Abstract Detail

Recent Topics Posters

Soomro , Wali Muhammad [1], Kutcher, H. Randy [2], Peng, Gary [3].

The occurrence of blackleg in relation to the Avr-allele profile of Leptosphaeria maculans in commercialcanola fields in western Canada.

The occurrence of blackleg in relation to the Avr-allele profile of Leptosphaeria maculans in commercial canola fields in western Canada. W. M. SOOMRO, H. R. KUTCHER AND G. PENG. Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada; and (H.R.K) Department of Plant Sciences, University of Saskatchewan, Saskatoon. SK S7N 5A8, Canada In western Canada, blackleg [L. maculans (Desmaz.) Ces. & de Not] of canola (Brassica napus) has increased in both prevalence and severity in recent years, possibly due to a shift in the pathogen population and erosion of cultivar resistance. The objective of this study was to assess the relationship between “resistance erosion” observed in commercial canola fields in 2012 and 2013 and the absence of particular avirulence (Avr) alleles in the pathogen population. Analysis of 350 isolates from 10 canola fields on a host differential set (12 lines) carrying known R genes showed that the alleles AvrLm1, AvrLm3, AvrLm9 and AvrLep2 were at very low or undetectable levels in these fields, while AvrLm2, AvrLm4, AvrLm6 and AvrLm7 were generally common. This indicates that the specific R genes Rlm1 and Rlm3, common in Canadian canola cultivars, have likely been defeated. Variation in Avr frequency was observed depending on the cultivar, field and region studied, but these differences seemed insufficient to explain the variation in blackleg severity observed in these fields. Subsequent studies showed that despite carrying no effective major R genes, many Canadian cultivars remain resistant to blackleg by limiting the spread of infection into the stem via petioles of infected cotyledons or by restricting rapid disease development in the stem. It appears that the absence of particular Avr alleles in the pathogen population is only one of the factors that contributes to blackleg severity in a given canola field in western Canada.   Abstracts reviewed by: Richard Gugel and Bruce Gossen

1 - Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK, S7N 0X2, Canada
2 - University of Saskatchewan, Plant Science, 51 Campus Drive, Saskatoon, SK, S7N 5A8, Canada
3 - Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, SK, S7N )X2, Canada

Keywords:
Profiling of Leptosphaeria maculans.

Presentation Type: Recent Topics Poster
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PRT037
Abstract ID:1823
Candidate for Awards:None