Diversity and biological functions of fungal secondary metabolites: Biocontrol agents for sustainable agriculture. A review.

Fungi produce a wide variety of secondary metabolites, including mycotoxins, antibiotics, and bioactive compounds, which have significant implications for human health and agriculture. These metabolites are synthesized through specialized biosynthetic pathways, which are often organized into gene clusters. Terpenoids, polyketides, non-ribosomal peptides, and hybrid compounds are primary categories of secondary metabolites, each with distinct biological roles. For example, terpenoids, such as deoxynivalenol and helvolic acid, polyketides, such as aflatoxins and lovastatin, and non-ribosomal peptides, such as penicillin G, have diverse applications, including as pharmaceuticals and biocontrol agents. Fungal metabolites also play a crucial role in microbial communication and agricultural pest control. Volatile metabolites released by fungi, including Fusarium and Trichoderma species, can inhibit plant pathogens and promote plant growth, thereby offering potential biocontrol strategies. Furthermore, entomopathogenic fungi produce secondary metabolites with insecticidal properties that facilitate their pathogenicity, including enzymes, toxins, and bioactive compounds. These metabolites have emerged as potential alternatives to synthetic insecticides in sustainable agricultural practices. A growing understanding of fungal secondary metabolites and their applications can contribute to advancements in pharmaceuticals, agriculture, and pest management.