The Symptom and Genetic Diversity of Cassava Brown Streak Viruses Infecting Cassava in East Africa

The genetic and symptom diversity of six virus isolates causing cassava brown streak disease (CBSD) in the endemic (Kenya, Mozambique, and Tanzania) and the recently affected epidemic areas (Uganda) of eastern Africa was studied. Five cassava varieties; Albert, Colombian, Ebwanateraka, TMS60444 (all...

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Main Authors: I. U. Mohammed, M. M. Abarshi, B. Muli, R. J. Hillocks, M. N. Maruthi
Format: Article
Language:English
Published: Wiley 2012-01-01
Series:Advances in Virology
Online Access:http://dx.doi.org/10.1155/2012/795697
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author I. U. Mohammed
M. M. Abarshi
B. Muli
R. J. Hillocks
M. N. Maruthi
author_facet I. U. Mohammed
M. M. Abarshi
B. Muli
R. J. Hillocks
M. N. Maruthi
author_sort I. U. Mohammed
collection DOAJ
description The genetic and symptom diversity of six virus isolates causing cassava brown streak disease (CBSD) in the endemic (Kenya, Mozambique, and Tanzania) and the recently affected epidemic areas (Uganda) of eastern Africa was studied. Five cassava varieties; Albert, Colombian, Ebwanateraka, TMS60444 (all susceptible) and Kiroba (tolerant) were graft inoculated with each isolate. Based on a number of parameters including the severity of leaf and root symptoms, and the extent of virus transmission by grafting, the viruses were classified as either severe or relatively mild. These results were further confirmed by the mechanical inoculation of 13 herbaceous hosts in which the virulent isolates caused plant death in Nicotiana clevelandii and N. benthamiana whereas the milder isolates did not. Phylogenetic analysis of complete coat protein gene sequences of these isolates together with sequences obtained from 14 other field-collected samples from Kenya and Zanzibar, and reference sequences grouped them into two distinct clusters, representing the two species of cassava brown streak viruses. Put together, these results did not suggest the association of a hypervirulent form of the virus with the current CBSD epidemic in Uganda. Identification of the severe and milder isolates, however, has further implications for disease management and quarantine requirements.
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spelling doaj-art-253bae2aa55943c7a55616f9f8c2d7ff2025-02-03T01:26:37ZengWileyAdvances in Virology1687-86391687-86472012-01-01201210.1155/2012/795697795697The Symptom and Genetic Diversity of Cassava Brown Streak Viruses Infecting Cassava in East AfricaI. U. Mohammed0M. M. Abarshi1B. Muli2R. J. Hillocks3M. N. Maruthi4Natural Resources Institute, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UKNatural Resources Institute, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UKFood Crops Programme, Kenya Agricultural Research Institute, P. O. Box 16-80109, Mtwapa, KenyaNatural Resources Institute, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UKNatural Resources Institute, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UKThe genetic and symptom diversity of six virus isolates causing cassava brown streak disease (CBSD) in the endemic (Kenya, Mozambique, and Tanzania) and the recently affected epidemic areas (Uganda) of eastern Africa was studied. Five cassava varieties; Albert, Colombian, Ebwanateraka, TMS60444 (all susceptible) and Kiroba (tolerant) were graft inoculated with each isolate. Based on a number of parameters including the severity of leaf and root symptoms, and the extent of virus transmission by grafting, the viruses were classified as either severe or relatively mild. These results were further confirmed by the mechanical inoculation of 13 herbaceous hosts in which the virulent isolates caused plant death in Nicotiana clevelandii and N. benthamiana whereas the milder isolates did not. Phylogenetic analysis of complete coat protein gene sequences of these isolates together with sequences obtained from 14 other field-collected samples from Kenya and Zanzibar, and reference sequences grouped them into two distinct clusters, representing the two species of cassava brown streak viruses. Put together, these results did not suggest the association of a hypervirulent form of the virus with the current CBSD epidemic in Uganda. Identification of the severe and milder isolates, however, has further implications for disease management and quarantine requirements.http://dx.doi.org/10.1155/2012/795697
spellingShingle I. U. Mohammed
M. M. Abarshi
B. Muli
R. J. Hillocks
M. N. Maruthi
The Symptom and Genetic Diversity of Cassava Brown Streak Viruses Infecting Cassava in East Africa
Advances in Virology
title The Symptom and Genetic Diversity of Cassava Brown Streak Viruses Infecting Cassava in East Africa
title_full The Symptom and Genetic Diversity of Cassava Brown Streak Viruses Infecting Cassava in East Africa
title_fullStr The Symptom and Genetic Diversity of Cassava Brown Streak Viruses Infecting Cassava in East Africa
title_full_unstemmed The Symptom and Genetic Diversity of Cassava Brown Streak Viruses Infecting Cassava in East Africa
title_short The Symptom and Genetic Diversity of Cassava Brown Streak Viruses Infecting Cassava in East Africa
title_sort symptom and genetic diversity of cassava brown streak viruses infecting cassava in east africa
url http://dx.doi.org/10.1155/2012/795697
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