Page 312 - PC2019 Program & Proceedings

PLANT CANADA 2019

P197. Efficacy of registered fungicides to control cucurbit downy mildew isolates collected in 2017
and 2018 from Québec and Ontario
2
1
Marchand, G. ; C. Trueman ; O. Carisse
1
1 Agriculture and Agri-Food Canada
2
University of Guelph, Ridgetown Campus

Cucurbit downy mildew (CDM), caused by the oomycete pathogen Pseudoperonospora cubensis, is a
threat to the production of field and greenhouse cucumbers in Canada, particularly for pickling cucumbers
as even low amounts of the pathogen interfere with the fermentation process. Host resistance has largely
been overcome by the pathogen, forcing growers to rely on fixed interval spray programs for management
of this disease. Resistance of P. cubensis to some currently registered fungicides (strobilurins,
fluopicolide) has previously been reported. A two year project was initiated in 2017 to evaluate the
efficacy of registered fungicides against this pathogen under controlled conditions. Isolates were collected
from field and greenhouse sites in Québec and Ontario in 2017 and 2018, and their susceptibility to nine
single site fungicide currently registered in Canada for CDM control was tested in growth chambers,
greenhouses, and fields at the St-Jean-sur-Richelieu (QC) and Harrow (ON) Research and Development
Centres between 2017 and 2019. Over the two years of testing at both sites, efficacy was consistently low
for strobilurin active ingredients (pyraclostrobin, fenamidone), while propamocarb, cyazofamid, and
oxathiapiprolin reliably provided the expected level of control. Results with fluopicolide, dimethomorph,
and mandipropamid were more variable, although the co-formulation of dimethomorph and ametoctradin
(Zampro) consistently provided control. Continued monitoring of fungicide efficacy is important,
particularly in the context of the re-evaluation of some protectant fungicides.

Genevieve Marchand (genevieve.marchand2@canada.ca)

TOPIC 22: Plant Physiology (Posters P198-P204)

P198. Characterization of a novel Arabidopsis protein kinase involved in flowering
Wang, L. ; R. Glen Uhrig
*
University of Alberta

Flowering transition is an important event that determines both the reproductive and vegetative
development of plants. Although many of the transcriptional elements involved in the flowering pathway
have been resolved, post-translational regulators of flowering transition remain largely unknown. So far,
protein kinases (e.g. SUCROSE NON-FERMENTING KINASE 1; SnRK1) and MAPK phosphatases
(e.g. PROPYZAMIDE HYPERSENSITIVE 1; PHS1) have been shown to have a role. SnRK1, for
example, functions as a central regulator of sugar and ABA signalling pathway, while being
simultaneously suggested to intersect with the flowering pathway through AKIN10-mediated
phosphorylation. With protein phosphorylation representing the most prolific regulatory post-translational
modification across all eukaryotes, characterization of proteins such as protein kinases and their
involvement in flowering can provide a deeper insight into the flowering transition network. Here we
present a new candidate, flowering kinase 1 (FK1), which is a suspected protein kinase involved in the
negative regulation of flowering. By using a combination of phenotypic, transcriptomic, proteomic, and
biochemical experimentation, our results outline a role for FK1 in the negative phosphorylation-mediated
regulation of flowering activities.

Le Wang (le7@ualberta.ca)

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