January 1, 2005
Source: British Soc. Plant Pathol., New Disease Reports, Vol. 10 [edited] <http://www.bspp.org.uk/ndr/jan2005/2004-84.asp>

First report of Papaya ringspot virus-W in bottlegourd (Lagenaria siceraria) from India
N.L. Mantri, Division of Molecular Virology, Mahyco Research Center, Dawalwadi, Jalna - 431203. Maharashtra State, India; A.S. Kitkatu (as for Mantri); M.B. Misal, Deparment of Genetics and Plant Breeding, Marathwada Agricultural University, Parbhani - 431401, India; and K.S. Ravi. Accepted for publication 22 Dec 2004.

Bottlegourd (_Lagenaria siceraria_) is an important vegetable crop of the _Cucurbitaceae_. In recent years, mosaic disease has been one of the major constraints to the cultivation of this crop in Maharashtra State. Surveys indicate that bottlegourd mosaic disease is endemic in the Nasik, Ahmednagar and Pune regions of the state, where the incidence varies from 10 to 100 percent.

A representative bottlegourd mosaic isolate -- (BgM-NW-3) collected from Wadner, Nasik -- was studied. It produced characteristic symptoms of mosaic: mottling, interveinal chlorotic bands, leaf distortion, fruit malformation and reduction in fruit size. In severe infections, surface blisters on fruit are a common occurrence.

The virus was transmitted by mechanical inoculation and also by the aphid vector _Aphis gossypii_. It produced systemic mosaic mottling symptoms in 11 cucurbitaceous and 3 solanaceous hosts but failed to infect leguminous ones.

ELISA testing using 16 antisera from 5 distinct virus groups (poty-, cucumo-, tobomo-, tospo- and ilarviruses) revealed that the virus isolate reacted strongly to Papaya ringspot virus (P and W strains) in addition to weaker reactions with 3 other potyvirus antisera: Tobacco etch virus, Chilli veinal mottle virus and Potato virus Y. It failed to react to Zucchini yellow mosaic virus (ZYMV) antiserum.

Electron microscopy of purified preparations of BgM-NW-3 revealed typical potyvirus-like flexuous particles of 750-780 nm long and 11-13 nm wide. The same preparations were decorated with PRSV-W antiserum after immunosorbent electron microscopy. Representative field isolates collected from Maharashtra, Andhra Pradesh, Karnataka and Chattisgarh tested positive for PRSV but negative for ZYMV by DAS-ELISA.

Cross-inoculation studies showed that a PRSV-P isolate from papaya infected bottlegourd but failed to infect Papaya, indicating that the virus isolate is a cucurbit isolate (W) and not a papaya isolate (P). In addition, _Beta vulgaris_, a non-host for PRSV-W, failed to infect that plant species.

These results indicate that the bottlegourd mosaic virus isolated from Nasik and other regions is a potyvirus closely related to PRSV-W and distinct from the virus previously reported by Verma et al. (2004).

Reference:

Verma R, Ahlawat YS, Tomer SPS, Prakash S, Pant RP, 2004. First Report of Zucchini yellow mosaic virus in bottlegourd (_Lagenaria siceraria_) in India. Plant Disease 88, 426.

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[Papaya ringspot virus (PRSV-W) infects only hosts in the _Cucurbitaceae_. PRSV-W is transmitted by aphids in a non-persistent manner, following acquisition of virus particles from a host reservoir, and are capable of transmitting it for 10-15 minutes in most cases. PRSV-W has been reported from Hawaii, Taiwan, Brazil, Thailand, the Caribbean islands and the Philippines. It is the major limiting factor in production of the crop. Disease management includes (1) the application of quarantine measures (prevention of the introduction of infected plants into a clean area; (2) preventing movement of papaya plants from areas known to be infected with the
virus; (3) roguing of infected plants; and (4) use of tolerant and resistant cultivars which do not produce severe symptoms.

The link to the original piece contains all of the text and graphics and is located at the top of the list of links.

Links:
<http://www.dpi.qld.gov.au/horticulture/5333.html> 
<http://pubs.caes.uga.edu/caespubs/pubcd/B1180.htm#Diseases>
<http://www.isb.vt.edu/proceedings99/proceedings.cucurbit.html>
<http://www.cropscience.org.au/icsc2004/symposia/3/7/153_zehrub.htm>
- Mod.DH]