scholarly journals Mapping of clubroot (Plasmodiophora brassicae) resistance in canola (Brassica napus)

2015 ◽  
Vol 65 (3) ◽  
pp. 435-440 ◽  
Author(s):  
H. Zhang ◽  
J. Feng ◽  
S.-F. Hwang ◽  
S. E. Strelkov ◽  
I. Falak ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Plasmodiophora Brassicae

scholarly journals Endosphere microbiome comparison between symptomatic and asymptomatic roots of Brassica napus infected with Plasmodiophora brassicae

PLoS ONE ◽  
2017 ◽  
Vol 12 (10) ◽  
pp. e0185907 ◽  
Author(s):  
Ying Zhao ◽  
Zhixiao Gao ◽  
Binnian Tian ◽  
Kai Bi ◽  
Tao Chen ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Plasmodiophora Brassicae

Emergence of new virulence phenotypes of Plasmodiophora brassicae on canola (Brassica napus) in Alberta, Canada

2016 ◽  
Vol 145 (3) ◽  
pp. 517-529 ◽  
Author(s):  
Stephen E. Strelkov ◽  
Sheau-Fang Hwang ◽  
Victor P. Manolii ◽  
Tiesen Cao ◽  
David Feindel
Keyword(s):  
Brassica Napus ◽  
Plasmodiophora Brassicae

Genetic structure of Plasmodiophora brassicae populations virulent on clubroot resistant canola (Brassica napus)

Plant Disease ◽  
2021 ◽  
Author(s):  
Homa Askarian ◽  
Alireza Akhavan ◽  
Leonardo Galindo González ◽  
Sheau-Fang Hwang ◽  
Stephen Ernest Strelkov
Keyword(s):  
Brassica Napus ◽  
Genetic Structure ◽  
Plasmodiophora Brassicae ◽  
Single Spore ◽  
Specific Primers ◽  
Brassica Napus L ◽  
Before And After ◽  
Differential Hosts ◽  
And Migration ◽  
Simple Sequence

Clubroot, caused by Plasmodiophora brassicae Woronin, is a significant threat to the canola (Brassica napus L.) industry in Canada. Clubroot resistance has been overcome in more than 200 fields since 2013, representing one of the biggest challenges to sustainable canola production. The genetic structure of 36 single-spore isolates derived from 12 field isolates of P. brassicae collected before and after the introduction of clubroot resistant (CR) canola cultivars (2005-2014) was evaluated by simple sequence repeat (SSR) marker analysis. Polymorphisms were detected in 32 loci with the identification of 93 distinct alleles. A low level of genetic diversity was found among the single-spore isolates. Haploid linkage disequilibrium and number of migrants suggested that recombination and migration were rare or almost absent in the tested P. brassicae population. A relatively clear relationship was found between the genetic structure and virulence phenotypes of the pathogen as defined on the differential hosts of Somé et al., Williams and the Canadian Clubroot Differential (CCD) set. Although genetic variability within each pathotype group, as classified on each differential system, was low, significant genetic differentiation was observed among the pathotypes. The highest correlation between genetic structure and virulence was found among matrices produced with genetic data and the hosts of the CCD set, with a threshold index of disease of 50% to distinguish susceptible from resistant reactions. Genetically homogeneous single-spore isolates provided a more complete and clearer picture of the population genetic structure of P. brassicae, and the results suggest some promise for the development of pathotype-specific primers.

scholarly journals Virulence Spectrum of Single-Spore and Field Isolates of Plasmodiophora brassicae Able to Overcome Resistance in Canola (Brassica napus)

Plant Disease ◽  
2021 ◽  
Vol 105 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Homa Askarian ◽  
Alireza Akhavan ◽  
Victor P. Manolii ◽  
Tiesen Cao ◽  
Sheau-Fang Hwang ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Confidence Interval ◽  
Plasmodiophora Brassicae ◽  
Large Collection ◽  
Single Spore ◽  
Brassica Napus L ◽  
Clubroot Resistance ◽  
Field Isolates ◽  
Virulence Spectrum ◽  
Important Disease

