Page 256 - PC2019 Program & Proceedings

PLANT CANADA 2019

P85. Identification and mapping of an unknown resistant locus in Brassica napus against
Leptosphaeria maculans
Liu, F.; Z. Zou; D. Fernando
University of Manitoba

Blackleg, caused by Leptosphearia maculans (L. maculans), is one of the most devastating diseases on
canola (Brassica napus) and causes significant yield losses each year. Growing resistant varieties is
believed to be the most durable, environmentally friendly and cost effective strategy for blackleg control.
Through screening of Chinese B. napus lines using differential blackleg isolates, we discovered that one
of the lines ‘8011’ contains unknown R genes. To understand the inheritance model, F1 and F2
populations were developed from a cross of ‘Westar’ and ‘8011’. The parent lines, F1 and F2 populations
were screened using the isolate umavr7 (AvrLm6), which caused resistant phenotype on ‘8011’. The
results showed that F1 was susceptible to umavr7, and separation of resistant and susceptible individuals
were found in the F2 population. Calculation of the segregation of resistant and susceptible individuals
2
fitted an expected Mendelian inheritance ratio: 1:3 (X =0.005590, P=0.940402). Bulked Segregant RNA-
Seq (BSR-seq) analysis was performed by RNA sequencing of segregated resistant pool and susceptible
pool, and the unknown resistant locus was mapped onto A07 chromosome. Molecular markers will be
developed from the information of BSR-seq to aid marker assisted selection as well as fine-mapping of
this locus.

Fei Liu (Fei.Liu@umanitoba.ca)

P86. Validation and discovery of genetic markers associated with loose smut resistance genes in a
durum wheat (Triticum durum L.) doubled haploid population DT676/DT802
1
2
3
1
1
1
4
Bokore, F. ; R. Knox ; Y. Ruan ; R. Cuthbert ; H. Campbell ; A. Sharpe ; E. Sari ; K. Boyle ; I. Piche ;
1
4
1
B. Meyer
1 AAFC
2 heather.campbell3@canada.ca
3 Global Institute for Food Security
4
National Research Council of Canada)

Identification and validation of genetic markers associated with loose smut (Ustilago tritici) resistance in
wheat aids the deployment of genes into new cultivars. The objective of this study was to validate known
SSR and KASP markers associated with loose smut resistance and find new SNP markers. A durum
wheat doubled haploid population comprising 174 lines from DT676/DT802 was evaluated against major
loose smut races T32 and T33, and a minor race T26. The population was genotyped by 2962 SNP
markers across the genome, and 7 SSR and 4 KASP markers on chromosomes 3A, 5A, 5B, 6B, 7A and
7B. The population was inoculated in the field near Swift Current in 2014, 2015 and 2017 and evaluated
in a greenhouse for disease incidence. Marker-trait associations were assessed by single point analysis
and by MapQTL. The single point analysis revealed significant associations of the markers with loose
smut resistance on 5A, 5BS, 7A and 7B derived from DT676. No association was discovered on 3A or
6B. The 5BS marker, Xgwm443, was associated with resistance to T32 and T33 over 3 years, and T26 in
1 year. The 5A, 7A and 7B markers were associated with resistance to T26 in a single year. The QTL
mapping detected only the locus located on 5BS; the SNP markers were more tightly linked with the
resistance than Xgwm443.

Firdissa Bokore (firdissa.bokore@canada.ca)

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