Page 131 - PC2019 Program & Proceedings

PLANT CANADA 2019

S47. Molecular surveillance of Fusarium species and chemotypes of wheat across western Canada
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Oghenekaro, A. ; P. Cholango-Martinez ; M. Oviedo-Ludena ; M. Harding ; X. Wang ;
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R. Kutcher ; D. Fernando
1 University of Manitoba
2 University of Saskatchewan
3 Agriculture and Forestry
4 AAFC
Fusarium head blight (FHB) is a disease that reduces both yield and quality of cereals. The dynamics and
temporal changes of the Fusarium species and their chemotypes associated with this disease across
western Canada have not been fully studied on a large scale. The objective of this study was to sample,
collect and identify Fusarium species from FHB diseased wheat spikes across the three western provinces
of Canada: Alberta, Saskatchewan and Manitoba. Diseased spikes were collected from all three provinces
from 146 naturally infected wheat fields from 2015 - 2018. More than 500 single spore isolates were
obtained so far. Fusarium graminearum was the most prevalent species (80%); other species identified
were F. culmorum, F. avenaceum, F. sporotrichiodes and F. proliferatum in Alberta; F. sporotrichiodes,
F. poae, and F. incarnatum-equiseti species complex in Saskatchewan; and F. culmorum and F.
avenaceum in Manitoba. There was a continuous change in chemotypes across western Canada from
15ADON to 3ADON. The chemotype distribution for both Saskatchewan and Manitoba was 75%
3ADON and 25% 15ADON. The comparative fungal population structure based on years, previous crop
and geographic location is being investigated to understand the reasons for this chemotype frequency.
Additionally, a greenhouse experiment is being conducted to examine the aggressiveness of select isolates
on multiple wheat cultivars that vary for resistance.

Abbot Oghenekaro (abbot.oghenekaro@umanitoba.ca)

S48. Race dynamic, diversity and virulence in Puccinia striiformis f. sp. tritici in Canada over the
last three decades
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Ghanbarnia , K.; R. Gourlie ; E. Amundsen ; X. Chen ; Aboukhaddour, R.
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1 AAFC
2 USDA

Stripe rust of wheat, caused by the fungal pathogen Puccinia striiformis f. sp. tritici (Pst), is one of the
most important cereal diseases worldwide. In this study, the pathogen population in Canada, representing
a time period from 1984 to 2017, was analysed for virulence diversity and geographical distribution. The
results were compared with previously described races in the USA. in this study, the virulence of 141
isolates of Pst was evaluated on 18 wheat Yr single-gene lines in the Avocet background. The seedlings
were inoculated with a spore/talc mixture (ratio 1:20) after 12 days of growth, and infection types (scale
of 0–9) on the second leaves were evaluated 18–21 days post-inoculation. The experiment was repeated
two independent times. In total, 85 different virulence patterns were observed. The dominant races in
Canada were very similar to the main races previously reported in the USA (PSTv-41, PSTv-37, PSTv-
52), which suggests long-distance migration of these races from the USA to Canada. However, the
presence of a considerable number of unique low-frequency races in Canada supports the hypothesis that
mutation of Pst also occurs in localized regions within Canada. Diversity analysis of the virulence spectra
and comparison between Canadian isolates with races from the Pacific Northwest, the central, and the
eastern regions of the USA are ongoing and will be presented.

Reem Aboukhaddour (reem.aboukhaddour@canada.ca)

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