Pediatric Acute-Onset Neuropsychiatric Syndrome: A Data Mining Approach to a Very Specific Constellation of Clinical Variables

Objectives: Pediatric acute onset neuropsychiatric syndrome (PANS) is a clinically heterogeneous disorder presenting with: unusually abrupt onset of obsessive compulsive disorder (OCD) or severe eating restrictions, with at least two concomitant cognitive, behavioral, or affective symptoms such as anxiety, obsessive-compulsive behavior, and irritability/depression. This study describes the clinical and laboratory variables of 39 children (13 female and 26 male) with a mean age at recruitment of 8.6 years (standard deviation 3.1). Methods: Using a mathematical approach based on Artificial Neural Networks, the putative associations between PANS working criteria, as defined at the NIH in July 2010 (Swedo et al. 2012), were explored by the Auto Contractive Map (Auto-CM) system, a mapping method able to compute the multidimensional association of strength of each variable with all other variables in predefined dataset. Results: The PANS symptoms were strictly linked to one another on the semantic connectivity map, shaping a central "diamond" encompassing anxiety, irritability/oppositional defiant disorder symptoms, obsessive-compulsive symptoms, behavioral regression, sensory motor abnormalities, school performance deterioration, sleep disturbances, and emotional lability/depression. The semantic connectivity map also showed the aggregation between PANS symptoms and laboratory and clinical variables. In particular, the emotional lability/depression resulted as a highly connected hub linked to autoimmune disease in pregnancy, allergic and atopic disorders, and low Natural Killer percentage. Also anxiety symptoms were shown to be strongly related with recurrent infectious disease remarking the possible role of infections as a risk factor for PANS. Conclusion: Our data mining approach shows a very specific constellation of symptoms having strong links to laboratory and clinical variables consistent with PANS feature.

The mycovirome of a fungal collection from the sea cucumber Holothuria polii

Holothuria polii is a marine animal with an important ecological and economic impact. In the present study we analysed the presence of mycoviruses associated to fungi that were isolated from different H. polii tissues. Among the 48 fungal isolates analysed we identified 10 viruses in 8 strains belonging to 7 fungal species. Five out of nine viruses have a dsRNA genome: three of them belong to the Partitiviridae family, one belongs to a still undefined clade of bipartite viruses and the last one belongs to the Chrysoviridae family. We also identified two viruses belonging to a recently proposed new mycovirus taxon named polymycovirus. Two viruses belong to the positive single stranded RNA clade: one falls into the new Botourmiaviridae family, specifically in the Magoulivirus genus, and the other one falls into a still undefined clade phylogenetically related to tombusviruses. Finally, we also identified a virus with a negative stranded RNA genome showing similarity to a group of viruses recently proposed as a new family of mycoviruses in the order Bunyavirales. A bioinformatics approach comparing two datasets of contigs containing two closely related mycobunyaviruses allowed us to identify putative nucleocapsids (Nc) and non-structural (Ns) associated proteins. The GenBank/eMBL/DDBJ accession numbers of the sequences reported in this paper are: PRJNA432529, MG913290, MG913291, MG887747, MG887748, MG887749, MG887750, MG887751, MG887752, MG887753, MG887754, MG887755, MG887756, MG887757, MG887758, MG887759, MG887760, MG887761, MG887762, MG887763, MG887764, MG887765, MG887766, MG887767, MH271211, MN163273, MN163274.

Mycoviruses mediate mycotoxin regulation in Aspergillus ochraceus

To date, no demonstration of a direct correlation between the presence of mycoviruses and the quantitative or qualitative modulation of mycotoxins has been shown. In our study, we transfected a virus-free ochratoxin A (OTA)-producing isolate of Aspergillus ochraceus with purified mycoviruses from a different A. ochraceus isolate and from Penicillium aurantiogriseum. Among the mycoviruses tested, only Aspergillus ochraceus virus (AoV), a partitivirus widespread in A. ochraceus, caused a specific interaction that led to an overproduction of OTA, which is regulated by the European Commission and is the second most important contaminant of food and feed commodities. Gene expression analysis failed to reveal a specific viral upregulation of the mRNA of genes considered to play a role in the OTA biosynthetic pathway. Furthermore, AoOTApks1, a polyketide synthase gene considered essential for OTA production, is surprisingly absent in the genome of our OTA-producing isolate. The possible biological and evolutionary implications of the mycoviral regulation of mycotoxin production are discussed.

