Identifying novel genetic sources of resistance to Verticillium stripe using synthetic Brassica napus lines
Term: 3 years
Status: Ongoing
Researcher(s): Harmeet Singh Chawla, Mohamed Samir Youssef, Fouad Daayf, U of M
SaskOilseeds Investment: $164,833.33
Total Project Cost: $247,250
Funding Partners: MCGA
Objective
Screening the resistance of a broad spectrum of 100 synthetic B. napus lines (= B. rapa X B. oleracea crosses).
Genetic analysis of Verticillium stripe resistance.
Screening the role of root exudates in VL microsclerotia germination.
Development of Molecular marker around the identified polymorphisms.
Project Description
Verticillium stripe (VS), caused by the soil-borne fungus Verticillium longisporum (VL), poses a significant threat to global canola production. The pathogen’s life cycle begins with the germination of microsclerotia in the soil, a process that might be initiated by brassica root exudates.
Following germination, mycelia penetrate the root and ascend to colonize the vascular tissue within the stem and causes Verticillium stripe (VS) disease. Root exudates, which are a complex mixture of organic compounds that are released from living plant roots in the rhizosphere. They may contain amino acids, organic acids, inorganic ions, aromatic acids, amides, aliphatic acids, sugars and volatile compounds in addition to ethylene, peptides, vitamins and enzymes. They play a crucial role in plant-microbe interactions. The interactions between plant and their microbial communities in the rhizosphere can have beneficial impacts on plants, including disease suppression. These exudates can act as chemical signals that either attract or repel microorganisms, including pathogens. Some compounds within the exudates can inhibit the growth or activity of V. longisporum, potentially reducing its ability to infect the plant. Liu et al. reported that root exudates of grafted eggplants inhibited mycelium growth of Verticillium dahliae. Mol and Riessen found that potato root exudates stimulated MS germination of V. dahliae. According to Farley et al., soil moistened with sucrose solution increased MS germination of V. dahliae. But there is little information available about the interaction between V. longisporum and canola root exudates. Therefore, one of the aims of this project is to determine the effect of synthetic canola root exudates (from selected tolerant and susceptible genotypes) on the pathogen V. longisporum. Additionally, the project will examine root exudates from non-host species. Suitable methods such as LC-MS, GC-MS, or HPLC will be used for root exudate profiling and analysis to identify candidate compounds that trigger or inhibit microsclerotia germination and fungal growth.
This disease can lead to yield losses of up to 80% in severe cases. With climate change and increasing inoculum levels exacerbating the issue. Synthetic canola lines, generated from interspecific crosses between B. rapa and B. oleracia, offer extensive genetic diversity and potential resistance traits. The development of resistant canola cultivars is crucial to protect Western Canadian producers from significant yield losses.