Plant viruses Research Papers - Academia.edu (original) (raw)

Commercial and outdoor fig orchards in four Iranian provinces were surveyed for the incidence of fig mosaic virus (FMV), fig leaf mottle associated virus 2 (FLMaV-2) and fig mild mottle associated virus (FMMaV) from March 2011 to October... more

Commercial and outdoor fig orchards in four Iranian provinces were surveyed for the incidence of fig mosaic virus (FMV), fig leaf mottle associated virus 2 (FLMaV-2) and fig mild mottle associated virus (FMMaV) from March 2011 to October 2012. A total of 350 asymptomatic and symptomatic fig samples were collected and tested by dot-immunobinding assay (DIBA) for the fig mosaic disease (FMD) using a polyclonal antiserum. According to DIBA results, FMD was present in 73% of the collected symptomatic samples from all visited regions. Samples with positive reactions in DIBA were then analyzed by RT-PCR using with specific primers. PCR results showed that about 14.8% of the FMD-positive samples from three inspected provinces are infected with at least one virus. FMV was the most widely spread virus (14%) followed by FLMaV-2 (1.5%), whereas FMMaV was not found. Phylogenetic analysis of the glycoprotein nucleotide and amino acid sequences of known FMV isolates showed two independent groups ...

Banana bunchy top virus (BBTV) DNA-3 to 6 have each previously been shown to contain one large open reading frame in the virion sense, whereas no large ORF had been identified in BBTV DNA-2. RNAs transcribed from the BBTV genome were... more

Banana bunchy top virus (BBTV) DNA-3 to 6 have each previously been shown to contain one large open reading frame in the virion sense, whereas no large ORF had been identified in BBTV DNA-2. RNAs transcribed from the BBTV genome were mapped using northern hybridisation and 3′ RACE. One mRNA was transcribed from each of BBTV DNA-2 to 6 and four of these mRNAs mapped to the ORFs previously identified in BBTV DNA-3 to 6. The mRNA of BBTV DNA-2 was transcribed from a virion sense ORF probably using a TATA box sequence different to that in BBTV DNA-1, and DNA-3 to 6. This ORF encoded a 10 kDa protein of unknown function. The 3′ untranslated region of the five mRNAs varied from 25 nucleotides (BBTV DNA-6) to 167 nucleotides (BBTV DNA-4) and each contained putative polyadenylation signals with associated GT rich sequences together with a possible termination signal (C/T/A)TGTAA conserved in all five mRNAs.

During spring 2009, lavender plants (Lavandula stoechas L.) showing a bright yellow mosaic of calico type and light stunting were observed in a commercial nursery in Liguria Province in northern Italy. Of 300 plants inspected, ~2% were... more

During spring 2009, lavender plants (Lavandula stoechas L.) showing a bright yellow mosaic of calico type and light stunting were observed in a commercial nursery in Liguria Province in northern Italy. Of 300 plants inspected, ~2% were symptomatic. Preliminary observations of leaf sap with the transmission electron microscope revealed bacilliform virus-like particles in three symptomatic plants, whereas no virus-like particles were observed in asymptomatic plants. The same symptomatic plants were tested by double-antibody sandwich-ELISA with polyclonal antisera against Cucumber mosaic virus, Potato virus Y, Tobacco mosaic virus, and Alfalfa mosaic virus (AMV). All three plants reacted positively against AMV antibodies, but not the other antibodies. A crude sap extract obtained from a single symptomatic plant, hereafter referred to as the Lst isolate, was prepared by macerating 1 g of fresh leaves in 4 ml of sodium phosphate 0.03 M, containing 0.2% sodium diethyldithiocarbamate, 75 m...

Plant viruses have evolved a wide array of strategies to ensure efficient transfer from one host to the next. Any organism feeding on infected plants and traveling between plants can potentially act as a virus transport device. Such... more

