ABSTRACT
During 2006-2007 growing seasons, survey were carried to identify a virus disease causing mosaic of soybean in the field in Southern region (Khozestan Province) of Iran. To detect the viral infection, diseased leaf samples showing mild mosaic and leaf malformation were collected from soybean fields in Dezful, located in Khozestan Province. Infected samples were carried to the lab in a proper condition on ice packages. TPIA and DAS-ELISA serological tests were applied to identify the viral agent. To investigate the host-range, several indicator plants were mechanically inoculated under green-house condition. Seed transmission of CPMMV was examined using the seeds obtained from infected plants. The virus isolate was not found to be seed-borne in Clark variety of soybean. Different steps of ultracentrifugation including sucrose density gradient (10-40%) were carried out in order to obtain partial purified virus. On the basis of biological, serological and EM results, CPMMV-Carla virus was identified in the infected soybean samples. This is the first report of CPMMV infection of soybean in Iran.
Subject(s)
Carlavirus/isolation & purification , Carlavirus/pathogenicity , Glycine max/virology , Plant Diseases/virology , Carlavirus/classification , Carlavirus/ultrastructure , Enzyme-Linked Immunosorbent Assay , Geography , Iran , Plant Leaves/virology , Seasons , Serotyping , Specimen HandlingABSTRACT
The complete genome sequence of the garlic latent virus (GLV) has been determined. The whole GLV genome consists of 8,353 nucleotides, excluding the 3'-end poly(A)+ tail, and contains six open-reading frames (ORFs). Putative proteins that were encoded by the reading frames contain the motifs that were conserved in carlavirus-specific RNA replicases, NTP-dependent DNA helicases, two viral membrane-bound proteins, a viral coat protein, and a zinc-finger. Overall, the GLV genome shows structural features that are common in carlaviruses. An in vitro translation analysis revealed that the zinc-finger protein is not produced as a transframe protein with the coat protein by ribosomal frameshifting. A Northern blot analysis showed that GLV-specific probes hybridized to garlic leaf RNA fragments of about 2.6 and 1.5 kb long, in addition to the 8.5 kb whole genome. The two subgenomic RNAs might be encapsidated into smaller viral particles. In garlic plants, 700 nm long flexuous rod-shaped virus particles were observed in the immunoelectron microscopy using polyclonal antibodies against the GLV coat proteins.
Subject(s)
Carlavirus/genetics , Garlic/virology , Genome, Viral , Amino Acid Sequence , Blotting, Northern , Capsid Proteins/biosynthesis , Capsid Proteins/genetics , Carlavirus/chemistry , Carlavirus/ultrastructure , Cloning, Molecular , Microscopy, Immunoelectron , Molecular Sequence Data , RNA/genetics , Sequence Alignment , Sequence Analysis, DNA , Viral Proteins/chemistry , Viral Proteins/geneticsABSTRACT
Electron microscopic studies on the stability of immunosorbed (trapped) virions of potato viruses X, S and Y0 (PVX, PVS and PVY0) revealed disintegration and dislodging of PVY0 virions upon incubation with (1) antisera to PVX, PVS, or both diluted in saline, (2) 0.86% NaCl (saline) or 0.1 mol/l CaCl2 but not with 0.1 mol/l CaSO4 or 0.1 mol/l MgSO4. PVX virions, on the other hand, showed partial dislodging upon incubation with an antiserum to PVS diluted in saline, but complete disintegration and dislodging with saline. 0.1 mol/l CaCl2 caused partial dislodging while MgCl2, CaSO4 or MgSO4 (all 0.1 mol/l) had no apparent adverse effect. PVS virions were not affected by saline, CaCl2, MgCl2, CaSO4 or MgSO4 (all 0.1 mol/l) and were only partially dislodged by antisera to PVX or PVY0. Disintegration and/or dislodging of the PVX and PVY0 virions was prevented when (1) they were fixed with glutaraldehyde prior to incubation or (2) the virus extract contained bovine serum albumin (BSA) or (3) heterologous antisera were diluted in 0.1 mol/l phosphate buffer (PB) before use except the PVS antiserum which still caused disintegration and dislodging of PVY0 virions. Prior fixation of virions prevented their disruption and dislodging by saline only in the case of PVY0 but not PVX. On the other hand, BSA reverted the adverse effect of saline but not that of the PVS antiserum on PVY0 virions. The results presented here suggest (1) a disruptive effect of Cl' on PVX and PVY0 virions particularly when it was associated with Na+ and (2) an interaction between the immunosorbed virions of PVX or PVY0 and the antiserum to PVS.