Endophytic Fungi: A Cryptic Fountainhead for Biodiversity, Functional Metabolites, Host Stress Tolerance, and Myco-mediated Nanoparticles (Nps) Synthesis

Abstract

The view on association of higher plants and fungi from past few decades confirms the belief that all plants foster their own endophytic fungal diversity as a host, and all plant species studied till date are found to harbor one or more endophytes. The diversity of endophytic fungi can have deep impressions on plant communities through adding fitness to their concerned host conferring tolerance against abiotic and biotic stresses. While endophytes have been outlined to biosynthesize a wide array of molecules, genome sequencing of such organisms has revealed that these have the potential to provide many more secondary metabolites than usual. Recently, various methods have been advanced to aid in the activation of cryptic biosynthetic pathways. Since the most important medicinal compound taxol (paclitaxel) has been isolated from the endophytic fungus therefore, more plant mimetic compounds may be expected from this hidden microbial source. Various enzymes (amylase, lipase, cellulase, protease, lactase, pectinases, peroxidase, catalase, and penicillinase) and toxins (aflatoxin, zearalenone, ochratoxin, citrinin, T-2 toxin, and fumonisins) may be isolated from this repertoire. Cell-free extract of many endophytic fungal isolates may also be utilized to synthesize the nanoparticles like copper (Cu), silver (Ag), platinum (Pt), and gold (Au) from respective metal salt solutions. This chapter also discusses different approaches such as co-culture of microbes, altering growth media and culture conditions, genetic as well as epigenetic strategies for obtaining the biochemical treasure hidden within these unique microbes. © 2019, Springer Nature Switzerland AG.