Evaluation of the root-associated fungus Olpidium brassicae and its interactions with Plasmodiophora brassicae
Term: 3 years, beginning in 2023
Status: Ongoing
Researcher(s): Jennifer Town, Agriculture and Agri-Food Canada
SaskCanola Investment: $167,200
Total Project Cost: $41,800
Funding Partners: TBC
Objectives
Examine the relationship between O. brassicae colonization and P. brassicae infection and disease severity.
Sequence the genome for O. brassicae strain ‘d3f1’.
Conduct a meta-analysis of O. brassicae distribution during canola production in SK and AB.
Project Description
New knowledge of the impact of clubroot infection on the diversity and composition of the root and rhizosphere microbiome in canola. Clubroot is one of the biggest threats to the canola industry in Western Canada, causing significant economic impacts to producers. Identifying the role of root epiphytes and endophytes in clubroot infection and severity can inform best management practices for producers to minimize clubroot related losses.
New knowledge of the impact of Olpidium brassicae colonization on canola roots on the severity of clubroot disease. We have found O. brassicae to be ubiquitous and highly abundant in canola grown across SK and AB, however the effect of this fungus on canola health, yield and susceptibility to disease remains unclear. A better understanding of the relationship between O. brassicae and clubroot infection and severity will help to quantify potential yield risks in low-diversity canola rotations. High quality draft genome sequence for the most common strain of Olpidium brassicae. Our previous research found that one particular strain of O. brassicae was ubiquitous and abundant in the soil, rhizosphere and root of canola samples from multiple sites in SK and AB.
A high-quality genome sequence of this strain will provide the first publicly available genome sequence for this species. It will also provide the opportunity to identify any genomic insights into possible mechanisms of infection, metabolism and pathogenicity. This in turn could provide further insight into the role of this fungus on canola health and yield, as well as further insights into mechanisms of infection for other zoosporic biotrophs including P. brassicae. New knowledge on the relationship between Olpidium brassicae colonization and agronomic performance. Our meta-analysis will include microbiome and agronomic data for studies across multiple sites in SK and AB, and facilitate a robust examination of the correlation between the abundance and diversity of O. brassicae strains and agronomic performance indicators. This analysis will help to identify any economic risks associated with low-diversity rotations and will be used to inform best management practices for canola production in Western Canada.
The root microbiome is the first line of defense against soil-borne pathogens including clubroot, one of the biggest threats to the canola industry in Canada. For this reason, it is critical to identify the role of root colonizers and endophytes in clubroot infection and overall plant health. Previous research by our group has identified a fungus, Olpidium brassicae, that is ubiquitous in the soil, rhizosphere, and root of canola in Western Canada and hyper-abundant under low-diversity rotations. Recent updates to the taxonomic classification of species within Olpidium has redefined the molecular identification of O. brassicae, however its role in the health of canola is unknown. Current literature describes this fungus as having either neutral or negative effects on yield depending on cultivar, management, and growing site. A better understanding of the role of this fungus in canola health will help identify any performance-related consequences from microbiome changes in low diversity rotations and whether they are cultivar- or site-specific. Understanding why O. brassicae is able to dominate the root fungal community and how it interacts with other zoosporic microorganisms, including plant pathogens such as the clubroot pathogen Plasmodiophora brassicae will provide important insights about mechanisms of root infection in Brassicas, potentially providing new targets for pathogen resistance. There has been very little information reported on the canola root-associated microbiota in the context of clubroot infections, with a recent Scopus search revealing a single manuscript examining the root microbiome in clubroot infected vs. healthy plants. These researchers determined that the composition of the root endosphere microbial communities of plants was impacted significantly by clubroot infection and suggested that microorganisms in the ecological niche of the root play a role in clubroot resistance. Our approach can provide data that will aid in elucidating the effects of clubroot infection on the root associated microbial ecosystem, including endophytes and rhizosphere microorganisms. Moreover, we will investigate the presence, abundance, and microbial co-associations of O. brassicae in the context of clubroot infections. They will use clubroot resistant near isogenic lines of canola that they have access to, and will compare rhizosphere microbiomes of each of those lines and compare to susceptible parental lines. 3 different soil types and clubroot pathotypes (5X and 6B, or mock control) will also be tested. Soil microbiomes will be collected over 28days post inoculation with the pathogen to determine changes to the microbiome communities over time.