Effect of canola (Brassica napus) cultivar rotation on Plasmodiophora brassicae pathotype composition

In Canada, clubroot (Plasmodiophora brassicae) disease is managed mainly by planting clubroot resistant (CR) canola (Brassica napus). New pathotypes of P. brassicae have emerged recently, however, which are virulent on most CR canola cultivars. To understand the impact of cultivar rotation on pathotype abundance, greenhouse experiments were conducted in which different canola cultivar rotations were grown in a soil mix containing equal amounts of pathotypes 5X and 3, which are virulent and avirulent, respectively, on CR canola. The rotation treatments included: T1, the same susceptible cultivar planted over four cycles; T2, the same CR cultivar planted over four cycles; and T3, different CR cultivars planted in each cycle. Clubroot severity increased from cycles one to four in all treatments, with the exception of one CR cultivar in T3 that may carry a different source of resistance. Pathogen populations were recovered with a susceptible bait crop and pathotyped on the differentials of Williams plus a CR host (B. napus ‘Mendel’). The percentage of galls classified as pathotype 5X in T1 declined from 50% to 6.7% over the course of the experiment, while galls classified as pathotype 5X increased from 50% to 66.7% in both T2 and T3. Quantitative PCR analysis of the soil with pathotype 5X-specific primers generally confirmed an increase in 5X DNA. The results suggest that continuous planting of CR canola favours a rapid proliferation of virulent pathotypes of P. brassicae, as indicated by the increases in pathotype 5X observed in this study.

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

Plant Disease ◽

10.1094/pdis-09-20-1980-re ◽

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.

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Suppression of Canola (Brassica napus) Resistance by Virulent Isolates of Plasmodiophora brassicae (Clubroot) During Primary Infection

Plant Disease ◽

10.1094/pdis-03-19-0659-re ◽

2020 ◽

Vol 104 (2) ◽

pp. 430-437

Author(s):

Junye Jiang ◽

Rudolph Fredua-Agyeman ◽

Stephen E. Strelkov ◽

Sheau-Fang Hwang

Keyword(s):

Brassica Napus ◽

Plasmodiophora Brassicae ◽

Negative Control ◽

Pcr Analysis ◽

High Concentration ◽

Clubroot Disease ◽

Low Concentrations ◽

High Concentrations ◽

Experimental Treatments ◽

Positive Controls

The planting of clubroot resistant (CR) canola (Brassica napus) is the most effective method to manage clubroot. Since 2013, many Plasmodiophora brassicae isolates capable of overcoming resistance have been detected, often in mixtures with avirulent isolates. To improve understanding of the effect of low concentrations of virulent isolates on host resistance, three CR canola cultivars (45H29, L135C, and L241C) were inoculated with pairs of isolates representing virulent/avirulent pathotypes (2*/2, 3*/3, and 5*/5) collected after or before the introduction of CR canola, respectively. Seven-day-old seedlings of each cultivar were incubated for 2 days in low concentrations (1 × 103 spores/ml) of the virulent isolates, followed by a second inoculation with a high concentration (1 × 107 spores/ml) of the avirulent isolates. Positive controls comprised seedlings inoculated with low concentrations of the virulent isolates followed by high concentrations of the virulent isolates (PC1) or only with high concentrations of virulent isolates (PC2). Negative controls comprised seedlings inoculated only with high concentrations of the avirulent isolates (NC1) or only with low concentrations of the virulent isolates (NC2). Clubroot severity was significantly higher in all nine experimental treatments (low virulent plus high avirulent) than in the negative control NC1 (high avirulent) but was lower in the experimental treatments than in the positive controls (PC1 and PC2). Low concentrations of virulent isolates alone (NC2) caused moderate clubroot. Disease severity correlated well with P. brassicae biomass in canola as determined by quantitative PCR analysis 28 to 35 days after inoculation. This study revealed that low concentrations of virulent isolates compromised canola resistance for infection by avirulent isolates.

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Greenhouse Evaluation of Clubroot Resistant-Brassica napus cv. Mendel and Its Efficacy Concerning Virulence and Soil Inoculum Levels of Plasmodiophora brassicae

Pathogens ◽

10.3390/pathogens10020151 ◽

2021 ◽

Vol 10 (2) ◽

pp. 151 ◽

Cited By ~ 1

Author(s):

Nazanin Zamani-Noor ◽

Imke Krohne ◽

Birger Koopmann

Keyword(s):

Brassica Napus ◽

Plasmodiophora Brassicae ◽

Root Weight ◽

Susceptible Cultivar ◽

Clubroot Resistance ◽

Soil Inoculum ◽

Resting Spore ◽

Greenhouse Evaluation ◽

Major Resistance Gene ◽

Resting Spores

Clubroot resistance of oilseed rape (OSR) cultivars frequently relies on a major resistance gene originating from cv. Mendel. The efficacy of this resistance was studied in greenhouse experiments using two Plasmodiophora brassicae isolates, which were either virulent (P1(+)) or avirulent (P1) on Mendel. Seeds of clubroot-susceptible cultivar Visby and clubroot-resistant cultivar Mendel were sown in soil mixtures inoculated with different concentrations of resting spores (101, 103, 105, and 107 resting spores/g soil). Clubroot severity, plant height, shoot and root weight as well as resting spore propagation were assessed for each isolate and cultivar separately at four dates after sowing. The OSR cultivars behaved significantly different in the measured parameters. The threshold of inoculum density to cause disease depended strongly on the virulence of the pathogen and susceptibility of the host plant. In Visby grown in soil infested with P1, clubroot symptoms and increases in root weight and the number of propagated resting spores occurred at inoculum levels of 101 resting spores and higher, whereas Mendel was not affected in soils under the three lowest inoculum densities. In contrast, the P1(+) isolate led to earlier and more severe symptoms, heavier galls, and a significantly higher number of new resting spores in both cultivars.

