scholarly journals Potato spindle tuber viroid: Stability on Common Surfaces and Inactivation With Disinfectants

Plant Disease ◽  
2015 ◽  
Vol 99 (6) ◽  
pp. 770-775 ◽  
Author(s):  
A. E. Mackie ◽  
B. A. Coutts ◽  
M. J. Barbetti ◽  
B. C. Rodoni ◽  
S. J. McKirdy ◽  
...  
Keyword(s):  
Human Skin ◽  
Skim Milk ◽  
Potato Spindle Tuber Viroid ◽  
Control Measures ◽  
Effective Management ◽  
Tomato Plants ◽  
Hygiene Practices ◽  
Infected Tomato ◽  
Polymerase Chain ◽  
The Stability

The length of time Potato spindle tuber viroid (PSTVd) remained infective in extracted tomato leaf sap on common surfaces and the effectiveness of disinfectants against it were investigated. When sap from PSTVd-infected tomato leaves was applied to eight common surfaces (cotton, wood, rubber tire, leather, metal, plastic, human skin, and string) and left for various periods of time (5 min to 24 h) before rehydrating the surface and rubbing onto healthy tomato plants, PSTVd remained infective for 24 h on all surfaces except human skin. It survived best on leather, plastic, and string. It survived less well after 6 h on wood, cotton, and rubber and after 60 min on metal. On human skin, PSTVd remained infective for only 30 min. In general, rubbing surfaces contaminated with dried infective sap directly onto leaves caused less infection than when the sap was rehydrated with distilled water but overall results were similar. The effectiveness of five disinfectant agents at inactivating PSTVd in sap extracts was investigated by adding them to sap from PSTVd-infected leaves before rubbing the treated sap onto leaves of healthy tomato plants. Of the disinfectants tested, 20% nonfat dried skim milk and a 1:4 dilution of household bleach (active ingredient sodium hypochlorite) were the most effective at inactivating PSTVd infectivity in infective sap. When reverse-transcription polymerase chain reaction was used to test the activity of the five disinfectants against PSTVd in infective sap, it detected PSTVd in all instances except in sap treated with 20% nonfat dried skim milk. This study highlights the stability of PSTVd in infective sap and the critical importance of utilizing hygiene practices such as decontamination of clothing, tools, and machinery, along with other control measures, to ensure effective management of PSTVd and, wherever possible, its elimination in solanaceous crops.

scholarly journals Potato spindle tuber viroid as Inducer of RNA Silencing in Infected Tomato

2001 ◽  
Vol 14 (11) ◽  
pp. 1332-1334 ◽  
Author(s):  
Asuka Itaya ◽  
Alexey Folimonov ◽  
Yoshie Matsuda ◽  
Richard S. Nelson ◽  
Biao Ding
Keyword(s):  
Plant Pathogen ◽  
Small Rnas ◽  
Rna Silencing ◽  
Potato Spindle Tuber Viroid ◽  
Sequence Specificity ◽  
Tomato Plants ◽  
Biological Features ◽  
Severe Strain ◽  
Infected Tomato ◽  
Systemic Symptoms

Potato spindle tuber viroid (PSTVd), an RNA plant pathogen encoding no known proteins, induces systemic symptoms on tomato plants. We report detection of small RNAs of approximately 25 nucleotides with sequence specificity to PSTVd in infected plants: an indication of the presence of RNA silencing. RNA silencing, however, did not appear to be responsible for the differing symptoms induced by a mild and a severe strain of PSTVd. The unique structural and biological features of viroids make them attractive experimental tools to investigate mechanisms of RNA silencing and pathogen counterdefense.

scholarly journals Rasta Disease of Tomato in Ghana is Caused by the Pospiviroids Potato spindle tuber viroid and Tomato apical stunt viroid

Plant Disease ◽  
2019 ◽  
Vol 103 (7) ◽  
pp. 1525-1535 ◽  
Author(s):  
Ozgur Batuman ◽  
Ö. Cem Çiftçi ◽  
Michael K. Osei ◽  
Sally A. Miller ◽  
Maria R. Rojas ◽  
...  
Keyword(s):  
Potato Spindle Tuber Viroid ◽  
Unknown Etiology ◽  
Rt Pcr ◽  
Tomato Cultivar ◽  
Tomato Plants ◽  
Tomato Seedlings ◽  
Stunt Viroid ◽  
Fta Cards ◽  
Polymerase Chain ◽  
Susceptible Tomato

