Pathotypes of <i>Plasmodiophora brassicae</i>, the cause of clubroot, in Australia

Donald, E. C.; Cross, Sashalee J.; Lawrence, James B.; Porter, Ian

doi:10.1111/j.1744-7348.2006.00062.x

Cited by 27 publications

(17 citation statements)

References 15 publications

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“…Resting spore suspensions of P. brassicae were prepared from frozen root galls that had been collected from cauliflower plants on a property in Cora Lynn, Victoria, Australia. The collection previously assigned the code 16/2/30 after screening against the European Clubroot Differential series of hosts (Donald et al ., 2006) was stored frozen at –2°C for 4 years before use. Root galls were defrosted at room temperature (20°C).…”

Section: Methodsmentioning

confidence: 99%

Pathology of cortical invasion by Plasmodiophora brassicae in clubroot resistant and susceptible Brassica oleracea hosts

Donald¹,

Jaudzems

Porter³

2008

Plant Pathology

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The differences in physiological response of Brassica oleracea to infection and growth of Plasmodiophora brassicae in infected tissue were studied in clubroot resistant and susceptible hosts, grown in sand solution culture artificially inoculated with spores of P. brassicae (10 8 spores mL -1). Primary (root hair) and secondary (cortical) stages of P. brassicae occurred in both resistant and susceptible hosts. Symptoms of cortical invasion by P. brassicae in resistant and susceptible hosts included cell wall breaks, presence of vesicles or inclusion bodies within the cell walls, cell wall thickening in association with plasmodesmata and enlarged and/or disorganized host nuclei. The main difference between the resistant and susceptible host reaction was the absence of degradation of the secondary thickening and cell walls of the xylem in the resistant host. This study supports the existence of an amoeboid form of the pathogen in addition to the recognized two-phase life history of P. brassicae. Furthermore, it suggests that resistance in B. oleracea does not prevent the development of this amoeboid form. A reduced number of cell wall breakages suggests movement of the amoeboid form, may have been restricted but not prevented in the resistant host.

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Section: Methodsmentioning

confidence: 99%

Pathology of cortical invasion by Plasmodiophora brassicae in clubroot resistant and susceptible Brassica oleracea hosts

Donald¹,

Jaudzems

Porter³

2008

Plant Pathology

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“…Hwang et al (201 la) detected seed yield losses of about 80% at an inoculum density of 105 spores cm-1 soil. Field isolates of the New World seemed to be less virulent against B. napus compared with field isolates of Europe (Donald et al 2006). This could be attributed to a high pathogenicity of the inoculum used in this study.…”

Section: Id (Spores Liter-1 Soil) Osr Cultivar DI (%) Dsmentioning

confidence: 62%

Risk Potential of Clubroot Disease on Winter Oilseed Rape

2015

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Strehlow, B., de Mol, F., and Struck, C. 2015. Risk potential of clubroot disease on winter oilseed rape. Plant Dis. 99:667-675. Clubroot disease caused by Plasmodiophora brassicae is an important dis ease of cruciferous plants. Although the pathogen is widespread and has been reported to cause high yield losses, the impact on winter oilseed rape (OSR) has not been experimentally verified. To quantify the risk potential of P. brassicae, we conducted two closely linked experiments. A semicontrolled experiment used artificial soil infestation at inoculum densities be tween 10® and 108 spores liter-1 of soil to detect the impact on seed yield and yield components of a susceptible and resistant OSR cultivar. A green house experiment was implemented using the soil of the semicontrolled experiment after cropping the two cultivars to quantify the influence of cultivar resistance on soil inoculum. According to cumulative link mixed models, disease rating was positively correlated with the amount of inoc ulum. Linear regression analyses revealed a negative correlation between seed yield and inoculum density. Yield losses of 60% already appeared at the lowest inoculum density. Plant losses and reduced seed per pod were accountable for yield losses. Although the resistant cultivar showed club root symptoms, seed yield was not affected by the pathogen. The green house experiment revealed that clubroot severity in subsequent OSR was reduced after cropping the resistant cultivar. This study showed signif icant yield damage of P. brassicae already at low infestation levels.

