Page 219 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

growing regions, including Phytophthora root rot. In the 2023 growing season, 58 soybean fields were
surveyed in Manitoba for root diseases, and Fusarium root rot was found to be the most prevalent root
disease. Phytophthora sojae was detected in 84% of soil samples from the surveyed fields using
molecular pathotyping. Additionally, charcoal rot, caused by Macrophomina phaseolina, was also
identified in 2023 in Manitoba, where it was first reported in 2020. Furthermore, a long-term field study
conducted near Brandon from 2014 to 2023 evaluated the effects of five crop rotations on soybean root
diseases. The soybean-based rotation study comprises five crop rotations of soybean(S), canola(C) and
wheat (W) with SC, SW, SWC, SCW and SSW, ranging in duration from two to three years in length. The
results suggest that longer crop rotations with greater diversity tend to exhibit lower severity of soybean
root rot disease in certain years, compared to shorter rotations or continuous soybean cropping. In
summary, soybeans have become Manitoba’s most important grain legume crop, and ongoing research
continues to shed light on effective disease management strategies.

*[P32] PATHOTYPE SHIFTING OF SINGLE-SPORE ISOLATES OF PLASMODIOPHORA BRASSICAE
OVER THREE MULTIPLICATION CYCLES. B. Kirk, A. Botero-Ramirez, S.F. Hwang, and S.E. Strelkov.
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5,
Canada
Correspondence to: brennon@ualberta.ca

The isolation of single-spores of the soilborne obligate parasite Plasmodiophora brassicae (clubroot of
crucifers) is critical for generating genetically homogeneous pathogen collections. Multiplication of these
isolates on various host genotypes can lead to shifts in their virulence, altering pathotype designations
and affecting research outcomes, particularly in resistance labeling for new crop varieties. In this study,
four single-spore isolates (SSIs) were used, two designated as pathotype 3H and two as pathotype 3A,
based on their virulence on the Canadian clubroot differential set (CCD). These SSIs were obtained from
a single gall previously classified as pathotype 3A that underwent three cycles of multiplication on the
susceptible host ECD05 (B. rapa var. pekinensis cv. ‘Granaat’) prior to initial testing. Two additional
multiplication cycles were conducted in ECD05 and a first-generation clubroot-resistant canola (Brassica
napus) cv. ‘45H29’. After each multiplication cycle, changes in the virulence pattern of each isolate were
assessed on a subset of CCD hosts, comprising ECD05, ECD06 (B. napus cv. ‘Nevin’), ECD10 (B. napus
var. napobrassica cv. ‘Wilhelmsburger’), B. napus cv. ‘Mendel’, and ‘45H29’. After four multiplication
cycles (three before the initial pathotyping and an additional round), three pathotypes retained their
original designations. However, one pathotype showed decreased virulence on three hosts (ECD10,
‘Mendel’, and ‘45H29’) following multiplication on ECD05, resulting in a shift in the pathotype designation
from 3A to 3D. These results emphasize the importance of strategic stewardship of P. brassicae
collections to maintain their stability and reliability, thereby enhancing the effectiveness of research and
breeding activities.

*[P33] FUSARIUM HEAD BLIGHT AND RUST FUNGI IDENTIFICATION VIA MALDI-TOF MASS
1
2 1
SPECTROMETRY. Shimosh Kurera , Matthew Bakker , and Sean Walkowiak . Department of
1,2
Microbiology, University of Manitoba, Winnipeg, MB, Canada R3T 2N2; and Canadian Grain
2
Commission, 196 Innovation Dr, Winnipeg, MB, Canada R3T 2N2
Correspondence to: sean.walkowiak@grainscanada.gc.ca; matthew.bakker@umanitoba.ca

Grain production contributes significantly to meeting human food and animal feed demands in Canada
and in export markets. One of the key limitations to grain production is fungal disease. Identification of
plant pathogenic fungi is important in effective disease management practices and can have implications
for trade. In this study, we developed a rapid method to identify fungi responsible for Fusarium head blight
(FHB) and rust cereal diseases using Matrix Assisted Laser Desorption/Ionization Time of Flight Mass
Spectrometry (MALDI-TOF MS). MALDI-TOF MS generates unique peptide mass fingerprint (PMF)
graphs from fungal proteins that can be used to distinguish one fungal species from another. To introduce
fungal proteins into the mass spectrometer, different cell types (i.e., mycelia, conidiospores,
urediniospores, or germinated urediniospore-mats) were used from Fusarium and Puccinia spp. To
prepare the protein extract input, fungal cells were disrupted with formic acid followed by addition of
acetonitrile to dissolve proteins. The protein extract is then ionized off of the target plate by the instrument
laser. Proteins in the gas phase travel to a detector, and results are analyzed to generate a PMF graph
for each fungal protein sample. The PMF profile is then compared to a reference library of known PMF

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