Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2002
Publication Date: N/A
Interpretive Summary: Fusarium head blight (FHB) or scab re-emerged in the 1990's as a major disease of wheat and barley in the U.S. and Canada. As they infect the plants, the fungi that are the primary causes of FHB produce deoxynivalenol (DON), a mycotoxin that enhances disease severity and poses a health hazard to humans and monogastric animals. To reduce the effects of DON on wheat, we used genetic transformation to introduce a gene that directs the modification of DON to a less toxic derivative. We detected expression from the introduced gene in four different transgenic plants and transgene-encoded enzyme activity in one of them. The flowers of the latter plants showed increased resistance, compared to non-transformed plants of the same cultivar, to the spread of infection after innoculation with spores from the fungi that causes FHB. If the protection conferred by the transgene is confirmed in field infection conditions, its deployment could increase Fusarium resistance of the wheat crop and reduce the levels of harmful mycotoxins in the wheat grain. This is the first report of the successful use of a fungal gene to combat fungal infection in wheat.
Technical Abstract: Fusarium head blight occurs in cereals throughout the world and is especially important in humid growing regions. Fusarium head blight (FHB) has re-emerged as a major disease of wheat and barley in the U.S. and Canada since 1993. The primary causal agents of FHB, F. graminearum and F. culmorum, can produce deoxynivalenol (DON), a trichothecene mycotoxin that enhances disease severity and poses a health hazard to humans and monogastric animals. To reduce the effects of DON on wheat, we have introduced FsTRI101, a Fusarium sporotrichioides gene formerly known as TriR, into the regenerable cultivar Bobwhite. TRI101 encodes an enzyme that transfers an acetyl moiety to the C3 hydroxyl group of trichothecenes. Four different transgenic plants carrying the FsTRI101 gene were identified. Although expression levels varied among the four lines, all accumulated FsTRI101 transcripts in endosperm and glume. TRI101-encoded acetyltransferase activity was detected in endosperm extracts of one plant that accumulated FsTRI101 mRNA. Greenhouse resistance tests indicated that the accumulation of FsTRI101-encoded acetyltransferase confers partial protection against the spread of F. graminearum in inoculated wheat heads (spikes).