Plasmodiophora brassicae (club root).

2021 ◽  
Author(s):  
Graham McGrann
Keyword(s):  
Crop Rotation ◽  
Plasmodiophora Brassicae ◽  
Brassica Species ◽  
Infested Soil ◽  
Yield Losses ◽  
Varietal Resistance ◽  
Weed Species ◽  
Clubroot Disease ◽  
Local Spread ◽  
Resting Spores

Abstract Plasmodiophora brassicae is a root-infecting protist pathogen that causes clubroot disease in brassica species. The organism is soil-borne and has long-lived resting spores that can survive in soil for more than 15 years. Local spread of motile zoospores can be facilitated by wet conditions but most dispersal of the pathogen is through the movement of infested soil. P. brassicae has a wide host range in the brassica family including numerous weed species. Control of the disease is difficult but clubroot can be managed by a combination of crop rotation, varietal resistance, improved agronomic practice such as improved drainage and the application of lime of related products to raise pH which can limit the effects of the disease. There are currently no effective fungicides for the widespread control of clubroot. Yield losses range from 10 to 15% but can exceed 50% under disease conducive environmental conditions.

scholarly journals Effect of pathogen virulence on pathogenicity, host range and reproduction of Plasmodiophora brassicae, the causal agent of clubroot disease

Plant Disease ◽  
2021 ◽  
Author(s):  
Nazanin Zamani-Noor ◽  
Sinja Brand ◽  
Hans-Peter Soechting
Keyword(s):  
Plasmodiophora Brassicae ◽  
Brassica Species ◽  
Post Inoculation ◽  
Clubroot Disease ◽  
Alopecurus Myosuroides ◽  
Pathogen Virulence ◽  
Iberis Amara ◽  
Thlaspi Arvense ◽  
Resting Spores ◽  
Pathogen Dna

A series of greenhouse experiments was conducted to evaluate the effect of Plasmodiophora brassicae virulence on clubroot development and propagation of resting spores in 86 plant species from 19 botanical families. Plants were artificially inoculated with two isolates of P. brassicae, which were either virulent on clubroot-resistant oilseed rape cv. Mendel (P1 (+)) or avirulent on this cultivar (P1). Clubroot severity and the number of resting spores inside the roots were assessed 35 days post inoculation. Typical clubroot symptoms were observed only in the Brassicaceae family. P1 (+)-inoculated species exhibited more severe symptoms (2 to 10–fold more severe), bigger galls (1.1 to 5.8 fold heavier) and higher number of resting spores than the P1-inoculated plants. Among all Brassica species, Bunias orientalis, Coronopus squamatus and Raphanus sativus were fully resistant against both isolates, while Camelina sativa, Capsella bursa-pastoris, Coincya momensis, Descurainia sophia, Diplotaxis muralis, Erucastrum gallicum, Neslia paniculata, Sinapis alba, S. arvensis, Sisymbrium altissimum, S. loeselii and Thlaspi arvense were highly susceptible. Conringia orientalis, Diplotaxis tenuifolia, Hirschfeldia incana, Iberis amara, Lepidium campestre and Neslia paniculata were completely or partially resistant to P1-isolate but highly susceptible to P1 (+). These results propose that the basis for resistance in these species may be similar to that found in some commercial cultivars, and that these species could contribute to the build-up of inoculum of virulent pathotypes. Furthermore, the pathogen DNA was detected in Alopecurus myosuroides, Phacelia tanacatifolia, Papaver rhoeas and Pisum sativum. It can concluded that the number and diversity of hosts for P. brassicae are greater than previously reported.

scholarly journals First Report of Clubroot on Capsella bursa-pastoris Caused by Plasmodiophora brassicae in Sichuan Province of China

Plant Disease ◽  
2014 ◽  
Vol 98 (5) ◽  
pp. 687-687 ◽  
Author(s):  
L. Ren ◽  
X. P. Fang ◽  
C. C. Sun ◽  
K. R. Chen ◽  
F. Liu ◽  
...  
Keyword(s):  
Plasmodiophora Brassicae ◽  
Tap Water ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Pcr Amplification ◽  
Sichuan Province ◽  
Clubroot Disease ◽  
Cruciferous Vegetable ◽  
First Report ◽  
Resting Spores

