Puccinia triticina (leaf rust) is an obligate biotrophic fungus. It is a major pathogen of
Triticum aestivum (wheat) all over the world. In a previous study, two differentially
expressed genes were cloned from resistant wheat infected with P. triticina. According
to the sequence analysis, the first encoded a cell wall invertase (TaCwi01) and the other a
monosaccharide transporter (TaMst01). These two genes and their encoded proteins
appear to play a role during sugar signaling. Sugar signaling has already been described
in several plant-pathogen interactions. In this study, the presence of sugar signaling as
well as the roles of TaCwi01, TaMst01 and a hexokinase gene in the leaf rust รข wheat
interaction were investigated.
Gene expression studies of all three genes showed both early as well as late changes in
expression. TaCwi01 gene expression showed an early induction in IS plants at 3 hpi
followed by an immediate and complete inhibition until 36 hpi. Expression in IR plants
was repressed for the duration of the study with a transient increase at 21 hpi. Enzyme
activity analysis revealed a similar pattern of the expression with a significant activation
in both IS and IR plants at 27 and 24 hpi respectively.
Results of TaMst01 expression revealed both an early induction at 3 to 6 hpi and a late
induction at 33 hpi in IS and IR plants. The later induction in expression of TaMst01 was
reflected in the significant increase in MST activity at 30 hpi. Hexokinase expression
analysis showed a slight increase in expression from 0 to 6 hpi in both IS and IR plants.
This was again associated with increased enzyme activity shortly after infection.
Furthermore it was shown that due to a SCPU domain in the polypeptide sequence of
TaCwi01, it is possible that this gene could have originated from the pathogen. It was
concluded that a putative sugar signaling took place during the infection of wheat with
leaf rust and that all three genes played a definite role.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-11272007-094901 |
| Date | 27 November 2007 |
| Creators | Liebenberg, Johannes Jacobus Rabie |
| Contributors | Prof AJ van der Westhuizen, Dr B Visser |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-11272007-094901/restricted/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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