Biological and Molecular Characterization of Chenopodium quinoa Mitovirus 1 Reveals a Distinct Small RNA Response Compared to Those of Cytoplasmic RNA Viruses

Indirect evidence of mitochondrial viruses in plants comes from discovery of genomic fragments integrated into the nuclear and mitochondrial DNA of a number of plant species. Here, we report the existence of replicating mitochondrial virus in plants: from transcriptome sequencing (RNA-seq) data of infected Chenopodium quinoa, a plant species commonly used as a test plant in virus host range experiments, among other virus contigs, we could assemble a 2.7-kb contig that had highest similarity to mitoviruses found in plant genomes. Northern blot analyses confirmed the existence of plus- and minus-strand RNA corresponding to the mitovirus genome. No DNA corresponding to the genomic RNA was detected, excluding the endogenization of such virus. We have tested a number of C. quinoa accessions, and the virus was present in a number of commercial varieties but absent from a large collection of Bolivian and Peruvian accessions. The virus could not be transmitted mechanically or by grafting, but it is transmitted vertically through seeds at a 100% rate. Small RNA analysis of a C. quinoa line carrying the mitovirus and infected by alfalfa mosaic virus showed that the typical antiviral silencing response active against cytoplasmic viruses (21- to 22-nucleotide [nt] vsRNA peaks) is not active against CqMV1, since in this specific case the longest accumulating vsRNA length is 16 nt, which is the same as that corresponding to RNA from mitochondrial genes. This is evidence of a distinct viral RNA degradation mechanism active inside mitochondria that also may have an antiviral effect.IMPORTANCE This paper reports the first biological characterization of a bona fide plant mitovirus in an important crop, Chenopodium quinoa, providing data supporting that mitoviruses have the typical features of cryptic (persistent) plant viruses. We, for the first time, demonstrate that plant mitoviruses are associated with mitochondria in plants. In contrast to fungal mitoviruses, plant mitoviruses are not substantially affected by the antiviral silencing pathway, and the most abundant mitovirus small RNA length is 16 nt.

Mycoviruses mediate mycotoxin regulation in Aspergillus ochraceus

To date, no demonstration of a direct correlation between the presence of mycoviruses and the quantitative or qualitative modulation of mycotoxins has been shown. In our study, we transfected a virus-free ochratoxin A (OTA)-producing isolate of Aspergillus ochraceus with purified mycoviruses from a different A. ochraceus isolate and from Penicillium aurantiogriseum. Among the mycoviruses tested, only Aspergillus ochraceus virus (AoV), a partitivirus widespread in A. ochraceus, caused a specific interaction that led to an overproduction of OTA, which is regulated by the European Commission and is the second most important contaminant of food and feed commodities. Gene expression analysis failed to reveal a specific viral upregulation of the mRNA of genes considered to play a role in the OTA biosynthetic pathway. Furthermore, AoOTApks1, a polyketide synthase gene considered essential for OTA production, is surprisingly absent in the genome of our OTA-producing isolate. The possible biological and evolutionary implications of the mycoviral regulation of mycotoxin production are discussed.

A new tobamovirus infecting tomato crops in Jordan

In this study, we completed the whole genome sequence of a new tobamovirus isolated from tomato plants grown in greenhouses in Jordan during the spring of 2015. The 6393-nt single-stranded RNA (ssRNA) genome encodes four proteins, as do other tobamoviruses: two replication-related proteins of 126 kDa and 183 kDa, a 30-kDa movement protein (MP) and a 17.5-kDa coat protein (CP). Phylogenetic analysis showed that this virus does not group with either the tomato mosaic virus (ToMV) or the tobacco mosaic virus (TMV) clades. Instead, it stems from a branch leading to the TMV clade. Analysis of possible recombination events between this virus and representative isolates of closely related tomato-infecting tobamoviruses showed that at least one region originated by recombination. We provide evidence that we have identified a new tobamovirus, for which we propose the name "tomato brown rugose fruit virus".

A Comparison between Children with ADHD and Children with Epilepsy in Self-Esteem and Parental Stress Level

Attention-deficit/hyperactivity disorder (ADHD) is frequently associated with negative psychological outcomes. This study explores the relationship between self-esteem, ADHD symptoms and parental stress. It compares children with ADHD, children with epilepsy (E) and typical developmental controls (TD). Participants included 65 children (aged 9-12 yrs) and their parents. The assessment was conducted by Multidimensional Self-Concept Scale (MSCS), Parent Stress Index (PSI) and Conners' Parent Rating Scales–Revised. Significant differences were found in Social, Competence and Academic areas of self-esteem between children with ADHD, with E and TD. Moreover, parents of children with ADHD showed a higher overall stress than both other groups. In conclusion, it seems important to evaluate the psychological aspects of ADHD con-dition, both in children and in parents, in order to suggest an individual multimodal treatment.