Rasta is a virus-like disease of unknown etiology affecting tomato (Solanum lycopersicum) plants in Ghana. Symptoms include stunting; epinasty, crumpling, and chlorosis of leaves; and necrosis of leaf veins, petioles, and stems. Leaf samples with rasta symptoms were collected from commercial tomato fields in Ghana in October 2012 and applied to FTA cards, and RNA extracts were prepared. Reverse-transcription polymerase chain reaction (RT-PCR) tests with primers for Columnea latent viroid, which causes rasta-like symptoms in tomato plants in Mali, were negative, whereas tests with degenerate viroid primer pairs were inconclusive. However, tomato seedlings (Early Pak 7) mechanically inoculated with RNA extracts of 10 of 13 samples developed rasta-like symptoms. In RT-PCR tests with RNA from leaves of the 10 symptomatic seedlings and primers for Potato spindle tuber viroid (PSTVd) or Tomato apical stunt viroid (TASVd), the expected size (approximately 360 bp) of DNA fragment was amplified from eight and two seedlings, respectively. Sequence analyses confirmed that these fragments were from PSTVd and TASVd isolates, and revealed a single PSTVd haplotype and two TASVd haplotypes. The PSTVd and TASVd isolates from Ghana had high nucleotide identities (>94%) with isolates from other geographic regions. In a host range study, PSTVd and TASVd isolates from Ghana induced rasta symptoms in the highly susceptible tomato cultivar Early Pak 7 and mild or no symptoms in Glamour, and symptomless infections in a number of other solanaceous species. PSTVd and TASVd isolates were seed associated and possibly seed transmitted.

Characterization of plant miRNAs and small RNAs derived from potato spindle tuber viroid (PSTVd) in infected tomato

2010 ◽  
Vol 391 (12) ◽  
Author(s):  
Natalie Diermann ◽  
Jaroslav Matoušek ◽  
Markus Junge ◽  
Detlev Riesner ◽  
Gerhard Steger
Keyword(s):  
Transcription Factors ◽  
Small Rnas ◽  
Rna Silencing ◽  
Potato Spindle Tuber Viroid ◽  
Regulation Of Transcription ◽  
Tomato Plants ◽  
Sequence Variations ◽  
Infected Tomato ◽  
Minor Sequence

Abstract To defend against invading pathogens, plants possess RNA silencing mechanisms involving small RNAs (miRNAs, siRNAs). Also viroids – plant infectious, non-coding, unencapsidated RNA – cause the production of viroid-specific small RNAs (vsRNA), but viroids do escape the cytoplasmic silencing mechanism. Viroids with minor sequence variations can produce different symptoms in infected plants, suggesting an involvement of vsRNAs in symptom production. We analyzed by deep sequencing the spectrum of vsRNAs induced by the PSTVd strain AS1, which causes strong symptoms such as dwarfing and necrosis upon infection of tomato plants cv Rutgers. Indeed, vsRNAs found with highest frequency mapped to the pathogenicity-modulating domain of PSTVd, supporting an involvement of vsRNAs in symptom production. Furthermore, in PSTVd AS1-infected plants the accumulation of some endogenous miRNAs, which are involved in leaf development via regulation of transcription factors, is suppressed. The latter finding supports the hypothesis that a miRNA-dependent (mis)regula-tion of transcription factors causes the viroid symptoms.

scholarly journals Infection by Candidatus Liberibacter solanacearum’ haplotypes A and B in Solanum lycopersicum ‘Moneymaker’

Plant Disease ◽  
2018 ◽  
Vol 102 (10) ◽  
pp. 2009-2015 ◽  
Author(s):  
Azucena Mendoza-Herrera ◽  
Julien Levy ◽  
Kyle Harrison ◽  
Jianxiu Yao ◽  
Freddy Ibanez ◽  
...  
Keyword(s):  
Solanum Lycopersicum ◽  
Quantitative Polymerase Chain Reaction ◽  
Bactericera Cockerelli ◽  
Tomato Plants ◽  
Candidatus Liberibacter Solanacearum ◽  
Measured Time ◽  
Candidatus Liberibacter ◽  
Yellowing Disease ◽  
Infected Tomato ◽  
Polymerase Chain

