First Report of East African Cassava Mosaic Begomovirus in Ghana

Abstract

Virus species causing cassava mosaic disease have been categorized into three classes based on their reaction with monoclonal antibodies (MAbs) and their distribution (2). These viruses have different, scarcely overlapping distribution: African cassava mosaic begomovirus (ACMV) occurs in Africa west of the Rift Valley and in South Africa; East African cassava mosaic (EACMV) occurs in Africa east of the Rift Valley and in Madagascar; and Indian cassava mosaic virus (ICMV) occurs in India and Sri Lanka (2). During 1998, surveys were conducted in farmers' fields in Ghana to assess the incidence and reaction of local cassava cultivars to cassava mosaic disease. Leaf samples from symptomatic plants were indexed by triple antibody sandwich-enzyme-linked immunosorbent assay with crude extracts and monoclonal antibodies obtained from the International Institute of Tropical Agriculture (IITA). Each sample was assayed with monoclonal antibody SCR 23, which detects ACMV and EACMV, SCR 33, which detects ACMV, and SCR 58, which detects ICMV. None of the samples reacted with SCR 58. Two of the samples collected from the western region of Ghana produced strong reactions with MAb SCR23 but did not react with ACMV-specific MAb SCR 33. This result was consistent in three separate experiments conducted on the samples, confirming that the virus was EACMV and not ACMV. The results extend the work by Ogbe et al. (1) and provide further evidence of the occurrence of EACMV in west Africa. References: (1) F. O. Ogbe et al. Plant Dis 83:398, 1999. (2) M. M. Swanson and B. D. Harrison. Trop. Sci. 34:15, 1994.

Effect of mosaic virus diseases on dry matter content and starch yield of five cassava (Manihot esculenta Crantz) accessions in Ghana

“…Until recently, EACMV and EACMV-Ug were only prevalent in East and Central African countries. The present observation confirms earlier reports by Offei et al (1999) and Were et al (2003) in which cassava leaves collected from Ghana were infected with both ACMV and EACMV but not with the Ugandan variant. The high rate of recombination of different geminiviruses co-infecting cassava (Patil and Fauquet, 2009) can result in the formation of virulent strains which reduce yield as observed in the Ugandan variant (EACMV-Ug) (Pita et al, 2001).…”

Assessment of genetic diversity among African cassava Manihot esculenta Grantz accessions resistant to the cassava mosaic virus disease using SSR markers

“…Recent surveys conducted in Africa between 1998 and show that severe forms of the disease due to EA-CMV-UgV has graduated from epidemic to pandemic proportions in Uganda and has spread to neighbouring countries such as Sudan, Rwanda, Kenya, Democratic Republic of Congo, Congo Brazzaville and Gabon (Legg and Fauquet 2004). Furthermore, the characteristic severe symptoms associated with mixed infections of ACMV and EACM identified in some West African countries (Offei et al 1999;Ogbe et al 1999), emphasizes the need to intensify efforts in managing the disease. In managing the spread of the disease, cultivating resistant genotypes has been demonstrated to be the most effective means of controlling CMD (CoursDarne 1968;Otim-Nape et al 1994;Thresh et al 1994) as well as being an environmentally sound and sustainable means of managing the spread of the disease.…”

Complete genome sequencing of two causative viruses of cassava mosaic disease in Ghana

“…Incidence of both ACMV and EACMV, and the importance of CMD in Ghana have been reported (Lamptey et al, 1998(Lamptey et al, , 2000Offei et al, 1999;Manu-Aduening et al, 2007;Torkpo, 2009). Though those studies report on CMD in Ghana, the molecular features of the virus have not been conclusively determined.…”