Understanding the role of the clubroot pathogen kinases in disease progress and resistance

Term: 4years, beginning in 2023
Status: Ongoing
Researcher(s): Edel Perez-Lopez, Laval University
SaskCanola Investment: $200,000
Total Project Cost: $449,650
Funding Partners: ACPC, MCGA

Objectives

Objective 1: To characterize clubroot host response to the presence of PbPKs.

1.1. In Arabidopsis thaliana

1.2. In Brassica napus

Objective 2: To identify the molecular mechanisms behind the phenotypes induced by PbPKs.

Project Description

Clubroot is a devastating disease putting at risk the Canadian canola industry. Nowadays clubroot management heavily relies on the use of clubroot resistant varieties. However, the current reality is that the resistance is being rapidly overcome by P. brassicae1, calling for new and well understood sources of resistance. Although there have been more than 70 clubroot resistance genes or loci reported, the mechanism mediating the resistance, or the identity of these genes is unknown, although several of these genes have been identified as nucleotide-binding leucine-rich repeat (NLR) receptors. Something we know is that to trigger NLR-mediated resistance, these receptors must interact directly or indirectly with pathogen avirulence factors.

Unfortunately, the identity of clubroot avirulence factors is also unknown, but our previous and new results indicate that the clubroot pathogen kinase proteins might be playing a key role on mediating resistance or tolerance to the clubroot pathogen4,5. Here, we will explore which of the 27 putative annotated protein kinases secreted by the clubroot pathogen induce resistance and the mechanisms mediating the resistance. The proposed research will fill existing gaps in the canola industry and will be essential for canola farmers and the canola industry in the long-term management of the clubroot disease.

Among the diseases affecting canola, clubroot caused by Plasmodiophora brassicae is one of the biggest threats for the Canadian canola industry. As genetic resistance to clubroot is breaking down, there is an urgent need to understand why, and to explore alternative sources of disease control. This is one of the main challenges facing the industry, the needs to identify new sources of clubroot resistance and to understand the mechanisms mediating the resistance. Based on other mechanisms mediating plant resistance to plant pathogens and our previous results, we hypothesize that the clubroot pathogen kinases could be triggering clubroot resistance and/or tolerance that can be exploited to improve canola elite cultivars. The main objective of this project is to identify and characterize the role of clubroot pathogen kinases in disease progress and resistance. This work will contribute to the development of new and successful clubroot resistant cultivars and will also expand our knowledge of the clubroot pathogen, two priorities of the Canola Agronomic Research Program. The proposed research addresses both our knowledge of clubroot resistance, and how this resistance works. Altogether, this research will contribute greatly to P. brassicae management and will empower canola breeders to make informed decisions when new varieties are developed and to canola producers to have access to better clubroot resistance and to have high production with or without the clubroot pathogen in their fields.