October 19, 2004
From: ProMED-mail<promed@promedmail.org>
Source: American Phytopathological Society, Plant Disease Notes [edited]

First report of Southern bean mosaic virus infecting French bean in Morocco
E. Segundo, F. M. Gil-Salas, D. Janssen, G. Martin, and I. M. Cuadrado, Unidad de Virologia, CIFA (IFAPA), Autovia del Mediterraneo, km 420, 04745, La Mojonera, Spain; and A. Remah, Institut Agronomique et  Veterinaire Hassan II. Complexe Horticole d'Agadir, Agadir, Morocco. Plant Dis.   88:1162, 2004; published on-line as D-2004-0721-01N, 2004. Accepted for publication 7 Jul 2004.

Common bean (_Phaseolus vulgaris_ L.) is grown on approximately 1500 ha in commercial greenhouses and is of major economic importance in the Souss-Massa Region, Agadir, Morocco. Since October 2003, symptoms resembling a viral disease, consisting of pod mosaic and distortion and mild to severe mosaic in leaves, have been observed on bean plants in several greenhouses.

Mechanical inoculation with symptomatic leaf extracts produced necrotic local lesions on _P. vulgaris_ 'Pinto' and systemic symptoms similar to those observed in the naturally infected bean plants _P. vulgaris_ 'Donna' (5 plants per cultivar).

Inoculated and naturally infected samples reacted positively using a double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) to Southern bean mosaic virus (SBMV) (DSMZ, Braunschweig, Germany), a member of the Sobemovirus genus that is transmitted by contact, soil, beetles, and seeds (1). Virions purified from a naturally infected 'Donna' plant contained a 30-kDa polypeptide that reacted positively using sodium dodecyl sulfate polyacrylamide gel electrophoresis and western blot analysis with SBMV antiserum (DSMZ).

Reverse transcription-polymerase chain reaction amplification with SMBV primers as described by Verhoeven et al. (2) produced an expected 870-bp band. The amplicon was cloned, sequenced (GenBank Accession No. AJ748276), and compared to those isolates available in GenBank and had a nucleotide sequence identity of 87 percent and a derived amino acid sequence identity of 95 percent with an SBMV isolate from Spain (2).

During a survey in different areas of the Souss-Massa Region, 20 symptomatic leaf and pod samples were randomly collected from 12 greenhouses (50 ha) where significant commercial losses were suffered because of this virus disease, and all samples were positive using DAS-ELISA for SBMV.

To our knowledge, this is the 1st report of SBMV in Morocco.

References:
(1) J. H. Tremaine and R. I. Hamilton. Southern bean mosaic virus. No. 274 in: Descriptions of Plant Viruses. CMI/AAB, Kew, Surrey, England, 1983.
(2) J. Th. J. Verhoeven et al. Eur. J. Plant Pathol. 109:935, 2003.

[SBMV, 1st reported in common bean in samples from USA (Louisiana and California) in 1943, also infects _Vigna unguiculata_, [Vu] _V. mungo_ and _Glycine max_, causing mosaic and/or mottle, and stunting (especially in Vu). It is transmitted in a semi-persistent manner by bean leaf beetles (_Ceratoma trifurcata_ and _Epilachna_ varieties), mechanical inoculation, grafting, by seed (3-44 percent) and by pollen. SBMV has been reported from Africa and from regions in the Americas (North, South and Central), and France. SBMV is transmitted to bean seedlings if germinating seeds are in contact with infective extracts or are planted in soil near roots of infected plants. Disease management essentially involves use of virus-free seed.
Link: <http://www3.res.bbsrc.ac.uk/webdpv/web/adpv.asp?dpvnum=57>
- Mod.DH]