Molecular investigations of subgroup I geminiviruses

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dc.contributor.advisorRybicki, Edward Pen_ZA
dc.contributor.authorHughes, Fiona Lesleyen_ZA
dc.date.accessioned2016-09-28T19:05:18Z
dc.date.available2016-09-28T19:05:18Z
dc.date.issued1991en_ZA
dc.descriptionBibliography: pages 139-150.en_ZA
dc.description.abstractThe diversity of Subgroup I geminiviruses causing streak disease in maize, sugarcane, and indigenous wild grasses was investigated. The virus. isolates studied originated from maize (several southern African isolates), two sugarcane cultivars (from Natal province, South Africa, and from Mauritius), wheat, and three grasses (Panicum, Setaria, and Eleusine spp. from South Africa). The following methods were used: analysis of restriction fragment length polymorphisms (RFLPs) between viral genomes in individual infected plants; DNA cross-hybridization between virus isolates; restriction endonuclease mapping of whole virus genomes; and nucleic acid sequencing. The complete genome of the Natal sugarcane streak virus isolate was sequenced. Partial sequences were obtained for other isolates, either by sequencing the ends of cloned viral genomes, or by sequencing a 250 base pair fragment of a highly conserved open reading frame that had been amplified using the polymerase chain reaction technique. The viruses being studied were compared both among themselves and with other Subgroup I geminiviruses of known DNA sequence, on the basis of sequence (nucleotide and amino acid) and restriction map data. Distance matrix methods were used to infer phylogenetic relationships between Subgroup I geminiviruses from restriction map and sequence data. Phylogenies deduced from sequence data were considered to be more accurate than those deduced from map data. Regardless of the method of analysis used, however, the relationships between the Subgroup I geminiviruses studied here remained constant. Thus, three strains of MSV (maize, Setaria, and Eleusine strains) were distinguished. Streak viruses distinct from MSV were also identified: panicum streak virus (PanSV), and two distantly related strains (Natal and Mauritius) of sugarcane streak virus (SSV). Restriction mapping of different geographical isolates of the maize strain of MSV demonstrated that variation existed within a single strain of virus. RFLP analysis indicated that minor variation existed between virus genomes within single diseased plants. Methods used to. type Subgroup I geminiviruses were evaluated, and discrepancies in the serological typing of geminiviruses from Subgroups I and III were pointed out. A unified scheme was proposed for distinguishing between distinct Subgroup I geminiviruses and strains of geminiviruses. The origins of maize and sugarcane streak viruses were speculated upon.en_ZA
dc.identifier.apacitationHughes, F. L. (1991). <i>Molecular investigations of subgroup I geminiviruses</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology. Retrieved from http://hdl.handle.net/11427/21979en_ZA
dc.identifier.chicagocitationHughes, Fiona Lesley. <i>"Molecular investigations of subgroup I geminiviruses."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 1991. http://hdl.handle.net/11427/21979en_ZA
dc.identifier.citationHughes, F. 1991. Molecular investigations of subgroup I geminiviruses. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Hughes, Fiona Lesley AB - The diversity of Subgroup I geminiviruses causing streak disease in maize, sugarcane, and indigenous wild grasses was investigated. The virus. isolates studied originated from maize (several southern African isolates), two sugarcane cultivars (from Natal province, South Africa, and from Mauritius), wheat, and three grasses (Panicum, Setaria, and Eleusine spp. from South Africa). The following methods were used: analysis of restriction fragment length polymorphisms (RFLPs) between viral genomes in individual infected plants; DNA cross-hybridization between virus isolates; restriction endonuclease mapping of whole virus genomes; and nucleic acid sequencing. The complete genome of the Natal sugarcane streak virus isolate was sequenced. Partial sequences were obtained for other isolates, either by sequencing the ends of cloned viral genomes, or by sequencing a 250 base pair fragment of a highly conserved open reading frame that had been amplified using the polymerase chain reaction technique. The viruses being studied were compared both among themselves and with other Subgroup I geminiviruses of known DNA sequence, on the basis of sequence (nucleotide and amino acid) and restriction map data. Distance matrix methods were used to infer phylogenetic relationships between Subgroup I geminiviruses from restriction map and sequence data. Phylogenies deduced from sequence data were considered to be more accurate than those deduced from map data. Regardless of the method of analysis used, however, the relationships between the Subgroup I geminiviruses studied here remained constant. Thus, three strains of MSV (maize, Setaria, and Eleusine strains) were distinguished. Streak viruses distinct from MSV were also identified: panicum streak virus (PanSV), and two distantly related strains (Natal and Mauritius) of sugarcane streak virus (SSV). Restriction mapping of different geographical isolates of the maize strain of MSV demonstrated that variation existed within a single strain of virus. RFLP analysis indicated that minor variation existed between virus genomes within single diseased plants. Methods used to. type Subgroup I geminiviruses were evaluated, and discrepancies in the serological typing of geminiviruses from Subgroups I and III were pointed out. A unified scheme was proposed for distinguishing between distinct Subgroup I geminiviruses and strains of geminiviruses. The origins of maize and sugarcane streak viruses were speculated upon. DA - 1991 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1991 T1 - Molecular investigations of subgroup I geminiviruses TI - Molecular investigations of subgroup I geminiviruses UR - http://hdl.handle.net/11427/21979 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/21979
dc.identifier.vancouvercitationHughes FL. Molecular investigations of subgroup I geminiviruses. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 1991 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/21979en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Molecular and Cell Biologyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherVirologyen_ZA
dc.titleMolecular investigations of subgroup I geminivirusesen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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