Guixia Hao 1, Nicholas Rhoades 1,2, Harold N. Trick 3, Susan McCormick 1
1. USDA, Agricultural Research Service, National Center for Agricultural Utilization Research, Mycotoxin Prevention and Applied Microbiology Research Unit., Peoria, IL. 61604, USA.
2. Oak Ridge Institute for Science and Education, USDA, Agricultural Research Service, National Center for Agricultural Utilization Research, Mycotoxin Prevention and Applied Microbiology Research Unit, Peoria, IL 61604, USA.
3. Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA.
Corresponding Author: Guixia Hao, Phone (309-681-6520); Email (guixia.hao@usda.gov)
Hao, Guixia
The fungal
pathogen Fusarium graminearum causes Fusarium head blight (FHB)
and produces various mycotoxins that contaminate grains and cause profound
health problems in humans and animals. Deoxynivalenol (DON) is the most prevalent
trichothecene mycotoxin found in contaminated grains. Our previous study showed
that transgenic wheat cultivar, Bobwhite, expressing F. graminearum trichothecene 3-O-acetyltransferase (FgTRI101)
can increase FHB
resistance and DON reduction. To further enhance FHB resistance and reduce
mycotoxin contamination, FgTRI101 was modified based on wheat
translational codons to increase its expression; Then, the modified mTRI101
was synthesized and introduced into moderately FHB resistant wheat cv Fielder
and Forefront, driven by the maize ubiquitin promoter (Ubi-1). Three
independent Fielder transgenic lines and one Forefront line containing mTRI101
were identified. Gene expression studies revealed high expression levels of mTRI101
in both wheat leaf and spike tissues in the transgenic lines. The
phytotoxic effects of purified DON on the root growth of transgenic wheat expressing
mTRI101 were compared to non-transgenic and parent controls. The mTRI101
transgenic seedlings had significantly longer root lengths on media containing
DON than the controls. The conversion of DON to 3-ADON in the mTRI101 transgenic
wheat florets was detected. FHB evaluation assays showed that transgenic wheat
plants expressing mTRI101 enhanced FHB resistance. Significantly less
DON accumulation was observed in mTRI101 expressing lines, but no 3-ADON
was detected in infected wheat spikes, suggesting that 3-ADON is unstable in
wheat. Our study suggests that the introduction of a codon-optimized mTRI101
gene in a moderately resistant wheat background is a promising strategy to
control FHB and mycotoxin contamination.
This material is based upon work supported by
the U.S. Department of Agriculture. This is a cooperative project with the U.S.
Wheat & Barley Scab Initiative. Any opinions, findings, conclusions, or
recommendations expressed in this publication are those of the author(s) and do
not necessarily reflect the view of the U.S. Department of Agriculture.
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