The complete genome sequence of polygonum ringspot virus

The complete genome sequence of polygonum ringspot virus (PolRSV), genus Tospovirus, family Bunyaviridae, was determined. This is the first report of the complete genome sequence for a European tospovirus isolate. The large RNA of PolRSV was 8893 nucleotides (nt) in size and contained a single open reading frame of 8628 nucleotides in the viral-complementary sense, coding for a predicted RNA-dependent RNA polymerase of 330.9 kDa. Two untranslated regions of 230 and 32 nucleotides were present at the 5' and 3' termini, respectively, which showed conserved terminal sequences, as commonly observed for tospovirus genomic RNAs. The medium and small (S) RNAs were 4710 and 2485 nucleotides in size, respectively, and showed 99 % homology to the corresponding genomic segment of a previously partially characterized PolRSV isolate, Plg3. Protein sequences for GN/GC, N and NSs were identical in length in the two PolRSV isolates, while an amino acid insertion was observed for the NSm protein of the newly characterized isolate. The noncoding intergenic region of the S RNA was very short (183 nt) and was not predicted to form a hairpin structure, confirming that this unique characteristic within tospoviruses, previously observed for Plg3, is not isolate specific.

The NSs protein of tomato spotted wilt virus is required for persistent infection and transmission by Frankliniella occidentalis

Tomato spotted wilt virus (TSWV) is the type member of tospoviruses (genus Tospovirus), plant-infecting viruses that cause severe damage to ornamental and vegetable crops. Tospoviruses are transmitted by thrips in the circulative propagative mode. We generated a collection of NSs-defective TSWV isolates and showed that TSWV coding for truncated NSs protein could not be transmitted by Frankliniella occidentalis. Quantitative reverse transcription (RT)-PCR and immunostaining of individual insects detected the mutant virus in second-instar larvae and adult insects, demonstrating that insects could acquire and accumulate the NSs-defective virus. Nevertheless, adults carried a significantly lower viral load, resulting in the absence of transmission. Genome sequencing and analyses of reassortant isolates showed genetic evidence of the association between the loss of competence in transmission and the mutation in the NSs coding sequence. Our findings offer new insight into the TSWV-thrips interaction and Tospovirus pathogenesis and highlight, for the first time in the Bunyaviridae family, a major role for the S segment, and specifically for the NSs protein, in virulence and efficient infection in insect vector individuals.

IMPORTANCE

Our work is the first to show a role for the NSs protein in virus accumulation in the insect vector in the Bunyaviridae family: demonstration was obtained for the system TSWV-F. occidentalis, arguably one of the most damaging combination for vegetable crops. Genetic evidence of the involvement of the NSs protein in vector transmission was provided with multiple approaches.

A new ilarvirus isolated from Viola × wittrockiana and its detection in pansy germoplasm by qRT-PCR

An infectious agent was transmitted mechanically from samples of Viola spp. showing white mosaic and leaf deformation to Nicotiana benthamiana. dsRNA extracted from the N. benthamiana plants migrated as four specific bands that were absent in non-inoculated plants. Sequence analysis of cDNA clones generated from the second-smallest dsRNA showed the greatest similarity to the RNA3 of prune dwarf virus (PDV) (genus Ilarvirus, family Bromoviridae). However, because of differences in molecular, biological, and serological properties between this virus isolate and PDV, a new ilarvirus species, named "Viola white distortion associated virus" (VWDaV) is proposed. Specific oligonucleotides and a TaqMan(®) probe were designed for diagnostic purposes. The possible association between the virus and the original white distortion symptoms is discussed.