‘Candidatus Liberibacter solanacearum’ is a plant pathogen associated with diseases affecting several crops of the Solanaceae and Apiaceae families. Two ‘Ca. L. solanacearum’ haplotypes (LsoA and LsoB) infect solanaceous crops in North America and are transmitted by the tomato psyllid Bactericera cockerelli. Although both ‘Ca. L. solanacearum’ haplotypes cause zebra chip in potato, the diseases associated with each haplotype in tomato (Solanum lycopersicum) have not been described. ‘Ca. L. solanacearum’-infected tomato plants exhibit symptoms resembling those of permanent yellowing disease (known in Mexico as “permanente del tomate”) and sometimes called psyllid yellows. In this study, the symptoms associated with each ‘Ca. L. solanacearum’ haplotype in tomato were compared, and the bacterial abundance in different nodes of the plants was measured by quantitative polymerase chain reaction. Surprisingly, both plant phenotype and bacterium distribution were different between LsoA- and LsoB-infected plants. Plants infected with LsoB died prematurely, whereas those infected with LsoA did not. Across the measured time points, LsoB abundance in infected plants was consistent with previous reports describing a sink to source gradient, while such gradient was only observed in LsoA-infected plants early after infection. This is the first report describing the differences in symptoms in tomato associated with two ‘Ca. L. solanacearum’ haplotypes, LsoA and LsoB.

scholarly journals Degradome Analysis of Tomato and Nicotiana benthamiana Plants Infected with Potato Spindle Tuber Viroid

2021 ◽  
Vol 22 (7) ◽  
pp. 3725
Author(s):  
Beatriz Navarro ◽  
Andreas Gisel ◽  
Pedro Serra ◽  
Michela Chiumenti ◽  
Francesco Di Serio ◽  
...  
Keyword(s):  
Nicotiana Benthamiana ◽  
Rna Silencing ◽  
High Throughput Sequencing ◽  
Potato Spindle Tuber Viroid ◽  
Degradome Analysis ◽  
Tomato Plants ◽  
Leaf Curling ◽  
Mrna Targets ◽  
Infected Tomato ◽  
Bona Fide

Viroids are infectious non-coding RNAs that infect plants. During infection, viroid RNAs are targeted by Dicer-like proteins, generating viroid-derived small RNAs (vd-sRNAs) that can guide the sequence specific cleavage of cognate host mRNAs via an RNA silencing mechanism. To assess the involvement of these pathways in pathogenesis associated with nuclear-replicating viroids, high-throughput sequencing of sRNAs and degradome analysis were carried out on tomato and Nicotiana benthamiana plants infected by potato spindle tuber viroid (PSTVd). Both hosts develop similar stunting and leaf curling symptoms when infected by PSTVd, thus allowing comparative analyses. About one hundred tomato mRNAs potentially targeted for degradation by vd-sRNAs were initially identified. However, data from biological replicates and comparisons between mock and infected samples reduced the number of bona fide targets—i.e., those identified with high confidence in two infected biological replicates but not in the mock controls—to only eight mRNAs that encode proteins involved in development, transcription or defense. Somewhat surprisingly, results of RT-qPCR assays revealed that the accumulation of only four of these mRNAs was inhibited in the PSTVd-infected tomato. When these analyses were extended to mock inoculated and PSTVd-infected N. benthamiana plants, a completely different set of potential mRNA targets was identified. The failure to identify homologous mRNA(s) targeted by PSTVd-sRNA suggests that different pathways could be involved in the elicitation of similar symptoms in these two species. Moreover, no significant modifications in the accumulation of miRNAs and in the cleavage of their targeted mRNAs were detected in the infected tomato plants with respect to the mock controls. Taken together, these data suggest that stunting and leaf curling symptoms induced by PSTVd are elicited by a complex plant response involving multiple mechanisms, with RNA silencing being only one of the possible components.

