Location: Natural Products Utilization Research
Title: Antifungal activity of extracts from endophytic fungi associated with Smallanthus maintained in vitro as autotrophic cultures and as pot plants in the greenhouse Authors
Submitted to: Canadian Journal of Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 27, 2012
Publication Date: October 15, 2012
Citation: Rosa, L., Tabanca, N., Techen, N., Pan, Z., Wedge, D.E., Moraes, R. 2012. Antifungal activity of extracts from endophytic fungi associated with Smallanthus maintained in vitro as autotrophic cultures and as pot plants in the greenhouse. Canadian Journal of Microbiology. 58:1202-1211. Interpretive Summary: This paper focuses on fungicidal and other medically beneficial impacts of endophytic fungi which are beneficial microorganisms that live within various plant groups. Medicinal plants are promising sources of bioactive endophytic fungi communities, which are able to produce a diversity of bioactive compounds. Echinacea purpurea, commonly referred to as purple coneflower, was used by Native Americans for the treatment of many illnesses including typhoid fever and respiratory infections. Echinacea products available in the United States are made from the aerial parts of E. purpurea and the roots of three additional Echinacea species: E. angustifolia DC, E. pallida (Nutt.) Nutt., and E. purpurea (L.) Moench. Echinacea is the second top-selling botanical supplement in the US market and is used for cold treatment and has shown immune-modulator activities. Endophytic fungi are known to produce compounds for host’s defense mechanism thus the objectives of the present study are to isolate and identity endophytic fungi community associated with E. purpurea for the ability to produce antifungal compounds against phytopathogenic fungi. Therefore, we evaluated endophytic fungi isolates from the plant, E. purpurea, for their antifungal activity against the plant pathogens.
Technical Abstract: Fungal endophytes associated with leaves, lateral shoots, and roots of Echinacea purpurea, a medicinal plant used by Native Americans, were evaluated for antifungal activity as well as larvicidal, adulticidal, and repellent activities against Aedes aegypti. A total of 39 fungal isolates were identified by sequence analysis of the ITS region of the rRNA gene. The 39 extracts from the isolates were screened for antifungal activity against the plant pathogen´s targets Colletotrichum fragariae, C. gloeosporioides, and C. acutatum. Eleven endophytic taxa represented by species of the genera Ceratobasidium, Cladosporium, Colletotrichum, Fusarium, Glomerella, Mycoleptodiscus, and one taxa of order Pleosporales were identified. The most abundant taxa isolated were Cladosporium cladosporioides, Fusarium oxysporum, and Colletotrichum gloeosporioides. A total of 16 extracts (41%) showed selective antifungal activities; among them, seven were strongly active against C. acutatum, six against C. fragariae, and eight against C. gloeosporioides. None of extracts showed promise as Ae. aegypti control agents. These results showed that bioactive endophytic fungal community associated with E. purpurea can be used as source of antifungal prototype molecules in the development of new environmental friendly pesticides against worldwide phytopathogenic fungi.