**Preface**

Marine fungi are an ecologically diverse group of microbes which play critical roles in the matter cycle and energy flow of marine ecosystems and are important sources of bioactive natural products. The most investigated fungi by natural product chemists are laboratory-cultivated ascomycetes, such as Aspergillus, Penicillium and Fusarium. In the past decades, great efforts have been focused on the isolation and characterization of novel bioactive natural products, especially those with anti-infectious and anticancer properties. However, because of the limitations of traditional natural product mining methods, the discovery of new secondary metabolites has become increasingly difficult. In this aspect, researchers continue to make progress towards uncovering marine fungal diversity by exploring new habitats and leveraging modern techniques. The metabolite producing potential of a group of uncommon genera, including Basidiomycota, Blastocladiomycota, Chytridiomycota and Mucoromycota, has been uncovered.

In the meantime, a package of tools, including OSMAC, epigenetic modulation, genome mining and even combinatorial biosynthesis tools, has been developed and applied to explore the metabolic capacity of target strains, which has greatly improved the efficiency of discovering natural products. Moreover, collaborations between marine fungal ecologists, evolutionary biologists and natural product chemists have proved effective strategies for all endeavors involved in marine fungi studies. The development of techniques such as genomic and metabolomic approaches will help acquire more insightful knowledge on the physiological and biological properties of marine-derived fungi and those concepts are essential to target broader scientific topics related to environmental maintenance and human health.

> **Dehai Li** *Editor*