Plant viruses have evolved a wide array of strategies to ensure efficient transfer from one host to the next. Any organism feeding on infected plants and traveling between plants can potentially act as a virus transport device. Such organisms, designated vectors, are found among parasitic fungi, root nematodes and plant-feeding arthropods, particularly insects. Due to their extremely specialized feeding behavior – exploring and sampling all plant tissues, from the epidermis to the phloem and xylem – aphids are by far the most important vectors, transmitting nearly 30% of all plant virus species described to date. Several different interaction patterns have evolved between viruses and aphid vectors and, over the past century, a tremendous number of studies have provided details of the underlying mechanisms. This article presents an overview of the different types of virus-aphid relationships, state-of-the-art knowledge of the molecular processes underlying these interactions, and the remaining black boxes waiting to be opened in the near future.Les virus de plantes ont développé une grande diversité de stratégies pour assurer leur transmission efficace d’un hôte malade vers un nouvel hôte sain. Tout organisme se nourrissant sur une plante infectée, et capable de se déplacer vers d’autres plantes, peut potentiellement transporter des virus. De tels organismes sont dénommés « vecteurs » et se trouvent parmi les champignons phytopathogènes, les nématodes des racines, et les arthropodes, en particulier les insectes. Du fait de leur comportement alimentaire très particulier, explorant et échantillonnant différents tissus végétaux (épiderme, mésophylle et tissus vasculaires), les pucerons sont de loin les vecteurs de virus les plus performants, transmettant près de 30 % des espèces de virus de plantes décrites à ce jour. Plusieurs mécanismes d’interaction virus-puceron très différents ont évolué et, depuis plus d’un siècle, un effort de recherche très important a permis de les décortiquer, au moins pour certaines espèces virales modèles. Cet article présente une synthèse de ces connaissances, les trajets des virus dans leurs pucerons vecteurs, les mécanismes cellulaires et moléculaires de leurs interactions et les grandes inconnues qui persistent et qui devront être élucidées dans les années à venir.

Pulses have always used to be integral part of food since the vedic times (Achaya, 1998). Agri-archaeological researches have revealed that pulses have been grown in the Indian sub-continent for more than 6000 years. We find references to... more

Pulses have always used to be integral part of food since the vedic times (Achaya, 1998). Agri-archaeological researches have revealed that pulses have been grown in the Indian sub-continent for more than 6000 years. We find references to most of the pulses, in the scriptures of ancient India, that we cultivate today (Nene, 2000). Pulses constitute a very important source of dietary protein for majority of the Indian people, as they provide a perfect mix of vegetable protein component of high biological value when supplemented with cereals. It is also an excellent feed and fodder for livestock. These crops are also endowed with the ability to improve nutrient supply in soils through addition of organic matter (leaf drop) and nitrogen, by fixing atmospheric nitrogen, carbon sequestration, and soil amelioration. Since pulses have ability to have low water requirement and capability to withstand harsh climate, pulses have remained an integral component of sustainable crop production system in the dry areas. They offer good scope for crop diversification and intensification. This is more significant in view of the impending danger of non-availability of nitrogen as fertilizer from petroleum

The frontline of plant defense against non-viral pathogens such as bacteria, fungi and oomycetes is provided by transmembrane pattern recognition receptors that detect conserved pathogen-associated molecular patterns (PAMPs), leading to... more

The frontline of plant defense against non-viral pathogens such as bacteria, fungi and oomycetes is provided by transmembrane pattern recognition receptors that detect conserved pathogen-associated molecular patterns (PAMPs), leading to pattern-triggered immunity (PTI). To counteract this innate defense, pathogens deploy effector proteins with a primary function to suppress PTI. In specific cases, plants have evolved intracellular resistance (R) proteins detecting isolate-specific pathogen effectors, leading to effector-triggered immunity (ETI), an amplified version of PTI, often associated with hypersensitive response (HR) and programmed cell death (PCD). In the case of plant viruses, no conserved PAMP was identified so far and the primary plant defense is thought to be based mainly on RNA silencing, an evolutionary conserved, sequence-specific mechanism that regulates gene expression and chromatin states and represses invasive nucleic acids such as transposons. Endogenous silencin...

Apple mosaic virus (ApMV) is an important virus of apple worldwide. Surveys were conducted in the states of Himachal Pradesh (HP) and Jammu & Kashmir (J&K), India, to determine the prevalence of ApMV and to develop ways for its early... more

Apple mosaic virus (ApMV) is an important virus of apple worldwide. Surveys were conducted in the states of Himachal Pradesh (HP) and Jammu & Kashmir (J&K), India, to determine the prevalence of ApMV and to develop ways for its early diagnosis. Symptomatic leaf samples, bud and bark were collected during spring and late summer. DAS-ELISA revealed the presence of ApMV in 13/198 samples from four districts in HP, indicating a disease incidence of approximately 6.5%. The sequence of amplicons produced by reverse transcription-polymerase chain reaction (RT-PCR) using virus-specific primers confirmed the ELISA results. Comparison of the sequences of three amplicons with nine complete available sequences of ApMV coat protein (CP) (from apple) at amino acid level revealed a maximum of 96% homology to a Korean isolate of ApMV (AY125977). Comparison of the amino acid sequence of the CP of the Indian isolate with the amino acid sequence of the CP from different hosts showed that the Indian isolate clustered most closely with an isolate found in pear and originating from Czechoslovakia. Cloned DNA was reliably used for diagnosis of the virus and was a useful tool for screening at nursery level using slot blot hybridization. This study confirms the presence of ApMV at the molecular level in India and reveals sequence information.