Shepherd's purse (Capsella bursa-pastoris (L.) Medicus) is an edible and wild medicinal plant widely distributed in China. This plant has been cultivated in Shanghai, China, since the end of the 19th century. Infection of C. bursa-pastoris by Plasmodiophora brassicae, the causal agent of clubroot disease on Brassica spp. has been reported in Korea (2), but is not known to occur in China. In February of 2011, stunted and wilted shepherd's purse (SP) plants were observed in a field planted to oilseed rapes (B. napus) in Sichuan Province of China. Symptomatic SP plants also exhibited root galls. Disease incidence was 6.2% and 100% for SP and B. napus, respectively. Root galls on diseased SP plants were collected for pathogen identification. Many resting spores were observed when the root galls were examined under a light microscope. The resting spores were circular in shape, measuring 2.0 to 3.1 μm in diameter (average 2.6 μm). PCR amplification was conducted to confirm the pathogen. DNA was extracted from root galls and healthy roots (control) of SP. Two primers, TC2F (5′-AAACAACGAGTCAGCTTGAATGCTAGTGTG-3′) and TC2R (5′-CTTTAGTTGTGTTTCGGCTAGGATGGTTCG-3′) were used to detect P. brassicae (1). No PCR amplifications were observed with the control DNA as template. A fragment of the expected size (approximately 520 bp) was obtained when DNA was amplified from diseased roots of SP. These results suggest that the pathogen in the galled roots of SP is P. brassicae. Pathogenicity of P. brassicae in SP was tested on plants of both SP and Chinese cabbage (CC) (B. campestris ssp. pekinensis). A resting spore suspension prepared from naturally infected SP roots was mixed with a sterilized soil in two plastic pots, resulting in a final concentration of 5 × 106 spores/g soil. Soil treated with the same volume of sterile water was used as a control. Seeds of SP and CC were pre-germinated on moist filter paper for 2 days (20°C) and seeded into the infested and control pots, one seed per pot for planted for CC and four seeds per pot for SP. The pots were placed in a chamber at 15 to 25°C under 12 h light and 12 h dark. Plants in each pot were uprooted after 4 weeks and the roots of each plant were washed under tap water and rated for clubroot disease. No disease symptoms were observed in the control treatments of SP or CC. Plants of both species showed symptoms of clubroot, with the disease incidence of 62.5% and 100% on SP and CC, respectively. The pathogen was isolated from diseased roots of each plant and confirmed as P. brassicae based on morphological characteristics and PCR detection. To our knowledge, this is the first report of clubroot disease on C. bursa-pastoris in Sichuan Province of China. This finding suggests that it may be necessary to manage C. bursa-pastoris in cruciferous vegetable (cabbage, turnip) and oilseed rape production fields. References: (1) T. Cao et al. Plant Dis. 91:80, 2007. (2) W. G. Kim et al. Microbiology 39:233, 2011.

A >2-year crop rotation reduces resting spores of Plasmodiophora brassicae in soil and the impact of clubroot on canola

2015 ◽  
Vol 70 ◽  
pp. 78-84 ◽  
Author(s):  
Gary Peng ◽  
Denis Pageau ◽  
Stephen E. Strelkov ◽  
Bruce D. Gossen ◽  
Sheau-Fang Hwang ◽  
...  
Keyword(s):  
Crop Rotation ◽  
Plasmodiophora Brassicae ◽  
Resting Spores ◽  
The Impact

scholarly journals First Report of Clubroot on Canola Caused by Plasmodiophora brassicae in North Dakota

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1438-1438 ◽  
Author(s):  
K. Chittem ◽  
S. M. Mansouripour ◽  
L. E. del Río Mendoza
Keyword(s):  
United States ◽  
North Dakota ◽  
Plasmodiophora Brassicae ◽  
The United States ◽  
Soil Samples ◽  
Pcr Analysis ◽  
Infested Soil ◽  
First Report ◽  
Resting Spores ◽  
Pathogenicity Tests

