An examination of stripe rust-winter wheat pathosystem in Ontario to improve genetic gain in breeding programs

Principal Investigator

Alireza Navabi

Research Institution

University of Guelph

Project Start

April 2017

Project End

March 2020

Objectives

  • Monitor the spread of the stripe rust pathogen (Puccinia striiformis) and characterize the races of stripe rust found in Ontario over the course of the project.
  • Study the symptoms of stripe rust in seedling and adult plant stages in a winter wheat breeding population and a winter wheat diversity panel.
  • Conduct a genome-wide search for stripe rust resistance genes in Winter wheat
  • Develop new molecular marker breeding tools as breeder-friendly assays to improve selection for rust resistance genes in breeding and to use these tools in pyramiding resistance to rusts with tolerance against Fusarium head blight (FHB) in wheat.
  • Understand the mechanism at the molecular level, by which wheat plant can defeat the attack by the pathogen.

Impacts

  • The understanding of the distribution of the stripe rust can be used by growers to choose appropriate disease management solutions, including choosing winter wheat with stripe rust resistance.
  • The development of new breeding tools may improve the efficiency of selecting resistance to stripe rust and allowing breeders to produce winter wheat varieties with resistance to both Fusarium head blight and stripe rust.
  • Understanding the molecular mechanism of rust resistance is what can significantly impact future progress in breeding for rust resistance.

Scientific Summary

The value of wheat crop in Ontario is estimated to be around $550 million per year. High yield and quality of Ontario winter wheat is seriously threatened by biotic and abiotic stresses, among which Fusarium head blight (FHB, caused by the fungal pathogen Fusarium graminearum) has historically been most damaging. The mycotoxin produced by this fungus is harmful for human health and livestock feed and productivity. More recently, stripe rust (or yellow rust YR, caused by the fungal pathogen Puccinia striiformis) has been causing serious damage to wheat production in Ontario. The stripe rust epidemic in Ontario wheat in 2016 was record-breaking with severities as high as 100% on susceptible winter wheat varieties in some areas. The reason for this is that the new races of stripe rust in North America are more aggressive and can tolerate higher spring temperatures. Conventional chemical fungicides are commonly used as an important mean to control these diseases. However, they are an added cost to producers. The use of genetically-resistant varieties and natural plant defense activators (PDAs) are among the most promising approach to control different plant diseases. Genetic resistance against diseases is often conditioned by the products of resistance genes that detect the pathogen and initiate a cascade of signaling events triggering defense mechanisms that combat the infection. Combining adult resistance genes with other seedling resistance genes is generally-known as an effective breeding strategy to achieve durable resistance to rust disease in wheat.

This research is designed to address the growing threat from stripe rust through a better understanding of the host-pathogen interaction. The project will expand the current winter wheat breeding program at the University of Guelph on fusarium head blight resistance breeding to include more focused work on the rust diseases. This project is expected to benefit Ontario winter wheat growers and the wheat industry in general by providing a better understanding of stripe rust races in Ontario, which are migrating from the south. Molecular markers will be used to identify major and durable resistant genes in wheat materials and to develop molecular tools for breeders to be able to select for resistance, even in the absence of disease. The potential development of molecular selection tools will provide the required information for winter wheat breeders to target the right combination of genes in their breeding programs for resistance to stripe rust.

External Funding Partners

Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA)-University of Guelph funding partnership

Matching in-kind contributions to Southern Ontario Smart Computing Innovation Platform (SOSCIP) and Ontario Centres of Excellence (OCE) expands this project’s objectives to include examining disease resistance in Fusarium, stripe rust and diseases in general.

Grain Farmers of Ontario is the province’s largest commodity organization, representing Ontario’s 28,000 barley, corn, oat, soybean and wheat farmers. The crops they grow cover 6 million acres of farm land across the province, generate over $2.5 billion in farm gate receipts, result in over $9 billion in economic output and are responsible for over 40,000 jobs in the province.