Clostero virus‐Like Particles of Two Types Associated with Diseased Grapevines

Abstract

Previous work led to the characterization of, and the production of an antiserum to a closterovirus referred to as grapevine stem pitting‐associated virus (GSP‐AV). Using this antiserum and immunoelectron microscopy, we now show that GSP‐AV is widespread in grapevines and that a second serologically distinct closterovirus‐like particle is also widely present. One or both of the closterovirus‐like particles were often but not always associated with leafroll symptoms. However, some plants indexed as suffering from stem pitting also contained one or both of the particles. As “grapevine stem pitting‐associated virus” no longer seems appropriate as a name, we suggest changing it to grapevine virus A (GVA). We provisionally refer to the second closterovirus‐like virus as grapevine virus B (GVB).

Properties of a filamentous virus isolated from grapevines affected by corky bark

“…[14-1, were dealing with fragmented particles rather than with a single specific entity, that could belong to any of the 6 or 7 non-GVA closteroviruses now known to occur in leafroll-and rugose wood-infected grapevine [7,11]. This likelihood, and the fact that Milne et al [14-1 did not detect their virus in a grapevine accession indexing positive for CB, strengthen the notion that: (a) the name GVB sensu Milne et al [14] cannot be attached to a recognized virus species; (b) the fragmented particles seen by those authors were unlikely to belong to the same virus described in the present paper.…”

“…The authors were unable to determine the modal length of this virus because a "poorly defined spread of values was obtained, the majority being around 250-400nm" [14]. It seems likely, then, that Milne etal.…”

“…The name GVB was used in the past to designate a possible closterovirus serologically unrelated to GVA, found in vines affected primarily by leafroll disease [14]. The authors were unable to determine the modal length of this virus because a "poorly defined spread of values was obtained, the majority being around 250-400nm" [14].…”

“…The gels were stained with Coomassie brilliant blue after application of 120V (constant voltage) for 2 h. The molecular weight of protein subunits was determined by comparison with the following reference markers (tool. wt in parenthesis): a-lactoalbumin (14,200), soybean trypsin inhibitor (20,100), trypsinogen (24,000), carbonic anhydrase (29,000), glyceraldehyde 3-phosphate d.h. (36,000), ovalbmTfin (45,000), bovine serum albumin (66,000), GVA coat protein (22,500).…”

The Effectiveness of in vitro Somatic Embryogenesis in Eliminating Fanleaf Virus and Leafroll Associated Viruses from Grapevines

“…The virus status of source material and of mature somatic embryos and plantlets was established by subjecting samples to both immunosorbent electron microscopy (ISEM) with decoration (Milne et al, 1984) and enzyme-linked immunosorbent assay (ELISA) with available kits (Clark & Adams, 1977).…”