The chemical environment of leaf surfaces with special reference to spore germination of pathogenic fungi

Blakeman, J.P.

doi:10.1002/ps.2780040415

Cited by 58 publications

(28 citation statements)

References 42 publications

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“…It is possible that lower temperatures may result in better survival of viruses as a result of slowing down the action of degrading compounds found on the leaf surface. Many plant leaves continuously secrete substances in small quantities that form the normal leachates on the leaf surface (6). These leachates might act as antimicrobials; for example, the leaf surface leachates of apple and tobacco have been shown to inhibit fungal pathogens (6).…”

Section: Fig 4 Sapovirus Interaction With Lettuce Leaf Milky (Latex) mentioning

confidence: 99%

“…Many plant leaves continuously secrete substances in small quantities that form the normal leachates on the leaf surface (6). These leachates might act as antimicrobials; for example, the leaf surface leachates of apple and tobacco have been shown to inhibit fungal pathogens (6). A previous study comparing the persistence of infectious MNV on cut lettuce leaf surfaces to nonbiological surfaces showed that the virus was inactivated more rapidly on lettuce (17).…”

Section: Fig 4 Sapovirus Interaction With Lettuce Leaf Milky (Latex) mentioning

confidence: 99%

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Internalization of Sapovirus, a Surrogate for Norovirus, in Romaine Lettuce and the Effect of Lettuce Latex on Virus Infectivity

Esseili

Wang

Zhang

et al. 2012

Appl Environ Microbiol

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ABSTRACTNoroviruses are the leading cause of food-borne outbreaks, including those that involve lettuce. The culturable porcine sapovirus (SaV) was used as a norovirus surrogate to study the persistence and the potential transfer of the virus from roots to leaves and from outer to inner leaves of lettuce plants. Treatment of lettuce with SaV was done through the roots of young plants, the soil, or the outer leaves of mature plants. Sampling of roots, xylem sap, and inner and outer leaves followed by RNA extraction and SaV-specific real-time reverse transcription (RT)-PCR was performed at 2 h and on postinoculation days (PID) 2, 5, 7, 14, and/or 28. When SaV was inoculated through the roots, viral RNA persisted on the roots and in the leaves until PID 28. When the virus was inoculated through the soil, viral RNA was detected on the roots and in the xylem sap until PID 14; viral RNA was detected in the leaves only until PID 2. No infectious virus was detected inside the leaves for either treatment. When SaV was inoculated through the outer leaves, viral RNA persisted on the leaves until PID 14; however, the virus did not transfer to inner leaves. Infectious viral particles on leaves were detected only at 2 h postinoculation. The milky sap (latex) of leaves, but not the roots' xylem sap, significantly decreased virus infectivity when testedin vitro. Collectively, our results showed the transfer of SaV from roots to leaves through the xylem system and the capacity of the sap of lettuce leaves to decrease virus infectivity in leaves.

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Section: Fig 4 Sapovirus Interaction With Lettuce Leaf Milky (Latex) mentioning

confidence: 99%

Section: Fig 4 Sapovirus Interaction With Lettuce Leaf Milky (Latex) mentioning

confidence: 99%

Internalization of Sapovirus, a Surrogate for Norovirus, in Romaine Lettuce and the Effect of Lettuce Latex on Virus Infectivity

Esseili

Wang

Zhang

et al. 2012

Appl Environ Microbiol

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“…Little is known about the ecological role of the phylloplane yeasts. The leaf surface characteristics may affect, both qualitatively and quantitatively, immigration of yeasts to the phylloplane (Blakeman 1973). Leaves are covered, to the various degrees, with surface waxes which function to repel water due to their hydrophobic nature (Holloway 1971).…”

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confidence: 99%

Yeasts colonizing the leaf surfaces

Sláviková

Vadkertiová

Vránová³

2007

J. Basic Microbiol.

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The yeasts were isolated from the leaf surfaces of ten species of trees. The study site was a forest park (Zelezná Studnicka) of the Small Carpathians mountain range. One hundred and thirty seven yeast strains belonging to 13 genera were isolated from 320 samples of leaves and needles. Seventeen yeast species were isolated, but only seven occurred regularly: Aureobasidium pullulans, Cryptococcus laurentii, Pichia anomala, Metschnikowia pulcherrima, Saccharomyces sp., Lachancea thermotolerans, and Rhodotorula glutinis. The remaining species were isolated from the leaves and needles of three or less tree species. A. pullulans, Cr. laurentii, and P. anomala were the most frequently found species and they occurred on leaves and needles of all ten tree species. Saccharomyces sp. occurred in leaf samples collected from eight kinds of trees. M. pulcherrima and L. thermotolerans were found in samples collected from six species of trees. Both these species occurred almost always on the leaves of deciduous trees. Rh. glutinis was the most frequently isolated carotenoids producing species. We have found out that the ascomycetous and basidiomycetous species were present in the leaf samples in approximately equal frequency, contrary to the soil samples taken from this forest park, where the ascomycetous species were found rarely.

