First record of Chickpea chlorotic dwarf virus (CpCDV) affecting faba bean (Vicia faba L.) crops in Egypt

A field visit was conducted in March 2002 to identify viruses infecting the faba bean (Vicia faba L.) crop in four governorates (Fayoum, Beni Suef, El-Nobareia and Bihera) in Egypt. A total of 71 faba bean samples with symptoms of viral infection (leaf rolling, yellowing and mosaic) were collected. These were tested at the Virology Laboratory of ICARDA, Syria, for seven viruses using the tissue-blot immunoassay procedure (Makkouk & Comeau, 1994). Specific rabbit polyclonal antisera were used to test for Chickpea chlorotic dwarf virus (CpCDV, genus Mastrevirus, family Geminiviridae) (provided by H.J. Vetten, BBA, Braunschweig, Germany); for Broad bean stain virus (BBSV, genus Comovirus, family Comoviridae); for Bean yellow mosaic virus (BYMV, genus Potyvirus, family Potyviridae) and for Pea seed borne mosaic virus (PSbMV, genus Potyvirus, family Potyviridae). In addition, three specific monoclonal antibodies were used to detect Faba bean necrotic yellows virus (FBNYV, genus Nanovirus, family Nanoviridae) (Franz et al., 1996); Bean leaf roll virus (BLRV, family Luteoviridae) (4B10; Katul, 1992) and Beet western yellows virus (BWYV, genus Polerovirus, family Luteoviridae) (ATCC PVAS-647; American Type Culture Collection, Manassas, VA).

Serological tests showed that BYMV, an aphid-transmitted and seed-borne virus that was identified in 89% of samples tested, was the most common virus. In most of the fields surveyed, BYMV symptoms were noted to occur at high levels (80-100% infection). PSbMV was detected in 9 samples (one from Fayoum and 8 from Beni Suef); FBNYV was detected in 11 samples (all from Beni Suef). CpCDV, a leafhopper-transmitted virus, was, by contrast, detected in only two samples, collected from the El-Nobareia governorate showing leaf rolling, yellowing and stunting. BWYV, BLRV and BBSV were not detected in any of the samples tested. In Egypt, FBNYV, BYMV and PSbMV have previously been reported in faba bean (Makkouk et al., 1994), but this is the first record of CpCDV affecting faba bean in Egypt. CpCDV is the only Geminivirus that is reported to naturally infect faba bean.