Ae. Glenn et al., Detoxification of corn antimicrobial compounds as the basis for isolating Fusarium verticillioides and some other Fusarium species from corn, APPL ENVIR, 67(7), 2001, pp. 2973-2981
The preformed antimicrobial compounds produced by maize, 2,4-dihydroxy-7-me
thoxy-2 H-1,4-benzoxazin-3-one and its desmethoxy derivative 2,4-dihydroxy-
2H-1,4-benzoxazin-3-one, are highly reactive benzoxazinoids that quickly de
grade to the antimicrobials 6-methoxy-2-benzoxazolinone (MBOA) and 2-benzox
azolinone (BOA), respectively. Fusarium verticillioides (= F, moniliforme)
is highly tolerant to MBOA and BOA and can actively transform these compoun
ds to nontoxic metabolites. Eleven of 29 Fusarium species had some level of
tolerance to MBOA and BOA; the most tolerant, in decreasing order, were F.
verticillioides, F, subglutinans, F. cerealis (= F, crookwellense), and F.
graminearum. The difference in tolerance among species was due to their ab
ility to detoxify the antimicrobials, The limited number of species having
tolerance suggested the potential utility of these compounds as biologicall
y active agents for inclusion within a semiselective isolation medium. By r
eplacing the pentachloronitrobenzene in Nash-Snyder medium with 1.0 mg of B
OA per mi, we developed a medium that resulted in superior frequencies of i
solation of F. verticillioides from corn while effectively suppressing comp
eting fungi. Since the BOA medium provided consistent, quantitative results
with reduced in vitro and taxonomic efforts, it should prove useful for su
rveys of F. verticillioides infection in field samples.