Host Adaptation of Soybean Dwarf Virus Following Serial Passages on Pea (Pisum sativum) and Soybean (Glycine max).

Soybean Dwarf Virus (SbDV) is an important plant pathogen, causing economic losses in soybean. In North America, indigenous strains of SbDV mainly infect clover, with occasional outbreaks in soybean. To evaluate the risk of a US clover strain of SbDV adapting to other plant hosts, the clover isolate SbDV-MD6 was serially transmitted to pea and soybean by aphid vectors.

Discovery and targeted LC-MS/MS of purified polerovirus reveals differences in the virus-host interactome associated with altered aphid transmission.

Circulative transmission of viruses in the Luteoviridae, such as cereal yellow dwarf virus (CYDV), requires a series of precisely orchestrated interactions between virus, plant, and aphid proteins. Natural selection has favored these viruses to be retained in the phloem to facilitate acquisition and transmission by aphids. We show that treatment of infected oat tissue homogenate with sodium sulfite reduces transmission of the purified virus by aphids.

Acquisition and Transmissibility of U.S. Soybean dwarf virus Isolates by the Soybean Aphid, Aphis glycines.

Soybean dwarf virus (SbDV) exists as several distinct strains based on symptomatology, vector specificity, and host range. Originally characterized Japanese isolates of SbDV were specifically transmitted by Aulacorthum solani. More recently, additional Japanese isolates and endemic U.

Experimental Verification of Seed Transmission of Zucchini yellow mosaic virus.

Within two decades of its discovery, Zucchini yellow mosaic virus (ZYMV) achieved a global distribution. However, whether or not seed transmission occurs in this economically significant crop pathogen is controversial, and the relative impact of seed transmission on the epidemiology of ZYMV remains unclear. Using reverse transcription-polymerase chain reaction, we observed a seed transmission rate of 1.

Molecular, ultrastructural, and biological characterization of Pennsylvania isolates of Plum pox virus.

Plum pox virus (PPV) was identified in Pennsylvania in 1999. The outbreak was limited to a four-county region in southern Pennsylvania. Initial serological and molecular characterization indicated that the isolates in Pennsylvania belong to the D strain of PPV.

Modeling temporal trends in aphid vector dispersal and cucumber mosaic virus epidemics in snap bean.

Cucumber mosaic virus (CMV) has become a major limiting factor in snap bean production in the Great Lakes region of North America, and epidemics have occurred more frequently since the soybean aphid, Aphis glycines Matsumura, was introduced. Major aphid vectors of CMV epidemics were identified by statistically relating their temporal dispersal trends to the incidence of CMV. Alates were monitored weekly using water pan traps in 74 snap bean fields in New York and Pennsylvania from 2002 to 2006.

The C terminus of the polerovirus p5 readthrough domain limits virus infection to the phloem.

Poleroviruses are restricted to vascular phloem tissues from which they are transmitted by their aphid vectors and are not transmissible mechanically. Phloem limitation has been attributed to the absence of virus proteins either facilitating movement or counteracting plant defense. The polerovirus capsid is composed of two forms of coat protein, the major P3 protein and the minor P3/P5 protein, a translational readthrough of P3.

Identification, characterization, and relatedness of luteovirus isolates from forage legumes.

ABSTRACT Virus isolates from forage legumes collected from eight different states were identified as luteoviruses closely related to soybean dwarf luteovirus dwarfing (SbDV-D) and yellowing (SbDV-Y) described in Japan. All isolates produced reddened leaf margins in subterranean clover and were transmitted in a persistent manner by Acrythosiphon pisum, but not by Aulacorthum solani. Specific monoclonal antibodies raised against SbDV-Y were differentially reactive with endemic isolates.

Aphid Acquisition and Cellular Transport of Potato leafroll virus-like Particles Lacking P5 Readthrough Protein.

ABSTRACT Lepidopteran cells (Spodoptera frugiperda) produced isometric virus-like particles (VLP) when infected with a recombinant baculovirus Ac61 that contained the Potato leafroll virus (PLRV) coat protein gene modified with an N-terminal histidine tag (P3-6H). Cells infected with AcFL, a recombinant baculovirus that expressed cDNA copies of the PLRV genome RNA, did not produce virus-like particles (VLP). In cell lines doubly infected with Ac61 and AcFL, VLP were formed that contained PLRV-RNA packaged in P3-6H coat protein (FL).

Genetic Regulation of Polerovirus and Luteovirus Transmission in the Aphid Schizaphis graminum.

