Welcome to the International Institute of Tropical Agriculture Research Repository
First report of the occurrence of East African cassava mosaic virusUganda (EACMVUG) in Angola
Abstract/Description
Cassava mosaic disease (CMD) is the major production constraint on
cassava (
Manihot esculenta
) in Angola. Previous reports derived from
single samples recorded the presence of
African cassava mosaic virus
(ACMV) and
East African cassava mosaic virus
(EACMV) in Angola.
Regional CMD monitoring initiatives have predicted the spread into
northern Angola of EACMV-Uganda (-UG), the unusually virulent
(aggressive) recombinant strain associated with the African CMD
pandemic (Legg
et al
., 2006). In view of this threat, an assessment survey
was conducted in north and central Angola in April 2008.
Eighteen cassava fields were sampled in Bengo, Cuanza Norte, Malanje
and Uige Provinces. Moderate to severe CMD symptoms were observed in
most fields. Sixty-three of 65 samples obtained from these fields tested
positive in TAS-ELISA using monoclonal antibody SCR 20. PCR was
performed using primer pairs previously described for the specific
identification of ACMV, EACMV, EACMV-UG,
East African cassava
mosaic Cameroon virus
(EACMCV) and
Indian cassava mosaic virus
(ICMV) (Ogbe
et al
., 2003),
East African cassava mosaic Malawi virus
(EACMMV) (Zhou
et al
., 1998),
East African cassava mosaic Zanzibar
virus
(EACMZV) (Were
et al
., 2004) and
South African cassava mosaic
virus
(SACMV) in mixed infections. This revealed the occurrence of
ACMV, EACMV and EACMV-UG, but not EACMZV, EACMMV,
SACMV or ICMV. Single infections of ACMV and EACMV were detected
in 32·3 and 9% of samples, respectively. Mixed infections of ACMV with
EACMV, EACMV with EACMV-UG and all three viruses were detected
in 35·3, 1·5 and 16·9% of samples, respectively. ACMV, detected in 84·6%
of samples, was the predominant species, followed by EACMV (63%) and
EACMV-UG (18·5%). Significantly, EACMV-UG occurred most
frequently in the northernmost part of the surveyed area (Uige Province)
immediately to the south of the Bas Congo region of the Democratic
Republic of Congo, already known to be affected by the pandemic. These
findings significantly broaden the known geographical extent of the CMD
pandemic and draw attention to the urgent need for the large-scale deployment
of resistant cassava varieties, which have been used to reduce losses
in pandemic-affected regions of East Africa.
Multi standard citation
Permanent link to this item
https://hdl.handle.net/20.500.12478/2845Digital Object Identifier (DOI)
https://dx.doi.org/10.1111/j.1365-3059.2008.02010.x