Identification of regulatory elements mediating responses of SOD and cystatin transcripts to salt stress and nitric oxide in soybean nodules

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dc.contributor.advisorLudidi, N. N.en_ZA
dc.contributor.advisorHills, Paul N.en_ZA
dc.contributor.authorJacobs, Frans Alexanderen_ZA
dc.contributor.otherStellenbosch University. Faculty of AgriSciences. Dept. of Genetics. Institute for Plant Biotechnologyen_ZA
dc.date.accessioned2012-01-23T09:24:33Zen_ZA
dc.date.accessioned2012-03-30T10:34:48Z
dc.date.available2012-01-23T09:24:33Zen_ZA
dc.date.available2012-03-30T10:34:48Z
dc.date.issued2012-03en_ZA
dc.descriptionThesis (MSc)--Stellenbosch University, 2012.en_ZA
dc.description.abstractENGLISH ABSTRACT: Nitric oxide (NO) has previously been shown to play a vital role in plants that are undergoing oxidative stress arising from abiotic stress. To better understand the role of NO on the antioxidative pathway, the effect of NO on Superoxide Dismutase (SOD) activity was studied during salt stress on soybean nodules. The enzymatic activity of specific MnSOD and FeSOD isoforms increased upon 1 week of exposure of nodules to NO or salt stress, the activity of CuZnSOD isoforms however increased in response to salt stress only. Furthermore, 4 putative FeSOD and MnSOD transcripts were identified and shown to increase in response to NO and salt stress. The promoter sequences of these NO-responsive putative SOD genes were analysed alongside a cystatin (AtCYS-1) which is also NO-inducible. Putative NO-responsive cis-acting elements as well as abiotic stress-responsive cis-acting elements were studied amongst these promoter sequences. The MYCL element and the AtMYB4 binding site were found to occur in all four NO-inducible SOD promoter sequences as well as in the AtCYS-1 promoter sequence. This suggests that NO acts via MYCL and/or AtMYB4 to up-regulate specific FeSODs and MnSODs, causing an increase in the activity of these SOD isoforms, thus reducing oxidative stress and cell death in soybean nodules. Furthermore, NO may also be up-regulating cystatins to inhibit cysteine proteases, thus preventing the onset of programmed cell death (PCD) and subsequently reducing salt stress-induced cell death.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Geen opsommingaf_ZA
dc.format.extent64 p. : ill.
dc.identifier.urihttp://hdl.handle.net/10019.1/20024
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch University
dc.subjectSODen_ZA
dc.subjectSuperoxide dismutaseen_ZA
dc.subjectNitric oxideen_ZA
dc.subjectCystatinen_ZA
dc.subjectSalt stress in plantsen_ZA
dc.subjectSoybeanen_ZA
dc.subjectNodulesen_ZA
dc.subjectDissertations -- Plant biotechnologyen_ZA
dc.subjectTheses -- Plant biotechnologyen_ZA
dc.subjectDissertations -- Geneticsen_ZA
dc.subjectTheses -- Geneticsen_ZA
dc.titleIdentification of regulatory elements mediating responses of SOD and cystatin transcripts to salt stress and nitric oxide in soybean nodulesen_ZA
dc.typeThesis
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