Location: Crop Production and Pest Control Research
Project Number: 5020-21220-014-000-D
Project Type: In-House Appropriated
Start Date: Mar 17, 2022
End Date: Mar 16, 2027
Objective 1: Investigate the mechanisms of fungal pathogenicity and other important biological traits in cereal crops. Sub-objective 1.A: Develop an improved genome sequence for the tar spot pathogen of maize, Phyllachora maydis. Sub-objective 1.B: Identify proteases and other potential effectors expressed by pathogens of wheat, barley and maize that are involved in pathogenicity. Sub-objective 1.C: Identify and test the function of genes expressed by fungal pathogens of wheat that are involved in survival and pathogenicity. Objective 2: Analyze microbiomes associated with resistance and susceptibility to identify vulnerabilities in fungal pathogens of cereal crops. Objective 3: Identify, genetically map and functionally characterize host resistance against fungal pathogens of cereal crops. Objective 4: Exploit knowledge of host-pathogen interactions and pathogen vulnerabilities to develop novel methods for increasing resistance in cereal crops. Sub-objective 4.A: Engineer gene-for-gene resistance to Fusarium Head Blight in wheat and barley. Sub-objective 4.B: Functional identification of wheat genes able to confer resistance to Fusarium head blight and crown rot (FCR) when their expression is induced by ethylene treatment.
Diseases caused by fungal pathogens pose significant economic threats to grain crop production. Currently, little is known about the molecular and genetic mechanisms that govern host resistance and fungal virulence in wheat. Research objectives and approaches in this project focus on identifying genes expressed by the host and the fungal pathogens during infection. The primary subjects of research will be septoria tritici blotch (STB) and Fusarium head blight (FCHB) and crown rot (FCR) of wheat. We will utilize RNA sequencing to identify wheat genes expressed during different types of resistance responses and fungal genes involved in pathogenicity and other important biological processes. Some of the host materials will include recently developed isogenic lines for resistance genes against STB. These genes are on different wheat chromosomes and the isogenic lines will allow us to test the hypothesis that they use different mechanisms for resistance. We will analyze nonhost resistance responses in interactions between barley and wheat inoculated with Mycosphaerella graminicola and Septoria passerinii, respectively. Gene function in the pathogens will be confirmed by generating knockout mutants and testing for phenotype and in the host by Virus-Induced Gene Silencing (VIGS). We also will use comparative genomics of resequenced isolates to identify essential genes in M. graminicola and will use these plus others identified from the RNA-seq experiments for both pathogens to identify genes that can be targeted for Host-Induced Gene Silencing (HIGS) to increase the level of resistance in wheat. Additional objectives are to develop a CRISPR/Cas9 system for M. graminicola and to do finescale genetic mapping for developing additional molecular markers linked to the resistance genes. Successful completion of the objectives will contribute to the basic understanding of diseases caused by plant-pathogenic fungi and will provide clues about potential targets for genetic modification of the crop to prevent or circumvent damage resulting from fungal pathogens.