First Report of a Carlavirus in Fuchsia spp. in New Zealand

The genus Fuchsia has 110 known species and numerous hybrids. These ornamental plants with brightly colored flowers originate from Central and South America, New Zealand, and Tahiti, but a wider variety are now grown all over the world. Few viruses have been reported in Fuchsia spp.: a carlavirus, Fuchsia latent virus (FLV) (1-3), a cucumovirus, Cucumber mosaic virus (CMV) (3), and two tospoviruses, Impatiens necrotic spot virus (INSV) and Tomato spotted wilt virus (TSWV) (4). In August 2009, five plants, each representing a different cultivar of Fuchsia hybrid, from home gardens in the Auckland and Southland regions of New Zealand, displayed variable symptoms including mild chlorosis, mild mottle, or purple spots on leaves. Plants tested negative for CMV, INSV, and TSWV using commercial ImmunoStrips (Agdia Inc., Elkhart, IN); however, flexuous particles of ~650 to 700 nm were found by electron microscopy in all samples. Local lesions were also observed on Chenopodium quinoa plants 4 weeks after sap inoculation. Total RNA was extracted from all plants with a RNeasy Plant Mini Kit (Qiagen Inc., Doncaster, Australia) and tested by reverse transcription (RT)-PCR using two generic sets of primers (R. van der Vlugt, personal communication) designed to amplify fragments of ~730 and 550 bp of the replicase and coat protein genes of carlaviruses, respectively. Amplicons of the expected size were obtained for all samples, cloned, and at least three clones per sample were sequenced. No differences within clones from the same samples were observed (GenBank Accession Nos. HQ197672 to HQ197681). A BLASTn search of the viral replicase fragment showed the highest nucleotide identity (76%) to Potato rough dwarf virus (PRDV) (EU020009), whereas the coat protein fragment had maximum nucleotide identity (70 to 72%) to PRDV (EU020009 and DQ640311) and Potato virus P (DQ516055). Sequences obtained were also pairwise aligned using the MegAlign program (DNASTAR, Inc., Madison, WI) and results showed that the isolates had 83 to 97% identity to each other within each genome region. Further sequences (HQ197925 and HQ197926) were obtained from a Fuchsia plant originating from Belgium, a BLASTn analysis showed high nucleotide identity (84 to 99%) to the New Zealand isolates. The low genetic identity to other Carlavirus members suggests that these isolates belong to a different species from those previously sequenced. On the basis of electron microscopy and herbaceous indexing, the isolates had similar characteristics to a carlavirus reported from Fuchsia in Italy (1) and FLV reported in Canada (2). The Italian carlavirus isolate was obtained and tested with the same primers by RT-PCR. Pairwise analysis of the Italian sequences (HQ197927 and HQ197928) with the New Zealand and Belgian sequences showed between 84 and 95% similarity within each genome region. These results suggest that the carlavirus infecting these plants is the same virus, possibly FLV. To our knowledge, this is the first report of this carlavirus infecting Fuchsia spp. in New Zealand, but the virus has probably been present for some time in this country and is likely to be distributed worldwide. References: (1) G. Dellavalle et al. Acta Hortic. 432:332, 1996. (2) L. J. John et al. Acta Hortic. 110:195, 1980. (3) P. Roggero et al. Plant Pathol. 49:802, 2000. (4) R. Wick and B. Dicklow. Diseases in Fuchsia. Common Names of Plant Diseases. Online publication. The American Phytopathological Society, St. Paul, MN, 1999.

First Report of Tomato spotted wilt virus on Pepper in Montenegro

In April 2009, chlorotic and necrotic ring spots, chlorotic line patterns, and stunting were observed on greenhouse-grown pepper plants in the vicinity of Podgorica, Montenegro. Disease symptom incidence was estimated at 40%. Symptomatic leaves were tested for the presence of Tomato spotted wilt virus (TSWV) with a commercial double-antibody sandwich (DAS)-ELISA diagnostic kit (Bioreba AG, Reinach, Switzerland). Commercial positive and negative controls were included in each ELISA. TSWV was detected serologically in 33 of 75 pepper samples. The virus was mechanically transmitted from ELISA-positive pepper samples to Nicotiana tabacum cv. Samsun using chilled 0.05 M phosphate buffer (pH 7) containing 0.1% sodium sulfite (1). Inoculated test plants produced chlorotic and necrotic concentric rings and necrotic spots, consistent with symptoms caused by TSWV on N. tabacum. For further confirmation of TSWV infection, reverse transcription (RT)-PCR was performed with the One-Step RT-PCR Kit (Qiagen, Hilden, Germany) using three sets of primers: S70-for/S890-rev (2) and S574-for/S1433-rev (3), both specific to the nonstructural (NSs) gene; and S1983-for/S2767-rev (2), specific to the nucleocapsid protein (N) gene. Total RNAs from naturally infected pepper and symptomatic N. tabacum cv. Samsun plants were extracted with the RNeasy Plant Mini Kit (Qiagen, Hilden, Germany). Total RNAs obtained from the Italian isolate of TSWV (GenBank Accession No. DQ398945) and healthy tobacco plants were used as positive and negative controls, respectively. The expected sizes of the RT-PCR products (820, 859, and 784 bp) were amplified from symptomatic pepper samples but not from healthy tissues. The PCR product obtained from isolate Is-344 using primers specific to N gene was purified by a QIAquick PCR Purification Kit (Qiagen), cloned into the pGEM-T Easy Vector (Promega, Madison, WI) and sequenced in both directions using the same primer pair as in RT-PCR. The sequences amplified with the two primer pairs specific to the NSs gene were obtained by direct sequencing (Bio-Fab Research Srl, Pomezia, Italy) and joined using MEGA4 software. Sequence analysis of the complete N gene (777 bp; GenBank Accession No. GU369717) revealed that the TSWV isolate originating from Montenegro shared 98.2 to 99.7% nucleotide identity (98.1 to 100% amino acid identities) with corresponding TSWV sequences deposited in GenBank. The Montenegrin isolate Is-344 was most closely related to Italian isolates from tomato (GU369725) and eggplant (GU369720). The partial (1,257 bp) nucleotide sequence of NSs gene (GU369737) showed 96 to 99.8% nucleotide identity (96.9 to 100% amino acid identity) with previously reported TSWV sequences, and in this case the highest identity was with French isolates from tomato (FR692835) and lettuce (FR692831). To our knowledge, this is the first report on the occurrence of TSWV in Montenegro. Data of this study sheds light on the importance of further survey studies and inspections of TSWV-susceptible crops cultivated in Montenegro. References: (1) Anonymous. OEPP/EPPO Bull. 29:465, 1999. (2) W. P. Qiu et al. Virology 244:186, 1998. (3) M. Tsompana et al. Mol. Ecol. 14:53, 2005.

