>Magister Scientiae - MSc / Agricultural production is one of the most important sectors which provide food for the
growing world population which is estimated to reach 9.7 billion by 2050, thus there is a need
to produce more food. Climate change, on the other hand, is negatively affecting major global
crops such as maize, sorghum, wheat and barley. Environmental factors such as salinity,
drought, high temperatures and pathogens affect plant production by oxidatively damaging the
physiological processes in plants, leading to plant death. Poor irrigation used to combat drought
result in salinasation, which is estimated to affect 50% of arable land by 2050. Plants have
developed several mechanisms that protect them against stress and these include
overexpression of stress responsive genes and altered signal transduction to change the
expression of stress responsive genes, among others. Cyclic 3’5’ guanosine monophosphate
(cGMP), a second messenger that is synthesised by guanylyl cyclase (GC), transmit signals to
various cellular functions in plants during plant development, growth and response to abiotic
and biotic stresses. Arabidopsis thaliana nitric oxide guanylyl cyclase 1 (AtNOGC1) is a
guanylyl cyclase which upon activation by nitric oxide (NO) leads to the production of more
cGMP. Cyclic GMP further activates protein kinases, ion gated channels and
phosphodiesterase which mediate response to various stresses.
In this project the role of AtNOGC1 was investigated in response to abiotic and biotic stresses
through analysis of its evolutionary relationships, promoter, gene expression and functional
analysis via the viability assays in Escherichia coli (E.coli). Phylogenetic tree, exon-intron
structure and conserved motifs were analysed using the Molecular Evolutionary Genetics
Analysis (MEGA V.7), Gene Structure Display Server 2.0 (GSDS 2.0), and Multiple
Expectation Maximisation for Motif Elicitation (MEME) tools respectively. AtNOGC1’s gene
expression was analysed by the Real-Time Quantitative Reverse Transcription Polymerase
Reaction (qRT-PCR), whereas functional analysis was carried out using the cell viability
(liquid and spot) assays to determine its ability to confer stress tolerance to E. coli.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uwc/oai:etd.uwc.ac.za:11394/6763 |
| Date | January 2018 |
| Creators | Muthevhuli, Mpho |
| Contributors | Mulaudzi-Masuku, Takalani, Iwuoha, Emmanuel, Donaldson, Lara |
| Publisher | University of the Western Cape |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Rights | University of the Western Cape |
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