Isolation and functional characterization of a fungal plant symbiont Nigrospora sphaerica, associated to Euphorbia hirta L.

Abstract

The endophytic fungi are the endosymbiont which play important role in improving host plant fitness and source of plethora of bioactive molecules. Present study includes the assessment of antimicrobial activity, phytochemical analysis and enzymes activity of fungal endophyte EHL2, isolated from leaf tissues of an Indian medicinal plant Euphorbia hirta L. The fungus exhibited the antibacterial and antifungal activities against a broad range of bacterial and fungal pathogens. To the best of our knowledge, this is the first report about the isolation and characterization of endophytic fungus Nigrospora sphaerica (EHL2) recovered from E. hirta L. The minimum inhibitory concentration (MIC) of the crude extract against pathogenic bacteria ranged from 0.45 to 3.14 mg/ml. For antifungal ativity of fungus, the highest percentage of inhibition was observed against Colletotrichum sp. (33.78%) while, minimum activity was noticed against Alternaria solani (16.60%). Preliminary mycochemical analysis revealed the positive tests for alkaloids, phenolics, flavonoids and terpenoids. The results showed that the total phenolic content (TPC) and total flavonoid content (TFC) of crude extracts were 78.11 ± 0.04 mg GAE/g and 235.94 ± 3.06 mg RE/g, respectively. Furthermore, the fungus also produced amylase, cellulase, protease and laccase enzymes. In conclusion, these positive results of mycochemicals and enzymes activity displayed by N. sphaerica of E. hirta provide an opportunity which could be exploited for host protection against pathogens and enzyme production. © 2022, Indian Phytopathological Society.