Evidence that DNA-A of a geminivirus associated with severe cassava mosaic disease in Uganda has arisen by interspecific recombination.

Abstract

Geminivirus isolates associated with the epidemic of severe cassava mosaic disease in Uganda were studied and compared with virus isolates from the part of Uganda outside the epidemic area, and with African cassava mosaic virus (ACMV) and East African cassava mosaic virus (EACMV). Isolates of a novel type [the Uganda variant (UgV

Disease control and its selection for damaging plant virus strains in vegetatively propagated staple food crops; a theoretical assessment

“…The recent highly damaging (Legg & Thresh 2000) Uganda variant (EACMV-UG) is an interspecific recombinant strain of the East African mosaic virus (Zhou et al 1997). All our parameter estimates relate to the African cassava mosaic virus.…”

Complete nucleotide sequence and host range of South African cassava mosaic virus: further evidence for recombination amongst begomoviruses

“…Group A, African cassava mosaic virus (ACMV), is found in West Africa, including Burundi, the western parts of Kenya, Chad, Uganda and recently, Cameroon (Fondong et al, 1998). Group B, East African cassava mosaic virus (EACMV), occurs in the eastern parts of Kenya, and in Madagascar, Malawi, Tanzania, Zimbabwe (Swanson & Harrison, 1994 ;, and has recently been detected in Uganda (Zhou et al, 1997), Zambia (Ogbe et al, 1997), Nigeria (Ogbe et al, 1999) and Cameroon (Fondong et al, 1998). Group C, Indian cassava mosaic virus (ICMV), occurs in India and Sri Lanka.…”

“…It is now well accepted that recombination may play an important role in the evolution of begomoviruses (Fondong et al, 2000 ;. Indeed, a documented natural recombinant (EACMV-UG), consisting of most of the CP gene of ACMV inserted in an EACMV-like A component, has played a major role in the cassava mosaic epidemic which has spread through Uganda and into neighbouring countries (Zhou et al, 1997 ;Deng et al, 1997). As a step towards determining the extent and nature of the variation in cassava-infecting begomoviruses, we report the thorough characterization of a novel begomovirus (SACMV) by sequence analysis of both DNA components and comparisons with those of other cassava-infecting begomoviruses, as well as biological characterization by host-range studies.…”

“…Three distinct groups of species of cassava-infecting whitefly-transmitted geminiviruses (WTGs, genus Begomovirus) have been distinguished based on their nucleotide sequences (Stanley & Gay, 1983 ;Hong et al, 1993 ;Zhou et al, 1997) and by their reactions with a panel of monoclonal antibodies (Harrison & Robinson, 1988 ;Swanson & Harrison, 1994). Group A, African cassava mosaic virus (ACMV), is found in West Africa, including Burundi, the western parts of Kenya, Chad, Uganda and recently, Cameroon (Fondong et al, 1998).…”

Tomato dwarf leaf curl virus, a new bipartite geminivirus associated with tomatoes and peppers in Jamaica and mixed infection with tomato yellow leaf curl virus

“…Recombinant geminiviruses were shown to be responsible for epidemics in cassava in Uganda and cotton in Pakistan (Zhou et al, 1997;Fauquet et al, 1998). Similar recombination may have contributed to geminivirus evolution in the recent past and may help to explain the rapid and sudden emergence of new geminiviruses, particularly in areas where mixed infections are common, such as Mexico, Latin America and 376…”