ISOLATION, MOLECULAR IDENTIFICATION AND ANTIMICROBIAL ACTIVITY OF ASPERGILLUS VERSICOLOR AND OTHER ENDOPHYTIC FUNGI FROM THUNBERGIA ERECTA

Abstract

Endophytic fungi are non-pathogenic microorganisms residing within healthy plant tissues and are known to produce diverse bioactive secondary metabolites. This study focused on isolating and characterizing endophytic fungi from Thunbergia erecta, a medicinal and ornamental plant. Six morphologically distinct fungal isolates were selected for analysis. Molecular identification confirmed Aspergillus versicolor (TE2) and Aspergillus micronesiensis (TE4), while Penicillium sp.1 (TE3) and Penicillium sp.2 (TE9) were identified based on morphology. TE7 and TE8 remained unidentified due to lack of molecular data. Antimicrobial activity was evaluated against four bacterial pathogens (Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus) and four fungal pathogens (Candida albicans, Aspergillus fumigatus, Fusarium oxysporum, and Penicillium chrysogenum). A. versicolor (TE2) exhibited the strongest antibacterial activity, with inhibition zones of 24 mm against B. subtilis and 22 mm against other bacteria, exceeding Gentamicin (18 mm). TE7 showed comparable antibacterial activity, while Penicillium sp.1, Aspergillus micronesiensis and  Penicillium sp.2 demonstrated moderate activity. TE8 exhibited relatively lower antibacterial effects. In antifungal assays, A. versicolor (TE2) showed significant inhibition against A. fumigatus (12 mm), C. albicans and F. oxysporum (10 mm), and P. chrysogenum (8 mm). TE7 and Penicillium sp.2  displayed moderate antifungal activity, while TE8 had limited effects. Penicillium sp.1 showed no antifungal inhibition. These findings highlight A. versicolor (TE2) as a promising source of antimicrobial compounds and encourage further research on T. erecta endophytes.