Page 220 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

profiles for identification. In this work, a custom reference library was created for several Fusarium and
Puccinia species, strains and races originating from across Canada. To create a single reference profile
for each fungal species/strain/race, 20 PMF graphs were combined. After populating the reference library,
we tested 710 unknown fungal samples isolated from Fusarium damaged kernels of wheat from 2021,
2022 and 2023 harvest years and were able to identify the Fusarium in these damaged kernels to the
level of species. To confirm the identity of these fungi, high-throughput quantitative PCR (HT-qPCR) was
performed using species specific DNA markers. MALDI-biotyping results agreed with the HT-qPCR
results approximately 96% of the time. Similarly, 86 samples of rust spores that originated from different
cereal hosts were identified to the species level with 100% accuracy using MALDI-biotyping. We also
compared PMF profiles across tissue types, which revealed tissue specific differences in the PMF graphs.
MALDI-biotyping of FHB pathogens to the species level is more accurate with PMF graphs derived from
conidiospores compared to from mycelia. MALDI-TOF MS is a promising tool for rapid identification of
both Fusarium and Puccinia spp. and can complement DNA-based testings that are currently used for
fungal identification.

[P34] POWDERY MILDEW SPECIES ON MAPLE TREES IN CANADA. Miao Liu, Parivash Shoukouhi,
Cameron Julie, and Sarah Hambleton. Ottawa Research and Development Centre, Agriculture and Agri-
Food Canada, 960 Carling Avenue, Ottawa, ON, Canada, K1A 0C6
Correspondence to: miaomindy.liu@agr.gc.camailto:xxx@gmail.com

Powdery mildew species that produce chasmothecia with hooked appendages on maple leaves were
historically classified in the genus of Uncinula in Canada. In an internal Canadian Host-Pathogen
Database, two species were reported, i.e. U. bicornis on Acer macrophyllum (bigleaf maple) from British
Columbia and U. circinata on A. rubrum (red maple), A. saccharinum (silver maple), A. saccharum (sugar
maple), and A. spicatum (mountain maple) from several provinces. As early as 1914, Japanese
mycologist Miyabe separated Uncinula spp. on maple trees into a new genus Sawadaea based on the
observation that a portion of chasmothecial appendages of maple ‘Uncinula’ were branched (either
dichotomously or trichotomously), differing from the unbranched appendages of the grape powdery
mildew Uncinula necator (current name: Erysiphe necator). In 1937, Homma accepted Miyabe’s
classification in his revision of Erysiphaceae in Japan, and recognized three Sawadaea spp. i.e S.
bicornis, S. tulasnei, and S. negundinis. A phylogenetic study by Hirose and colleagues in 2005 proved
Sawadaea is distantly related with ‘Uninula lineage’ in Erysiphe. Up to date, ten species were accepted.
Sawadaea bicornis, with its broad host and geographic range, was considered the only species present in
North America until 2006 when Weiland and Stanosz reported the first incidence of S. tulasnei, an Old-
world species, in North America. The identities of the Canadian maple powdery mildews need to be re-
assessed under the up-to-date classification framework. Through phylogenetic analyses of rDNA ITS
sequences and morphological examination of samples collected from Ottawa vicinity in recent years as
well as historical specimens housed in Canadian National Mycological Herbarium (DAOM), we recovered
two Sawadaea species on several maple species, i.e. S. bicornis on Acer macrophyllum, A. negundo, and
S. tulasnei on A. platanoides. In addition, several specimens on A. rubrum, A. saccharum, and A.
spicatum identified previously as U. circinata were confirmed belonging to the monotypic genus
Takamatsuella (as T. circinata), erected by Braun and Shi (2012) based on its long genetic distance to
Sawadaea. Through examining a large number of specimens, they observed that this species is often
only present at teleomorph stage, which might reflect its unique biological characteristics.

[P35] DOWNCAST IS EFFECTIVE FOR FORECASTING ONION DOWNY MILDEW IN ONTARIO. Tyler
Blauel, Kevin Vander Kooi, Julia Scicluna, Geoff Farintosh, and Mary Ruth McDonald. University of
Guelph, Department of Plant Agriculture, Guelph
Correspondence to: mrmcdona@uoguelph.ca

Onion downy mildew, caused by the Oomycete Peronospora destructor, is a highly destructive foliar
disease of onion. The disease does not occur every year in the Holland Marsh, Ontario. Symptoms
develop 10 – 14 days after infection and downy mildew specific fungicides must be applied prior to
infection to be effective. Disease forecasting is used to indicate when there is no risk of disease and no
fungicides are needed and to properly time fungicide applications when there is disease risk. The
integrated pest management program at the Ontario Crops Research Centre – Bradford is located in the
Holland Marsh and provides disease management information to local growers. The program uses the

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