Apple Mosaic Virus Research Articles

SURVEY OF STONE FRUIT VIRUSES AND VIROIDS IN CHILE

Stone fruits orchards from three Chilean regions were visited to collect leaf samples which were tested for the presence of the most important viruses and viroids. Molecular nonradioactive hybridization (MH) testing of 2,456 samples and confirmatory RT-PCR of some MH-negative samples gave the following infection rates: 31.5% for Prunus necrotic ringspot virus (PNRSV); 31.3% for Prune dwarf virus (PDV); 25.7% for Peach latent mosaic viroid (PLMVd); 3.1% for Tomato ringspot virus (ToRSV) only in rootstocks; 1.8% for Plum pox virus (PPV); 1.2% for Hop stunt viroid (HSVd); 1.1% for Apple mosaic virus (ApMV); and 0.9% for Apple chlorotic leaf spot virus (ACLSV). American plum line pattern virus (APLPV) was not detected. The overall infection rate in the surveyed orchards was 29.6%, specifically 28.2% (Region Metropolitana), 23.4% (Valparaiso) and 33% (Bernardo O’Higgins) in the three regions surveyed. ApMV and HSVd, detected only in peach and nectarine, are new records in stone fruits in Chile.

Occurrence of Several Viruses Infecting Wild Growing Stone Fruit Trees in Central Bohemia

Abstract The phytosanitary status of wild growing stone fruit trees and shrubs was examined in surveys conducted in 2013 and 2014 in the region of Central Bohemia, Czech Republic. A total of 159 leaf samples were collected (42 cherries, 77 bird cherries, 10 cherry plums, 13 blackthorns, 2 round plums, 15 plums) and tested for the presence of Plum pox virus (PPV), Prunus necrotic ringspot virus (PNRSV), Prune dwarf virus (PDV), Apple mosaic virus (ApMV), Apple chlorotic leaf spot virus (ACLSV), Cherry virus A (CVA), Cherry necrotic rusty mottle virus (CNRMV), Cherry green ring mottle virus (CGRMV), and Cherry leafroll virus (CLRV) using reverse transcription-polymerase chain reaction (RT-PCR). Totally 28.3% of the investigated trees and shrubs were infected by at least one monitored virus. Mixed infection occurred in 5 out of 159 trees (3.1%). PPV was the most widespread virus (13.2% of samples), followed by PDV (11.3%). Contrary to these two most relevant viral pathogens, the incidence of CLRV and CVA was negligible in individually growing trees of the genus Prunus and ApMV, ACLSV, CGRMV, and CNRMV were not detected at all.

Діагностика плодових насаджень як елемент фітовірусологічного моніторингу південно-західного регіону України

Діагностика плодових насаджень як елемент фітовірусологічного моніторингу південно-західного регіону України

Quantitative detection of four pome fruit viruses in apple trees throughout the year

A one-step real-time RT-PCR assay (RT-qPCR) with melting curve analysis, using the green fluorescence dye SYBR Green I, was developed to detect and quantify RNA targets from Apple mosaic virus (ApMV), Apple stem grooving virus (ASGV), Apple stem pitting virus (ASPV) and Apple chlorotic leaf spot virus (ACLSV) in infected apple trees. Single PCR products of 87 bp (ApMV), 70 bp (ASGV), 104 bp (ASPV) and 148 bp (ACLSV) were obtained, and melting curve analyses revealed distinct melting temperature peaks for each virus. A dilution series using in vitro synthesized transcripts containing the target sequences as standards yielded a reproducible quantitative assay, with a wide dynamic range of detection and low coefficients of variance. The content of selected viruses in apple plant tissues was stable throughout the year, and their accumulation did not significantly change between different plant tissues. The only minor exceptions were for ApMV and ACLSV, in which noticeable differences in their concentrations in various biological material were observed within the year. This divergence did not influence their year-round detectability. This one-step RT-qPCR assay is a valuable tool for year-round diagnostics, and molecular studies of the biology of ApMV, ASGV, ASPV and ACLSV.

