Current status of viral diseases affecting cool-season food legumes in the Arab region

Abstract

Food legumes (faba bean, chickpea and lentil) are widely cultivated in the Arab region, providing protein and calories to a large segment of the population. Viral diseases are a major constraint that limits the realization of legume production potential and causes yield instability. Twenty viruses have been identified in 11 Arab countries (Algeria, Egypt, Libya, Morocco, Sudan, Tunisia, Iraq, Jordan, Lebanon, Syria and Yemen). These viruses are widespread in specific areas within specific countries, and yield losses can be quite serious, but vary based on strains, infected growth stage, cultivars, and environmental conditions. Viruses of greatest economic impact are Faba bean necrotic yellows virus (FBNYV), Bean leafroll virus (BLRV), Beet western yellows virus (BWYV), Chickpea chlorotic stunt virus (CpCSV), Chickpea chlorotic dwarf virus (CpCDV), Bean yellow mosaic virus (BYMV), Broad bean mottle virus (BBMV), and Pea seed-borne mosaic virus (PSbMV). Other viruses, such as Alfalfa mosaic virus (AMV), Cucumber mosaic virus (CMV), Broad bean stain virus (BBSV), Broad bean wilt virus (BBWV), Broad bean true mosaic virus (BBTMV), Pea early browning virus (PEBV), Pea enation mosaic virus (PEMV), Cucurbit aphid-borne yellows virus (CABYV), Soybean dwarf virus (SbDV), Pepper vein yellows virus (PeVYV), Pepo aphid-borne yellows virus (PABYV), and Cotton leafroll dwarf virus (CLRDV), can be important in specific locations. FBNYV, BLRV, BWYV, SbDV, CpCSV, CABYV, PeVYV, PABYV and CLRDV are transmitted persistently by aphids; CpCDV is transmitted by leafhopper; AMV, BBWV, BYMV, CMV, PEMV and PSbMV are transmitted non-persistently by aphids and seeds; BBSV, BBMV and BBTMV are transmitted by beetles and seeds; and PEBV is transmitted by nematode and seeds. FBNYV (genus Nanovirus) has been reported in all 11 Arab countries, with high incidences reported in Egypt, Jordan, Syria and Tunisia, with epidemics occurring every 3-5 years, depending on the region. In addition, CpCSV and BWYV (genus Polerovirus) causes economic losses on chickpea in Lebanon, Syria and Tunisia. CpCDV (genus Mastervirus) was found to be the virus with the greatest economic impact on chickpea in Sudan, while PEBV has been reported in only three Arab countries in North Africa (Algeria, Libya, and Morocco). Recently, molecular analyses have provided a basic, sufficient, and reliable characterization for four chickpea viruses (belonging to the genus Polerovirus) in Sudan: CABYV, PeVYV, PABYV, and CLRDV. However, surveys and identification of viral diseases affecting food legumes in the Arab region remain incomplete. In some Arab countries, lack of necessary equipment, and virus identification entirely based on field observation or serological testing using non-specific antibodies. There is an urgent need to develop virus detection tools and introduce modern technologies for accurate virus identification to support breeding for resistance and effective disease management to ensure sustainable legume production and enhance regional food security.