scholarly journals Interactions of soil nutrient environment, pathogenesis and host resistance

2002 ◽  
Vol 38 (SI 1 - 6th Conf EFPP 2002) ◽  
pp. S87-S94 ◽  
Author(s):  
G.R. Dixon
Keyword(s):  
Host Resistance ◽  
Host Plants ◽  
Plasmodiophora Brassicae ◽  
Integrated Control ◽  
Nutrient Status ◽  
Pythium Ultimum ◽  
Chemical Components ◽  
Clubroot Disease ◽  
Organic Nutrients ◽  
The Impact

Host plants and soil borne pathogens that attack them exist within an ecological matrix populated by numerous microbial species that may influence the access of pathogenesis. These events are moderated by physical and chemical components of the soil. The impact of inorganic and organic nutrients on pathogenesis and the development of host resistance are discussed in this review using two host – pathogen combinations as examples. Calcium, boron, nitrogen and pH have been demonstrated to affect the processes of resting spore germination, host invasion and colonisation in the Plasmodiophora brassicae-Brassica combination that results in clubroot disease. Organic nutrients that have associated biostimulant properties have been demonstrated to influence the development of Pythium ultimum-Brassica combination that results in damping-off disease. This latter combination is affected by the presence of antagonistic microbial flora as demonstrated by increased ATP, extra-cellular enzyme and siderophore production. In both examples there are indications of the manner by which host resistance to pathogenesis may be enhanced by changes to the nutrient status surrounding host plants. These effects are discussed in relation to the development of integrated control strategies that permit disease control with minimal environmental impact.

Clubroot in Brassica: Recent advances in genomics, breeding and disease management

Genome ◽  
2021 ◽  
Author(s):  
Muhammad Jakir Hasan ◽  
Swati Megha ◽  
Habibur Rahman
Keyword(s):  
Host Resistance ◽  
Molecular Basis ◽  
Host Plants ◽  
Cultural Practices ◽  
Plasmodiophora Brassicae ◽  
Genetic Resistance ◽  
Vegetable Production ◽  
Comprehensive Understanding ◽  
Clubroot Disease

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.

scholarly journals THE EFFECTIVENESS OF IMMUNOLOGICAL EVALUATION OF RESISTANCE OF THE WHITE CABBAGE LINES TO PLASMODIOPHORA BRASSICAE WOR. AGAINST ARTIFICIAL INFECTION BACKGROUND

2018 ◽  
pp. 97-100
Author(s):  
A. A. Ushakov ◽  
L. L. Bondareva ◽  
I. A. Engalycheva
Keyword(s):  
Plasmodiophora Brassicae ◽  
Background Intensity ◽  
Federal State ◽  
Causative Organism ◽  
Atmospheric Conditions ◽  
Artificial Infection ◽  
Entire Area ◽  
Clubroot Disease ◽  
White Cabbage ◽  
The Impact

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.

scholarly journals Temporal dynamics of bacterial and fungal communities during the infection of Brassica rapa roots by the protist Plasmodiophora brassicae: The impact of a pathogen on the plant root and rhizosphere microbiota

2018 ◽  
Author(s):  
Lionel Lebreton ◽  
Anne-Yvonne Guillerm-Erckelboudt ◽  
Kévin Gazengel ◽  
Juliette Linglin ◽  
Morgane Ourry ◽  
...  
Keyword(s):  
Chinese Cabbage ◽  
Temporal Dynamics ◽  
Plasmodiophora Brassicae ◽  
Plant Root ◽  
Fungal Communities ◽  
Clubroot Disease ◽  
Bacterial Phyla ◽  
Mutualistic Relationship ◽  
The Impact ◽  
Root Microbiota

AbstractThe temporal dynamics of rhizosphere and root microbiota composition was compared between healthy and infected Chinese cabbage plants by the pathogen Plasmodiophora brassicae. When inoculated with P. brassicae, disease was measured at five sampling dates from early root hair infection to late gall development. The first symptoms of clubroot disease appeared 14 days after inoculation (DAI) and increased drastically between 14 and 35 DAI. The structure of microbial communities associated to rhizosphere soil and root from healthy and inoculated plants was characterized through high-throughput DNA sequencing of bacterial (16S) and fungal (18S) molecular markers and compared at each sampling date. In healthy plants, Proteobacteria and Bacteroidetes bacterial phyla dominated the rhizosphere and root microbiota of Chinese cabbage. Rhizosphere bacterial communities contained higher abundances of Actinobacteria and Firmicutes compared to the roots. Moreover, a drastic shift of fungal communities of healthy plants occurred between the two last sampling dates, especially in plant roots, where most of Ascomycota fungi dominated until they were replaced by a fungus assigned to the Chytridiomycota phylum. Parasitic invasion by P. brassicae disrupted the rhizosphere and root-associated community assembly at a late step during the root secondary cortical infection stage of clubroot disease. At this stage, Flavisolibacter and Streptomyces in the rhizosphere, and Bacillus in the roots, were drastically less abundant upon parasite invasion. Rhizosphere of plants colonized by P. brassicae was significantly more invaded by the Chytridiomycota fungus, which could reflect a mutualistic relationship in this compartment between these two microorganisms.