Molecular characterization of two distinct strains of blueberry scorch virus (BlScV) in northern Italy

During blueberry scorch virus (BlScV) surveys of highbush blueberries in Italy between 2005 and 2010, we initially discovered infected orchards only in Piedmont. Since 2009, however, three infected orchards have also been found in Trentino, where a new host species, Vaccinium ashei, was found to be infected by BlScV. Molecular characterization of isolates during the study period suggests that two very distinct epidemics are now present in Italy: the Piedmont isolates belong to a new BlScV strain, whereas the Trentino isolates are almost identical to the Washington State strain.

A New Tospovirus sp. in Cucurbit Crops in Mexico

During the 2007 growing season, melon (Cucumis melo) samples from the state of Guerrero in Mexico showing mosaic and other virus-like symptoms were collected for analysis. Electron microscopic examination of negatively stained leaf-dip extracts revealed the presence of abundant virus-like particles with features characteristic of the family Bunyaviridae. No other viral particles were observed in these preparations. However, enzyme-linked immunosorbent assays (ELISAs) specific for the most common Tospovirus spp. gave negative results. Antibodies raised against purified nucleocapsids reacted specifically with the infected leaf extracts in Western blots and double-antibody sandwich ELISA. The viral RNA was used as a template for a cDNA library, and nucleotide sequence analysis identified cloned cDNAs representing sequences corresponding to the three Tospovirus genome segments. Sequence comparisons showed that the new virus had the highest similarity to Chrysanthemum stem necrosis virus (CSNV). Phylogenetic analysis of two genome regions confirmed that this virus, provisionally named Melon severe mosaic virus (MeSMV), is a previously undescribed Tospovirus sp. belonging to the "new world" clade of Tospovirus spp. An initial survey of various cucurbit crops in various states of Mexico confirmed the widespread occurrence of this virus.

Evidence that the nonstructural protein of Tomato spotted wilt virus is the avirulence determinant in the interaction with resistant pepper carrying the TSW gene

All known pepper cultivars resistant to Tomato spotted wilt virus (TSWV) possess a single dominant resistance gene, Tsw. Recently, naturally occurring resistance-breaking (RB) TSWV strains have been identified, causing major concerns. We used a collection of such strains to identify the specific genetic determinant that allows the virus to overcome the Tsw gene in Capsicum spp. A reverse genetic approach is still not feasible for TSWV; therefore, we analyzed reassortants between wild-type (WT) and RB strains. Our results confirmed that the S RNA, which encodes both the nucleocapsid protein (N) and a nonstructural protein (NSs), carries the genetic determinant responsible for Tsw resistance breakdown. We then used full-length S RNA segments or the proteins they encode to compare the sequences of WT and related RB strains, and obtained indirect evidence that the NSs protein is the avirulence factor in question. Transient expression of NSs protein from WT and RB strains showed that they both can equally suppress post-transcriptional gene silencing (PTGS). Moreover, biological characterization of two RB strains carrying deletions in the NSs protein showed that NSs is important in maintaining TSWV infection in newly emerging leaves over time, preventing recovery. Analysis of another RB strain phenotype allowed us to conclude that local necrotic response is not sufficient for resistance in Capsicum spp. carrying the Tsw gene.

Characterization of Four Viral Species Belonging to the Family Potyviridae Isolated from Ranunculus asiaticus

ABSTRACT Four different viral species were isolated from diseased Ranunculus asiaticus plants growing in Imperia Province (Italian Riviera-Liguria Region). Infected plants exhibited mosaic symptoms and growth abnormalities. The viruses were mechanically inoculated to a range of herbaceous hosts and differentiated biologically. Long flexuous particles were present in leaf dip extracts observed by electron microscopy. A general protocol for the amplification of potyvirus genome fragments through reverse transcription-polymerase chain reaction generated products that were cloned and sequenced. Sequence and phylogenetic analysis suggested that three of these isolates could be considered new viral species belonging to the genus Potyvirus. The fourth isolate is a new member of the genus Macluravirus. Purified virus was used as antigen to produce a specific polyclonal antiserum in rabbit; serological features were established through double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), antigen coated plate (ACP)-ELISA, and western blot analysis. DAS-ELISA was highly specific for each virus isolate, whereas some cross-reactivity was shown in ACP-ELISA and western blot analysis. Aphid transmission by Myzus persicae was demonstrated in a controlled environment for each of the four viral isolates, whereas no transmission through seed was observed.

