Molecular investigations of subgroup I geminiviruses

 

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dc.contributor.advisor Rybicki, Edward P en_ZA
dc.contributor.author Hughes, Fiona Lesley en_ZA
dc.date.accessioned 2016-09-28T19:05:18Z
dc.date.available 2016-09-28T19:05:18Z
dc.date.issued 1991 en_ZA
dc.identifier.citation Hughes, F. 1991. Molecular investigations of subgroup I geminiviruses. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/21979
dc.description Bibliography: pages 139-150. en_ZA
dc.description.abstract 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. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Virology en_ZA
dc.title Molecular investigations of subgroup I geminiviruses en_ZA
dc.type Thesis / Dissertation en_ZA
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Department of Molecular and Cell Biology en_ZA
dc.type.qualificationlevel Doctoral en_ZA
dc.type.qualificationname PhD en_ZA
uct.type.filetype Text
uct.type.filetype Image


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