INFLUENCE OF GREENHOUSE SHADING AND DIFFERENT NUTRIENT MANAGEMENT PRACTICES ON ALLEVIATING HEAT STRESS, IMPROVING PLANT NUTRIENTS STATUS, FLOWERING GROWTH AND YIELD OF TOMATO

2020 ◽  
Vol 51 (4) ◽  
pp. 1001-1014
Author(s):  
Sulaiman & Sadiq
Keyword(s):  
Heat Stress ◽  
Management Practices ◽  
Nutrient Management ◽  
Block Design ◽  
Nutrient Status ◽  
Growth And Yield ◽  
Reproductive Growth ◽  
Positive Effects ◽  
Nutrition Programs ◽  
The Impact

The experiment was conducted in a greenhouse during 2017 and 2018 growing seasons to evaluate the impact of the shading and various nutrition programs on mitigating heat stress, reducing the use of chemical minerals, improving the reproductive growth and yield of tomato plant. Split-plot within Randomized Complete Block Design (RCBD) with three replications was conducted in this study. Shading factor was allocated in the main plots and the nutrition programs distributed randomly in the subplots. Results indicate that shading resulted in the decrease of daytime temperature by 5.7˚C as an average for both seasons; thus a significant increasing was found in leaf contents of macro nutrients (Nitrogen, Phosphorous, and Potassium), and micro nutrients (Iron, Zinc and Boron), except the Iron content in 2018 growing season. Furthermore, shading improved significantly the reproductive growth and tomato yield. Among the plant nutrition programs, the integrated nutrient management (INM) including the application of organic substances, bio inoculum of AMF and 50% of the recommended dose of chemical fertilizers; lead to the enhancement of nutrients content, reproductive characteristics and plant yield. Generally, combination of both shading and INM showed positive effects on plants nutrient status and persisting balance on tomato flowering growth and fruits yield.

scholarly journals A New Identification Method Reveals the Resistance of an Extensive-Source Radish Collection to Plasmodiophora brassicae Race 4

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 792
Author(s):  
Haohui Yang ◽  
Yuxiang Yuan ◽  
Xiaochun Wei ◽  
Xiaohui Zhang ◽  
Haiping Wang ◽  
...  
Keyword(s):  
Plasmodiophora Brassicae ◽  
Central China ◽  
Clubroot Disease ◽  
Cruciferous Vegetable ◽  
Inoculation Methods ◽  
Identification Method ◽  
South Central ◽  
Disease Occurrence ◽  
Resistant Varieties ◽  
The Stability

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.

scholarly journals Assessment of Pellets from Three Forest Species: From Raw Material to End Use

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 447
Author(s):  
Miguel Alfonso Quiñones-Reveles ◽  
Víctor Manuel Ruiz-García ◽  
Sarai Ramos-Vargas ◽  
Benedicto Vargas-Larreta ◽  
Omar Masera-Cerutti ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Ash Content ◽  
Hot Water ◽  
Raw Material ◽  
Chemical Components ◽  
Energy Yield ◽  
Cellulose Content ◽  
Fixed Carbon ◽  
End Use ◽  
The Impact

This study aimed to evaluate and compare the relationship between chemical properties, energy efficiency, and emissions of wood and pellets from madroño Arbutus xalapensis Kunth, tázcate Juniperus deppeana Steud, and encino colorado Quercus sideroxyla Humb. & Bonpl. in two gasifiers (top-lit-up-draft (T-LUD) and electricity generation wood camp stove (EGWCS)) in order to determine the reduction of footprint carbon. In accordance with conventional methodologies, we determined the extracts and chemical components (lignin, cellulose, holocellulose), and the immediate analyses were carried out (volatile materials, fixed carbon, ash content and microanalysis of said ash), as well as the evaluation of emission factors (total suspended particulate matter (PM2.5), CO, CO2, CH4, black carbon (BC), elemental carbon (EC), and organic carbon (OC)). The results were statistically analyzed to compare each variable among species and gasifiers. The raw material analyzed showed how the pH ranged from 5.01 to 5.57, and the ash content ranged between 0.39 and 0.53%. The content values of Cu, Zn, Fe, Mg, and Ca ranged from 0.08 to 0.22, 0.18 to 0.19, 0.38 to 0.84, 1.75 to 1.90, and 3.62 to 3.74 mg kg−1, respectively. The extractive ranges from cyclohexane were 2.48–4.79%, acetone 2.42–4.08%, methanol 3.17–7.99%, and hot water 2.12–4.83%. The range of lignin was 18.08–28.60%. The cellulose content ranged from 43.30 to 53.90%, and holocellulose from 53.50 to 64.02%. The volatile material range was 81.2–87.42%, while fixed carbon was 11.30–17.48%; the higher heating value (HHV) of raw material and pellets presented the ranges 17.68–20.21 and 19.72–21.81 MJ kg−1, respectively. Thermal efficiency showed statistically significant differences (p < 0.05) between pellets and gasifiers, with an average of 31% Tier 3 in ISO (International Organization for Standardization) for the T-LUD and 14% (ISO Tier 1) for EGWCS, with Arbutus xalapensis being the species with the highest energy yield. The use of improved combustion devices, as well as that of selected raw material species, can reduce the impact of global warming by up to 33% on a cooking task compared to the three-stone burner.