Characterization of Apple mosaic virus isolates detected in hazelnut in Poland

Apple mosaic virus (ApMV) infects over 65 plants species of Rosaceae family including hazelnut. The virus causes chlorotic or yellow patterns, rings and mosaic symptoms on the leaves and losses in yield of nuts. The occurrence and genetic diversity of ApMV were evaluated in 14 plantations of hazelnut in Poland. A total of 13 of 125 hazelnut samples tested positive for ApMV using ELISA and reverse transcriptase-polymerase chain reaction. Several primer pairs were used for RT-PCR to amplify the coat protein (CP) and movement protein (MP) genes as well as complete RNA-3 of the ApMV. Genetic diversity was observed in full-length sequences of RNA-3 of the ApMV isolates from hazelnut. The similarity of nucleotide sequence of the CP and MP genes of the isolates was 90.3–99.9, and 87–99.7 %, respectively. Phylogenetic analysis showed that ApMV isolates from hazelnut grouped separately from the virus strains found in other plant species.

Analysis of virus structure variants in before- and after-thermotherapy-treated apple plants

ABSTRACTPre-thermotherapy apple plants and their homologous regenerated virus-infected apple plants were used to analyze the effect of high temperature on the structure of plant virus variants. The target bands of apple chlorotic leaf spot virus (ACLSV), apple stem grooving virus (ASGV), and apple mosaic virus (ApMV) in the plants of the two populations were purified and cloned, and 16 positive clones of each sample were randomly selected for single-strand conformation polymorphism (SSCP) analysis. The results showed that a predominant haplotype could be found in the two populations. The main variant was the same both in the regenerated and homologous treated plants, but the percentages in regenerated plants could be lower than, the same as, or higher than that in pre-thermotherapy plants. Two types could be divided depending on the percentage of the predominant haplotype in the treated plants, diversity (less 70%) and simple (more 80%), respectively. The clones of different haplotype in each isolates were sent to sequence, and the alignment results in accordance with that of the SSCP analysis. All the results indicated that thermotherapy could not affect the predominant variants of virus in treated plants, just change its percentage.

Apple mosaic virus

Apple mosaic, rose mosaic, plum and birch line pattern, horse chestnut yellow mosaic, and hazel mosaic are some of many diseases caused by one of the longest-known pome fruit viruses: Apple mosaic virus . The worldwide distribution of Apple mosaic virus and its negative impacts on fruit, nut and hop production are sufficient to cause international interest. This review endeavors to piece together all known information about the virus. We describe taxonomic position, virion structure, the host range and symptoms, modes of transmission and diagnostics for the virus, as well as distribution and control of the diseases it causes.

The complete nucleotide sequence and genomic characterization of tropical soda apple mosaic virus.

We report the first complete genome sequence of tropical soda apple mosaic virus (TSAMV), a tobamovirus originally isolated from tropical soda apple (Solanum viarum) collected in Okeechobee, Florida. The complete genome of TSAMV is 6,350 nucleotides long and contains four open reading frames encoding the following proteins: i) 126-kDa methyltransferase/helicase (3354 nt), ii) 183-kDa polymerase (4839 nt), iii) movement protein (771 nt) and iv) coat protein (483 nt). The complete genome sequence of TSAMV shares 80.4% nucleotide sequence identity with pepper mild mottle virus (PMMoV) and 71.2-74.2% identity with other tobamoviruses naturally infecting members of the Solanaceae plant family. Phylogenetic analysis of the deduced amino acid sequences of the 126-kDa and 183-kDa proteins and the complete genome sequence place TSAMV in a subcluster with PMMoV within the Solanaceae-infecting subgroup of tobamoviruses.

Sanitary Status of Pome and Stone Fruit Collection in Gene Bank in Republic of Srpska

Detection of viruses presence were carried out for the 225 a of pome and stone fruit trees from the collection of the Genetic Resources Institute of University of Banja Luka, located within the Botanical Garden of the University, tested by DAS-ELISA. The pome fruit trees were analyzed on presence of the following viruses: Apple Chlorotic Leaf Spot Virus (ACLSV), Apple Stem Grooving Virus (ASGV), Apple Stem Pitting Virus (ASPV) and Apple Mosaic Virus (ApMV). The stone fruits were analyzed on presence of Plum Pox Virus (PPV), Prune Dwarf Virus (PDV) and Prunus Necrotic Ring Spot Virus (PNRSV). All samples were tested serologically by DAS-ELISA. In addition to this, virus negative pear and apple accessions were tested for 'Candidatus Phytoplasma mali' and 'Candidatus Phytoplasma pyri' presence using nested-PCR/RFLP analyses.

