Macrocyclic Trichothecene Mycotoxins in Brazilian Species ofBaccharis

Abstract

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. No 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 or Myrothecium spp. produced macrocylic trichothecences. Baccharis spp. are probably acquiring fungally produced macrocyclic trichothecenes (roridins) and in some cases metabolizing these toxins to baccharinoids. The fungal species responsible is not as yet known, however.