scholarly journals Batf3-Dependent Dendritic Cells Promote Optimal CD8 T Cell Responses against Respiratory Poxvirus Infection

2018 ◽  
Vol 92 (16) ◽  
Author(s):  
Pritesh Desai ◽  
Vikas Tahiliani ◽  
Georges Abboud ◽  
Jessica Stanfield ◽  
Shahram Salek-Ardakani
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Vaccinia Virus ◽  
Respiratory Infection ◽  
Host Resistance ◽  
T Cell Responses ◽  
Cell Responses ◽  
Ifn Γ ◽  
The Impact

ABSTRACTRespiratory infection with vaccinia virus (VacV) elicits robust CD8+T cell responses that play an important role in host resistance. In the lung, VacV encounters multiple tissue-resident antigen-presenting cell (APC) populations, but which cell plays a dominant role in priming of virus-specific CD8+effector T cell responses remains poorly defined. We used Batf3−/−mice to investigate the impact of CD103+and CD8α+dendritic cell (DC) deficiency on anti-VacV CD8+T cell responses. We found that Batf3−/−mice were more susceptible to VacV infection, exhibiting profound weight loss, which correlated with impaired accumulation of gamma interferon (IFN-γ)-producing CD8+T cells in the lungs. This was largely due to defective priming since early in the response, antigen-specific CD8+T cells in the draining lymph nodes of Batf3−/−mice expressed significantly reduced levels of Ki67, CD25, and T-bet. These results underscore a specific role for Batf3-dependent DCs in regulating priming and expansion of effector CD8+T cells necessary for host resistance against acute respiratory VacV infection.IMPORTANCEDuring respiratory infection with vaccinia virus (VacV), a member ofPoxviridaefamily, CD8+T cells play important role in resolving the primary infection. Effector CD8+T cells clear the virus by accumulating in the infected lungs in large numbers and secreting molecules such as IFN-γ that kill virally infected cells. However, precise cell types that regulate the generation of effector CD8+T cells in the lungs are not well defined. Dendritic cells (DCs) are a heterogeneous population of immune cells that are recognized as key initiators and regulators of T-cell-mediated immunity. In this study, we reveal that a specific subset of DCs that are dependent on the transcription factor Batf3 for their development regulate the magnitude of CD8+T cell effector responses in the lungs, thereby providing protection during pulmonary VacV infection.

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 Effect of biofertilizers on soil microbial count, nutrient availability and uptake under november sown onion

2017 ◽  
Vol 9 (1) ◽  
pp. 55-59
Author(s):  
Dilpreet Talwar ◽  
Kulbir Singh ◽  
Jagdish Singh
Keyword(s):  
Nutrient Availability ◽  
Arbuscular Mycorrhizae ◽  
N Uptake ◽  
Nutrient Status ◽  
Recommended Dose ◽  
Available Phosphorus ◽  
Microbial Count ◽  
Available Nitrogen ◽  
Soil Microbial ◽  
The Impact

Biofertilizers improves the soil microbial content, Soil nutrient status and nutrient uptake by plant. In an experiment, fifteen treatments comprised of various combinations of biofertilizers, organic manures and chemical fertilizers were compared to access the impact of different sources of nutrient on performance of onion. The highest soil organic carbon (0.40%) was observed in the treatments T12 (Farm Yard Manure (FYM) @ 20 t/ha) and T11 (FYM myctes count (29.9 X 104) was recorded in T11 (FYM @ 20 t/ha + Azotobacter + VAM) treatment while highest fungal @ 20 t/ha + Azotobacter + Vesicular-Arbuscular Mycorrhizae (VAM)). Highest bacterial (24.5 X 106) and actino-count (17.5 X 103) was observed in T3 (Azospirillium+ Recommended dose of NPK) treatment. At the time of harvesting, available nitrogen (N), available phosphorus (P) and available potassium (K) were higher in treatment T3 (Azospirillium + Recommended dose of NPK), T9 (Azotobacter+ VAM + Recommended dose of NPK) and T13 (Poultry treatment (162.6 Kg ha-1) as compared to all other treatments except T1 and T9 treatments while P uptake (13.6 Kg ha-Manure @ 5t/ha) treatments respectively than that in other treatments. Azospirillum and Azotobacter application along with recommended dose of N, P and K improved the fertility status of soil. The N uptake was significantly higher in T3 treatments. The present study highlights the need of use of biofertilizers along with organic and inorganic 1) was significantly higher in T9 treatment than that in other treatments except T1, T3, T5 and T7 treatments. The K uptake was significantly higher in T3 treatment (126.9 Kg ha-1) as compare to all other treatments except T1 and T9 manures/fertilizer to enhance the nutrient availability and improve soil health.

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