FIRST REPORT OF CUCUMBER MOSAIC VIRUS INFECTING APPLE IN CHINA

A survey for apple viruses was conducted in October of 2014 in Shanxi, Gansu, Sichuan, Liaoning and Hebei provinces of China. A total of 189 leaf samples with mosaic symptoms and five symptomless samples were collected and tested for viruses. Apple mosaic virus (ApMV) (Lakshmi et al., 2011; Robertson, 2012) was not detected by RT-PCR with total RNA and primers ApMV-F (5’-CGTGAGGAAGTTTAGGTTG-3’)/ApMV-R (5’-GCCTCCTAATCGGGGCATCAA-3’). Neither were Tobacco mosaic virus (TMV), Turnip mosaic virus (TuMV), Potato virus Y (PVY) and Potato virus X (PVX) by a multiplex RT-PCR assay previously developed in our laboratory, with the exception of Cucumber mosaic virus (CMV), for which a partial fragment (322 bp) of the coat protein (CP) gene was amplified from 153 symptomatic samples using specific primers CMV-F (5’-GATAAGAAGCTTGTTTCGCG-3’)/CMV-R (5’-GCTCGATGTCGACATGAAGT-3’). To confirm these preliminary results, primer pair CMV-CP-F (5’-A TGGACAAA TCTGAA TCAACC-3’)/ CMV-CP-R (5’-TCAGACTGGGAGCACCCC-3’) were designed to amplify a 657 bp CMV CP amplicon by simplex RT-PCR. The expected product was obtained from each sample identified as positive by multiplex RT-PCR. Five amplicons were randomly selected for cloning and sequencing (GenBank accession Nos. KP307919-KP307922 and KP641344). Sequence alignments showed the highest CMV sequence identity at the nucleotide level (97.3% to 99.2%) of the five isolates with that of a CMV isolate from tobacco in Sichuan province (KJ746016). Phylogenetic analysis indicated the five isolates cluster into CMV subgroup I. Using the CMV-specific monoclonal antibody 3C12 (Yu et al., 2005), the 153 symptomatic samples were positive for CMV in ELISA. No virus was detected in the five symptomless samples. To our knowledge, this is the first report of CMV infecting apple in China.

Molecular characterization of the coat protein gene of prunus necrotic ringspot virus infecting peach in Montenegro

In 2011 and 2012, two major peach-growing areas in Montenegro were surveyed for the occurrence of eleven peach viruses. Samples collected from 105 peach and nectarine trees were tested by Reverse transcription-polymerase chain reaction (RT-PCR) using sets of primers specific for the detection of Apple chlorotic leaf spot virus (ACLSV), Apple mosaic virus (ApMV), Cherry mottle leaf virus (CMLV), Prunus necrotic ringspot virus (PNRSV), Prune dwarf virus (PDV), Peach mosaic virus (PMV), Peach rosette mosaic virus (PRMV), Tobacco ringspot virus (TRSV) and Tomato ringspot virus (ToRSV). The occurrence of Strawberry latent ringspot virus (SLRSV) was examined using nested RT-PCR, while a Real-time quantitative RT-PCR method was applied for detection of Plum pox virus (PPV). PPV, PNRSV and PDV were detected in 42.9, 24.8 and 0.9 % of samples. Mixed viral infections were recorded in 6.7 % of samples, while results showed the absence of ACLSV, ApMV, PMV, CMLV, SLRSV, PRMV, TRSV and ToRSV from all assayed samples. In particular, the PCR products of complete coat protein (CP) gene was cloned and sequenced from fourteen PNRSV isolates. A high identity (87.5–100 %) was found between CP nucleotide sequences of Montenegrin isolates and other PNRSV isolates from different hosts and geographic regions retrieved from GenBank. CP nucleotide sequence comparison, as well as phylogenetic reconstruction confirmed the clustering of the isolates into three molecular groups (PV-96, PV-32 and PE-5), whereby Montenegrin isolates were separated into two phylogroups (PV-96 and PE-5). Comparative sequence and phylogenetic analysis showed that clustering of various isolates was not associated with geographic and host origin.

