Serological and biological variation between and within subgroup I and II strains of cucumber mosaic virus

Abstract

Fourteen strains of cucumber mosaic virus (CMV) from Australia have been characterized by their host range and symptomatology. They were classified as subgroup I or II strains by a dot‐blot molecular hybridization assay between their total viral RNAs and selected cDNAs. The strains FNY and LNy, both from the USA, were used as the subgroup I‐ and subgroup II‐type strains, respectively. A range of serological tests was used to compare these isolates. Gel immunodiffusion tests, with standard antigens homologous to the antisera prepared against glutaraldehyde‐fixed virus of 11 strains, showed that they could be divided into three serogroups on the basis of spur formation in heterologous reactions. Two of the serogroups included either subgroup I or subgroup II isolates, whereas the third serogroup consisted of only one strain (YWA) which was homologous to all the strains tested. Use of heterologous standard antigens in this test failed to show further subgrouping of the antigens. Double‐antibody sandwich (DAS) ELISA using polyclonal antibodies to distinct virus strains also placed the 14 strains in the same three serogroups. When eight different monoclonal antibodies (MAbs) were used in indirect ELISA, one of them distinguished subgroup‐I strains and another distinguished subgroup‐II strains; the YWA strain fell into subgroup II. Other MAbs showed narrower or broader specificity. Thus both molecular hybridization with total RNA and specific MAbs may be useful for separating isolates of CMV into subgroups I and II. Spur formation using heterologous standard antigens to the antisera, as well as being more difficult to interpret, was not a reliable criterion for classification.

Host range, symptom expression and RNA 3 sequence analyses of six Australian strains ofCucumber mosaic virus

“…CMV infection causes a broad spectrum of symptoms from mild to severe mosaic, stunting, filiformism, chlorosis and necrosis, depending on virus strain and host (Carrère et al 1999). In tobacco, CMV strains belonging to subgroup I tend to cause severe mosaic whereas subgroup II strains lead to mild mosaic (Wahyuni et al 1992;Zhang et al 1994). Some subgroup I strains cause fern-shaped or filiform leaves in tomato (Hellwald et al 2000b;Stamova and Chetelat 2000).…”

“…Some subgroup I strains cause fern-shaped or filiform leaves in tomato (Hellwald et al 2000b;Stamova and Chetelat 2000). Maize appears to be resistant to systemic infection by most subgroup II strains (Wahyuni et al 1992;Carrère et al 1999;Ryu et al 1998). CMV sequences that control symptom type and virulence have been mapped to the 3a and CP genes on RNA 3 (Carrère et al 1999;Suzuki et al 1995;Sugiyama et al 2000;Szilassy et al 1999), but RNAs 1 and 2 have also been implicated (Roossinck and Palukaitis 1990;Zhang et al 1994;Hellwald et al 2000b;Soards et al 2002).…”

“…Host range and symptomatology were used to characterise 14 Australian CMV strains and classify them into subgroups I or II by dot blot hybridisation of their RNAs (Wahyuni et al 1992). A range of serological tests using poly-and monoclonal antibodies divided these strains (except Ly-CMV) into two serogroups that mirrored the RNA hybridisation-based subgroups.…”

Mapping Local and Systemic Symptom Determinants of Cucumber Mosaic Cucumovirus in Tobacco

“…subgroup II strain of CMV and causes milder, systemic symptoms on tobacco (Wahyuni et al, 1992) as well as symptoms on the inoculated leaves consisting of numerous necrotic rings, or ' etching' (Fig. 1 a).…”

Identification of epitopes in cucumber mosaic virus using a phage-displayed random peptide library.

“…Serologically, the two subgroups are closely related, as shown by the cross reactions of polyclonal antibodies (Devergne & Cardin, 1973 ;Wahyuni et al, 1991). Some monoclonal antibodies produced against the CPs of subgroups I and II can differentiate the two, indicating the presence of unique epitopes for each (Porta et al, 1989 ;Wahyuni et al, 1991). Recently, the molecular structure of CMV has been determined at 23 A H resolution by cryoelectron microscopy and image reconstruction (Wikoff et al, 1997).…”