Page 44 - TriSociety Virtual Event

Abstracts

nostic process. The decision­making process BronZe leaf is a destructive disease that 56. Characterization of genomic and
of disease diagnosis may involve the use of afects 'Tower ' poplar (Populus × canescens pathogenic diversity in Sclerotinia scle-
multiple microbiological, immunological and Smith), Swedish columnar aspen (P. tremula rotiorum population needed for develop­
molecular assays, which can be time consum­ L ) and Trembling A spen (P. tremuloides ment of resistant canola
ing, labor intensive and costly. The advent of Michx) and can cause economic losses to the L BUCHWALDT H GARG K D PURI J DUR­
high throughput sequencing (HTS) techniques nurser y crop processed wood industries and KIN J ADAM M HARRINGTON D LIABEUF A
makes it possible to accurately identify most property owners where poplar and aspen DAVIES D D HEGEDUS A G SHARPE AND K
pathogenic organisms in a single analysis. trees are ofen used in amenity and shelter­ K GALI (L.B., H.G., J.D., J.A., M.H., A.D., D.D.H.)
By coupling available taxonomic information belt plantings Apioplagiostoma populi Barr Agriculture and Agri-Food Canada, Saskatoon
and using the latest sequencing data filtration (anamorph Discula sp ) is the casual agent of Research and Development Centre, 107 Science
strategies, it is now possible to assess unique bronZe leaf disease; however confirmation Place, Saskatoon, Canada, S7N 0X2; (H..G)
genetic variants that can precisely identify of the causal pathogen is challenging as it School of Life and Environmental Sciences,
pathogenic organisms. We evaluated the relies on obser vation of disease symptoms the University of Sydney, NSW, Australia; (K.P.)
identification accuracy potential by HTS on and morphological characteristics of A. populi Department of Plant Pathology, University of
nearly 500 diagnosed cases received at the when fruiting bodies form on infected leaves California, Davis, CA, USA; (D.L.) Driscoll’s, Wat­
Laboratoire d’expertise et de diagnostic en Afected tissues de velop a conspicuous bron­ sonville, California, USA; (A.G.S.) Global Institute
phytoprotection (MAPAQ) and at the Centre Ze­colored pigment that becomes pronoun­ for Food Security, University of Saskatchewan,
de recherche sur les grains (CEROM). These ced in late summer The symptoms reduce the Saskatoon, SK, Canada, S7N 0W9; (K.K.G.) Crop
cases represented diverse crops (crucifers, aesthetic and commercial value of infected Development Centre, Department of Plant
cucurbits, potatoes, field crops and tomato) trees and dieback can lead to premature Sciences, University of Saskatchewan, SK, S7N
and pathogens. Amplicon­based HTS was death In this study we characteriZed the 5A8 Canada.
used to assess pathogenic groups by targeting bronZe leaf disease morphology in Canada
respective DNA regions, including the fungal and identified pathogen­specific sequences Sclerotinia sclerotiorum causes yield loss in
Internal transcribed spacer ITS, bacterial and for sensitive diagnostics that indicate systemic dicotyledonous crops worldwide In order to
archaeal 16S rDNA gene, eukaryota18S rDNA infection of vascular tissues Leaf samples select suitable isolates for resistance screening
and Fusarium Elongation factor 1­alpha (EF1ɑ) from symptomatic trees were collected from in canola breeding programs we genotyped
regions. The HTS approach is based on an British Columbia Alberta and Manitoba and 127 isolates collected in western Canada using
adapted sequence processing strategy, involv­ examined for perithecia to microscopically simple sequence repeat (SSR) markers repre­
ing the use of public and custom­curated ref­ characteriZe A. populi asci and ascospores senting all chromosomes The result revealed
erence sequence databases. The HTS­based Disease­associated �­tubulin 2 translation each isolate was an unique haplotype Isolates
diagnostics results showed a good agreement elongation factor­1­ � chain and the internal from Manitoba were highly interconnected
with the diagnostic approaches used by transcribed spacer (ITS) 5 8S region of the nu­ since 61% of the isolates were mycelium com­
LEDP for several pathogenic genera including clear ribosomal DNA sequences were isolated patible forming three clones of three to five
Fusarium. The HTS data will be stored in a from perithecia and symptomatic tree sam­ isolates with 86­95% similar SSR haplotype
relational database and analysed to define ples Morphological and molecular biological as well as long stings of pairwise compatible
interpretation thresholds. A web application data were used to characteriZe the relations­ isolates In contrast only 35% and 39% of
is to be developed to facilitate visualization of hip and epidemiolog y of A. populi to develop isolates were mycelium compatible in Alberta
diagnosis based on HTS data. a rapid diagnostic test to facilitate reliable and Saskatchewan with a single clone of six
early detection and thereby help prevent and/ isolates but no strings The diference can
54 Molecular diagnostics for bronze leaf or reduce aesthetic and economic losses from be explained by wetter growing seasons and
disease affecting Canadian poplar and this devastating disease more susceptible crops species in Manitoba
aspen trees favouring frequent mycelium interaction and
M L KALISCHUK C P WIJEKOON R J 55. The 168­year taxonomy of Claviceps more life cycles over time Analysis of linkage
HOWARD AND L M KAWCHUK Department in the light of variations: From three mor­ disequilibrium re ected random recombi­
of Plant Agriculture, University of Guelph, phological species to four sections based nation consistent with a self­fertile fungus
50 Stone Road East, Guelph, ON N1G 2W1, on multigene phylogenies Genomic recombination between non­sister
Canada; (C.P.W.) Canadian Centre for Agri-Food M LIU Ottawa Research and Development chromatids during meiosis in the ascospore
Research in Health and Medicine, 351 Taché Centre (ORDC), Agriculture and Agri-Food stage is rare since mycelium incompatibility
Ave., Winnipeg, MN, R2H 2A6, Canada; (L.M.K.) Canada, 960 Carling Ave. Ottawa. ON K1A 0C6. inhibits isolates with diferent nuclei coming
Lethbridge Research Center, 5403 1 Ave. Road, Canada. together More probable sources of genomic
st
Lethbridge, AB T1J 4B1, Canada.; (R.J.H.) RJH diversity is slippage during DNA replication
Ag Research Solutions Ltd., Box 1456, Brooks, Abstract Withdrawn and point mutation of single nucleotides A
AB, T1R 1C3, Canada. phylogenetic tree based on SSR haplotype
grouped isolates into 17 sub­populations
Aggressiveness was tested by inoculating one

44 /