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Postharvest Pathology and Mycotoxins

Macrocyclic Trichothecene Mycotoxins in Brazilian Species of Baccharis. B. B. Jarvis, Department of Chemistry and Biochemistry, University of Maryland, College Park 20742; K. M. Wells(2), Y.-W. Lee(3), G. A. Bean(4), T. Kommedahl(5), C. S. Barros(6), and S. S. Barros(7). (2)(3)Department of Chemistry and Biochemistry, University of Maryland, College Park 20742; (4)Department of Botany, University of Maryland, College Park 20742; (5)Department of Plant Pathology, University of Minnesota, St. Paul 55108; (6)(7)Departamento de Veterinary Science, Universidade de Santa Maria, Santa Maria, RS, Brazil. Phytopathology 77:980-984. Accepted for publication 7 January 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/Phyto-77-980.

The occurrence and distribution of macrocyclic trichothecenes in Baccharis spp. plants and the soil in which they were growing were investigated. The six major macrocyclic trichothecenes found were roridins A, D, and E in B. coridifolia and baccharinoids B3, B4, and B5 in B. megapotamica. Not all plants or plant parts contained trichothecenes, however, and amounts varied from 0 to 480 ppm. Some soils in which Baccharis spp. plants were growing also contained trichothecenes. Myrothecium spp. known to produce macrocyclic trichothecenes in culture constituted less than 1% of the fungal colonies isolated from soil and rhizospheres. In liquid culture and on rice, only one isolate of Myrothecium spp. produced macrocylic trichothecenes. Baccharis spp. are probably acquiring fungally produced macrocylic trichothecenes (roridins) and in some cases metabolizing these toxins to baccharinoids. The fungal species responsible is not as yet known, however.