Page 53 - TriSociety Virtual Event

phenolic compounds Genes involved in the Session 16. Society award winners ofers a new opportunity for plant pathologists
corresponding pathways of these metabolites to explain the importance of their work to the
were also upregulated These results show 86. A. Levesque: CPS Lifetime career general public and continue to build on the
the role of cell­wall reinforcement in clubroot award momentum digitiZation has provided towards
resistance as well as the stages where P. bras­ a better understanding of the role and impact
sicae may be arrested by resistance mecha­ Riding the wave of digitization – towards of fungi and oomycetes
nisms during the infection process a better understanding of the role and
impact of fungi and oomycetes. 87. Widespread Herbicide Resistance in
85. Elimination of zebra chip in Canada C A LEVESQUE. Department of Biological Pigweed Species in Ontario Carrot Pro­
L KAWCHUK D JOHNSON S MEERS Q XIA Sciences, Simon Fraser University, 8888 Uni­ duction is Due to Multiple Photosystem II
AND J LYNN Lethbridge Research Centre, versity Drive, Burnaby, BC V5A 1S6, Canada; Mutations. DAVIS G LETARTE J GRAINGER
Agriculture and Agriculture-Food Canada, Vancouver Research Station, Agriculture Cana­ CM RAJCAN I TARDIF FJ ���� Can J Plant
5403 – 1 Avenue South, Lethbridge, AB T1J 4B1, da, 6660 N.W. Marine Drive, Vancouver, British Sci 100 56-67 doi 10 1139/c ps­2019­0114
Canada; (D.J., Q.X.) Department of Geography Columbia V6T 1X2; Pacific Agri-Food Research Fran�ois Tardif CSA Best CJPS paper award
and Environment, University of Lethbridge, 4401 Centre, Agriculture and Agri-Food Canada,
University Drive West, Lethbridge, AB T1K 3M4, 4200 Highway 97, Summerland, BC V0H 1Z0, Widespread Herbicide Resistance in
Canada; (S.M.) Mayland Consulting, 1412 17A Canada; Ottawa Research and Development Pigweed Species in Ontario Carrot Pro­
Street NE, Calgary, AB T2E 4V5, Canada. Centre, Agriculture and Agri-Food Canada, 960 duction is Due to Multiple Photosystem II
Carling Avenue, Ottawa, ON K1A 0C6, Canada; Mutations
Zebra chip is a potentially devastating disease Canadian Food Inspection Agency, 1400 Meri­ G DAVIS J LETARTE C M GRAINGER I
of solanaceous crops caused by 'Candi­ vale Road, Ottawa, ON K1A 0Y9, Canada. RAJCAN AND F J TARDIF Department of Plant
datus Liberibacter solanacearum' (Lso) a Agriculture, University of Guelph, 50 Stone Road
phloem­limited gram­negative bacterium that In plant pathology identifying the causal East, Guelph, ON N1G 2W1, Canada.
is transmitted by the potato­tomato psyllid agent of a disease from the species to the
(TPP) Bactericera cockerelli (�ulc) Originating most critical expressed genes and predic­ The apparent eficacy of linuron to control
in Mexico the disease has become more ting its impact and managing it can provide pigweeds (Amaranthus spp ) has declined in
prevalent and migrated northward through significant economic and environmental Ontario Canada in past decades possibly
the US over several decades To determine benefits As a graduate student I recogniZed due to resistance Samples were collected in
occurrence and epidemiolog y in Canada that identification of soil­borne isolates of multiple fields across Ontario with reported
TPP were collected from thousands of yellow Pythium Prings and Fusarium Link was a ma­ linuron failure These were characteriZed
sticky cards and hundreds of samples or bottleneck afecting my research into the at the whole plant and molecular le vels
from plants that exhibited putative disease mode of action of the herbicide glyphosate Screening with linuron revealed resistance
symptoms were collected during 2013 to 2020 There were ver y few taxonomy specialists for in six out of nine green pigweed (A. powellii
from commercial farms The TPP vector was these genera who could help me identify and S Watson) populations and 36 of 38 popu­
obser ved primarily in AB with fewer found in separate those species which were pathoge­ lations of redroot pigweed (A. retroflexus L )
SK and MB Under 100 TPP were obser ved nic saprophytic or even used as biological Sequencing of the psbA gene showed resistant
annually except in 2017 Total nucleic acid was control agents among the many strains that I plants had mutations conferring resistance
isolated from psyllids or plant samples and had isolated Afer I obtained my Ph D PCR to PSII inhibitors The most commonly seen
the cytochrome oxidase I or 16S ribosomal technolog y became available and DNA­based mutation was coding for a Val219Ile substitu­
DNA was amplified with TPP and Lso specific technologies improved significantly as a result tion while other populations had Ala251Val or
PCR primers respectively All samples were of that I became a specialist on Zoosporic Phe274Val Two populations were documen­
negative for Lso except four TPP and a single fungi and in collaborations with other taxo­ ted with a double mutation at Val219Ile and
post­har vest potato tuber recovered from nomists I was involved in generating many Phe274Val All substitutions endowed plants
southeastern Alberta in 2017 The Lso­positive reference DNA sequence databases With with low to moderate resistance to linuron
potato tuber produced symptomatic plants the advent of high throughput sequencing with various le vels of cross resistance to other
with the proliferation of axillar y shoots and technologies the ability to digitally identify or PSII inhibitors The double mutants were
abnormal tubers BL AST analysis of the TPP detect Zoosporic fungi has been streamlined characteriZed by higher levels of resistance
and plant Lso showed central and western to near real­time Species identification is now to linuron and diuron compared to each
TPP haplotype and an identical match to Lso supported by the large body of fully annotated single substitution The widespread failure of
haplotype A isolates from the United States genomes available and can be carried out linuron to control pigweed species in many
Detection of Lso in Canada indicates the with practically any expressed genes There carrot fields in Ontario is due to selection of
pathogen may be spreading to new areas is a growing public understanding of epide­ PSII mutants This is the first report of double
possibly due to favorable environmental miology of emerging diseases and DNA­based mutation in psbA in any weed species and the
conditions and industry should continue to technologies because of SARS­CoV­2 This first report of the Ala251Val and Phe273Val in
monitor movement of the vector and disease pigweed species The presence of a double
to minimiZe losses

/ 53