Secondary Metabolites from Endophytic Fungi: Chemical Diversity and Application

Abstract

Two major challenges facing the world today are antibiotic resistance, an emerging threat to human health, and, in agriculture, deterioration in crop yields due to pathogenic microorganisms, which is a primary issue for viable food production in developing countries. Microorganisms present in the environment play a beneficial role in overcoming these two major problems. Endophytic fungi are ubiquitous microorganisms existing within the interior region of plants in a symbiotic relation. They inhabit the space beneath the epidermal layer of plant tissue, obtain their nutrition from the plants, and enhance host plant growth. They synthesize a variety of biologically active compounds with diverse biological activities such as insecticidal, antioxidant, cytotoxic, antibacterial, antiviral, antifungal and antimalarial compounds. The secondary metabolites produced by endophytic fungi are phenols, alkaloids, polyketides, quinones, steroids, enzymes, and peptides, which possess higher therapeutic value. This chemical diversity also protects host plants from pathogens by inhibiting plant pathogen growth and boosting host immune system to amplify plant defense mechanisms. The endophytic fungi and their secondary metabolites have a beneficial role to play in the field of medicine and agriculture. Recent research has shown that endophytes acquire genes from host plants for bioactive compound production. Activation of silent biosynthetic pathways and epigenetic modifications are some of the strategies that enhance endophytic fungal potential for the production of secondary metabolites. Systematic research is required to discover the chemical ecology behind the natural bioactive compound synthesis.