ABSTRACT Sexual forms of two genotypes of the aphid Schizaphis graminum, one a vector, the other a nonvector of two viruses that cause barley yellow dwarf disease (Barley yellow dwarf virus [BYDV]-SGV, luteovirus and Cereal yellow dwarf virus-RPV, polerovirus), were mated to generate F1 and F2 populations. Segregation of the transmission phenotype for both viruses in the F1 and F2 populations indicated that the transmission phenotype is under genetic control and that the parents are heterozygous for genes involved in transmission. The ability to transmit both viruses was correlated within the F1 and F2 populations, suggesting that a major gene or linked genes regulate the transmission.

Transmission efficiency of Cucumber mosaic virus by aphids associated with virus epidemics in snap bean.

Cucumber mosaic virus (CMV) is a major component of the virus complex that has become more pronounced in snap bean in the midwestern and northeastern United States since 2001. Multiple-vector-transfer tests were done to estimate the CMV transmission efficiencies (p) of the main aphid species identified in commercial snap bean fields in New York and Pennsylvania. The four most efficient vectors (p > 0.

Plum pox in north america: identification of aphid vectors and a potential role for fruit in virus spread.

ABSTRACT Thirteen aphid species were tested for their ability to transmit Pennsylvania isolates of Plum pox virus (PPV) collected in Columbia (PENN-3), Franklin (PENN-4), and York (PENN-7) Counties, PA. Four species, Aphis fabae, A. spiraecola, Brachycaudus persicae, and Myzus persicae, consistently transmitted PPV in preliminary transmission tests.

Coupling genetics and proteomics to identify aphid proteins associated with vector-specific transmission of polerovirus (luteoviridae).

Cereal yellow dwarf virus-RPV (CYDV-RPV) is transmitted specifically by the aphids Rhopalosiphum padi and Schizaphis graminum in a circulative nonpropagative manner. The high level of vector specificity results from the vector aphids having the functional components of the receptor-mediated endocytotic pathways to allow virus to transverse the gut and salivary tissues. Studies of F(2) progeny from crosses of vector and nonvector genotypes of S.

Adaptation of plum pox virus to a herbaceous host (Pisum sativum) following serial passages.

Plum pox virus (PPV) populations from peaches are able to adapt consistently to herbaceous hosts, characterized by a reduction in time to symptom development, increases in inoculation efficiency and increased titres. PPV adaptation was studied by using pea (Pisum sativum) as an alternative host. Two isolates of PPV from peaches were inoculated and passaged in peas ten times using either aphid or mechanical inoculation, generating four independent passage lines.

Development of a Real-Time RT-PCR SYBR Green Assay for Tomato ring spot virus in Grape.

Grapevines infected with Tomato ring spot virus (ToRSV) pose an economic risk for growers in the northeastern United States. This study describes a one-step real-time reverse-transcription polymerase chain reaction (RT-PCR) SYBR Green assay for detecting ToRSV in grapevines. Two newly designed primer pairs based on the ToRSV coat protein gene sequence were evaluated for specificity and optimized for a SYBR Green assay.

Point mutations in the potato leafroll virus major capsid protein alter virion stability and aphid transmission.

The coat protein (CP) of potato leafroll virus (PLRV) is the primary component of the capsid, and is a multifunctional protein known to be involved in vector transmission and virus movement within plant hosts, in addition to particle assembly. Thirteen mutations were generated in various regions of the CP and tested for their ability to affect virus-host and virus-vector interactions. Nine of the mutations prevented the assembly of stable virions.

Prunus Host Range of Plum pox virus (PPV) in the United States by Aphid and Graft Inoculation.

Plum pox (Sharka) is a serious virus disease of stone fruits caused by the Plum pox virus (PPV). To determine which species could function as potential hosts and virus reservoirs, we used aphid transmission and bud or chip grafting to evaluate the susceptibility of commercial, ornamental, and wild Prunus species to isolates of PPV found in Pennsylvania, USA. Following inoculation, test trees were observed for symptoms, analyzed by enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR), back-assayed to healthy peach, and followed through at least four cold-induced dormancy (CID) cycles over 4 years.

Aphid (Hemiptera: Aphididae) species composition and potential aphid vectors of plum pox virus in Pennsylvania peach orchards.