Necrotic streak disease of tomato in Florida caused by a new ilarvirus species related to Tulare apple mosaic virus

During surveys for the emerging tospoviruses Tomato chlorotic spot virus (TCSV) and Groundnut ringspot virus (GRSV), virus-like necrosis of leaves, petioles and stems (Fig. 1), and necrotic rings or spots on fruits (Fig. 2) of fresh market…

English

Apple mosaic virus (ApMV) is the most important viral pathogen of hazelnut. The Black Sea region is the main hazelnut producing area in Turkey. Hazelnut growing areas from Giresun which are located in the Black Sea region were surveyed for occurrence and distribution of ApMV in 2011-2012. Hazelnut leaf samples were collected randomly from non-symptomatic and symptomatic plants displaying yellow rings and lines, yellow flecking, oak leaf pattern and broad vein banding. Leaves from 229 samples collected in 35 fields were tested for the presence of ApMV using enzyme-linked immunosorbent assay (ELISA) with a commercial antiserum. Based on the ELISA results, 18 out of 229 samples (7.86%) were infected with ApMV.

Molecular characterization of Apple mosaic virus isolates from apple and rose

Apple mosaic virus (ApMV) is one of the important viruses of apple and rose. Although the virus occurs worldwide the information on the virus presence in Poland and Belarus is limited. Genetic diversity of ApMV isolates from apple originated from Poland and Belarus as well as rose isolates from Poland was investigated based on phylogenetic analyses of movement protein (MP) and coat protein (CP) genes. Comparison of CP gene sequences showed the high sequence identity of the studied ApMV isolates and their clustering with apple and pear strains of ApMV deposited in the GenBank database. There was no correlation between the geographical origin and CP gene sequence variability of Polish and Belarusian ApMV isolates.

Efficiency of virus elimination from potted apple plants by thermotherapy coupled with shoot-tip grafting

Four varieties of potted apple were subjected to thermotherapy (37 ± 1 °C) coupled with shoot tip grafting. Using reverse transcription-polymerase chain reaction assays prior to treatment, mixed infections with Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV), Apple stem grooving virus (ASGV), Apple mosaic virus (ApMV) and Apple scar skin viroid (ASSVd) were detected in 95.8 % of treated plants. It was found that the sprouts of Dahongrong (DHR) and Qiyuetianxian (QYT) variety buds were inhibited by high temperature, although some buds of these two varieties were able to sprout, the growth was slow. The average survival rate of shoot tips cut after thermotherapy was 41.2 % (61/148). The survival rate of DHR (63.2 %) was highest among the four varieties. Sixty-one surviving apple plants were detected over two periods, indicative of an average elimination rate of 65.6 % (40/61) for new leaves (June) and 37.7 % (23/61) for dormant branches (November). The difference of elimination rate for DHR between the two periods was the most obvious. Detections rates of viruses were also different in the two periods; ASGV in dormant branches were 27.8 % higher than those in new leaves, and ASPV (90.6 %) remained the same over the two periods.

IMPROVED DETECTION OF ILARVIRUSES AND NEPOVIRUSES AFFECTING FRUIT TREES USING QUANTITATIVE RT-qPCR

Reverse transcription quantitative PCR (RT-qPCR) assays were developed for the detection of the ilarviruses Prunus necrotic ringspot virus (PNRSV), Prune dwarf virus (PDV), Apple mosaic virus (ApMV), and American plum line pattern virus (APLPV), and the nepoviruses Tomato ringspot virus (ToRSV) and Cherry leafroll virus (CLRV). These viruses affect various stone fruits such as apricots, cherries, peaches, plums, and almonds. The goal of this work was to improve the RT-qPCR detection of PNRSV, PDV, and ApMV in addition to developing three new RT-qPCR assays for the detection of APLPV, ToRSV and CLRV. Primers for conventional RT-PCR as well as primers and probes for RT-qPCR assays were designed after aligning coat protein (CP) gene sequences of geographically diverse isolates with the corresponding CP gene sequences from GenBank, targeting regions with 100% sequence identity. The efficiency of each RT-qPCR assay, as well as the intra- and inter-assay variability, were determined. These conventional RT-PCR and RT-qPCR assays were validated using purified total RNAs from 221 trees from the USDA Clonal Germplasm Repository orchards. The data showed that more isolates were detected by RT-qPCR than by RT-PCR.