An Epidemiological Analysis of COVID-19 Confirmed Cases, Reported at National Institute of Health, Pakistan (Preprint)

2020 ◽  
Author(s):  
Ambreen Chaudhry
Keyword(s):  
Age Groups ◽  
Target Population ◽  
Control Measures ◽  
Contact Tracing ◽  
Bivariate Analysis ◽  
Travel History ◽  
Disease Epidemiology ◽  
Hygiene Practices ◽  
Multi Center Study ◽  
Epidemiological Characteristics

BACKGROUND Coronavirus disease (Covid-19) is a zoonotic disease of novel origin that posed a continuous threat to health worldwide after taking the shape of the pandemic. An understanding of disease epidemiology is supportive in timely preventive and control measures as well as contact tracing and curbing surveillance activities. OBJECTIVE The objective of our study was to determine the epidemiological characteristics of COVID-19 confirmed cases reported at the National Institute of Health Pakistan and elements of its spread in Pakistan. METHODS A retrospective record review was conducted at the National Institute of Health (NIH) Islamabad, Pakistan from January 25 to April 4, 2020. Univariate and bivariate analysis was done with 95% CI and p<0.05. RESULTS A total of 14,422 samples of suspected COVID-19 cases were received with a positivity rate of 9% (n=1348). Among all 70% (n=939) were male. The median age was 41years of age (range: 01-99Years). Among all, 19% were from 30-39 years old followed by 50-59 years old (17%). Children remained the least affected by 3% (n=35). Of the total reported cases, 55% (n=735) have reported the travel history within the last 14 days. Among these travelers’ international travelers were 23% (n=166) and domestic travelers were 77% (n=569). Travel history including both international and domestic remained significantly associated with the different age groups and Young adults remained more vulnerable to COVID-19 (P=0.03). Fever, SOB, and Cough remained the most significantly associated (P<0.05) in all age groups. CONCLUSIONS A higher incidence of COVID-19 among elderly men suggests robust quarantine measures for this target population. An escalating incidence of local transmission needs strict social distancing and hygiene practices to help flatten the curve. An extensive multi-center study is also recommended for a full understanding of disease dynamics.

Pooling Raw Shell Eggs: Salmonella Contamination and High Risk Practices in the United Kingdom Food Service Sector

2010 ◽  
Vol 73 (3) ◽  
pp. 574-578 ◽  
Author(s):  
F. J. GORMLEY ◽  
C. L. LITTLE ◽  
N. MURPHY ◽  
E. de PINNA ◽  
J. MCLAUCHLIN
Keyword(s):  
United Kingdom ◽  
Food Safety ◽  
High Risk ◽  
Service Sector ◽  
Safety Management ◽  
Food Service ◽  
Control Measures ◽  
Hygiene Practices ◽  
Risk Practices ◽  
Handling Practices

Salmonella contamination of pooled raw shelled egg mix (RSEM) used as an ingredient in lightly cooked or uncooked foods and high-risk kitchen hygiene practices in United Kingdom food service establishments using RSEM were investigated. Samples were collected from 934 premises. Salmonella was found in 1 (0.13%) of 764 RSEM samples, 2 (0.3%) of 726 samples from surfaces where ready-to-eat foods were prepared, and 7 (1.3%) of 550 cleaning cloths. Poor RSEM storage and handling practices were highlighted. Workers in 40% of the premises sampled failed to use designated utensils when RSEM was added to other ingredients, workers in 17% of the premises did not clean surfaces and utensils thoroughly after use with RSEM and before preparing other foods, only 42% of workers washed and dried their hands after handling eggs or RSEM, workers in 41% of the premises did not store RSEM at refrigeration temperature before use, and workers in 8% of the premises added RSEM to cooked rice at the end of cooking when preparing egg fried rice. Take-away premises, especially those serving Chinese cuisine, were least likely to have a documented food safety management system and awareness of the key food safety points concerning the use of RSEM compared with other food service premises (P &lt; 0.0001). Food service businesses using RSEM must be aware of the continuing hazard from Salmonella, must adopt appropriate control measures, and must follow advice provided by national food agencies to reduce the risk of Salmonella infection.

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