Page 160 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

influenced by the plant's ripening stage. To address these limitations, we aim to enhance the phenotyping
process by developing a quantitative PCR (qPCR) method that accurately differentiates levels of
quantitative resistance to V. longisporum in canola genotypes under field conditions. In this study, we are
screening a diverse collection of 260 B. napus genotypes for resistance to VS using qPCR. Genome-wide
association studies (GWAS) will be employed to identify QTL associated with VS resistance. The GWAS
panel includes commercial canola cultivars, re-synthesized B. napus genotypes, and other genetically
diverse germplasm. Upon identifying the most relevant polymorphisms, such as SNPs and Indels in the
VS resistance QTL, we will develop KASP or simple PCR-based markers. These markers will be pivotal in
introducing newly identified VS resistance alleles into elite Western Canadian breeding materials and
cultivars. Our research aims to provide a robust tool for improving canola resistance to verticillium stripe,
enhancing yield stability and sustainability for canola producers in Western Canada.

*[O115] IDENTIFICATION OF MICROORGANISMS WITH CLUBROOT BIOCONTROL POTENTIAL
1
2
AND INVESTIGATION OF MECHANISMS OF THEIR ACTION. Ananya Sarkar , Anna Kisiala , Vedanti
2
1
1 1
Ghatwala , Neil Emery , Habibur Rahman , and Nat N.V. Kav . Department of Agricultural, Food &
2
2
Nutritional Science, University of Alberta, Edmonton, AB, Canada; and Biology Department, Trent
University, Peterborough, ON, Canada
Correspondence to: asarkar@ualberta.ca

Clubroot disease, caused by Plasmodiophora brassicae, results in substantial crop losses in crucifers in
Canada and worldwide. The disease forms club-shaped galls in susceptible Brassica hosts that reduce
yield and productivity. Microbial biocontrol agents can antagonize plant pathogens through their wide
range of mechanisms, including induction of broad-spectrum resistance. In our study, we observed
improvement in plant parameters when susceptible Brassica napus roots were treated with selected
Bacillus, Pseudomonas and Trichoderma strains in presence of P. brassicae pathotypes 2B, 3H, 3D and
5X-LG1. Application of a cocktail formulation comprising of Bacillus atrophaeus (DSM 7264),
Pseudomonas parafulva (DSM 17004) and Trichoderma virens (DSM 1963) resulted in up to 35%
reduction of clubroot severity, as well as improvement in plant parameters such as root length, length of
inflorescence and number of silique against pathotype 3H. Levels of endogenous phytohormones (e.g.
auxin, jasmonic acid, cytokinin (CK) ribosides and glucosides) as well as secondary metabolites (e.g.
coniferin, syringin) and glucosinolates (e.g, gluconasturtiin, glucobrassicin) were altered in the roots of
treated plants across 1-, 4-, and 7 days post-inoculation (DPI), along with modulation of gene expression
related to these biological metabolites and their pathways. Additionally, analysis of CKs secreted by the
individual microbial strains revealed striking differences in CK forms (e.g. free-bases, ribosides,
glucosides) and types (e.g. cZ and iP) in both those released to the culture supernatant and retained in
the cellular pellet fractions. These differences may represent important underlying factors to account for
the beneficial effects observed on treated plants. Taken together, our results suggest that the three
microbial strains identified may be used for biocontrol of clubroot disease in canola and have provided
insights into their possible modes of action, which will be useful for research that develops new agents of
biocontrol.

[O116] MODULATION OF PLASTIDIAL PROTEIN TURNOVER BY PBPAE, A PLASMODIOPHORA
BRASSICAE PLASTID-ASSOCIATED EFFECTOR THAT FACILITATES CLUBROOT DISEASE
PROGRESSION IN ARABIDOPSIS. Musharaf Hossain, Christopher D. Todd, Yangdou Wei, and Peta C.
Bonham-Smith. Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK,
Canada, S7N 5E2
Correspondence to: musharaf.hossain@usask.ca

Clubroot disease, caused by the soilborne protist Plasmodiophora brassicae, is a major threat to
Canada’s ~$30 billion annual canola industry. A typical disease symptom is the formation of root galls,
through induced hyperplasia and hypertrophy of infected tissues, establishing in a nutrient sink to sustain
intracellular pathogen development. As an intracellular obligate biotroph, Plasmodiophora brassicae
secretes an array of effectors while colonizing host plant root tissues, resulting in clubroot disease. During
P. brassicae pathogenesis amyloplast (containing starch grains) abundance increases and they become
tightly associated with secondary plasmodial structures prior to their dynamic turnover during late
secondary stage clubroot progression. To date, P. brassicae effectors required for the manipulation of
source-sink carbon allocation, together with the identity of host metabolite transporters seconded to the

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