Plum pox, an invasive disease recently identified in Pennsylvania stone fruit orchards, is caused by the aphid-transmitted Plum pox virus (genus Potyvirus, family Potyviridae, PPV). To identify potential vectors, we described the aphid species communities and the seasonal dynamics of the dominant aphid species within Pennsylvania peach orchards. Aphids were trapped weekly in 2002 and 2003 from mid-April through mid-November within two central Pennsylvania orchards by using yellow and green water pan traps.

Complete deletion of Wheat streak mosaic virus HC-Pro: a null mutant is viable for systemic infection.

A Wheat streak mosaic virus (WSMV) genome lacking HC-Pro was constructed and confirmed by reverse transcription-PCR to systemically infect wheat, oat, and corn. Coupled in vitro transcription/translation reactions indicated that WSMV P1 proteinase cleaved the polyprotein at the P1/P3 junction of the HC-Pro null mutant. The WSMV HC-Pro null mutant was competent for virion formation, but the virus titer was reduced 4.

Plant virus HC-Pro is a determinant of eriophyid mite transmission.

The eriophyid mite transmitted Wheat streak mosaic virus (WSMV; genus Tritimovirus, family Potyviridae) shares a common genome organization with aphid transmitted species of the genus Potyvirus. Although both tritimoviruses and potyviruses encode helper component-proteinase (HC-Pro) homologues (required for nonpersistent aphid transmission of potyviruses), sequence conservation is low (amino acid identity, approximately 16%), and a role for HC-Pro in semipersistent transmission of WSMV by the wheat curl mite (Aceria tosichella [Keifer]) has not been investigated. Wheat curl mite transmissibility was abolished by replacement of WSMV HC-Pro with homologues of an aphid transmitted potyvirus (Turnip mosaic virus), a rymovirus (Agropyron mosaic virus) vectored by a different eriophyid mite, or a closely related tritimovirus (Oat necrotic mottle virus; ONMV) with no known vector.

Luteovirus-aphid interactions.

Members of the Luteoviridae are transmitted by aphids in a circulative, nonpropagative manner that requires the virus to be acquired through gut tissue into the aphid hemocoel and then exit through salivary tissues. This process is aphid species-specific and involves specific recognition of the virus by unidentified components on the membranes of gut and salivary tissues. Transport through the tissues is an endocytosis/exocytosis process.

Studies on the role of the minor capsid protein in transport of Beet western yellows virus through Myzus persicae.

Beet western yellows virus (BWYV), family Luteoviridae, is an icosahedral plant virus which is strictly transmitted by aphids in a persistent and circulative manner. Virions cross two cellular barriers in the aphid by receptor-based mechanisms involving endocytosis and exocytosis. Particles are first transported across intestinal cells into the haemolymph and then across accessory salivary gland cells for delivery to the plant via saliva.

Vector specificity of barley yellow dwarf virus (BYDV) transmission: identification of potential cellular receptors binding BYDV-MAV in the aphid, Sitobion avenae.

Two proteins (SaM35 and SaM50) isolated from head tissues of the aphid vector, Sitobion avenae, were identified as potential receptors for barley yellow dwarf virus MAV isolate (Luteoviridae) based on MAV virus overlay assays and immunoblots of urea SDS 2-D gels. An anti-idiotypic antibody (MAV4 anti-ID) that mimics an epitope on MAV virions and competes with MAV in antibody binding assays also bound to SaM50 and SaM35 and to six additional proteins including a GroEL homolog. No MAV-binding proteins were detected from the nonvector aphid, Rhopalosiphum maidis, although MAV4 anti-ID did react with four proteins from R.

Barley yellow dwarf virus: effects on carbohydrate metabolism in oat (Avena sativa) during cold hardening.

Barley yellow dwarf virus (BYDV) causes significant losses in yield and in overwintering ability of winter cereals. Mechanisms by which the physiology of plants is affected by the virus are not clear. To see how carbohydrates in the crown of winter cereals were affected by BYDV, fructan isomers of degree of polymerization (DP) 3-5, fructan DP>6 and the simple sugars, glucose, fructose and sucrose, were measured before and during cold hardening in three oat (Avena sativa L.

Herbaceous Weeds Are Not Ecologically Important Reservoirs of Erwinia tracheiphila.

The potential of herbaceous weeds commonly growing in or adjacent to cucurbit crops to serve as alternate hosts and overwintering reservoirs of Erwinia tracheiphila, a causal agent of cucurbit wilt, was investigated. Methods for isolation, maintenance, long-term storage, and detection of E. tracheiphila from infected plants were developed.