EXPLORING THE ROLE OF ETHYLENE SIGNALING IN FUSARIUM HEAD BLIGHT RESISTANCE (FHB) AND SUSCEPTIBILITY
Crop Production and Pest Control Research
2010 Annual Report
1a.Objectives (from AD-416)
1. Full-length cDNAs will be obtained for the wheat SAM-synthase, EIN2 and ERF genes from Ning7840 wheat.
2. 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.
3. 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.
4. T0 seed will be collected from transgenic lines identified as expressing each construct.
5. T1 transgenic plants expressing each construct will be assessed for their resistance or susceptibility to FHB.
6. 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.
We are working to identify genes involved in major disease resistance pathways of wheat, so that we can utilize them to engineer wheat with improved disease resistance. The SCA we have established with Kansas State University is focused on the generating transgenic wheat plants that overexpress these genes. Our ARS unit currently lacks the ability to generate transgenic wheat plants. Once available, the transgenic plants will be tested for improved FHB resistance. The main activity in the first year of this project has been the generation of full-length cDNA clones for the genes that will be transformed into wheat and assembly of the transformation constructs. The ADODR monitoring of this project is occurring through frequent phone discussions and email exchanges with the collaborator.