Submitted to: Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/4/2006
Publication Date: 8/2/2006
Citation: Manoharan, M., Dahleen, L.S., Hohn, T.M., Neate, S.M., Yu, X., Alexander, N.J., Mc Cormick, S.P., Bregitzer, P., Schwarz, P.B., Horsley, R.D. 2006. Expression of 3-OH trichothecene acetyltransferase in barley (Hordeum vulgare L.) and effects on deoxynivalenol. Plant Science. 171:699-706. Interpretive Summary: Fusarium head blight (FHB) has been one of the most destructive diseases of barley in the USA since the early 1990s, causing large economic losses for growers. The fungus also produces toxins like deoxynivalenol (DON), which are harmful to humans and livestock. We inserted a gene (TRI101) from a Fusarium fungus that modifies DON to a less toxic form and tested the transgenic barley plants to see if TRI101 had any effect on FHB and/or DON. Plants tested in the greenhouse with low stress and moderate disease levels showed reduced FHB and DON. When plants were grown in the field under higher stress and disease levels, they had more disease and toxin accumulation than non-transgenic plants. This lack of effectiveness in the field may be from mutations caused by the transformation procedure.
Technical Abstract: Fusarium Head Blight (FHB), caused primarily by Fusarium graminearum, has been the most destructive disease of barley (Hordeum vulgare L.) in the USA since the early 1990s, resulting in large economic losses for growers. The fungus produces the mycotoxin deoxynivalenol (DON), a protein synthesis inhibitor and potential pathogen virulence factor, which is harmful to humans and livestock. Chemically modifying DON could improve FHB resistance while reducing DON accumulation in the grain. We introduced TRI101, which encodes a 3-OH trichothecene acetyltransferase that converts DON to a less toxic acetylated form, into the cultivar Conlon through particle bombardment of callus in an attempt to create resistance against FHB and to detoxify DON. Southern analyses confirmed seven independent integrations of TRI101 into the barley genome. Northern, Western and trichothecene acetyltransferase activity analyses confirmed the inheritance and expression of TRI101 in the progenies of three independent transgenic lines. Greenhouse tests of T3 and T4 transgenic lines showed a significant reduction in FHB infection and/or DON concentration. Field tests of T2-T4 transgenic showed mixed results for FHB severity and DON accumulation, with high inoculum levels and conducive environmental conditions easily overwhelming any protection offered by TRI101.