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United States Department of Agriculture

Agricultural Research Service

Research Project: BIOCONTROL OF FUMONISIN AND OTHER MYCOTOXINS IN CORN AND TALL FESCUE WITH MICROBIAL ENDOPHYTES

Location: Toxicology and Mycotoxin Research

Title: Allelochemical effects of volatile compounds and organic extracts from Muscodor yucatanensis, a tropical endophytic fungus from Bursera simaruba

Authors
item Macias-Rubalcava, Martha -
item Hernandez-Bautista, Blanca -
item Oropeza, Fabiola -
item Duarte, Georgina -
item Gonzalez, Maria -
item Glenn, Anthony
item Hanlin, Richard -
item Anaya, Ana Luisa -

Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 16, 2010
Publication Date: August 31, 2010
Repository URL: http://naldc.nal.usda.gov/download/54720/PDF
Citation: Macias-Rubalcava, M.L., Hernandez-Bautista, B.E., Oropeza, F., Duarte, G., Gonzalez, M.C., Glenn, A.E., Hanlin, R.T., Anaya, A. 2010. Allelochemical effects of volatile compounds and organic extracts from Muscodor yucatanensis, a tropical endophytic fungus from Bursera simaruba. Journal of Chemical Ecology. 36:1122-1131.

Interpretive Summary: Most plants possess fungal endophytes, which are fungi that generally grow within plant tissues without causing any harm to the host plant. These endophytes often have very active physiological activity and produce an array of secondary metabolites, some of which may actually benefit the plant-fungus association. Muscodor yucatanensis is a recently described endophytic fungus isolated from the leaves of Bursera simaruba (Burseraceae) growing in the dry, semideciduous tropical forest of the Ecological Reserve El Eden, Quintana Roo, Mexico. In the present study we tested in vitro the mixture of volatile organic compounds (VOCs) produced by M. yucatanensis for inhibitory effects against other endophytic fungi, phytopathogenic fungi and fungoids, and plants. We also tested organic extracts of the mycelium and culture medium. VOCs were lethal to a range of other fungal species (Guignardia mangifera, Colletotrichum sp., Phomopsis sp., Alternaria solani, Rhizoctonia sp., Phytophthora capsici, and P. parasitica) but had no effect on the growth of some species (Fusarium oxysporum, Xylaria sp., and the unidentified endophytic isolate 120). VOCs didn’t have any self-inhibitory effect on the growth of M. yucatanensis, but they did exhibit phytotoxic activity causing inhibition of root length of amaranth, tomato, and barnyard grass. The majority of VOCs were identified by gas chromatography/mass spectrometry. Almost all compounds identified in the VOCs mixture were not previously reported from other Muscodor species. We also investigated the effects of organic extracts from the culture medium and mycelium of M. yucatanensis on the same endophytes, phytopathogens, and plants. In general, root length of plants was more inhibited than radial growth of endophytic and phytopathogens fungi. The culture medium extract produced more inhibition than the mycelium extract. G. mangifera was the only endophytic fungus that was significantly stimulated by both extracts regardless their concentration. Compounds in both organic extracts were identified by gas chromatography/mass spectrometry. We discuss the possible role that the metabolites of M. yucatanensis play in its ecological interactions with its host plant and other organisms.

Technical Abstract: Muscodor yucatanensis, a recently described endophytic fungus, was isolated from the leaves of Bursera simaruba (Burseraceae) growing in the dry, semideciduous tropical forest of the Ecological Reserve El Eden, Quintana Roo, Mexico. In the present study we tested in vitro the mixture of volatile organic compounds (VOCs) produced by M. yucatanensis for the allelochemical effects against other endophytic fungi, phytopathogenic fungi and fungoids, and plants. We also tested organic extracts of the mycelium and culture medium. VOCs were lethal to Guignardia mangifera, Colletotrichum sp., Phomopsis sp., Alternaria solani, Rhizoctonia sp., Phytophthora capsici, and P. parasitica, but had no effect on Fusarium oxysporum, Xylaria sp., and the endophytic isolate 120. VOCs didn’t have any self-inhibitory effect on the growth of M. yucatanensis, but they did exhibit phytotoxic activity causing inhibition of root length of amaranth, tomato, and barnyard grass, particularly in the first 15 days of growth of the fungus. The majority of VOCs were identified by gas chromatography/mass spectrometry. Almost all compounds identified in the VOCs mixture were not previously reported from other Muscodor species. Only five known compounds appeared in the VOCs mixture of M. yucatanensis: octane, 1-butanol, 2-methyl-acetate, furan, 2-pentyl-, caryophyllene and aromadendrene. We also investigated the effects of organic extracts from the culture medium and mycelium of M. yucatanensis on the same endophytes, phytopathogens, and plants. In general, root length of plants was more inhibited than radial growth of endophytic and phytopathogens fungi. The culture medium extract produced more inhibition than the mycelium extract. The IC50 values of the culture medium extract on the root growth of plants were 112.2 µg/ml for tomato, 194.3 µg/ml for amaranth and 432.7 µg/ml for barnyard grass. The culture medium extract was more active than the commercial herbicide glifosate on the root length of amaranth (IC50 = 234.42 µg/ml). G. mangifera was the only endophytic fungus that was significantly stimulated by both extracts regardless their concentration. For G. mangifera the 50% stimulatory concentration (SC50) was 94.2 µg/ml for the M. yucatanensis culture medium extract, and was 103.5 µg/ml for the mycelium extract. Compounds in both organic extracts were identified by gas chromatography/mass spectrometry. We discuss the possible allelopathic role that the metabolites of M. yucatanensis play in its ecological interactions with its host plant and other organisms.

Last Modified: 4/21/2014
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