Submitted to: Plant Cell Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/29/2005
Publication Date: 4/1/2006
Citation: Mackintosh, C.A., Garvin, D.F., Radmer, L.E., Heinen, S.J., Muehlbauer, G.J. 2006. A model wheat cultivar for transformation to improve resistance to Fusarium head blight. Plant Cell Reports. 25:313-319. Interpretive Summary: The disease Fusarium head blight (FHB) has caused billions of dollars of economic damage to the U.S. wheat crop since 1993. Development of new wheat varieties with improved resistance will reduce crop losses to this disease. One strategy for accomplishing this is to use the process of genetic transformation to introduce novel genes into wheat that will increase FHB resistance. One limiting factor to this approach is that transformation is a slow process, due in part to the long generation time of the current wheat variety used for transformation, as well as the fact that FHB resistance can only be assessed at flowering. This study reports the identification of a wheat variety that has the attributes needed to serve as an alternative choice for transformation research to improve FHB resistance. This wheat variety is susceptible to FHB, is readily transformed, and completes its life cycle far faster than the current variety used for transformation. Further, the dwarf habit of this new variety makes it very easy to grow and manipulate. The use of this alternative variety for FHB resistance transformation research will allow researchers to develop FHB-resistant wheat significantly faster than is currently possible. New FHB-resistant wheat varieties will reduce wheat crop losses due to this disease, and as a result increase grower profits.
Technical Abstract: Fusarium head blight (FHB), caused primarily by the fungal pathogen Fusarium graminearum, is a major disease problem in wheat (Triticum aestivum). F. graminearum infects wheat spikes from anthesis and reduces grain yield. Genetic engineering holds significant potential to aid breeders in their quest to produce FHB resistant wheat. Due to the requirement of FHB screening on mature plants, the number of disease screens that can be carried out in a year on transgenic wheat is limited. The ability to conduct efficient transformation in a wheat cultivar that is more rapidly maturing than the commonly used cultivar Bobwhite would significantly accelerate the ability to screen transgenics for FHB resistance, and subsequently deliver transgenes of interest more rapidly into breeding programs. Our objectives were to evaluate the feasibility of using the rapid-maturing dwarf wheat 'Apogee' as an alternative cultivar for transgenic FHB resistance research. We found that this cultivar regenerated well in tissue culture and transformants could be recovered at approximately 1.33%, a frequency that is similar to the standard wheat transformation cultivar 'Bobwhite'. 'Apogee' was found to exhibit FHB susceptibility at a level similar to that of the common FHB-susceptible check cultivar 'Wheaton'. Further, 'Apogee' reaches anthesis significantly faster than 'Bobwhite' under both growth chamber and greenhouse conditions; under growth chamber conditions the cultivar can be tested for FHB resistance in approximately 4 weeks, and healthy mature seed can be harvested in 2 months. SSR marker haplotype analysis of 'Apogee' indicates that the chromosome 3BS QTL for FHB resistance may be deleted. Our results indicate that 'Apogee' is well-suited for use in accelerating transgenic FHB resistance research.