North Dakota leads the United States in canola (Brassica napus L.) production (4). A canola field with a distinct patch of dead plants spreading over an area of approximately 0.4 ha was detected in Cavalier County, North Dakota, in early September 2013. Numerous spots within the patch had plant mortalities >80%. Dead plants pulled from the soil had roots with severe galling and clubbing. Clubbed roots were brittle and disintegrated easily when pressed between fingers. Root and soil samples collected at several locations within and outside the affected patch were pooled in separate groups. All plants collected in the patch were symptomatic but those collected outside were not. In the lab, total genomic DNA from three symptomatic and two healthy root samples was extracted using standard procedures and freehand slices were prepared for observation with a compound microscope. Also, DNA from pooled soil samples was extracted using FastDNA Spin Kit for Soil (MP Biomedicals, Solon, OH). Round resting structures ranging from 2.2 to 4.2 μm in diameter were observed by microscopic examination of symptomatic root tissues. These structures resembled those typically produced by Plasmodiophora brassicae Woronin. This initial identification was later confirmed through PCR analysis using the species specific primers TC1F/R and TC2F/R (1). PCR products of 548 bp (TC1F/R) and 519 bp (TC2F/R) were produced in the three symptomatic and two infested soil samples, confirming the presence of P. brassicae. PCR amplicons were not detected in healthy root and soil samples. Pathogenicity tests were conducted in greenhouse to fulfill Koch's postulates. Briefly, five square plastic pots (10 × 10 × 13 cm) were filled with a 10-cm layer of Sunshine Mix #1 potting mix (Fison Horticulture, Vancouver, BC, Canada) and then 1 g of ground root galls (approximately 5 × 105 resting spores) was spread evenly on its surface and covered with 2 cm of soilless mix. A similar number of pots were filled only with soilless mix and used as controls. All pots were planted with two seeds of canola cv. Westar and incubated in greenhouse conditions at 21°C and 16 h light daily. The experiment was conducted twice. Four weeks after planting, all plants in the inoculated pots had developed galls while plants in control pots were symptomless. Presence of P. brassicae resting spores in the newly developed galls was confirmed by microscopic observations and PCR. Based on the symptoms, morphology of resting spores, PCR reactions, and pathogenicity tests, we confirm the presence of P. brassicae on canola. While P. brassicae has been reported as widespread in North America (2), to our knowledge, this is the first report of clubroot on canola in North Dakota and the United States. Clubroot became the most important disease affecting canola production in central Alberta, Canada, within 5 years of its discovery in 2003 (3); since then, the disease has been detected in Saskatchewan and Manitoba (3), Canadian provinces that share borders with North Dakota. Considering the difficulties in management of clubroot, measures should be initiated to limit the spread of the disease before it could pose a threat to United States canola production. References: (1) T. Cao et al. Plant Dis. 91:80, 2007. (2) G. Dixon J. Plant Growth Regul. 28:194, 2009. (3) S. Strelkov and S. Hwang. Can. J. Plant Pathol. 36(S1):27, 2014. (4) USDA-NASS, Ag. Statistics No. 81, 2012.

Seedling age and inoculum density affect clubroot severity and seed yield in canola

2011 ◽  
Vol 91 (1) ◽  
pp. 183-190 ◽  
Author(s):  
S. F. Hwang ◽  
H. U. Ahmed ◽  
S. E. Strelkov ◽  
B. D. Gossen ◽  
G. D. Turnbull ◽  
...  
Keyword(s):  
Plant Height ◽  
Seed Yield ◽  
Negative Impact ◽  
Plasmodiophora Brassicae ◽  
Inoculum Density ◽  
Infested Soil ◽  
Seedling Age ◽  
Control Seed ◽  
Resting Spores ◽  
Infested Field

Hwang, S. F., Ahmed, H. U., Strelkov, S. E., Gossen, B. D., Turnbull, G. D., Peng, G. and Howard, R. J. 2011. Seedling age and inoculum density affect clubroot severity and seed yield in canola. Can. J. Plant Sci. 91: 183–190. Clubroot, caused by Plasmodiophora brassicae, is a serious threat to canola (Brassica napus, B. rapa) production in western Canada because of its long-lived resting spores, high spore production potential, and negative impact on seed yield when inoculum pressure is high. The effect of inoculum density was studied by diluting heavily infested field soil with pathogen-free soil-less potting mix at seven increments, ranging from completely pathogen-free to 100% infested soil, and also by incorporating resting spores into the soil-less mix at concentrations of 1×105 to 1×108 spores cm−3, along with a non-inoculated control. Seed of the susceptible canola cultivar 34 SS 65 was planted in soil of each treatment, grown to maturity, and rated for plant height, seed yield, and clubroot severity (0–3 scale) at harvest. Clubroot severity increased and plant height and seed yield decreased with increasing inoculum density. To assess the effect of seedling age on reaction to clubroot, resting spores of P. brassicae were inoculated onto roots of 1-, 2-, 3- and 4-wk-old seedlings of 34 SS 65. In addition, seed (i.e., 0-wk-old seedlings) was sown into infested soil. Inoculation of young seedlings resulted in higher clubroot severity, shorter plants and lower yield than inoculation of older seedlings. These results indicate that seed treatment fungicides with a long residual period (4 wk or more) may be useful for the management of clubroot.

Molecular Detection of Plasmodiophora brassicae, Causal Agent of Clubroot of Crucifers, in Plant and Soil

Plant Disease ◽  
2007 ◽  
Vol 91 (1) ◽  
pp. 80-87 ◽  
Author(s):  
Tiesen Cao ◽  
Jalpa Tewari ◽  
Stephen E. Strelkov
Keyword(s):  
Ribosomal Rna ◽  
Plasmodiophora Brassicae ◽  
Rrna Gene ◽  
Infested Soil ◽  
Resting Spores ◽  
One Step ◽  
Dna Fragment ◽  
Polymerase Chain ◽  
Total P ◽  
Step Polymerase Chain Reaction