Papaya meleira virus (PMeV) is the causal agent of papaya sticky disease, which is characterized by a spontaneous exudation of fluid and aqueous latex from the papaya fruit and leaves. The latex oxidizes after atmospheric exposure,... more

Papaya meleira virus (PMeV) is the causal agent of papaya sticky disease, which is characterized by a spontaneous exudation of fluid and aqueous latex from the papaya fruit and leaves. The latex oxidizes after atmospheric exposure, resulting in a sticky feature on the fruit from which the name of the disease originates. PMeV is an isometric virus particle with a double-stranded RNA (dsRNA) genome of approximately 12 Kb. Unusual for a plant virus, PMeV particles are localized on and linked to the polymers present in the latex. The ability of the PMeV to inhabit such a hostile environment demonstrates an intriguing interaction of the virus with the papaya. A hypersensitivity response is triggered against PMeV infection, and there is a reduction in the proteolytic activity of papaya latex during sticky disease. In papaya leaf tissues, stress responsive proteins, mostly calreticulin and proteasome-related proteins, are up regulated and proteins related to metabolism are down-regulated. ...

In this paper we present the first identification of the Tomato clack ring vi-rus isolated from zucchini with mosaic and deformation of leaves in Poland. Immunosorbent electron microscopy, ELISA test and IC-RT-PCR confirmed the... more

In this paper we present the first identification of the Tomato clack ring vi-rus isolated from zucchini with mosaic and deformation of leaves in Poland. Immunosorbent electron microscopy, ELISA test and IC-RT-PCR confirmed the identification of TBRV. RNA extracted from purified virus (size about 7.4 kb and 4.6 kb) was characteristic to this virus. Zucchini (Cucurbita pepo L. convar giromantiina) is not popular vegetable in Poland such as cucumber (Cucumis sativus) however, its production is steadily increasing mainly due to development of appropriate growing techniques, especially in the field. Diseases, especially viral ones, are main problems in the production of cucurbit plants. Symptoms of viral infection on zucchini are mosaic, yellowing, stunting, leaf chlorosis and fruit deformations. In 2005, similar symptoms were observed on zuc-chini grown in the home garden and in the field. This paper presents the identifica-tion of the virus isolated from zucchini with mosaic and sligh...

The objective of this study was to determine the extent of adoption of Salt tolerant variety BRRI dhan 47 in Noakhali district. Data were collected from randomly selected 100 farmers via pre-tested interview schedule during September 20... more

The objective of this study was to determine the extent of adoption of Salt
tolerant variety BRRI dhan 47 in Noakhali district. Data were collected
from randomly selected 100 farmers via pre-tested interview schedule
during September 20 to October 10, 2012. After data collection, were
coded for processing and analysis. SPSS was used to perform the data
analysis. Percentage, mean, standard deviation were calculated.
Coefficients of correlation (r) were computed to find out the relationship
between adoption of BRRI dhan 47 and the selected socio-economic
characteristics of farmers. Majority of the respondents were middle aged
(48%), having primary level education (46%), medium family size (60%),
small farm size (51%), medium annual income (66%), very low
organizational participation (65%), low innovativeness (72%), medium
extension contact (64%), and medium knowledge on rice cultivation
(70%). Majority (53%) of the respondents had low adoption of BRRI dhan
47 whereas 42 % medium and only 5% under high adoption category.
Farmers’ education, farm size, annual income, innovativeness, extension
contact, and knowledge on rice cultivation showed significant and positive
relationship with adoption of BRRI dhan 47. Shattering problem, cost on
irrigation, natural calamities were the major problems faced by the farmers
in cultivating BRRI dhan 47. Proper extensions activities are needed to
disseminate BRRI dhan 47 to bring the uncultivated areas under rigorous
cultivation for ensure a better livelihood on the coastal farmers.

We describe the metagenomics-derived feline enteric virome in the faeces of 25 cats from a single shelter in California. More than 90 % of the recognizable viral reads were related to mammalian viruses and the rest to bacterial viruses.... more

We describe the metagenomics-derived feline enteric virome in the faeces of 25 cats from a single shelter in California. More than 90 % of the recognizable viral reads were related to mammalian viruses and the rest to bacterial viruses. Eight viral families were detected: Astroviridae, Coronaviridae, Parvoviridae, Circoviridae, Herpesviridae, Anelloviridae, Caliciviridae and Picobirnaviridae. Six previously known viruses were also identified: feline coronavirus type 1, felid herpes 1, feline calicivirus, feline norovirus, feline panleukopenia virus and picobirnavirus. Novel species of astroviruses and bocaviruses, and the first genome of a cyclovirus in a feline were characterized. The RNA-dependent RNA polymerase region from four highly divergent partial viral genomes in the order Picornavirales were sequenced. The detection of such a diverse collection of viruses shed within a single shelter suggested that such animals experience robust viral exposures. This study increases our un...

