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Molecular characterization of cassava mosaic geminiviruses in Tanzania
Thesis (PhD)--University of Pretoria, 2007.
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University of Pretoria
2013
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| _version_ | 1867613507711664128 |
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| access_status_str | Open Access |
| author2 | Aveling, Terry A.S. |
| author_browse | Aveling, Terry A.S. |
| author_facet | Aveling, Terry A.S. |
| collection | Thesis |
| dc_rights_str_mv | © 2016, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Thesis (PhD)--University of Pretoria, 2007. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/30648 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:37:15.129Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/30648 Molecular characterization of cassava mosaic geminiviruses in Tanzania Aveling, Terry A.S. Ndunguru, Joseph Cassava mosaic geminiviruses Cassava African cassava mosaic virus Cassava mosaic disease Tanzania East African cassava mosaic virus Dna-a molecular characterisation Dna-b molecular characterisation UCTD Thesis (PhD)--University of Pretoria, 2007. Cassava (Manihot esculenta Crantz) is a basic staple food crop in Tanzania. Cassava mosaic disease (CMD) caused by cassava mosaic geminiviruses (CMGs) constitutes a major limiting factor to cassava production in the country. This study was undertaken to characterize the CMGs occurring in Tanzania using molecular techniques and to map their geographical distribution to generate information on which the formulation of control measures can be based. Using Polymerase Chain Reaction (PCR) and Restriction Fragment Length Polymorphism (RFLP) for analysis of CMGs DNA-A genomes, different CMGs were found to be associated with CMD. Higher molecular diversity was observed among East African cassava mosaic viruses (EACMVs) than African cassava mosaic viruses (ACMVs), which was confirmed later by complete nucleotide sequence analysis. In addition to EACMV and ACMV isolates, two isolates of EACMV Cameroon virus (EACMCV) were found in Tanzania. These were confirmed to be strains of EACMCV Cameroon, originally described in Cameroon, West Africa and here named EACMCV- [TZ1] and EACMCV-[TZ7]. They had high (92%) overall DNA-A nucleotide sequence identity and EACMCV-[TZ1] was widespread in the southern part of the country. A subgenomic DNA form of CMG that appeared to be truncated was identified in a CMD-infected cassava plant. It was confirmed upon sequence analysis to be a defect of EACMV DNA-A and had a capacity of attenuating symptoms when coinoculated with wild-type EACMV. In addition, this study revealed for the first time the presence of two novel non-geminivirus single-stranded DNA (ssDNA) sub-genomic molecules associated with CMG infection. They were shown to be dependent on CMG for replication and movement within the plants, confirming their status as satellite molecules named here as satDNA-II and satDNA-III. When present in coinfection with CMGs, they enhance symptoms and can break high levels of resistance in a cassava landrace. Finally a simple, inexpensive technique is described of archiving, transporting and recovering plant DNA for downstream geminivirus characterisation. Microbiology and Plant Pathology Unrestricted 2013-09-09T07:21:56Z 2006-02-27 2013-09-09T07:21:56Z 2005-08-06 2007-02-27 2006-02-27 Thesis Ndunguru, J 2005, Molecular characterization of cassava mosaic geminiviruses in Tanzania, PhD thesis, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/30648 > A2016 http://hdl.handle.net/2263/30648 http://upetd.up.ac.za/thesis/available/etd-02272006-092153/ © 2016, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf University of Pretoria |
| spellingShingle | Cassava mosaic geminiviruses Cassava African cassava mosaic virus Cassava mosaic disease Tanzania East African cassava mosaic virus Dna-a molecular characterisation Dna-b molecular characterisation UCTD Molecular characterization of cassava mosaic geminiviruses in Tanzania |
| title | Molecular characterization of cassava mosaic geminiviruses in Tanzania |
| title_full | Molecular characterization of cassava mosaic geminiviruses in Tanzania |
| title_fullStr | Molecular characterization of cassava mosaic geminiviruses in Tanzania |
| title_full_unstemmed | Molecular characterization of cassava mosaic geminiviruses in Tanzania |
| title_short | Molecular characterization of cassava mosaic geminiviruses in Tanzania |
| title_sort | molecular characterization of cassava mosaic geminiviruses in tanzania |
| topic | Cassava mosaic geminiviruses Cassava African cassava mosaic virus Cassava mosaic disease Tanzania East African cassava mosaic virus Dna-a molecular characterisation Dna-b molecular characterisation UCTD |
| url | http://hdl.handle.net/2263/30648 http://upetd.up.ac.za/thesis/available/etd-02272006-092153/ |