Clubroot of crucifers, caused by Plasmodiophora brassicae, recently has been identified in canola (Brassica napus) fields in Alberta, Canada. An effective strategy for managing the disease is to avoid planting cruciferous crops in P. brassicae-infested soil, because the pathogen produces resting spores that can remain infectious for many years. A simple, one-step polymerase chain reaction (PCR) protocol was developed to detect the pathogen in plant and soil samples. The primers TC1F and TC1R, based on a P. brassicae partial 18S ribosomal RNA (rRNA) gene sequence from GenBank, yielded a 548-bp product in the optimized PCR. A second pair of primers, TC2F and TC2R, which amplified a fragment of the 18S and internal transcribed spacer (ITS) 1 regions of the rDNA repeat, also was tested and produced a 519-bp product. Neither set of primers amplified any DNA fragment from noninfected plant hosts, noninfested soil, or common soil fungi and bacteria tested in this study. Quantities of 100 fg or less of total P. brassicae DNA, or 1 × 103 resting spores per gram of soil, could be detected consistently using these primers and PCR protocol, corresponding to an index of disease of 11% or lower when the soil was bioassayed. The protocol also enabled detection of P. brassicae in symptomless root tissue 3 days after inoculation with the pathogen. Therefore, the PCR assay described in this study could provide a reliable diagnosis for routine detection of P. brassicae in plant and soil materials in a specific and rapid manner.

scholarly journals Assessing BactoMix 5 efficacy for clubroot control in naturally infested soil

2020 ◽  
Vol 57 (No. 1) ◽  
pp. 14-20
Author(s):  
Kaire Loit ◽  
Riinu Kiiker ◽  
Britt Puidet ◽  
Liina Soonvald ◽  
Marian Põldmets ◽  
...  
Keyword(s):  
Plasmodiophora Brassicae ◽  
Bacterial Species ◽  
Antagonistic Activity ◽  
Infested Soil ◽  
Yield Losses ◽  
Bacterial Product ◽  
Disease Symptoms ◽  
Soil Microbiota ◽  
Regional Production ◽  
Native Soil

The cultivation of cruciferous crops is threatened by extensive yield losses caused by the soil-borne pathogen Plasmodiophora brassicae Woronin, 1877. The objective of the study was to assess the potential of the bacterial product BactoMix 5 for the control of clubroot on a naturally infested soil in growth chamber trials using a P. brassicae-specific qPCR methodology. The results did not show a significant decrease in the P. brassicae in the soil nor a reduction of the disease symptoms on the plants. The native soil microbiota may have exhibited an antagonistic activity against the bacterial species from BactoMix 5 and evoked the poor effect of the product. Therefore, potential biological control agents should be tested with native soil microbiota and the regional production should be advanced to increase the product efficacy in the environment

scholarly journals Methods for Assessment of Viability and Germination of Plasmodiophora brassicae Resting Spores

2022 ◽  
Vol 12 ◽  
Author(s):  
Yao Wang ◽  
Birger Koopmann ◽  
Andreas von Tiedemann
Keyword(s):  
Evans Blue ◽  
Plasmodiophora Brassicae ◽  
Germination Rate ◽  
Inoculum Potential ◽  
Differential Interference Contrast Microscopy ◽  
Calcofluor White ◽  
Clubroot Disease ◽  
Resting Spores ◽  
Dual Staining

Clubroot caused by the obligate biotrophic parasite Plasmodiophora brassicae is a destructive soil borne disease of cruciferous crops. Resting spores of P. brassicae can survive in the soil for a long period without hosts or external stimulants. The viability and germination rate of resting spores are crucial factors of the inoculum potential in the field. The accurate assessment of viability and germination rate is the foundation to evaluate the effect of control methods. In this study, we evaluated several methods for the assessment of viability and germination rate of P. brassicae resting spores. Dual staining with calcofluor white-propidium iodide (CFW-PI) or single stain with Evans blue showed reliable accuracy in estimating viability. CFW-PI was capable of reliably determining the viability within 10 min, while Evans blue required overnight incubation to obtain accurate results. Due to DNA degradation of heat treatments, acetone was selected to evaluate the efficiency of propidium monoazide (PMA)–quantitative PCR (qPCR) used for the quantification of DNA from viable cells. The staining with 4,6-Diamidine-2-phenylindole dihydrochloride (DAPI) and the use of differential interference contrast microscopy were suitable for the determination of resting spore germination rates. The latter method also allowed recording individual germination states of spores. Alternatively, dual staining with CFW-Nile red was successfully used to assess the germination rate of resting spores with a lethal pre-treatment. This study evaluates and confirms the suitability of various microscopic and molecular genetic methods for the determination of viability and germination of P. brassicae resting spores. Such methods are required to study factors in the soil regulating survival, dormancy and germination of P. brassicae resting spores causing clubroot disease in Brassicaceae hosts and therefore are fundamental to develop novel strategies of control.

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