In vitro evaluation of antifungal activity of endophytic fungal extracts from selected rice plant pathogens.

Fungal endophytes are considered as natural bioactive reservoir that could be used as agents for antifungal activity. Echinochloa colonum (L.) Link an invasive rice weed compete with plant resources but houses several essential endophytes. However, a notable gap exists since few to none were conducted regarding the use of fungal extracts isolated from the weed E. colonum. Thus, evaluation of fungal endophytes from weeds needs to be established that may lead to development of biocontrol agent against fungal pathogens. Therefore, extracts from endophytic fungi isolated from the leaves of E. colonum were evaluated its antifungal activity against rice plant pathogens such as Aspergillus flavus, Fusarium oxysporum, Rhizoctonia solani, and Aspergillus oryzae, Curvularia umbiliciformis, Curvularia chiangmaiensis, and Bipolaris panici-miliacei were successfully isolated from the leaves of E. colonum and were identified based on cultural, morphological and molecular data. Additionally, using morphological and cultural techniques, Aspergillus sp. was also identified as another endophyte. Identified fungi were fermented using solid state fermentation to obtain fungal extracts. The 50µL of endophytic fungal extracts were used and exhibited varying antifungal activities in the agar well diffusion method. Extracts from Aspergillus sp., and B. panici-miliacei showed absence to weak antifungal activity against different fungal rice pathogens. While, C. chiangmaiensis extracts showed weak (11.83 ± 0.06 mm) to comparable (30.83 ± 0.40 mm) antifungal activity against A. flavus and F. oxysporum after 48 hours of incubation. Among the four fungal extracts, C. umbiliciformis extracts showed antifungal activity against A. flavus (18.53±0.40 mm), F. oxysporum (11.23±0.15 mm), and R. solani (31.73 ± 1.00 mm), and A. oryzae (36.77 ± 4.89 mm) after 48 hours of observation. Furthermore, statistics revealed that C. umbiliciformis extract showed comparable antifungal activity against R. solani. Therefore, fungal endophytic extracts can be expressed as a good source of antifungal agent against selected rice pathogen.