Characterization of a potyvirus isolated from Tradescantia fluminensis in northern Italy

We isolated a potyvirus from Tradescantia fluminensis that was causing leaf distortion and mild mosaic. We cloned and sequenced a 1500 bp cDNA obtained by RT-PCR corresponding to the 3' proximal region of the genome. We determined the host range and tested a series of potyviral antisera against our tradescantia virus isolate by immuno-enzymatic methods. Based on our results, we suggest that our viral isolate could be considered a new potyvirus species named Tradescantia mild mosaic potyvirus. Phylogenetic analysis confirmed that Tradescantia mild mosaic virus belongs to the genus Potyvirus within the family Potyviridae, but the virus could not be assigned to any of the potyvirus groupings recently defined.

The expression of a single-chain Fv antibody fragment in different plant hosts and tissues by using Potato virus X as a vector

Some aspects of the expression of a single-chain Fv antibody fragment (scFv) driven by the plant viral vector Potato virus X (PVX) have been studied by quantitative ELISA. After inoculation of the infectious transcript, the vector was stable only for a few passages of sap transmission in the inoculated leaves of Nicotiana benthamiana and the reversal to wild type was more pronounced in the systemically invaded leaves. The amount of synthesized scFv varied when different solanaceous hosts were tested, being generally higher and less variable in inoculated than in systemically invaded leaves. In tomato and Datura stramonium the scFv was synthesized only in the inoculated leaves. The scFv was also synthesized in the PVX local hosts Chenopodium amaranticolor and C. quinoa. No correlation was found between PVX and scFv concentration in the inoculated and systemically invaded leaves of N. benthamiana and N. clevelandii.

First Report of Tobacco vein banding mosaic virus in China (Xian, Shaanxi Province) in Datura stramonium and Tobacco

Tobacco vein banding mosaic virus (TVBMV) has been reported in Taiwan (1), North America (Tennessee) (2), and Japan (3) and induces a severe disease of tobacco. During surveys on viruses of vegetables in China, TVBMV was isolated from a Datura stramonium weed plant in July 1998 in Shaanxi Province. It showed severe mosaic with blistering of the leaves. The plant was also infected by Cucumber mosaic virus (CMV). When sap from D. stramonium was frozen, thawed, and mechanically inoculated, only TVBMV was recovered. The 3'-end of the viral genome was amplified by reverse transcription-polymerase chain reaction (RT-PCR) using primers derived from the potyviridae primers (4) and cloned in pBlueScript. The sequence of 1,630 bp (GenBank AF274315) was determined on both DNA strands and found to have approximately 94% homology with other TVBMV sequences (L 28816 from Tennessee, X77637 from Taiwan, and AB020524 from Japan). The host range of the Chinese isolate was similar to that reported for the U.S. isolate. D. stramonium, Nicotiana benthamiana, N. clevelandii, N. glutinosa, N. tabacum Samsun, White Burley type and Xanthi, Lycopersicon esculentum cv. Marmande, and Petunia hybrida were systemically infected. A local infection developed in N. rustica, Chenopodium amaranticolor, C. quinoa, and Ocimum basilicum. The Chinese isolate did not infect Capsicum annuum cv. Quadrato d'Asti, Solanum melongena, or several Cucurbitaceae and Leguminosae species. Myzus persicae transmitted the Chinese TVBMV in a non-persistent mode from both D. stramonium and tobacco to the same plants and to tomato. No seed transmission occurred in experimentally infected D. stramonium (20 seedlings), tobacco White Burley type (200 seedlings), and tomato cv. Marmande (100 seedlings). The virus was found in the roots of D. stramonium and tobacco. Since the virus was not seed-transmissible, overwintering rootstocks may provide sites for winter survival of the virus. An antiserum was produced against the virus and an enzyme-linked immunosorbent assay survey was carried out in solanaceous crops including D. stramonium collected in July 1999 in Shaanxi, Shanxi, Henan, and Hebei provinces and Beijing surroundings. TVBMV was found only in the same field as in 1998 in four D. stramonium plants in association with CMV and in a tobacco plant 200 m from D. stramonium. TVBMV was not found in the closest tomato crops, where infection of CMV was severe. This is the first report of TVBMV in China, and Xian is the most northern location in which this virus has been found. References: (1) J. K. Chiang et al. Bull. Tobacco Res. Inst. 32:39, 1990. (2) B. B. Reddick et al. Plant Dis. 76:856, 1992. (3) H. Tochihara. Rev. Plant Prot. Res. 13:122, 1980. (4) A. Gibbs and A. Mackenzie. J. Virol. Meth. 63:9, 1997.

