Page 163 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

coumarate-CoA-ligase and chalcone-flavanone-isomerase triggered by Sys treatment. In addition, the
proteomic and enzymatic analyses revealed that Sys conditioned the primary metabolism towards the
production of available sugars that could be fuelling the priming of callose deposition in Sys-treated
plants; furthermore, PR1 appeared as a key element in Sys-IR. Collectively, the direct induction of
proteins and priming of specific secondary metabolites in Sys-treated plants indicated that
posttranslational protein regulation is an additional component of priming against necrotrophic fungi.

[O120] BLACKLEG PREVENTION IN POTATO BY PATHOGEN AND BACTERIOPHAGE
IDENTIFICATION. Binod Pageni, Michele Konschuh, Jonathan Neilson, Melanie Kalischuk, and
Lawrence Kawchuk. Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada,
5403 – 1 Avenue South, Lethbridge, AB, Canada, T1J 4B1; Department of Biological Sciences, 4401
University Drive, University of Lethbridge, Lethbridge, AB, Canada, T1K 3M4; and Department of Plant
Agriculture, 601 Gordon Street, University of Guelph, Guelph, ON, Canada, N1G 1Y2
Correspondence to: lawrence.kawchuk@agr.gc.ca

Pectobacterium and Dickeya species are Gram-negative pectolytic pathogens that may cause blackleg
and soft rot in potato. Blackleg is a seed-borne disease distributed largely by movement of certified
potato seed within and between potato growing areas. Analysis of diseased potato samples from western
Canada between 2021 and 2024 by multi-locus sequence typing (MLST) revealed an increase in the
Pectobacterium species diversity and confirmed the absence of the relatively aggressive Dickeya
species. Previous studies reported that blackleg and soft rot in Canada were caused mostly by
Pectobacterium atrosepticum and Pectobacterium carotovorum. Recovery of additional Pectobacterium
species, including Pectobacterium polaris, Pectobacterium parmentieri, and most recently Pectobacterium
brasiliense, was observed in the present study. Pectobacterium brasiliense is considered one of the most
pathogenic species among the Pectobacteriaceae and has a broad host range among horticultural crops.
An expanding industry increases disease pressure by seed movement between regions and
environmental conditions associated with climate change, appear to be contributing to blackleg incidence,
diversity, and impact. Although low temperatures and high moisture levels at sprouting usually increase
the incidence of blackleg, the occurrence of highly pathogenic Pectobacterium species results in blackleg
even under relatively dry warm conditions. Identifying closely related blackleg pathogens through the
development of in-field isothermal diagnostics provides easy and rapid confirmation of bacterial species
associated with disease. Isolation and genomic sequencing of blackleg pathogen endemic lytic
bacteriophage from field samples, identified members of the Podoviridae, Myoviridae, and
Siphoviridae. Most phage show a high specificity, only infecting one pathogen from specific farms or
regions, but broad host range phage were occasionally isolated. Identification of specific sequences such
as clustered regularly interspaced short palindromic repeats (CRISPR) Cas 4 RecB-like nuclease in some
phage suggests an ability to defeat the pathogen’s defensive capabilities. Laboratory and field trials
confirmed that the phage reduced disease incidence and severity and increased yields by 100%,
providing an environmentally friendly biocontrol treatment to enhance potato production for an expanding
market.

*[O121] SOIL MICROBIOME AND SOIL PROPERTIES ASSOCIATED WITH THE RISK OF CAVITY
SPOT ON CARROTS IN HIGH ORGANIC MATTER SOILS. Umbrin Ilyas , Lindsey J. du Toit , M.
1
2
1 1
1
Kalischuk , and Mary Ruth McDonald . Department of Plant Agriculture, University of Guelph, Guelph,
Ontario, Canada, N1G 2W1; and Department of Plant Pathology, Washington State University, Mount
2
Vernon, WA, USA, 98273
Correspondence to: uilyas@uoguelph.ca

Cavity spot is an economically important disease of carrot that is caused by several soilborne species of
Pythium and Globisporangium. The disease appears as superficial dark lesions on carrot roots impacting
quality. Currently, disease management is limited to pre-seeding fungicide application, and avoidance of
fields with a history of cavity spot. Diagnostic tools are unavailable to identify fields with high-risk for cavity
spot. It is hypothesized that the soil microbiome and soil properties, in addition to soilborne inoculum,
influence disease development. Bulk muck soil (organic matter 40–80%) was collected from six fields in
2021, twelve fields in 2022, and twelve fields in 2023 in the Holland Marsh, Ontario. These samples were
collected soon after seeding for microbiome and soil nutrient analysis. The fields were grouped as low or
high-risk based on cavity spot severity assessed in previous years by the local integrated pest

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