Sokoine University of Agriculture

Molecular diversity of DNA-B component of east African cassava mosaic viruses in Tanzania

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dc.contributor.author Lupembe, M. D.
dc.date.accessioned 2018-04-26T08:35:15Z
dc.date.available 2018-04-26T08:35:15Z
dc.date.issued 2017
dc.identifier.uri https://www.suaire.sua.ac.tz/handle/123456789/2109
dc.description A DISSERTATION SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN MOLECULAR BIOLOGY AND BIOTECHNOLOGY OF SOKOINE UNIVERSITY OF AGRICULTURE. MOROGORO, TANZANIA. 2017 en_US
dc.description.abstract Begomoviruses are whitefly-transmitted viruses belonging to the family Geminiviridae presenting most devastating threat to food security. This study was initiated to asses cassava mosaic disease (CMD) severity and genetic diversity of DNA-B component of East African cassava mosaic viruses (CMD) that infect cassava plants from main cassava growing regions in Tanzania. The study involved field survey, rolling cycle amplification (RCA) followed by next generation sequencing (NGS). The symptoms of CMD severity in the areas where samples were collected ranged from moderate (2.82) to high (3.95) using a 1-5 (CMD symptoms severity score scale). Nucleotide sequence identity of 39 isolates identified in this study and that of 32 sequences retrieved from database ranged from 30% to 100%. Current study has reported the presence of EACMMV-Malawi (Accession number JX658684) from isolate TZ_KIB1 shared 98% nts identity and 93% to 98% nt identity with other isolates that were found in the same cluster (branch) with 2753 nts sequence length. Moreover, the presence of four isolates TZ_MBE, TZ_SUM, TZ_KIR and TZ_KAS from southern zone has also been described, shared 97% to 100% nts identity with EACMCV-TZ1 (Accession number AF112355) and 100% nts identity with other isolates from the study. Also, African Cassava Mosaic Virus (ACMV) from isolate TZ_TAR1 with 100% nucleotides (nts) identity to ACMV [(Nigeria /Ogo) Accession Number AJ427911] and 2718 nts sequence length from lake zone of Tanzania has been identified. Moreover, in this study isolates TZ_TAR3, TZ_ROR1, TZ_MIS, TZ_HAN and TZ_KIB1 showed recombination associated within themselves as well as with other isolates identified in the previous studies. In conclusion, the current study showed a greater genetic diversity of begomoviruses DNA-B being more diverse than previously thought that could be linked to geographical area and high rate of recombination. en_US
dc.language.iso en en_US
dc.subject Molecular diversity en_US
dc.subject Cassava mosaic viruses en_US
dc.subject Tanzania en_US
dc.subject DNA-B component en_US
dc.subject Begomoviruses en_US
dc.title Molecular diversity of DNA-B component of east African cassava mosaic viruses in Tanzania en_US
dc.type Thesis en_US


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