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Endurance Training Regulates Expression of Some Angiogenesis-Related Genes in Cardiac Tissue of Experimentally Induced Diabetic Rats

Biomolecules ◽

10.3390/biom11040498 ◽

2021 ◽

Vol 11 (4) ◽

pp. 498

Author(s):

Mojdeh Khajehlandi ◽

Lotfali Bolboli ◽

Marefat Siahkuhian ◽

Mohammad Rami ◽

Mohammadreza Tabandeh ◽

...

Keyword(s):

Gene Expression ◽

Endurance Training ◽

Molecular Mechanisms ◽

Cardiac Tissue ◽

Critical Role ◽

Diabetic Rats ◽

Moderate Intensity ◽

Pcr Analysis ◽

Cardiac Tissues ◽

The Impact

Exercise can ameliorate cardiovascular dysfunctions in the diabetes condition, but its precise molecular mechanisms have not been entirely understood. The aim of the present study was to determine the impact of endurance training on expression of angiogenesis-related genes in cardiac tissue of diabetic rats. Thirty adults male Wistar rats were randomly divided into three groups (N = 10) including diabetic training (DT), sedentary diabetes (SD), and sedentary healthy (SH), in which diabetes was induced by a single dose of streptozotocin (50 mg/kg). Endurance training (ET) with moderate-intensity was performed on a motorized treadmill for six weeks. Training duration and treadmill speed were increased during five weeks, but they were kept constant at the final week, and slope was zero at all stages. Real-time polymerase chain reaction (RT-PCR) analysis was used to measure the expression of myocyte enhancer factor-2C (MEF2C), histone deacetylase-4 (HDAC4) and Calmodulin-dependent protein kinase II (CaMKII) in cardiac tissues of the rats. Our results demonstrated that six weeks of ET increased gene expression of MEF2C significantly (p < 0.05), and caused a significant reduction in HDAC4 and CaMKII gene expression in the DT rats compared to the SD rats (p < 0.05). We concluded that moderate-intensity ET could play a critical role in ameliorating cardiovascular dysfunction in a diabetes condition by regulating the expression of some angiogenesis-related genes in cardiac tissues.

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

Plant Pathology ◽

10.1111/ppa.12422 ◽

2015 ◽

Vol 65 (3) ◽

pp. 435-440 ◽

Cited By ~ 17

Author(s):

H. Zhang ◽

J. Feng ◽

S.-F. Hwang ◽

S. E. Strelkov ◽

I. Falak ◽

...

Keyword(s):

Brassica Napus ◽

Plasmodiophora Brassicae

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Zinc limitation in Klebsiella pneumoniae profiled by quantitative proteomics influences transcriptional regulation and cation transporter-associated capsule production

BMC Microbiology ◽

10.1186/s12866-021-02091-8 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

A. Sukumaran ◽

S. Pladwig ◽

J. Geddes-McAlister

Keyword(s):

Klebsiella Pneumoniae ◽

Metal Ion ◽

Ion Homeostasis ◽

Cellular Protein ◽

Pcr Analysis ◽

Phenotypic Analysis ◽

Metal Ion Homeostasis ◽

Capsule Production ◽

The Impact

Abstract Background Microbial organisms encounter a variety of environmental conditions, including changes to metal ion availability. Metal ions play an important role in many biological processes for growth and survival. As such, microbes alter their cellular protein levels and secretion patterns in adaptation to a changing environment. This study focuses on Klebsiella pneumoniae, an opportunistic bacterium responsible for nosocomial infections. By using K. pneumoniae, we aim to determine how a nutrient-limited environment (e.g., zinc depletion) modulates the cellular proteome and secretome of the bacterium. By testing virulence in vitro, we provide novel insight into bacterial responses to limited environments in the presence of the host. Results Analysis of intra- and extracellular changes identified 2380 proteins from the total cellular proteome (cell pellet) and 246 secreted proteins (supernatant). Specifically, HutC, a repressor of the histidine utilization operon, showed significantly increased abundance under zinc-replete conditions, which coincided with an expected reduction in expression of genes within the hut operon from our validating qRT-PCR analysis. Additionally, we characterized a putative cation transport regulator, ChaB that showed significantly higher abundance under zinc-replete vs. -limited conditions, suggesting a role in metal ion homeostasis. Phenotypic analysis of a chaB deletion strain demonstrated a reduction in capsule production, zinc-dependent growth and ion utilization, and reduced virulence when compared to the wild-type strain. Conclusions This is first study to comprehensively profile the impact of zinc availability on the proteome and secretome of K. pneumoniae and uncover a novel connection between zinc transport and capsule production in the bacterial system.

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