RESUMO
A survey was conducted from 2003 to 2004 to identify viruses infecting common bean (Phaseolus vulgaris L.) in different growing areas of East Azarbaejan Province of Iran. A total of 300 French bean samples with symptoms of viral infection (mosaic, vein clearing, leaf rolling, yellowing, and leaf distortion) were collected. The samples were tested for eight viruses using the tissue-blot immunoassay procedures (TBIA) (2) and double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) according to the manufacturer's instructions (DSMZ, Braun-schweig, Germany). ELISA tests for Alfalfa mosaic virus (AMV), Bean yellow mosaic virus (BYMV), Bean common mosaic virus (BCMV), Bean common mosaic necrosis virus (BCMNV), Cucumber mosaic virus (CMV), Bean leaf roll virus (BLRV), and Southern bean mosaic virus (SBMV) were used. In addition, antiserum was provided by S. A. Ghabrial (University of Kentucky, Lexington) to test for Bean pod mottle virus (BPMV). Serological tests showed that SBMV and BPMV were present in 12% (35 samples) and 5% (15 samples) of samples, respectively. BCMV, BCMNV, BYMV, BLRV, CMV, and AMV were more common and were detected in 155, 105, 80, 46, 30, and 10 samples of 300 samples, respectively. These six viruses were previously reported in other pulses and in French bean in Iran (1). The presence of SBMV and BPMV were verified in samples by transmission to French bean (Phaseolus vulgaris), cowpea (Vigna unguiculata), and soybean (Glycine max) indicator test plants (3,4). Inoculation with extracts from SBMV-positive plants produced systemic mottle and mosaic symptoms in soybean (cv. Gorgan-3) and French bean (cvs. Dubbele Witte and Cheete). In cowpea (cv. Mashad) and French bean (cv. Pinto), inoculation produced necrotic local lesions. Inoculation with extracts from BPMV-positive plants produced severe mosaic, leaf distortion, and puckering in soybean (cv. Gorgan-3) and French bean (cv. Ten-dergreen). No symptoms were observed in cowpea (cv. Mashad). Cvs. Pinto and Bountiful bean reacted with necrotic local lesions. All indicator test plants tested positive for the presence of SBMV or BPMV as expected using DAS-ELISA. To our knowledge, this is the first report of BPMV and SBMV naturally infecting French bean in Iran. These viruses can cause a serious problem to other leguminous crops grown in Iran. References: (1) W. J. Kaiser et al. Plant Dis. Rep. 52:687, 1968. (2) K. M. Makkouk and A. Comeau. Eur. J. Plant Pathol. 100:71, 1994. (3) J. S. Semancik. Bean pod mottle virus. No. 108 in: Descriptions of Plant Viruses. CMI/AAB, Kew, Surrey, England, 1972. (4) J. H. Tremain and R. I. Hamilton. Southern bean mosaic virus. No. 274 in: Descriptions of Plant Viruses. CMI/AAB, Kew, Surrey, England, 1983.
RESUMO
Soybean (Glycine max (L.) Merr.) has been increasing in importance and acreage for the past 5 years in Iran and is now planted on approximately 108,000 ha. Previous surveys in Iran of viruses infecting soybean failed to identify Bean pod mottle virus (BPMV), but the incidence of other common viruses of soybean in the field has been reported (1). During October 2004, symptoms characteristic of those caused by BPMV including mosaic, puckering of trifoliate leaves, and delayed maturity of stems or green stems were observed in soybean fields in the Takhti Mahaleh, Versen, and Hashemabad areas located in the Gorgan Province. Sporadic incidence of plants infected with BPMV has been usually of minor importance to growers. Symptoms were often overlooked or considered to be physiological disorders. A visual assessment was made to determine incidence of green stem in the commonly grown soybean cv. Sahar. Forty soybean plants showing symptoms of crinkling, mottling, green stem, and retaining green leaves were sampled by collecting one trifoliate leaf near the top of the plant. All samples were tested in parallel for BPMV using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). BPMV was detected in 40% of the samples. Seven of the samples shown to be infected with BPMV using DAS-ELISA were mechanically (2) transferred to soybean seedlings in the greenhouse. These plants developed systemic mottle symptoms typical of those caused by BPMV and tested positive for BPMV using DAS-ELISA. The distribution of BPMV within soybean-growing regions, exploration of potential virus reservoirs, and economic impact of this virus have yet to be determined. There is no published report on the presence of potential BPMV vectors including the bean leaf beetle (Cerotoma trifurcata) from soybean fields in Iran. To our knowledge, this is the first report of BPMV in Iran. References: (1) A. R. Golnaraghi et al. Plant Dis.88:1069, 2004. (2) R. Louie et al. Plant Dis.84:1133, 2000.