Optimization of the cultural medium and conditions for production of antifungal substances by Streptomyces platensis 3-10 and evaluation of its efficacy in suppression of clubroot disease ( Plasmodiophora brassicae ) of oilseed rape

2016 ◽  
Vol 101 ◽  
pp. 59-68 ◽  
Author(s):  
Qaiser Shakeel ◽  
Ang Lyu ◽  
Jing Zhang ◽  
Mingde Wu ◽  
Shouwen Chen ◽  
...  
2012 ◽  
Vol 92 (3) ◽  
pp. 501-515 ◽  
Author(s):  
Muhammad Jakir Hasan ◽  
Stephen E. Strelkov ◽  
Ronald J. Howard ◽  
Habibur Rahman

Hasan, M. J., Strelkov, S. E., Howard, R. J. and Rahman, H. 2012. Screening of Brassica germplasm for resistance to Plasmodiophora brassicae pathotypes prevalent in Canada for broadening diversity in clubroot resistance. Can. J. Plant Sci. 92: 501–515. Clubroot disease of crucifers, caused by Plasmodiophora brassicae, poses a threat to the Canadian canola industry, and the development of resistant cultivars is urgently needed. Germplasm resistant to local pathotype(s) is the prime requirement for breeding clubroot-resistant cultivars. The objective of this study was to identify Brassica germplasm possessing resistance to P. brassicae pathotypes prevalent in Alberta. Pathotype-specific resistance was identified in the diploid species Brassica rapa (AA) and B. oleracea (CC), and in the amphidiploid B. napus (AACC). Among B. rapa genotypes, turnip was the most resistant, followed by winter type and spring type oilseed rape. The rutabaga group of B. napus, on the other hand, was homogeneous for resistance to Canadian P. brassicae pathotypes. The diploid species B. nigra (BB) also showed pathotype-specific resistance. However, the two amphidiploids carrying the B. nigra genome, B. juncea (AABB) and B. carinata (BBCC) were completely susceptible to clubroot.


Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 792
Author(s):  
Haohui Yang ◽  
Yuxiang Yuan ◽  
Xiaochun Wei ◽  
Xiaohui Zhang ◽  
Haiping Wang ◽  
...  

Raphanus sativus, an important cruciferous vegetable, has been increasingly affected by clubroot disease. Establishing a stable and accurate resistance identification method for screening resistant germplasms is urgently needed in radish. In this study, the influence of inoculum concentration, inoculation methods, and pH of the substrate on disease occurrence was studied. The result showed that the disease index (DI) was highest at 2 × 108 spores/mL, the efficiency of two-stage combined inoculation methods was higher than others, and pH 6.5 was favorable for the infection of P. brassicae. By using this new method, DIs of 349 radish germplasms varying from 0.00 to 97.04, presented significantly different levels of resistance. Analysis showed that 85.06% germplasms from China were susceptible to P. brassicae, whilst 28 accessions were resistant and mainly distributed in east, southwest, northwest, and south-central China. Most of the exotic germplasms were resistant. Repeated experiments verified the stability and reliability of the method and the identity of germplasm resistance. In total, 13 immune, 5 highly resistant and 21 resistant radish accessions were identified. This study provides an original clubroot-tolerance evaluation technology and valuable materials for the development of broad-spectrum resistant varieties for sustainable clubroot management in radish and other cruciferous crops.


2017 ◽  
Vol 92 ◽  
pp. 60-69 ◽  
Author(s):  
Veronika Řičařová ◽  
Jan Kazda ◽  
Petr Baranyk ◽  
Pavel Ryšánek

2014 ◽  
Vol 104 (5) ◽  
pp. 532-538 ◽  
Author(s):  
Becke Strehlow ◽  
Friederike de Mol ◽  
Christine Struck

The soilborne pathogen Plasmodiophora brassicae causes clubroot on Brassica crops, a common disease in many oilseed rape growing regions. Here, we investigate genetic diversity and geographic differentiation of P. brassicae populations from different regions in Germany. We compared three regions that differ in oilseed rape cropping history, oilseed rape acreage, and incidence of clubroot. These regions were either spatially separated or separated by the former inner German border. Plasmodiophora isolates were collected from 59 fields (29, 17, and 13 fields per region, respectively) and 174 amplified fragment length polymorphism (AFLP) markers were analyzed. Every field isolate showed a unique genotype pattern; that is, no genotype was shared among the regions and different fields. The mean gene diversity was 0.27, suggesting that P. brassicae is a genetically diverse species. The comparison of indexes (gene diversity, genotypic diversity, and linkage disequilibrium) between the regions does not support our hypotheses that cropping history, oilseed rape acreage, and incidence of clubroot affect these estimates. Principal component analysis (PCA), fixation index (FST), and generalized linear model (GLM) were suitable to specify regional differences. PCA revealed two clusters of isolates based on the geographic origin of the isolates and FST showed that these clusters were highly differentiated. Hypotheses about association of genotypes with different spatial scales were tested with GLM: the region, reflecting the cropping history, and the individual field had a significant effect on the AFLP pattern. We propose that individual field isolates represent a discrete population and that geographic differentiation results from low levels of gene flow due to the limited dispersal of this soilborne pathogen and from localized selection pressure as unifying force on the genotypes.


