scholarly journals Acidovorax citrulli Seed Inoculum Load Affects Seedling Transmission and Spread of Bacterial Fruit Blotch of Watermelon Under Greenhouse Conditions

Plant Disease ◽  
2012 ◽  
Vol 96 (5) ◽  
pp. 705-711 ◽  
Author(s):  
B. Dutta ◽  
H. Scherm ◽  
R. D. Gitaitis ◽  
R. R. Walcott

Infested seed are typically the primary source of inoculum for bacterial fruit blotch (BFB) of cucurbits. An inoculum threshold of 1 infested seed per 10,000 seeds is widely used in seed health testing for Acidovorax citrulli. However, the influence of seed inoculum load on BFB seedling transmission has not been elucidated. In this study, watermelon seedlots (128 seeds/lot) containing one seed inoculated with A. citrulli at levels ranging from 1 × 101 to 1 × 107 CFU were used to investigate the effect of seed inoculum load on seedling transmission and spatiotemporal spread of BFB under greenhouse conditions. The relationship between A. citrulli seed inoculum load and frequency of BFB seedling transmission followed a sigmoidal pattern (R2 = 0.986, P = 0.0047). In all, 100 and 96.6% of seedlots containing one seed with 1 × 107 and 1 × 105 CFU of A. citrulli, respectively, transmitted the pathogen to seedlings; in contrast, the proportion of seedlots that yielded BFB-infected seedlings was lower for lots with one seed infested with 1 × 103 (46.6%) and 1 × 101 (16.7%) CFU of A. citrulli. The relationship between A. citrulli seed inoculum load and frequency of pathogen detection in seedlots using immunomagnetic separation combined with a real-time polymerase chain reaction assay also followed a sigmoidal pattern (R2 = 0.997, P = 0.0034). Whereas 100% of samples from seedlots (10,000 seeds/lot) with one seed containing ≥1 × 105 CFU tested positive for A. citrulli, 75% of samples from lots with one seed containing 1 × 103 CFU tested positive for the pathogen, and only 16.7% of samples with one seed containing 10 CFU tested positive. Because disease transmission was observed for lots with just one seed containing 10 A. citrulli CFU, zero tolerance for seedborne A. citrulli is recommended for effective BFB management. The seedling transmission experiments also revealed that temporal spread of BFB in 128-cell seedling trays increased linearly with A. citrulli inoculum load (r2 = 0.976, P = 0.0037). Additionally, the frequency of spatial spread of BFB from an inoculated seedling in the center of a planting tray to adjacent healthy seedlings over one-, two-, or three-cell distances was greater for lots with one seed infested with at least 1 × 105 CFU than for lots with one seed infested at lower inoculum loads (1 × 101 and 1 × 103 CFU/seed).

2019 ◽  
Vol 20 (11) ◽  
pp. 2715 ◽  
Author(s):  
Md. Rafiqul Islam ◽  
Mohammad Rashed Hossain ◽  
Hoy-Taek Kim ◽  
Denison Michael Immanuel Jesse ◽  
Md. Abuyusuf ◽  
...  

Acidovorax citrulli (A. citrulli) strains cause bacterial fruit blotch (BFB) in cucurbit crops and affect melon significantly. Numerous strains of the bacterium have been isolated from melon hosts globally. Strains that are aggressively virulent towards melon and diagnostic markers for detecting such strains are yet to be identified. Using a cross-inoculation assay, we demonstrated that two Korean strains of A. citrulli, NIHHS15-280 and KACC18782, are highly virulent towards melon but avirulent/mildly virulent to the other cucurbit crops. The whole genomes of three A. citrulli strains isolated from melon and three from watermelon were aligned, allowing the design of three primer sets (AcM13, AcM380, and AcM797) that are specific to melon host strains, from three pathogenesis-related genes. These primers successfully detected the target strain NIHHS15-280 in polymerase chain reaction (PCR) assays from a very low concentration of bacterial gDNA. They were also effective in detecting the target strains from artificially infected leaf, fruit, and seed washing suspensions, without requiring the extraction of bacterial DNA. This is the first report of PCR-based markers that offer reliable, sensitive, and rapid detection of strains of A. citrulli causing BFB in melon. These markers may also be useful in early disease detection in the field samples, in seed health tests, and for international quarantine purposes.


2012 ◽  
Vol 40 (3) ◽  
pp. 309-319 ◽  
Author(s):  
B. Dutta ◽  
M.A.C. Vernaiz ◽  
A.C. Castro-Sparks ◽  
H. Scherm ◽  
R.R. Walcott

2003 ◽  
Vol 93 (5) ◽  
pp. 528-534 ◽  
Author(s):  
R. R. Walcott ◽  
R. D. Gitaitis ◽  
A. C. Castro

