Coupling Genetics and Proteomics To Identify Aphid Proteins Associated with Vector-Specific Transmission of Polerovirus ( Luteoviridae )

Abstract

Cereal yellow dwarf virus-RPV (CYDV-RPV) is transmitted specifically by the aphids Rhopalosiphum padi andSchizaphis 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. graminum showed that virus transmission efficiency is a heritable trait regulated by multiple genes acting in an additive fashion and that gut-and salivary gland-associated factors are not genetically linked. Utilizing two-dimensional difference gel electrophoresis to compare the proteomes of vector and nonvector parental and F 2 genotypes, four aphid proteins (S4, S8, S29, and S405) were specifically associated with the ability of S. graminum to transmit CYDV-RPV. The four proteins were coimmunoprecipitated with purified RPV, indicating that the aphid proteins are capable of binding to virus. Analysis by mass spectrometry identified S4 as a luciferase and S29 as a cyclophilin, both of which have been implicated in macromolecular transport. Proteins S8 and S405 were not identified from available databases. Study of this unique genetic system coupled with proteomic analysis indicated that these four virus-binding aphid proteins were specifically inherited and conserved in different generations of vector genotypes and suggests that they play a major role in regulating polerovirus transmission.Viruses in the family Luteoviridae, including Barley yellow dwarf virus (BYDV), Cereal yellow dwarf virus (CYDV), Potato leafroll virus, and Beet western yellows virus, are collectively referred to in this paper as luteovirids. They are transmitted in a circulative persistent nonpropagative manner only by aphids (Aphididae: Hemiptera) (20). Ultrastructural studies indicate that all luteovirids follow a similar pathway through their aphid vectors (12). Aphids acquire the viruses from infected phloem cells while feeding with their piercing-sucking stylets. Virions are drawn up the food canal of the stylets and into the gut lumen within the aphid. Subsequently, virions traverse the lining of the midgut, hindgut, or both (7,8,25) and are released into the body cavity (hemocoel) to circulate in the hemolymph. Virions suspended in hemolymph that contact the paired accessory salivary glands (ASG) are actively transported by endocytosis into the ASG cells and then transported into the salivary duct to be transmitted into potential host plants. Interestingly, each luteovirid species is transmitted most efficiently only by a specific set of aphid species or populations within an aphid species, thus demonstrating a high level of vector specificity. The cellular mechanisms responsible for vector specificity are regulated by distinct interactions between the two virus structural proteins and unknown proteins in the aphid (12).The discovery of Gildow and Rochow (9) that competition occurred between se...

Proteomic Analysis of Frankliniella occidentalis and Differentially Expressed Proteins in Response toTomato Spotted Wilt VirusInfection

“…For example, incorporation of cyclophilin A into the newly synthesized human immunodeficiency virus 1 (HIV-1) particles is required for virion attachment to host cells (64), while its recruitment by the GAG polyprotein during HIV-1 infection (11) promotes HIV-1 replication (12). Cyclophilins were identified in greenbugs (Schizaphis graminum) that are vectors of Cereal yellow dwarf virus (family Luteoviridae) but not in nonvectors of the same aphid species (85). Two different proteins coresolved within spot 283, the protein yellow-like and 26S protease regulatory subunit 7, which have been associated with melanization and behavior of D. melanogaster (22,83) and the ATP-dependent degradation of ubiquitinated proteins (14), respectively.…”

Genetics Coupled to Quantitative Intact Proteomics Links Heritable Aphid and Endosymbiont Protein Expression to Circulative Polerovirus Transmission

“…We combined genetics and proteomics to identify several proteins in S. graminum that interact with and/or direct the movement of Cereal yellow dwarf virus-RPV (CYDV-RPV) along the circulative transmission pathway (77). That study demonstrated the discovery potential of the F2 population for revealing proteins involved in virus circulative transmission.…”

The Conformation of a Plasma Membrane-Localized Somatic Embryogenesis Receptor Kinase Complex Is Altered by a Potato Aphid-Derived Effector

“…Aphid soluble proteins were extracted from mixed developmental stages by homogenizing the tissues in liquid N 2 using a mortar and pestle. An extraction buffer (50 mM Tris-HCl, pH 7.5, and 150 mM NaCl) was added to the aphid powder at a ratio of 1 mL of buffer to 1 g of aphids and frozen overnight (Yang et al, 2008). After centrifugation at 13,000g for 30 min, at 4°C, the supernatant was used for assays after adjusting the protein concentration to 1 mg/mL as determined with a Bradford assay using bovine serum albumin as a standard.…”