EXPLORING THE ROLE OF ETHYLENE SIGNALING IN FUSARIUM HEAD BLIGHT RESISTANCE (FHB) AND SUSCEPTIBILITY
Crop Production and Pest Control Research
2012 Annual Report
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.
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. This Specific Cooperative Agreement is focused on the generating transgenic wheat plants that overexpress these genes. Once available, the transgenic plants will be tested for improved Fusarium head blight (FHB) resistance. During FY12, full-length cDNAs were cloned into transformation vectors and transferred to Kansas State University for wheat transformation. Transgenic wheat plants are currently being generated. During FY12, trangenic lines overexpressing an ethylene responsisve transcription factor that plays an essential role in FHB resistance were identified and homozygous lines are currently being bulked so that adequate seed will be available to conduct tests for improvement in FHB resistance.