Simultaneous detection of four viruses affecting apple and pear by molecular hybridization using a polyprobe

The viruses Apple stem grooving virus (ASGV), Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV) and Apple mosaic virus (ApMV) are common in apples and pears and main targets of detection in propagation materials. This study aimed at demonstrating the usefulness of the hybridization method with a non-radioactive probe for simultaneous detection of these four viruses. The sensitivity of this method was sufficiently high enabling the detection of ASGV, ACLSV, ASPV and ApMV in total RNA extracted from infected samples. The probe specificity was confirmed by reaction with homologous viral cDNA, individually cloned for each virus.

Scientific Opinion on the pest categorisation ofPrunus necrotic ringspot virus

The Panel on Plant Health performed a pest categorisation of Prunus necrotic ringspot virus (PNRSV) for the European Union (EU) territory. PNRSV is a well-defined virus species of the genus Ilarvirus for which the entire genome sequence and molecular detection assays are available. It is transmitted by vegetative multiplication of infected hosts and also via seeds and pollen (both horizontally and vertically) in some of its hosts. PNRSV has a somewhat restricted natural host range, which contains Prunus spp., hops, roses and Rubus ellipticus (yellow Himalayan raspberry). It is listed on plants of Rubus for planting in Annex IIAI of Directive 2000/29EC, probably as a result of confusion with the closely related Apple mosaic virus. PNRSV is widely present in the EU, but there are no records on its regulated hosts. It is not expected to be affected by ecoclimatic conditions wherever its hosts are present, and it has the potential to establish in large parts of the EU territory. PNRSV can spread through efficient seedand pollen-mediated transmission mechanisms and through the movement of vegetatively propagated plants for planting. However, the existence of efficient and widely adopted certification systems for Prunus spp. constitutes a limitation to PNRSV spread. Although the virus alone or when in mixed infection can cause significant diseases in some hosts, the actual impact of PNRSV appears to be limited. © European Food Safety Authority, 2014

English

Apple mosaic virus (ApMV) is one of the most important diseases limiting the production of hazelnut and apple in Turkey and the objectives of this research were to determine the convenient and reliable method for RNA isolation and also to determine primer pair for real time polymerase chain reaction (RT-PCR) detection of coat protein gene for Turkish ApMV isolates. Apple mosaic virus isolates were collected in 2007 to 2010 and the presence of the pathogen was detected by double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and RT-PCR tests. Six different RNA extraction protocols and three primer pairs were applied in RT-PCR amplifications and 44 hazelnut and 15 apple ApMV isolates were obtained. All of the amplicons were subjected to enzymatic digestion with restriction endonuclease enzymes and phylogenetic analysis were performed according to the digestion profiles.   Key words: Apple mosaic virus, coat protein gene, hazelnut.

Detection of viruses in apples and pears by real time RT-PCR using 5′-hydrolysis probes.

Apple stem pitting virus (ASPV), Apple stem grooving virus (ASGV), Apple chlorotic leaf spot virus (ACLSV) and Apple mosaic virus (ApMV) are common in apples and pears and the main targets of virus elimination from propagation material. The objective of this work was to design primers and probes for a real time RT-PCR protocol for detection of the four above viruses. FAM/TAMRA-labeled probes and primers were designed by searching for highly conserved nucleotide regions in the coat protein gene of the four viruses. Infection levels in analyzed apple samples were 92.6, 96.4, 100 and 88% for ASGV, ASPV, ACLSV and ApMV, respectively. In pears, all pre-existing ASPV infections were detected. Viral infections were confirmed in a selection of commercial cultivars of apples and pear scions, and quince rootstocks, demonstrating the sensitivity and reliability of the designed primers and probes. Real time RT-PCR using 5'-labeled probes is suitable for checking sanitary quality as a routine test in certification programs.