Diversity, plant growth promoting and downy mildew disease suppression potential of cultivable endophytic fungal communities associated with pearl millet

In the present study, endophytic fungi were isolated from different parts of pearl millet crop from different regions of Karnataka. Endophytes were screened for diversity in tissue types, plant growth promoting (PGP) traits and downy mildew disease suppression ability in pearl millet. A total of 202 fungal isolates were isolated from leaves, shoot and root regions. The diversity analysis revealed that the plant harbored diverse fungal groups and the dominant fungi varied according to the sampling regions. The isolates were assigned to 29 fungal species based on morphology and molecular characterization using ITS sequence. All the isolates belonged to the phylum Ascomycota. Fusarium species were the most dominant fungi. Out of 29 representative isolates tested for plant growth promoting traits in vitro and in vivo, seven isolates were observed to improve the growth of pearl millet in comparison to control. Among the seven isolates, Fusarium oxysporum, Trichoderma asperellum and Acremonium sp. were found to suppress the downy mildew disease incidence by 36% in greenhouse conditions. The potent isolates were confirmed to behave as endophytes using pathogenicity, SEM and confocal microscopy experiments. This paper underlines the value of the endophytes as untapped suitable source of beneficial microorganisms that can be used to control pathogens in a sustainable way.