Many agricultural landscapes are characterized by a high degree of heterogeneity and fragmentation. Landscape ecology focuses on the influence of habitat heterogeneity in space and time on ecological processes. Landscape epidemiology aims... more

Many agricultural landscapes are characterized by a high degree of heterogeneity and fragmentation. Landscape ecology focuses on the influence of habitat heterogeneity in space and time on ecological processes. Landscape epidemiology aims at applying concepts and approaches originating from landscape ecology to the study of pathogen dynamics at the landscape scale. However, despite the strong influence that the landscape properties may have on the spread of plant diseases, landscape epidemiology has still received little attention from plant pathologists. Some recent methodological and technological progress provides new and powerful tools to describe and analyse the spatial patterns of host-pathogen interactions. Here, we review some important topics in plant pathology that may benefit from a landscape perspective. These include the influence of: landscape composition on the global inoculum pressure; landscape heterogeneity on pathogen dynamics; landscape structure on pathogen dispersal; and landscape properties on the emergence of pathogens and on their evolution.

Insect pests, pathogens, and other types of plant attackers cause great losses and uncertainties to agriculture, increasing economic costs for producers. Apart from decreasing the yield, they lower crop quality by releasing toxins and... more

Insect pests, pathogens, and other types of plant attackers cause great losses and uncertainties to agriculture, increasing economic costs for producers. Apart from decreasing the yield, they lower crop quality by releasing toxins and viruses; insects in fact transmit approximately 80% of all plant viruses. Insecticidal solutions may have detrimental effects on the ecosystem by damaging non-target organisms and pests may quickly develop resistance to such practice. Hence, host plant resistance, via both conventional and transgenic breeding of R genes, is an essential measure for eco-friendly integrated pest management. Yet, R genes are occasionally a scarce resource in some crops’ gene pools; in such cases, other transgenic approaches have been developed to increase crop endurance against insects. Exploring R genes, specifically the tomato Mi-1 gene, will review current knowledge and technological advance in this field. Moreover, insight into other transgenic approaches used for coffee plants will give an appreciation of other available options to confer resistance.

Native virus-plant interactions require more understanding and their study will provide a basis from which to identify potential sources of emerging destructive viruses in crops. A novel tymovirus sequence was detected in Asclepias... more

Native virus-plant interactions require more understanding and their study will provide a basis from which to identify potential sources of emerging destructive viruses in crops. A novel tymovirus sequence was detected in Asclepias viridis (green milkweed), a perennial growing in a natural setting in the Tallgrass Prairie Preserve (TGPP) of Oklahoma. It was abundant within and frequent among A. viridis plants and, to varying extents, within other dicotyledonous and one grass (Panicum virgatum) species obtained from the TGPP. Extracts from A. viridis containing the sequence were infectious to a limited number of species. The virus genome was cloned and determined to be closely related to Kennedya yellow mosaic virus. The persistence of the virus within the Oklahoma A. viridis population was monitored for five successive years. Virus was present in a high percentage of plants within representative areas of the TGPP in all years and was spreading to additional plants. Virus was present...

The intergenic regions of banana bunchy top virus (BBTV) DNA-1 to -5 were fused to the green fluorescent protein (GFP) and uidA reporter genes and assessed for promoter activity in transgenic banana (Musa spp. cv. Bluggoe). Promoter... more

The intergenic regions of banana bunchy top virus (BBTV) DNA-1 to -5 were fused to the green fluorescent protein (GFP) and uidA reporter genes and assessed for promoter activity in transgenic banana (Musa spp. cv. Bluggoe). Promoter activity associated with the BBTV-derived promoters was transgene dependent with greatest activity observed using the GFP reporter. The BBTV promoters (BT1 to BT5) directed expression primarily in vascular-associated cells, although levels of activity varied between individual promoters. Promoters BT4 and BT5 directed the highest levels of GFP expression, while activity from BT1, BT2 and BT3 promoters was considerably weaker. Intron-mediated enhancement, using the maize polyubiquitin 1 (ubi1) intron, generated a significant increase in GUS expression directed by the BBTV promoters in transgenic plants.