1a. Objectives (from AD-416):
Full-length cDNAs will be obtained for the wheat SAM-synthase, EIN2 and ERF genes from Ning7840 wheat. Transgenic plants will be generated in the susceptible Bobwhite genotype that constitutively express SAM-synthase, EIN2 and ERF as RNAi constructs. These RNAi lines will be crossed into FHB1 resistant lines. These lines will permit us to confirm that silencing SAM-synthase, EIN2 and ERF, by a method other than VIGS, abolishes FHB resistance. Transgenic plants will be created in the susceptible wheat genotype Bobwhite that express the SAM-synthase, EIN2 or ERF cDNAs constitutively from the maize ubiquitin promoter or specifically in the lemma and palea tissues using the barley Lem1 promoter. T0 seed will be collected from transgenic lines identified as expressing each construct. T1 transgenic plants expressing each construct will be assessed for their resistance or susceptibility to FHB. T0 transgenic lines will be crossed into FHB1 lines to see if the transgenes will augment the resistance provided by FHB1.
1b. Approach (from AD-416):
Previous work by the Crop Production and Pest Control Research Unit has indicated that genes involved in ethylene signaling are essential for type II resistance to Fusarium head blight in wheat. This project will test if overexpresssion of these genes in transgenic wheat will confer FHB resistance to normally susceptible wheat genotypes.
3. Progress Report:
The purpose of this collaborative project is to generate transgenic wheat plants that express transgene constructs designed to improve the resistance to Fusarium head blight. Over the past year the collaborator’s laboratory has performed biolistic transformation of the FHB susceptible variety, Bobwhite, with four constructs designed to overexpress genes functioning in the basal defense pathway. Seeds from the resulting transgenic lines were collected and transferred to the SY’s laboratory, where they have been bulked up and are now being evaluated in greenhouse Fusarium head blight assays. As the basal defense pathway is known to provide defense action a broad range of pathogens, the lines will also be tested for improved resistance against other fungal pathogens.