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“…Furthermore, other biological factors, such as leaf leachates (12,69), may impact the survival of both viruses and bacteria on leaves. However, since virus-like particles of HuNoV were previously reported to adhere to certain locations on the plant phyllosphere (14,70,71) where native bacteria are reported to adhere, such as the leaf veins and stomata (72), it is possible that the HuNoVs contaminating plant leaves occupy niches similar to those that native bacteria occupy and therefore directly interact with those bacteria.…”

Section: Discussionmentioning

confidence: 99%

Abiotic Stress and Phyllosphere Bacteria Influence the Survival of Human Norovirus and Its Surrogates on Preharvest Leafy Greens

Esseili

Gao

Tegtmeier

et al. 2016

Appl Environ Microbiol

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Foodborne outbreaks of human noroviruses (HuNoVs) are frequently associated with leafy greens. Because there is no effective method to eliminate HuNoV from postharvest leafy greens, understanding virus survival under preharvest conditions is crucial. The objective of this study was to evaluate the survival of HuNoV and its surrogate viruses, murine norovirus (MNV), porcine sapovirus (SaV), and Tulane virus (TV), on preharvest lettuce and spinach that were subjected to abiotic stress (physical damage, heat, or flood). We also examined the bacteria culturable from the phyllosphere in response to abiotic stress and in relation to viral persistence. Mature plants were subjected to stressors 2 days prior to inoculation of the viruses on leaves. We quantified the viral RNA, determined the infectivity of the surrogates, and performed bacterial counts on postinoculation days (PIDs) 0, 1, 7, and 14. For both plant types, time exerted significant effects on HuNoV, MNV, SaV, and TV RNA titers, with greater effects being seen for the surrogates. Infectious surrogate viruses were undetectable on PID 14. Only physical damage on PID 14 significantly enhanced HuNoV RNA persistence on lettuce, while the three stressors differentially enhanced the persistence of MNV and TV RNA. Bacterial counts were significantly affected by time and plant type but not by the stressors. However, bacterial counts correlated significantly with HuNoV RNA titers on spinach and with the presence of surrogate viruses on both plant types under various conditions. In conclusion, abiotic stressors and phyllosphere bacterial density may differentially influence the survival of HuNoV and its surrogates on lettuce and spinach, emphasizing the need for the use of preventive measures at the preharvest stage.H uman noroviruses (HuNoVs) are the leading cause of acute gastroenteritis and foodborne illnesses in the United States, causing 19 million to 21 million cases, 570 to 800 deaths, and $777 million in health care-associated costs annually (1). These singlestranded RNA viruses belong to the Caliciviridae family and are 28 to 35 nm in diameter and nonenveloped. Although these viruses cause self-limiting gastroenteritis, more serious infections can develop in high-risk groups, such as the elderly and immunocompromised populations (2). The virus is mainly transmitted to humans via the fecal-oral route either by contact with an infected person or fomites or by ingestion of contaminated food and water (2). Leafy greens are frequently associated with HuNoV outbreaks (1) and are globally recognized to be a high priority in terms of the microbial safety of fresh produce (3). Contamination of leafy greens with HuNoVs can occur at any stage along the farm-to-fork chain (3) through a number of sources, including fecally contaminated water used for irrigation, improperly treated sewage sludge used for fertilization, and food harvesters or food handlers who use improper hygiene practices (4, 5). Because HuNoVs have a low infectious dose (ϳ18 to 1,000 viral particles) (6) ...

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The chemical environment of leaf surfaces with special reference to spore germination of pathogenic fungi

Cited by 58 publications

References 42 publications

Internalization of Sapovirus, a Surrogate for Norovirus, in Romaine Lettuce and the Effect of Lettuce Latex on Virus Infectivity

Internalization of Sapovirus, a Surrogate for Norovirus, in Romaine Lettuce and the Effect of Lettuce Latex on Virus Infectivity

Yeasts colonizing the leaf surfaces

Abiotic Stress and Phyllosphere Bacteria Influence the Survival of Human Norovirus and Its Surrogates on Preharvest Leafy Greens

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