Gene expression associated with drought tolerance in Xerophyta viscosa Baker

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dc.contributor.advisorMundree, Sagadevan Gen_ZA
dc.contributor.advisorFarrant, Jill Men_ZA
dc.contributor.advisorThomson, Jennifer Annen_ZA
dc.contributor.authorNdima, Tozama Beautyen_ZA
dc.date.accessioned2014-07-30T17:40:29Z
dc.date.available2014-07-30T17:40:29Z
dc.date.issued2000en_ZA
dc.descriptionBibliography: leaves 89-100.
dc.description.abstractHerophyta viscosa (Baker) is a monocytyledonous resurrection plant that can tolerate extremes of dessication. Upon rewatering, it rehydrates completely and assumes its full physiological activities. Studies on changes in gene expression associated with dehydration stress tolerance were conducted. A cDNA library constructed from m RNA isolated from dehydrated (85%, 37% and 5% relative water content) X. viscosa leaves, was differently screened. Of the 192 randomly selected cDNAs screened, 30 showed higher expression levels when X. viscosa was dehydrated while 20 showed lower expession. XVLEA, XVDH and XVLEC represent three cDNAs that were upregulated during dehydration stress. XVLEA showed the highest identity at the amino acid level with a late embryogenesis abundant protein, LEA29G, from Gossipium hirsutum (30%) and LEA D-29 from cotton (50%). XVDH exhibited significant identity to dehydrin proteins from Arabidopsis thaliana (45%) and Pisum sativum (43%) at the amino acid level. It encodes a glycine-rich protein (27kDa) which is largely hydrophilic and contains a hydrophobic segment at the C-terminus. XVLEC showed 28% identity and 50% similarity to a lectin-like protein from Arabidopsis thaliana. Southern blot analysis confirmed the presence of the three cDNAs in the X.viscosa genome. Both XVLEA and XVDH transcripts were highly expressed during dehydration- (37% RWC) and rehydration (4%, 32%, 72% RWC) treatment of the plant ͌ 1.0kb was observed. However, with XVDH a transcript of ͌ 1.0 kb and 1.09 kb were observed. XVDH transcripts accumulated in X. viscosa plants in response to low temperature, heat and dehydration stresses, as well as to exogenous supply of abscisic acid, ethylene and methyl jasmonate. Localization studies of the XVDH encoded protein showed that XVDH is located in the plasma membrane-cell wall region.en_ZA
dc.identifier.apacitationNdima, T. B. (2000). <i>Gene expression associated with drought tolerance in Xerophyta viscosa Baker</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology. Retrieved from http://hdl.handle.net/11427/4309en_ZA
dc.identifier.chicagocitationNdima, Tozama Beauty. <i>"Gene expression associated with drought tolerance in Xerophyta viscosa Baker."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 2000. http://hdl.handle.net/11427/4309en_ZA
dc.identifier.citationNdima, T. 2000. Gene expression associated with drought tolerance in Xerophyta viscosa Baker. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Ndima, Tozama Beauty AB - Herophyta viscosa (Baker) is a monocytyledonous resurrection plant that can tolerate extremes of dessication. Upon rewatering, it rehydrates completely and assumes its full physiological activities. Studies on changes in gene expression associated with dehydration stress tolerance were conducted. A cDNA library constructed from m RNA isolated from dehydrated (85%, 37% and 5% relative water content) X. viscosa leaves, was differently screened. Of the 192 randomly selected cDNAs screened, 30 showed higher expression levels when X. viscosa was dehydrated while 20 showed lower expession. XVLEA, XVDH and XVLEC represent three cDNAs that were upregulated during dehydration stress. XVLEA showed the highest identity at the amino acid level with a late embryogenesis abundant protein, LEA29G, from Gossipium hirsutum (30%) and LEA D-29 from cotton (50%). XVDH exhibited significant identity to dehydrin proteins from Arabidopsis thaliana (45%) and Pisum sativum (43%) at the amino acid level. It encodes a glycine-rich protein (27kDa) which is largely hydrophilic and contains a hydrophobic segment at the C-terminus. XVLEC showed 28% identity and 50% similarity to a lectin-like protein from Arabidopsis thaliana. Southern blot analysis confirmed the presence of the three cDNAs in the X.viscosa genome. Both XVLEA and XVDH transcripts were highly expressed during dehydration- (37% RWC) and rehydration (4%, 32%, 72% RWC) treatment of the plant ͌ 1.0kb was observed. However, with XVDH a transcript of ͌ 1.0 kb and 1.09 kb were observed. XVDH transcripts accumulated in X. viscosa plants in response to low temperature, heat and dehydration stresses, as well as to exogenous supply of abscisic acid, ethylene and methyl jasmonate. Localization studies of the XVDH encoded protein showed that XVDH is located in the plasma membrane-cell wall region. DA - 2000 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2000 T1 - Gene expression associated with drought tolerance in Xerophyta viscosa Baker TI - Gene expression associated with drought tolerance in Xerophyta viscosa Baker UR - http://hdl.handle.net/11427/4309 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/4309
dc.identifier.vancouvercitationNdima TB. Gene expression associated with drought tolerance in Xerophyta viscosa Baker. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 2000 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/4309en_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.otherMicrobiologyen_ZA
dc.titleGene expression associated with drought tolerance in Xerophyta viscosa Bakeren_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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