Clubroot, caused by Plasmodiophora brassicae Woronin, is an important disease of canola (Brassica napus L.) that is managed mainly by planting clubroot-resistant (CR) cultivars. Field isolates of P. brassicae can be heterogeneous mixtures of various pathotypes, making assessments of the genetics of host–pathogen interactions challenging. Thirty-four single-spore isolates were obtained from nine field isolates of the pathogen collected from CR canola cultivars. The virulence patterns of the single-spore and field isolates were assessed on the 13 host genotypes of the Canadian Clubroot Differential (CCD) set, which includes the differentials of Williams and Somé et al. Indices of disease (IDs) severity of 25, 33, and 50% (±95% confidence interval) were compared as potential thresholds to distinguish between resistant and susceptible reactions, with an ID of 50% giving the most consistent responses for pathotype classification purposes. With this threshold, 13 pathotypes could be distinguished based on the CCD system, 7 on the differentials of Williams, and 3 on the hosts of Somé et al. The highest correlations were observed among virulence matrices generated using the three threshold IDs on the CCD set. Genetically homogeneous single-spore isolates gave a clearer profile of the P. brassicae pathotype structure. Novel pathotypes, not reported in Canada previously, were identified among the isolates. This large collection of single-spore isolates can serve as a reference in screening and breeding for clubroot resistance.

Influence of resistant cultivars and crop intervals on clubroot of canola

2019 ◽  
Vol 99 (6) ◽  
pp. 862-872 ◽  
Author(s):  
S.F. Hwang ◽  
H.U. Ahmed ◽  
Q. Zhou ◽  
H. Fu ◽  
G.D. Turnbull ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Seed Yield ◽  
Plant Biomass ◽  
Plasmodiophora Brassicae ◽  
Disease Index ◽  
Yield Increase ◽  
Resting Spore ◽  
Important Constraint ◽  
Significant Yield ◽  
Very High

Clubroot, caused by Plasmodiophora brassicae, is an important constraint on canola (Brassica napus) production in Canada. Rotations of clubroot-resistant (CR) canola cultivars in various sequences and planting intervals between canola with non-host crops and fallow periods were evaluated to determine their effects on clubroot severity and P. brassicae resting spore populations under field and micro-plot conditions. Under micro-plot conditions, the rotation sequences including CR canola, continuous fallow, and the non-host barley reduced gall weight by 63%–100% and clubroot severity by 34%–100% compared with continuous planting of susceptible canola. No visible clubroot symptoms developed following continuous fallow or the non-host crop. Under field conditions, clubroot severity was very high (78% disease index) in the continuous susceptible canola sequence. Most of the CR canola rotation sequences significantly reduced clubroot severity by 12%–23%, but continuous fallow, continuous barley, and alternating the CR canola cultivars ‘45H29’ or ‘73-47’ with ‘TC72429-10’ reduced clubroot severity by 32%–36%. A comparison of intervals between canola crops and four cropping sequences (continuous susceptible canola, alternating canola with barley or pea, a 2-yr non-host interval between canola crops, and a 3-yr non-host interval between canola crops) was conducted over 5 yr. A 2- or 3-yr non-host interval improved plant height, plant biomass, and seed yield, and reduced gall mass, P. brassicae propagules in the soil, and clubroot severity. A significant yield increase of more than 3600% was observed in a 3-yr non-host interval.

Management of clubroot (Plasmodiophora brassicae) on canola (Brassica napus) in western Canada

2014 ◽  
Vol 36 (sup1) ◽  
pp. 49-65 ◽  
Author(s):  
S.-F. Hwang ◽  
R. J. Howard ◽  
S. E. Strelkov ◽  
B. D. Gossen ◽  
G. Peng
Keyword(s):  
Brassica Napus ◽  
Plasmodiophora Brassicae ◽  
Western Canada

scholarly journals Influence of cultivar resistance and inoculum density on root hair infection of canola (Brassica napus) by Plasmodiophora brassicae

2011 ◽  
Vol 60 (5) ◽  
pp. 820-829 ◽  
Author(s):  
S. F. Hwang ◽  
H. U. Ahmed ◽  
Q. Zhou ◽  
S. E. Strelkov ◽  
B. D. Gossen ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Root Hair ◽  
Plasmodiophora Brassicae ◽  
Inoculum Density ◽  
Cultivar Resistance ◽  
Root Hair Infection

Variation for virulence on Brassica napus L. amongst Plasmodiophora brassicae collections from France and derived single‐spore isolates

1996 ◽  
Vol 45 (3) ◽  
pp. 432-439 ◽  
Author(s):  
A. SOME ◽  
M. J. MANZANARES ◽  
F. LAURENS ◽  
F. BARON ◽  
G. THOMAS ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Plasmodiophora Brassicae ◽  
Single Spore ◽  
Brassica Napus L
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