Genome ◽  
2021 ◽  
Author(s):  
Muhammad Jakir Hasan ◽  
Swati Megha ◽  
Habibur Rahman

Clubroot disease, caused by Plasmodiophora brassicae, affects Brassica oilseed and vegetable production worldwide. This review is focused on various aspects of clubroot disease and its management, including understanding the pathogen and resistance in the host plants. Advances in genetics, molecular biology techniques and ‘omics’ research have helped to identify several major loci, QTL and genes from the Brassica genomes involved in the control of clubroot resistance. Transcriptomic studies have helped to extend our understanding of the mechanism of infection by the pathogen and the molecular basis of resistance/susceptibility in the host plants. A comprehensive understanding of the clubroot disease and host resistance would allow developing a better strategy by integrating the genetic resistance with cultural practices to manage this disease from a long-term perspective.


Plant Disease ◽  
2021 ◽  
Author(s):  
Nazanin Zamani-Noor ◽  
Sinja Brand ◽  
Hans-Peter Soechting

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.


2018 ◽  
pp. 97-100
Author(s):  
A. A. Ushakov ◽  
L. L. Bondareva ◽  
I. A. Engalycheva

Clubroot disease (causative organism Plasmodiophora brassicae Wor.) is among the most economically important and harmful diseases of the cole crops, and the damage due to this disease may reach up to 50-75% of the yield and even 100% in epiphytotics years. Even resistant varieties become susceptible over the years, because of appearance of the new pathogen races and change of climatic conditions in the main growing areas of the crop. In this context the Laboratory of Plant Immunity and Protection, of Federal State Budgetary Scientific Institution “Federal Scientific Vegetable Center” implements continuous phytoimmunological evaluation of collection and selection specimens and also directional material rather than just annual monitoring of causative organism dissemination in order to find new resistance sources. For this purpose an artificial infection background is used: compost obtained from decomposed nodules on the cabbage roots affected by clubroot disease (infection load 105-106 spores/cm3). The resistance of white cabbage varieties was evaluated during the harvesting period using five-point score of the root system damage, which formed the basis for categorization into resistance groups. For the analysis of artificial background intensity and specimen ranking the individual plants of the white cabbage variety Slava 1305, which is a susceptibility standard, were randomly planted in the entire area of the infection background. The impact of atmospheric conditions in the study year on the results of phytopathological evaluation of cabbage selection specimens against the infection background is demonstrated. Under unfavorable conditions for pathogen development (2014) the most specimens (74%) were categorized as relatively resistant, while in favourable for pathogen year 2015 relatively resistant specimens comprised only 5% of the total number of studied specimens. Since the same specimen may show different level of resistance depending on the year conditions, the stability of character manifestation is the important criterion for identification of the resistance resources. Phytopathological evaluation aimed on selection of clubroot-resistant forms in the Moscow region should last for at least three years even with the use of infection background. Long-lasting evaluation showed that the strains No 234/15,140/14,216/17 exhibiting high resistance to clubroot against artificial infection background regardless of the year conditions are the most valuable for selection. The resistance of white cabbage selection varieties to clubroot disease was studied against the infection background.


2020 ◽  
Vol 110 (10) ◽  
pp. 1704-1712 ◽  
Author(s):  
Lijiang Liu ◽  
Li Qin ◽  
Zhuqing Zhou ◽  
Wilhelmina G. H. M. Hendriks ◽  
Shengyi Liu ◽  
...  

As a soilborne protist pathogen, Plasmodiophora brassicae causes the devastating clubroot disease on Brassicaceae crops worldwide. Due to its intracellular obligate biotrophic nature, the life cycle of P. brassicae is still not fully understood. Here, we used fluorescent probe-based confocal microscopy and transmission electron microscopy (TEM) to investigate the infection process of P. brassicae on the susceptible host Arabidopsis under controlled conditions. We found that P. brassicae can initiate the primary infection in both root hairs and epidermal cells, producing the uninucleate primary plasmodium at 1 day postinoculation (dpi). After that, the developed multinucleate primary plasmodium underwent condensing and cytoplasm cleavage into uninucleate zoosporangia from 1 to 4 dpi. This was subsequently followed by the formation of multinucleate zoosporangia and the production of secondary zoospores within zoosporangium. Importantly, the secondary zoospores performed a conjugation in the root epidermal cells after their release. TEM revealed extensive uninucleate secondary plasmodium in cortical cells at 8 dpi, indicating the establishment of the secondary infection. The P. brassicae subsequently developed into binucleate, quadrinucleate, and multinucleate secondary plasmodia from 10 to 15 dpi, during which the clubroot symptoms appeared. The uninucleate resting spores were first observed in the cortical cells at 24 dpi, marking the completion of a life cycle. We also provided evidence that the secondary infection of P. brassicae may represent the diploid sexual life stage. From these findings, we propose a refined life cycle of P. brassicae which will contribute to understanding of the complicated infection biology of P. brassicae.


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