rhizospheres and marine environments. Due to the prominent capabilities of bioconversion and biosynthesis, A. terreus has become attractive in biotechnical and pharmaceutical industry. In this work, an A. terreus strain, B12, was isolated from sponge in South China Sea, which demonstrated broad bacteriostatic effects against a variety of pathogenic bacteria. The whole genome was sequenced, showing a genetic richness of BGCs, which might underpin the metabolic plasticity and adaptive resilience for the strain. Genome mining identified 67 biosynthetic gene clusters (BGCs), among which, 6 gene clusters could allocate to known BGCs (100% identity), corresponding to diverse metabolites like clavaric acid, dihydroisoflavipucine /isoflavipucine, dimethylcoprogen, alternariol, aspterric acid and pyranonigrin E. However, instead of the putative compounds, several other products were obtained from the B12 fermentation, including terrein, butyrolactone I, terretonin A&E, acoapetaline B and epi-aszonalenins A. Of note, acoapetaline B and epi-aszonalenins A, discovered natural products recently with little information, unexpectedly were reported in this A. terreus strain. The genomic and heterogeneity observed in strain B12, should be at least partially attributed to the genetic variability and biochemical diversity of A. terreus , which could be an interesting issue open to future efforts.