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A new icosahedral DNA virus was isolated from aphids (Myzus persicae) that showed abnormal growth and development. The purified virus particles have a diameter of 20 nm and contain a single-stranded DNA molecule of approximately 5.7 kb. The viral particles are composed of five structural proteins (92, 85, 68, 64, and 57 kDa). As the main biophysical properties of this virus are similar to those of the members of the genus Densovirus it was tentatively named Myzus persicae densovirus (MpDNV). A PCR-based detection method and a polyclonal antiserum raised against MpDNV allowed the detection of the virus in a single-infected aphid. MpDNV is immunologically related to Junonia coenia densovirus, but not to other members of the subfamily Densovirinae. Biological assays showed that MpDNV could be both transmitted transovarially and horizontally via honeydew and saliva. MpDNV was able to infect whiteflies but not other aphid species tested.

A new virus was isolated from the pea aphid, Acyrthosiphon pisum, and tentatively named Acyrthosiphon pisum virus (APV). The isometric virus particles were approximately 31 nm in diameter and contained a single-stranded RNA molecule of approximately 10 kb. Four structural proteins were observed with molecular masses of approximately 23.3, 24.2, 34.5, and 66.2 kDa. The 34.5-kDa capsid protein was the most abundant product in purified virions. Computer-assisted analysis revealed no significant homology between an internal sequence of 37 amino acids of the 34.5-kDa protein of APV and other polypeptides of viral origin. APV was not immunologically related to other ssRNA viruses from hemipteroid insects, such as aphid lethal paralysis virus, Rhopalosiphum padi virus, and Nezara viridula virus type 1. Immunolocalization on ultrathin sections of 3-day-old nymphs of A. pisum showed that APV antigen was predominantly present in the epithelial cells of the digestive tract. Virus particles were also observed associated with the microvilli of the intestine. Occasionally, muscle cells and mycetocyte cells were found infected. Purified APV, fed to 1-day-old A. pisum nymphs, significantly reduced the growth of the aphid and increased the time needed to reach maturity.