The role of watermelon blossom inoculation in seed infestation by Acidovorax avenae subsp. citrulli was investigated. Approximately 98% (84/87) of fruit developed from blossoms inoculated with 1 × 107 or 1 × 109 CFU of A. avenae subsp. citrulli per blossom were asymptomatic. Using immunomagnetic separation and the polymerase chain reaction, A. avenae subsp. citrulli was detected in 44% of the seed lots assayed, despite the lack of fruit symptoms. Furthermore, viable colonies were recovered from 31% of the seed lots. Of these lots, 27% also yielded seedlings expressing bacterial fruit blotch symptoms when planted under conditions of 30°C and 90% relative humidity. A. avenae subsp. citrulli was detected and recovered from the pulp of 33 and 19%, respectively, of symptomless fruit whose blossoms were inoculated with A. avenae subsp. citrulli. The ability to penetrate watermelon flowers was not unique to A. avenae subsp. citrulli, because blossoms inoculated with Pantoea ananatis also resulted in infested seed and pulp. The data indicate that watermelon blossoms are a potential site of ingress for fruit and seed infestation by A. avenae subsp. citrulli.


Plant Disease ◽  
2013 ◽  
Vol 97 (7) ◽  
pp. 961-966 ◽  
Author(s):  
Yanli Tian ◽  
Yuqiang Zhao ◽  
Sa Bai ◽  
R. R. Walcott ◽  
Baishi Hu ◽  
...  

A method was developed using a padlock probe (PLP) and dot-blot hybridization for detecting Acidovorax citrulli in cucurbit seed. The PLP was designed based on the 16S-23S internal transcribed spacer ribosomal DNA sequence from A. citrulli. The detection threshold for the PLP assay was 100 fg of genomic DNA, and A. citrulli was detected in 100% of artificially infested seedlots with 0.1% infestation or greater. In addition, using the PLP assay, 4 of 8 melon seedlots collected from Xinjang province and 15 of 47 watermelon seedlots collected from Ningxia province were positive for A. citrulli. In contrast, a conventional polymerase chain reaction (PCR) assay that relied on primers WFB1 and WFB2 facilitated A. citrulli detection in 1 of 8 and 5 of 47 seedlots from Xinjiang and Ningxia provinces, respectively. These data indicate that the PLP and dot-blot hybridization technique was more effective than conventional PCR for seed health testing.


2014 ◽  
Vol 143 (3) ◽  
pp. 586-599 ◽  
Author(s):  
F. AYRAL ◽  
J. ARTOIS ◽  
A.-L. ZILBER ◽  
F. WIDÉN ◽  
K.C. POUNDER ◽  
...  

SUMMARYLeptospira interrogans, hantaviruses (particularly Seoul virus), hepatitis E virus (HEV), and Toxoplasma gondii are rat-associated zoonoses that are responsible for human morbidity and mortality worldwide. This study aimed to describe the infection patterns of these four pathogens in wild rats (Rattus norvegicus) across socioeconomic levels in neighbourhoods in Lyon, France. The infection or exposure status was determined using polymerase chain reaction or serology for 178 wild rats captured in 23 locations; additionally, confirmatory culture or mouse inoculation was performed. Multivariate logistic regression analyses were used to investigate whether morphological and socioeconomic data could predict the infection status of the rats. This study revealed that the rat colony's age structure may influence the prevalence of L. interrogans, hantavirus, and HEV. In addition, areas with high human population densities and low incomes may be associated with a greater number of infected rats and an increased risk of disease transmission.


2018 ◽  
Vol 6 (2) ◽  
pp. 30-35
Author(s):  
Ade Ella Nur Rizky Oktaviyanti

One of the factors that influence compliance is individual motivation. There are still many pulmonary tuberculosis patients who do not wear masks, this can have an impact on disease transmission. Poor individual motivation can affect someone's compliance. The purpose of this research is to determine the relationship of patient motivation regarding prevention of transmission with adherence to the use of masks in patients with pulmonary tuberculosis in Rambipuji Health Center, Jember Regency. This research uses descriptive correlative type of research. In this study using a cross-sectional approach. The sample of this study was taken using simple random sampling, namely pulmonary tuberculosis patients at the Rambipuji Health Center in Jember Regency, totaling 105 patients but only 50 patients were used as samples. This research was conducted by giving a questionnaire to pulmonary tuberculosis patients to find out the patient's motivation about preventing transmission by adhering to the use of masks. The results of the study were analyzed using the Lambda Correlation Test, the results of the analysis found that the motivation of patients was good motivation (22%), patient motivation was sufficient (56%), and patient motivation was less motivation (22%). Whereas adherence to the use of masks in pulmonary tuberculosis patients is compliant (36%), and non-compliant (64%). The Lambda Correlation Test results obtained from the variable compliance with ρ = 0.389 positive direction with a value of ρ count of 0.027 <0.05 which means there is a relationship between patient motivation about prevention of transmission with compliance with the use of masks in patients with pulmonary tuberculosis in Rambipuji Health Center, Jember District. It is recommended that further studies be able to conduct more in-depth research related to the relationship of patient motivation regarding the prevention of transmission with adherence to the use of masks in pulmonary tuberculosis patients


2019 ◽  
Vol 16 (4) ◽  
pp. 365-372 ◽  
Author(s):  
Qishuai Liu ◽  
Li Wang ◽  
Guizhen Yan ◽  
Weifa Zhang ◽  
Zhigang Huan ◽  
...  

