Biodiversity of Endophytic Fungi from Diverse Niches and Their Biotechnological Applications

Abstract

Microbes colonizing the inner part of plants, viz., root, stem, or seeds, are referred to as endophytes. Diverse groups of microbes (archaea, bacteria, and eukarya) have been reported as niche-specific endophytes allied with different crop ecosystems. Among the diverse groups, endophytic fungi may play a biological role with their host plant for different attributes. Endophytic fungi influence the development of plants by producing plant growth hormones while at the same time improving nutrition by the bidirectional transfer of nutrients and the health of plants by protecting them against pathogens. Endophytic fungal associations with plants confer protection against adverse environmental conditions such as tolerance to heavy metals (Cu, Zn, and Pb) and increased drought resistance and successfully compete with saprobic fungi. Endophytes are ubiquitous organisms valued for their ability to synthesize various bioactive compounds and have proven to be important sources of new bioactive compounds and extracellular enzymes (amylase, asparaginase cellulase, chitinase, laccase, lipase, protease, and tyrosinase). Plants infected with endophytic fungi see significant increases in biomass, improve commercial plant production, and are thus useful in agroforestry and flori-horticulture applications. Endophytic fungi are of biotechnological interest due to their potential for use as genetic vectors, biological control agents, sources of secondary metabolites, antimicrobial agents, antitumor compounds, antibiotics, immunosuppressants, producers of natural antioxidants, antiviral compounds, insecticidal products, and antidiabetic agents. This chapter presents a critical review of the isolation, characterization, identification, biodiversity, and potential applications of endophytic fungi in agriculture and allied sectors.