An Ophiovirus isolated from lettuce with big-vein symptoms

Big-vein is a widespread and damaging disease of lettuce, transmitted through soil by the chytrid fungus Olpidium brassicae, and generally supposed to be caused by Lettuce big-vein virus (LBVV; genus Varicosavirus). This virus is reported to have rigid rod-shaped particles, a divided double-stranded RNA genome, and one capsid protein of 48 kD, but has not been isolated or rigorously shown to cause the disease. We provide evidence that a totally different virus, here named Mirafiori lettuce virus (MiLV), is also very frequently associated with lettuce showing big-vein symptoms. MiLV was mechanically transmissible from lettuce to Chenopodium quinoa and to several other herbaceous test plants. The virus was partially purified, and an antiserum prepared, which did not react with LBVV particles in decoration tests. As reported for LBVV, MiLV was labile, soil-transmitted and had a single capsid protein of 48 kD, but the particles morphologically resembled those of ophioviruses, and like these, MiLV had a genome of three RNA segments approximately 8.5, 1.9 and 1.7 kb in size. MiLV preparations reacted strongly in Western blots and in ISEM with antiserum to Tulip mild mottle mosaic virus, an ophiovirus from Japan also apparently Olpidium-transmitted. They reacted weakly but clearly in Western blots with antiserum to Ranunculus white mottle virus, another ophiovirus. When lettuce seedlings were mechanically inoculated with crude or partially purified extracts from MiLV-infected test plants, many became systemically infected with MiLV and some developed big-vein symptoms. Such plants did not react in ELISA using an LBVV antiserum or an antiserum to tobacco stunt virus, and varicosavirus-like particles were never seen in them in the EM after negative staining. We conclude that MiLV is a hitherto undescribed virus assignable to the genus Ophiovirus. The cause or causes of lettuce big-vein disease and the properties of LBVV may need to be re-evaluated in light of our results.

Additional Ornamental Species as Hosts of Impatiens Necrotic Spot Tospovirus in Italy

Impatiens necrotic spot (INSV) and tomato spotted wilt (TSWV) tospoviruses are among the most important viral pathogens of glasshouse ornamental plants worldwide (1). Tospovirus infections drastically reduce the market value of plants and create certification problems for international traders. As with TSWV, the number of natural host species recorded for INSV is steadily increasing (2). In 1998, severe INSV infections were found on different ornamental plants in glasshouses in the Piedmont Region of northwestern Italy, together with heavy infestations of the thrips Frankliniella occidentalis. A high proportion of plants were infected with INSV, as shown by enzyme-linked immunosorbent assay (ELISA) with polyclonal antisera and monoclonal antibodies against its nucleocapsid protein. Results were confirmed by sap-inoculation to indicator hosts. Some species were already known to be susceptible to INSV, but others are apparently new hosts (2): Ageratum houstonianum (Asteraceae), showing small necrotic rings and leaf malformation; Cordyline terminalis (Agavaceae), showing chlorotic-necrotic ringspots and leaf malformation; Dianthus chinensis (Caryophyllaceae), showing stunting, mosaic, and leaf malformation (some plants had symptomless infections); Episcia capreata (Gesneriaceae), showing necrotic spots on stems and leaves; Godetia grandiflora (Onagraceae), showing necrotic rings; Maranta leuconeura (Marantaceae), showing chlorotic-necrotic spots and apical malformation; Peperomia obtusifolia (Piperaceae), showing necrotic ringspots and leaf malformations; Scindapsus aureus (Araceae), showing necrotic spots and rings; Torenia fournieri (Scrophulariaceae), showing necrosis on stems and apexes. Thrips feeding damage was high on some species, particularly those showing necrotic ringspot symptoms. It often was difficult to distinguish between true systemic symptoms and local INSV infection at thrips feeding sites. Capsicum sp., Coleus blumei, and Dahlia sp., which also were infected in our study, are species known to be infrequent hosts of INSV (2). References: (1) M. L. Daughtrey et al. Plant Dis. 81:1220, 1997. (2) D. Peters. 1998. Pages 107-110 in: Abstr. 4th Int. Symp. Tospovirus Thrips Floral Vegetable Crops. University of Wageningen, The Netherlands.

