February 2, 2005
Source: British Society for Plant Pathology, New Disease Reports, Vol. 10 [edited] <http://www.bspp.org.uk/ndr/jan2005/2005-03.asp>

First report of Bean common mosaic potyvirus in Western Australia
M. Saqib,WA State Agricultural Biotechnology Centre, School of Biological Sciences and Biotechnology, Murdoch University, Perth, WA 6150, Australia; R. A. C. Jones, Crop Improvement Institute, Department of Agriculture of Western Australia, Locked Bag No. 4, Bentley Delivery Centre, Perth, WA 6983, Australia; B. Cayford (as for Saqib); and M. G. K Jones, <m.jones@murdoch.edu.au> (as for Saqib). Accepted for publication 1 Jun 2005.

Bean common mosaic virus (BCMV; Family _Potyviridae_, genus _Potyvirus_) infects _Phaseolus vulgaris_ crops in many regions of the world. It is transmitted in a non-persistent manner by aphids and is also readily seed-transmitted (Hongying et al., 2002).

The disease it causes decreases crop production. In Australia, BCMV has been reported in New South Wales, Queensland, Tasmania and Victoria, based on serology and amino acid composition (Moghal & Francki, 1976; 1981). However, there is no information about isolates or its origin, and no further confirmation or any sequence data for BCMV from Australia. It has not been reported in the Northern Territory, South Australia or Western Australia.

In July 2004, at Kununurra in the east Kimberly region of Western Australia, _P. vulgaris_ plants with mottle and leaf deformation, severe mosaic, malformation of leaves and pods, downward curling of leaves and reduction in leaf size were observed in the field. Extracts of symptomatic leaf samples tested positive with generic potyvirus monoclonal antibody in ELISA and infected _Chenopodium quinoa_, _C. amaranticolor_ and _Nicotiana benthamiana_ when manually inoculated.

For molecular identification, total RNA was isolated from symptomatic leaf tissues using an RNeasy Plant Mini Kit (Qiagen). The RNA samples were tested using RT-PCR and generic potyvirus specific primers that amplify a 1700 bp fragment from the 3' end of the genome [5'GTTTTCCCAGTCACGA C(T)15; 5' GGNAAYAAYAGYGGNCARCC] (Chen et al., 2001). A portion of the PCR product (482 bp) was sequenced at the 3' end (Acc. No. AY850005) and the data compared against other BCMV sequences in GenBank. The isolate shared 97 percent nucleotide identity with the 'NL1' and 'Type' strains of BCMV (Acc. Nos AY112735 and U55319).

This sequence result provides the 1st reliable confirmation of BCMV in Australia and is the 1st report of its occurrence in Western Australia.

References

Chen J, Chen J, Adams MJ, 2001. A universal PCR primer to detect members of the Potyviridae and its use to examine the taxonomic status of several members of the family. Archives of Virology 146, 757-766.

Hongying Z, Jiong C, Jianping C, Michael JA, Mingsheng H, 2002. Bean common mosaic virus isolates causing different symptoms in asparagus bean in China differ greatly in the 5 parts of their genomes. Archives of Virology 147, 1257-1262.

Moghal SM, Francki RIB, 1976. Towards a system for the identification and classification of potyviruses, I. Serology and amino acid composition of six distinct viruses. Virology 73, 350-362.

Moghal SM, Francki RIB, 1981. Towards a system for the identification and classification of potyviruses, II. Virus particle length, symptomatology, and cytopathology of six distinct viruses. Virology 112, 210-216.

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[BCMV almost certainly entered Western Australia via infected seed. Its seedborne nature guarantees its spread, and infected seedlings are sources of virus inoculum. Many BCMV strains have been distinguished (Drijfhout et
al., 1978). Those once grouped as serotype A are now considered isolates of a separate potyvirus species -- Bean common necrosis virus -- and several viruses, once considered to be distinct, have now been shown to be strains of this virus (McKern et al., 1992). The latter include: azuki bean mosaic virus, blackeye cowpea mosaic virus, cowpea (aphid-borne) mosaic virus, cowpea (blackeye) mosaic virus, cowpea vein-banding mosaic virus, peanut blotch virus, peanut stripe virus and some isolates from soybean. Genetic studies using F2 populations of _P. vulgaris_ from crosses between differential cultivars of _P. vulgaris_ and novel isolates of BCMV and Bean
common mosaic necrosis virus (BCMNV) from Africa have revealed that there are previously undescribed resistance genes in _P. vulgaris_. These genes are currently under investigation using other novel isolates of BCMV and BCMNV. The primary aim of research on the molecular genetics of legume viruses is for the genetic improvement of _Phaseolus vulgaris_ in Africa for resistance to viruses. Disease management is basically planting of virus-free seed.

The link to the original piece contains all of the text and graphics and is located under the list of authors.

Links:
<http://axp.ipm.ucdavis.edu/PMG/r52101611.html>
<http://www.gov.on.ca/OMAFRA/english/crops/pub811/7mosc.htm>

Additional reference:

Brunt, A.A., Crabtree, K., Dallwitz, M.J., Gibbs, A.J., Watson, L. and Zurcher, E.J. (eds.) (1996 onwards). Plant Viruses Online: Descriptions and Lists from the VIDE Database. Version: 20th August 1996. URL:
<http://biology.anu.edu.au/Groups/MES/vide/> - Mod.DH]