Volatile signals from non-host plants deter growth and aflatoxin production by the fungus Aspergillus
M. BRODHAGEN (1), R. Kelsey (2), J. Young (3), A. Batson (4), J. Levy (3), J. McCollum (5), B. Kinash (6) (1) Western Washington University, U.S.A.; (2) US Forest Service, U.S.A.; (3) Western Washington University, U.S.A.; (4) Adaptive Symbiotic Technologies, U.S.A.; (5) Infectious Disease Research Institute, U.S.A.; (6) Twiss Labs, U.S.A.

Volatile signals mediating intra- and interspecific organismal interaction are widely described, and fungi are no exception. We present evidence that non-host plant volatiles inhibit 1) growth and 2) secondary metabolism of Aspergillus. First, we observed that incubation of Aspergillus nidulans spores with aqueous extracts from freshly-ground non-host (Arabidopsis thaliana) seeds resulted in an Aspergillus-inhibitory, volatile signal. Signal generation required contact between spores and seed extract: fungi cultured above a spore/seed extract mixture produced ten-fold fewer conidia than fungi cultured above the seed extract or water controls.  In a second set of experiments, we observed that volatiles from extracts of Abies amabilis inhibited aflatoxin production by A. flavus.  We first screened extracts against indicator strains that accumulate the pigmented aflatoxin precursor, norsolorinic acid.  The reduction of norsolorinic acid in the presence of A. amabilis volatiles was correlated with a reduction in aflatoxin concentrations.  Individual compounds abundant in A. amabilis extracts that also inhibited norsolorinic acid accumulation were the terpenes β-pinene and 3-carene.  Together, our data from these diverse experiments suggest that Aspergillus perceives and responds to a milieu of airborne information, including those signals generated by non-hosts.

Abstract Number: P8-227
Session Type: Poster