Submitted to: National Fusarium Head Blight Forum Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/30/2001
Publication Date: N/A
Technical Abstract: Host plant resistance is an efficient, cost-effective and environmentally friendly way to fight plant disease and would be particularly helpful in decreasing grower losses due to Fusarium head blight. More sources of resistance, preferably tagged with molecular markers, are needed. We are using genetic transformation in a biotechnology approach to introduce novel candidate anti-Fusarium genes into hexaploid wheat. The genes encode proteins targeted against either the fungus itself or the mycotoxins it produces during infection. Six different candidate anti-Fusarium coding regions were fused to the maize Ubi1 promoter, first intron and exon for widespread expression. Several transgenic plants have been obtained for each construct. The transgenics show a range of expression levels in semi-quantitative RT-PCR assays. On average, expression from a construct with a wheat coding region is higher than from those with fungal coding regions. Homozygous plants have been identified for many of the transgenic events. Ten of these have been tested in greenhouse trials for Type II resistance. Two transgenic lines exhibited small increases in resistance, compared to their non-transformed parent, in three independent tests. One of these lines accumulates DON acetyltransferase enzyme activity encoded by a transgene containing the Fusarium sporotrichioides TRI101 gene. The other line contains a transgene that encodes a Fusarium venenatum glucanase (FvGlu). In an effort to boost the expression levels of the two most promising transgenes, we have modified sections of the FvGlu and TRI101 coding regions to make them more wheat-like in sequence. These improved constructs are currently being introduced into wheat.