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“…pekinensis cv Granaat (suscetível) apresentaram hérnias quando inoculadas monosporicamente, considerando-se as 450 inoculadas menos de 1% de sucesso foi obtido utilizando esta técnica. Donald et al (2006) também observaram a interferência das condições climáticas de cultivo no desenvolvimento de sintomas em linhas diferenciadoras da ECD (European Clubroot Differential), infectadas por esporos produzidos nestes mesmos hospedeiros, na Austrália. As linhas diferenciadoras (ECD) utilizadas mostraram reações intermediárias de severidade em função das diferentes condições climáticas (luz, matéria orgânica, temperatura, pH) encontradas nesse país, que diferem das condições de cultivo européias.…”

Section: Resultsunclassified

Caracterização patogênica e molecular de Plasmodiophora brassicae

Cruz¹,

Souza²,

Nakatani³

et al. 2008

Trop. plant pathol.

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INTRODUÇÃOPlasmodiophora brassicae Woronin é o patógeno responsável pela doença popularmente conhecida como hérnia das crucíferas (HDC), uma das mais importantes nas regiões produtoras de brássicas no mundo. Esta doença, característica de regiões de temperaturas amenas, em torno de ± 20°C, vem ganhando expressão em áreas agrícolas tradicionalmente cultivadas com brássicas no Brasil. Uma vez presente no solo, as estruturas de resistência do patógeno podem sobreviver por mais de 15 anos (Wallenhammar, 1996), o que dificulta seu controle.Em decorrência da dificuldade de seu isolamento, por se tratar de um parasita obrigatório, pouco se sabe sobre seu desenvolvimento em condições brasileiras de cultivo, o que explica a existência de maior número de trabalhos que avaliam o comportamento de populações de P. brassicae, como os realizados por Ito et al. (1999b) RESUMOPoucos estudos foram desenvolvidos no Brasil sobre a doença hérnia das crucíferas, causada por Plasmodiophora brassicae. Realizou-se testes de severidade da doença causada por diferentes populações do patógeno em espécies de brássicas (couve-flor, couvechinesa suscetível, couve-chinesa resistente, brócolis e repolho). As populações de P. brassicae foram obtidas de raízes de brássicas infectadas originárias de algumas regiões produtoras no Brasil. Os testes de severidade foram realizados em casa de vegetação (25±2°C) mediante inoculações, no colo de cada planta com 2 mL da suspensão de esporos do patógeno, na concentração de 10 7 esporos mL ��1 . As avaliações ocorreram 35 dias após a inoculação. Em laboratório foi realizada a extração de DNA dessas populações e análises de PCR-RAPD para a comparação das características genéticas. As populações obtidas nas regiões de Carandaí MG e Colombo PR mostraram-se mais agressivas, manifestando patogenicidade até mesmo em cultivar considerada resistente. Entretanto, não foi observado um padrão genético específico quanto ao local de origem das populações avaliadas, sugerindo que mesmo em locais distantes e com diferenças quanto à severidade, tais populações são geneticamente semelhantes. Palavras chaves: hérnia das crucíferas, PCR, patógeno de solo, Brassicaceae. ABSTRACT Pathogenic and molecular characterization of Plasmodiophora brassicaeFew studies have been conducted with clubroot disease in Brazil, caused by Plasmodiophora brassicae. Tests on severity of disease using different populations were carried out in brassica species (cauliflower, susceptible Chinese cabbage, resistant Chinese cabbage, broccoli, and cabbage). P. brassicae populations were obtained from infected roots in several commercial production regions in Brazil. Severity tests were conducted under greenhouse conditions (25±2°C) with inoculations (2 mL) of spore suspension at concentration of 10 7 spores. mL ��1 , applied in the collar root of each plant. Disease evaluations were performed 35 days after inoculation. DNA extraction and PCR-RAPD analyses for these populations were conducted to compare genetic traits. The populations obtained from the r...

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Pathotypes of Plasmodiophora brassicae, the cause of clubroot, in Australia

Cited by 27 publications

References 15 publications

Pathology of cortical invasion by Plasmodiophora brassicae in clubroot resistant and susceptible Brassica oleracea hosts

Pathology of cortical invasion by Plasmodiophora brassicae in clubroot resistant and susceptible Brassica oleracea hosts

Risk Potential of Clubroot Disease on Winter Oilseed Rape

Caracterização patogênica e molecular de Plasmodiophora brassicae

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