Two Field Isolates of Tomato Spotted Wilt Tospovirus Overcome the Hypersensitive Response of a Pepper (Capsicum annuum) Hybrid with Resistance Introgressed from C. chinense PI152225

The hypersensitive response to tomato spotted wilt tospovirus (TSWV) present in Capsicum chinense PI152225 (1) was introgressed into C. annuum cultivars. During the summer of 1998, a hybrid with good agronomic performance was grown in glasshouses in Albenga, Liguzia Region of northwestern Italy, an area where infection by TSWV in pepper has been severe since 1992. In August, observations of different susceptible cultivars revealed that >50% of plants had TSWV-like symptoms, whereas the resistant hybrid remained healthy, except for two plants that showed virus-like symptoms on apical leaves and fruits. From the infected plants, tospoviruses (coded P164/6 and P166) were transmitted by sap-inoculation to Nicotiana benthamiana. Triple-antibody sandwich enzyme-linked immunosorbent assay with a panel of monoclonal antibodies against the TSWV nucleocapsid, but with different reactivity to the related species groundnut ringspot (GRSV) and tomato chlorotic spot (TCSV) viruses, indicated the isolates were TSWV. The host ranges of the isolates were wide and typical of normal TSWV isolates. Thus, they incited typical symptoms in all 50 TSWV-susceptible C. annuum cv. Quadrato d'Asti plants. However, isolate P164/6 also systemically infected 12 of 27 C. chinense PI152225 and 14 of 19 C. chinense PI159236 plants. These accessions are normally resistant to TSWV (1). Isolate P166 systemically infected 7 of 17 C. chinense PI152225 and 6 of 11 C. chinense PI159236 plants. Systemically infected plants showed severe necrosis, and some plants died. Other plants showed only necrotic local lesions. The response by C. chinense differed from that caused by typical TSWV, which causes only local lesions, and from both GRSV and TCSV, which cause mosaic but no necrosis in 100% of plants. The two new TSWV isolates were tested for transmission using a local population of Frankliniella occidentalis in a leaf disk assay with susceptible C. annuum. Transmission rates were high: 93.7% (63 thrips) for isolate P164/6 and 89.9% (49 thrips) for P166. Thus, the fitness of the two TSWV resistance-breaking isolates (a wide experimental host range and high transmission rates by the natural vector) was as high as that of typical TSWV. The absence of systemic infection in some C. chinense PI152225 and PI159236 plants that are resistant to typical TSWV suggests the possibility of selecting plants resistant to these pathotypes. This is the first report of field tospovirus isolates typed as TSWV (according to the current taxonomy based on nucleocapsid serology) overcoming the hypersensitive response of C. chinense PI152225 and PI159236, an ability previously found only in closely related viruses: TCSV and GRSV (2). Other TSWV-like isolates systemic on C. chinense were not typed further (3,4). References: (1) L. L. Black et al. Plant Dis. 75:863, 1991. (2) L. S. Boiteux and A. C. DeAvila. Euphytica 75:139, 1994. (3) H. A. Hobbs et al. Plant Dis. 78:1220, 1994. (4) B. Moury et al. Euphytica 94:45, 1997.

Natural Infection of Muskmelon by Eggplant Mottled Dwarf Rhabdovirus in Italy

Eggplant mottled dwarf rhabdovirus (EMDV) is endemic in the Mediterranean area but within the family Cucurbitaceae has been reported only in cucumber (1). In the spring of 1998 unusual symptoms of stunting, short internodes, fruit deformation, and vein yellowing were observed in about 5% of muskmelon (Cucumis melo L. var. reticulatus Naudin) cv. Hombre F¹ grown under plastic in Tuscany (Central Italy). Electron microscopy of negatively stained preparations of crude sap from such melon plants revealed the presence of large numbers of particles resembling rhabdovirus. The virus, sap transmitted to several test plant species, had a host range identical to that of typical EMDV isolates, including the isolate from cucumber. Based on both electron microscopy and test plant reactions, the presence of other viruses was excluded. As with other known isolates, symptoms did not appear until about 30 days after inoculation, except for necrotic local lesions in Gomphrena globosa, which appeared in 10 days. Systemic leaf symptoms of field melon were reproduced by mechanically inoculating glasshouse melon seedlings with sap from infected White Burley tobacco. The virus was identified as EMDV by serology with an antiserum (As-0136) against the type isolate (EMDV-PV-0031), both obtained from the Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH (DSMZ), Germany. No differences in protein pattern in Western blots (immunoblots) were observed by coelectrophoresis of the type isolate and our melon isolate. The virus was easily detected in several experimental hosts by antigen-coated plate enzyme-linked immunosorbent assay (ELISA). The vector of EMDV is unknown, but the virus generally infects in low percentage a wide range of plant species belonging to different families. This suggests that a polyphagous insect with low vector efficiency may be involved in transmission. Reference: (1) P. Roggero et al. Plant Dis. 79:321, 1995.