Page 296 - PC2019 Program & Proceedings

PLANT CANADA 2019

P165. A potential QTL on Chromosome 3BS with major effect on adult plant resistance to stripe
rust in a Canadian winter wheat diversity panel
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Serajazari, M. ; H. Sidhu ; J. Follings ; N. Wilker ; P. Pauls ; A. Navabi
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1 University of Guelph
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Ontario Ministry of Agriculture, Food and Rural Affairs
Stripe rust caused by Puccinia striiformis has been spreading to new areas in North America with highest
severity on Ontario winter wheat in 2016 due to pathogen and climate changes. The objective of this
research was to identify stripe rust resistance genes in winter wheat by examining seedling and adult plant
responses of a Canadian Winter Wheat Diversity Panel (CWWDP; n = 430). Seedling and field infection
analyses indicated that about 5% and 56% of the panel carry effective seedling and adult plant resistance,
respectively, against the Ontario P. striiformis isolate UOGWYR16001. This population was genotyped
using Illumina iSelect wheat 90K SNP beadchip, which provided 20K SNPs for a Genome-Wide
Association Study (GWAS) of stripe rust resistance components. GWAS revealed a significant marker-
trait association for adult plant resistance on the short arm of chromosome 3B. The associated region to
the SNP marker RAC875_c3956_659 decreased stripe rust severity by 30% in the field. Further analysis
of the chromosomal region linked to this marker detected 44 genes. TraesCS3B01G063100, the closest
gene to the marker, is located in the 35.3 Mbp region distal to the tip of the chromosome 3BS and
encodes a protease inhibitor/seed storage/lipid transfer protein (LTP). LTP is a member of the
pathogenesis-related proteins family. TraesCS3B01G063100 represents an interesting candidate gene for
adult plant stripe rust resistance in winter wheat.

Mitra Serajazari (mserajaz@uoguelph.ca)

P166. Several grass crops reduce resting spores of Plasmodiophora brassicae in soil
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Sedaghatkish, A. ; B. Gossen ; M.R. McDonald
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1 University of Guelph
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Agriculture and Agri-Food Canada

Plasmodiophora brassicae Woronin causes clubroot on brassica plants. It also infects non-brassica
species such as perennial ryegrass but cannot complete its life cycle in these plants. Our objective was to
determine if sod-forming grasses reduce the concentration of resting spores in soil, by stimulating spore
germination. The grasses assessed were: smooth bromegrass (Bromus inermis L.) cvs. Radisson, Signal
and a common seedlot, meadow bromegrass (B. riparius R.) cv. Fleet, and perennial ryegrass (Lolium
perenne L.) cvs. Norlea, Fiesta, and All Star. Plants were grown for 6 weeks in pots of field soil
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inoculated with 5 x 10 resting spores of P. brassicae g soil under controlled conditions in three similar
studies. There was a negative control (bare soil) and a positive control (pak choi, Brassica rapa cv. Mei
Qing Choi, susceptible). Clubroot developed on the positive control. The spore concentration in soil was
quantified using qPCR conducted with and without propidium monoazide (PMA), which suppresses
amplification of non-viable spores. Pretreatment with PMA did not affect spore counts. Resting spore
concentration was reduced by one or more cultivars of all three grass species (Fleet, Fiesta, Radisson, and
common smooth bromegrass) compared to the bare soil, but Norlea, All Star and Signal had no effect.
This indicated that many cover crops can reduce spore numbers in patches of clubroot, as well as reducing
spore movement from the patches.

Afsaneh Sedaghatkish (asedagha@uoguelph.ca)

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