Fungal endophytes: Classification, diversity, ecological role, and their relevance in sustainable agriculture

Endophyte is defined as an important group of widespread and diverse plant symbionts that live asymptomatically and sometimes systematically within plant tissues without any harm or causing diseases in host plants. Fungal endophytes establish a beneficial symbiotic relationship with host plants and have been demonstrated to have high impact on host plants. The association of fungal communities with their host plants improves growth, immunity, and overall developments of plants. The fungal endophytes have been reported for unrevealing benefits to their host plants including plant growth promotion, production of secondary metabolites, and other bioactive compounds, amelioration of various abiotic and biotic stresses, improving agricultural productivity, providing disease resistance against dreadful phytopathogens, all of which promotes the crop production through sustainable approaches. Further, the investigation of defensive mechanism provided by these fungal communities would be helpful in their utilization at commercial scale for bio-formulations. Endophytic fungus represents formerly uncharted fungal lineages and comprises vast amounts of fungal diversity in associated plants Therefore, there is a high probability of discovering potential endophytic fungi with major application in all sectors including agriculture, therapeutic, and for commercial exploitation.