First Report of Onion yellow dwarf virus in Allium chinense in China

Allium chinense (G. Don) is an economically important vegetable that has been considered to be of Asian origin (2). In April of 2007, plants of cultivated A. chinense showing mosaic, chlorotic streak, twist, and crinkle on leaves were collected from fields at Jiangxia, a suburban district of Wuhan, Hubei Province, China, and transplanted into pots in a greenhouse. Ultrathin sections of diseased leaves were observed under an electron microscope. Pinwheel or cylindrical inclusions, typical of a potyvirus infection, were observed. Filamentous virus particles (820 nm long) were also observed in the crude extract from the same plant. To identify the virus species, viral RNAs were extracted from partially purified virion preparation (3) and used as a template. First-strand cDNA was synthesized with M4-T (5′-GTT TTC CCA GTC ACG AC (T)15-3′) as a complementary primer. The 3′-terminus of viral RNA was amplified using primer M4 (5′-GTT TTC CCA GTC ACG AC-3′) in combination with a degenerate primer (5′-GGXAAYAAYAGY GGX CARCC-3′) that was specific for potyviruses (1). Amplified products were cloned and nine clones were sequenced. Sequence analysis showed that the size of the amplified fragment, excluding the poly A tail, was 1,625 bp, which had the typical characteristics of the 3′-terminus of the potyvirus genome, including the partial NIb gene (636 bp) and the complete coat protein (CP gene; 771 bp). The 1,625-bp sequence from A. chinense (Genbank Accession No. FJ765739) had the highest identity at the nucleotide level with sequences of Onion yellow dwarf virus (OYDV), ranging from 76% (Genbank Accession Nos. AB219833 and AB219834) to 99% (Genbank Accession No. AJ409313). The CP gene had 88% (Genbank Accession Nos. AB219833 and AB219834) to 99% (Genbank Accession Nos. AJ409313 and AJ409310) identity at the amino acid level with corresponding regions of known OYDV isolates from other hosts. Until now, only Scallion mosaic virus (ScaMV), in the genus Potyvirus, had been detected from A. chinense (1); however, OYDV was reported in rakkyo, the same species as Chinese scallion, in Japan (4). To our knowledge, this is the first report of OYDV infecting A. chinense in China. References: (1) J. Chen et al. Arch. Virol. 147:683, 2002. (2) L. K. Mann and W. T. Stearn. Econ. Bot. 14:69, 1960. (3) T. Nagakubo et al. Phytopathology 84:640,1994. (4) I. Sako et al. Ann. Phytopathol. Soc. Jpn. 57:65, 1991.

Isolation and Preliminary Characterization of Herpes Simplex Virus 1 Primary Enveloped Virions from the Perinuclear Space

ABSTRACT Herpes simplex virus 1 (HSV-1) nucleocapsids exit the nucleus by budding into the inner nuclear membrane, where they exist briefly as primary enveloped virions. These virus particles subsequently fuse their envelopes with the outer nuclear membrane, permitting nucleocapsids to then enter the cytoplasm and complete assembly. We have developed a method to isolate primary enveloped virions from HSV-1-infected cells and subjected the primary enveloped virion preparation to MALDI-MS/MS (matrix-assisted laser desorption ionization-tandem mass spectrometry) analyses. We identified most capsid proteins, a tegument protein (VP22), a glycoprotein (gD), and a cellular protein (annexin A2) in the primary enveloped virion preparation. We determined that annexin A2 does not play an essential role in infection under our experimental conditions. Elucidating the structure and biochemical properties of this unique virus assembly intermediate will provide new insights into HSV-1 biology.