Investigating the role of pyrophosphate fructose 6-phosphate 1-phosphotransferase in phloem loading

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dc.contributor.advisorGroenewald, J.-H.en_ZA
dc.contributor.authorSmith, Marthinus Lutheren_ZA
dc.contributor.otherStellenbosch University. Faculty of AgriSciences. Dept. of Genetics. Institute for Plant Biotechnology.
dc.date.accessioned2008-11-25T12:10:35Zen_ZA
dc.date.accessioned2010-06-01T09:05:16Z
dc.date.available2008-11-25T12:10:35Zen_ZA
dc.date.available2010-06-01T09:05:16Z
dc.date.issued2008-12
dc.descriptionThesis (MSc (Genetics. Plant Biotechnology)) --Stellenbosch University, 2008.
dc.description.abstractThe main aim of the work presented in this thesis was to further our understanding of the role of Pyrrophosphate: fructose 6-phosphate 1-phosphotransferase (PFP) in sugarcane, by specifically investigating its potential contribution to phloem metabolism. PFP activity in sugarcane internodal tissue is inversely correlated to sucrose content across varieties that differ in their sucrose accumulation abilities. This apparent correlation is in contrast to previous studies that suggest PFP plays an insignificant role in metabolism. In the first part of this study an immunological characterisation of the two subunits of sugarcane PFP was conducted to establish whether it differ significantly from other plant species in terms of size and distribution. Both the alpha and beta subunit appears to be approximately sixty kilo Daltons in size and uniform in their relative distribution to each other in the various plant organs of sugarcane. Although the observed alpha subunit size is less than that predicted this could be explained at the hand of post translational modification, in essence the sugarcane PFP subunits appear similar than that described for other plants especially that of tobacco which was employed as a model system later on in this study. The only direct way to investigate PFP’s contribution to phloem metabolism is to alter its activity by recombinant DNA technologies. Therefore, in the second part of the study transformation systems were designed for both the constitutive and phloem specific downand up-regulation of PFP activity. For the down-regulation of activity a post transcriptional gene silencing system, i.e. a complementary strand intron hairpin RNA (ihpRNA) silencing system, was employed. A partial sequence of the PFP-beta subunit was isolated and used in vector construction. For the over-expression the Giardia lamblia PFP gene was used. The model plant tobacco was employed to investigate PFP’s effect on phloem metabolism and transport of assimilate. Transgene insertion was accomplished by means of Agobacterium mediated transformation and tissue specific manipulation of PFP activity was confirmed by in situ activity staining.en_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/3062
dc.language.isoenen_ZA
dc.publisherStellenbosch : Stellenbosch University
dc.rights.holderStellenbosch University
dc.subjectPyrophosphateen_ZA
dc.subjectPhloem metabolismen_ZA
dc.subjectPhosphotransferaseen_ZA
dc.subjectSugarcane geneticsen_ZA
dc.subjectTheses -- Plant biotechnologyen_ZA
dc.subjectDissertations -- Plant biotechnologyen_ZA
dc.subject.lcshPlant cells and tissuesen-ZA
dc.subject.lcshVascular system of plantsen_ZA
dc.subject.lcshSugarcane -- Biotechnologyen_ZA
dc.subject.otherGeneticsen_ZA
dc.subject.otherInstitute for Plant Biotechnologyen_ZA
dc.titleInvestigating the role of pyrophosphate fructose 6-phosphate 1-phosphotransferase in phloem loadingen_ZA
dc.typeThesisen_ZA
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