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United States Department of Agriculture

Agricultural Research Service

Research Project: Chemistry of Natural Products for Nutraceutical Use, Pest Management and Crop Development

Location: Natural Products Utilization Research

Title: Coniochaeta ligniaria: antifungal activity of the cryptic endophytic fungus associated with autotrophic cultures of the medicinal plant Smallanthus sonchifolius (Asteraceae)

Authors
item Rosa, Luiz -
item Quieroz, Sonia -
item Moraes, Rita -
item Wang, Xiaoning -
item Techen, Natascha -
item Pan, Zhiqiang
item Cantrell, Charles
item Wedge, David

Submitted to: Symbiosis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2013
Publication Date: June 29, 2013
Citation: Rosa, L., Quieroz, S., Moraes, R., Wang, X., Techen, N., Pan, Z., Cantrell, C.L., Wedge, D.E. 2013. Coniochaeta ligniaria: antifungal activity of the cryptic endophytic fungus associated with autotrophic cultures of the medicinal plant Smallanthus sonchifolius (Asteraceae). Symbiosis. 60:133-142.

Interpretive Summary: This research describes the studies of a fungus that infests the medicine plant Smallanthus sonchifolius. The fungal species was identified as Coniochaeta ligniaria using molecular, physiological and morphological methods. The crude extract of C. ligniaria displayed antifungal activity and the identification of the active constituents was done by systematic bioactivity-guided fractionation of the dichloromethane extract against the phytopathogenic Colletotrichum species, NMR spectroscopy and GC-FID analysis. The antifungal fractions from the C. ligniaria were identified as a mixture of 12 antifungal fatty acids. The identification of the fungus C. ligniaria isolated from tissue culture of S. sonchifolius suggest that plants can shelter specific fungal communities with a special symbiosis with their plant hosts, this may be a tool to study taxonomy, ecology, evolution and biotechnological applications of endophytic fungi studies.

Technical Abstract: Few studies have addressed the presence and bioactivity of endophytic fungi living in plantlets growing under in vitro conditions. We isolated a fungus UM 109 from autotrophic cultures of the medicinal plant Smallanthus sonchifolius (yacon). The species was identified as Coniochaeta ligniaria using molecular, physiological and morphological methods. The crude extract of C. ligniaria displayed antifungal activity and the identification of the active constituents was done by systematic bioactivity-guided fractionation of the dichloromethane extract against the phytopathogenic Colletotrichum species, NMR spectroscopy and GC-FID analysis. The antifungal fractions from the C. ligniaria were identified as a mixture of 12 antifungal fatty acids, including caproic, caprylic, myristic, palmitic, heptadecanoic, stearic, oleic, linoleic and stearic. The presence of antifungal fatty acids was not unique to the fractions of C. ligniaria culture and caproic, caprylic, myristic, palmitic, heptadecanoic, stearic, oleic and linoleic acids were isolated and detected in the antifungal fractions of S. sonchifolius. In addition, caproic, caprylic and palmitic were the majors fatty acids produced by the C. ligniaria and found as majority compounds in the S. sonchifolius fraction groups. The identification of the fungus C. ligniaria isolated from tissue culture of S. sonchifolius suggest that plants in vitro autotrophic cultures can shelter specific endophytic fungal communities with a special symbiosis with their plant hosts, which could be a tool on taxonomy, ecology, evolution and biotechnological applications of endophytic fungi studies. In addition, the detection of the eight antifungal fatty acids produced by C. ligniaria in the plant fractions suggests that bioactive compounds, together with others bioactive compounds produced by the plant, may help S. sonchifolius to resist to phytopathogenic fungal attacks, indicating the existence of an interesting chemical symbiosis between

Last Modified: 10/21/2014
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