Background: MicroRNAs (miRNA) are known to play a key role in the etiology and treatment of epilepsy through controlling the expression of gene. However, miR-125a-5p in the epilepsy is little known. Epilepsy in rat models was induced by Pentylenetetrazol (PTZ) and miR- 125a-5p profiles in the hippocampus were investigated in our experiment. Also, the relationship between miR-125a-5p and calmodulin-dependent protein kinase IV (CAMK4) was identified and the related mechanism was also illustrated. Methods: The miR-125a-5p mRNA expression levels were evaluated by quantitative real time polymerase chain reaction (qRT-PCR). Western Blot (WB) was used to analyze the CAMK4 protein expression levels. Seizure score, latency and duration were determined based on a Racine scale. The enzyme-linked immunosorbent assay (ELISA) was used to analyze the inflammatory factor expression. The relationship between miR-125a-5p and CAMK4 was detected through dual luciferase assay. Results: Downregulation of miR-125a-5p was observed in the hippocampus of PTZ-induced epilepsy rats. The overexpression of miR-125a-5p attenuated seizure and decreased inflammatory factor level in the hippocampus of PTZ-induced rats. The miR-125a-5p alleviated epileptic seizure and inflammation in PTZ-induced rats by suppressing its target gene, CAMK4. Conclusion: miR-125a-5p may represent a novel therapeutic treatment for PTZ-induced epilepsy by preventing the activation of CAMK4.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Jizhe Yu ◽  
Yushuang Qin ◽  
Naxin Zhou

Abstract Background The dysregulation of circular RNAs (circRNAs) has been identified in various human diseases, including osteoarthritis (OA). The purpose of this study was to identify the role and mechanism of circ_SLC39A8 in regulating the progression of OA. Methods The expression levels of circ_SLC39A8, miR-591, and its potential target gene, interleukin-1-receptor-associated kinase 3 (IRAK3), were identified by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability and apoptosis were determined by Cell Counting Kit-8 (CCK-8) assay and flow cytometry, respectively. The relationship between miR-591 and circ_SLC39A8 or IRAK3 was predicted by bioinformatics tools and verified by dual-luciferase reporter. Results Circ_SLC39A8 and IRAK3 were upregulated and miR-591 was downregulated in OA cartilage tissues. Knockdown of circ_SLC39A8 inhibited apoptosis and inflammation in OA chondrocytes, while these effects were reversed by downregulating miR-591. Promotion cell viability effects of miR-591 were partially reversed by IRAK3 overexpression. Conclusion Our findings indicated that knockdown of circ_SLC39A8 delayed the progression of OA via modulating the miR-591-IRAK3 axis, providing new insight into the molecular mechanisms of OA pathogenesis.


2021 ◽  
pp. 101053952110090
Author(s):  
Hüseyin Bilgin ◽  
Ahmet Topuzoğlu ◽  
Volkan Korten

Epidemics caused by airborne viruses in cities with large populations create a big problem as in the current COVID-19 pandemic. Cramped lifestyle, busy workplaces, crowded public transportation, and higher household member counts are responsible for the transmission of the disease. In Turkey, Istanbul has taken the lead in the number of cases since the beginning of the epidemic. The excess population density is the major cause for disease transmission. It is essential to monitor the contaminated regions with geographical information systems on city maps. Outbreak maps visualize and help analyze the patterns of transmission and serve as a communication and education tool. A dynamic heat map video of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) polymerase chain reaction positive cases in a county of Istanbul was generated. The heat map visualizes how the epidemic spread to all the districts and the cumulative cases increased in one county of Istanbul with real attack rates.


2020 ◽  
Vol 15 (1) ◽  
pp. 1013-1023
Author(s):  
Lina Xing ◽  
Jinhai Ren ◽  
Xiaonan Guo ◽  
Shukai Qiao ◽  
Tian Tian

AbstractPrevious research has revealed the involvement of microRNA-212-5p (miR-212-5p) and cyclin T2 (CCNT2) in acute myeloid leukemia (AML). However, whether the miR-212-5p/CCNT2 axis is required for the function of decitabine in AML has not been well elucidated. Quantitative reverse transcription-polymerase chain reaction was used to examine enrichment of miR-212-5p. The relationship between CCNT2 and miR-212-5p was verified by the luciferase reporter assay. Cell apoptosis was evaluated by flow cytometry and western blot. CCK-8 assay was performed to determine cell viability. Decitabine significantly repressed cell viability, while promoted cell apoptosis. Meanwhile, the expression levels of cyclinD1, CDK4, and Bcl-2 were suppressed in cells with decitabine exposure, but Bax and caspase-3 expression levels were upregulated. Besides, miR-212-5p upregulation had the similar function with decitabine in AML cell proliferation and apoptosis. Subsequently, restoration of CCNT2 attenuated miR-212-5p overexpression-induced effects in Kasumi-1 and SKNO-1 cells. In addition, miR-212-5p depletion reversed decitabine-induced CCNT2 downregulation. The miR-212-5p/CCNT2 axis had an implication in the anti-leukemic effect of decitabine in AML.


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