First report of Faba bean necrotic yellows virus (FBNYV) infecting chickpea (Cicer arietinum) and faba bean (Vicia faba) crops in Sudan
A total of 45 faba bean samples (Vicia faba) and 130 chickpea samples (Cicer arietinum) were collected from plants with symptoms that suggested a viral infection (leaf rolling, yellowing and stunting) during the period 1999–2001 at the Shambat and Hudeiba Research Stations, Sudan. These samples were tested, using the tissue‐blot immunoassay procedure (Makkouk & Comeau, 1994), at the Virology Laboratory of ICARDA, Syria. The antisera used included both monoclonal and polyclonal antibodies. The monoclonal antibodies were ATCC PVAS‐647 (American Type Culture Collection, Manassas, VA, USA), used to test for Beet western yellows virus (BWYV, genus Polerovirus, family Luteoviridae); ATCC PVAS‐650, used to test for Soybean dwarf virus (SbDV, family Luteoviridae); 4B10, used to test for Bean leaf roll virus (BLRV, family Luteoviridae; Katul, 1992); and 3‐2E9 and 2‐5H9, used to test for Faba bean necrotic yellows virus (FBNYV, genus Nanovirus, family Nanoviridae) – the latter monoclonal is FBNYV‐specific (Franz et al., 1996). A polyclonal antibody (provided by H.J. Vetten, BBA, Braunschweig, Germany) was used to test for Chickpea chlorotic dwarf virus (CpCDV, genus Mastrevirus, family Geminiviridae). Laboratory tests showed that CpCDV, a leafhopper‐transmitted virus, was the most abundant virus in chickpea; however, FBNYV, an aphid‐transmitted virus, was the most common virus in faba bean samples. FBNYV has been reported to infect food legumes in many countries in western Asia and North Africa, and reaches epidemic levels in some countries, including Egypt (Makkouk et al., 1994). CpCDV was detected in 77·0% of chickpea and 15·5% of faba bean samples tested, whereas FBNYV was detected in 95·5% of faba bean and 6·2% of chickpea samples tested. Only two chickpea samples tested positive for BWYV, while SbDV and BLRV were not detected in any of the samples. Based on the reaction with the FBNYV‐specific monoclonal (2‐5H9) and the characteristic symptoms of leaf rolling, stunting and yellowing of leaves, with necrosis of the leaf periphery in faba bean and yellowing and stunting in chickpea, this is the first record of FBNYV affecting faba bean and chickpea in Sudan.