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Expression profiling marker genes of the salicylic acid and methyl jasmonate signalling pathways in Eucalyptus grandis
Dissertation (MSc)--University of Pretoria, 2014.
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| Language: | English |
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University of Pretoria
2013
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| _version_ | 1867613703211319296 |
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| access_status_str | Open Access |
| author2 | Naidoo, Sanushka |
| author_browse | Naidoo, Sanushka |
| author_facet | Naidoo, Sanushka |
| collection | Thesis |
| dc_rights_str_mv | © 2011, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. E12/4/514/ |
| description | Dissertation (MSc)--University of Pretoria, 2014. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/31151 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:40:21.476Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/31151 Expression profiling marker genes of the salicylic acid and methyl jasmonate signalling pathways in Eucalyptus grandis Naidoo, Sanushka Berger, David Kenneth Myburg, Alexander Andrew Naidoo, Ronishree Eucalyptus species UCTD Salicylic acid Methyl jasmonate Eucalyptus grandis Dissertation (MSc)--University of Pretoria, 2014. Eucalyptus species form an integral part of the South African forestry industry and their uses extend from paper and pulp production to the synthesis of essential oils which are used in various cosmetic products. Throughout their lifetime these hosts are naturally challenged with various pests and pathogens, most of which cause devastating diseases. An approach to curb the spread of pathogens is to enhance the defence response of the host. Most of the information pertaining to defence against pathogens stems from studies conducted in model organisms such as Arabidopsis, however such information is scarce in woody species such as Eucalyptus. It is understood, from model systems, that once the pathogen is perceived by the host, a cascade of defences are initiated such as the activation of salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) signalling pathways. These pathways in turn activate the expression of genes involved in limiting the spread of the pathogen such as pathogenesis-related (PR) proteins. Certain PR genes have also been shown to be markers of the induction of a specific pathway e.g. PR2 is a marker for the SA pathway. This study aimed to elucidate marker genes specific to the SA (PR1, PR2 and PR5) and JA (PR3, PR4 and LOX) signalling pathways in Eucalyptus grandis using the genome sequence, bioinformatics tools and sequence information from other plant species. A co-phylogenetic approach using neighbour joining analysis and maximum likelihood was used to identify and add confidence in the selection of putative orthologs. Following the selection of orthologous markers, the expression profile of these candidate genes was assessed using Reverse transcriptase quantitative PCR (RT-qPCR). Transcript profiling was conducted under mock induction of the signalling pathways as well as under pathogen stress. For the mock induction of the pathways, the expression profiles of the putative marker genes were investigated under various concentrations of the inducer and at various time points. In the interaction with Chrysoporthe austroafricana it was observed that the SA signalling pathway could have a role in facilitating resistance due to the expression profile observed for EgrPR2. In the tolerant genotype (TAG5) this gene was induced at an earlier time point as opposed to the susceptible genotype (ZG14). These putative markers could provide a diagnostic tool for the screening of pathogen challenged eucalypts to determine which signalling pathway(s) are activated against various pathogens. In addition, this research adds to our knowledge of defence responses in E. grandis by elucidating genes that can be used as targets for improving resistance. Additionally this study provides a stepping stone for understanding mechanisms to curb future tree diseases. Genetics Unrestricted 2013-09-09T12:06:48Z 2012-08-14 2013-09-09T12:06:48Z 2012-04-19 2012-08-14 2012-08-10 Dissertation Naidoo, R 2014, Expression profiling marker genes of the salicylic acid and methyl jasmonate signalling pathways in Eucalyptus grandis, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/31151> E12/4/514/gm http://hdl.handle.net/2263/31151 http://upetd.up.ac.za/thesis/available/etd-08102012-160146/ en © 2011, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. E12/4/514/ application/pdf University of Pretoria |
| spellingShingle | Eucalyptus species UCTD Salicylic acid Methyl jasmonate Eucalyptus grandis Expression profiling marker genes of the salicylic acid and methyl jasmonate signalling pathways in Eucalyptus grandis |
| title | Expression profiling marker genes of the salicylic acid and methyl jasmonate signalling pathways in Eucalyptus grandis |
| title_full | Expression profiling marker genes of the salicylic acid and methyl jasmonate signalling pathways in Eucalyptus grandis |
| title_fullStr | Expression profiling marker genes of the salicylic acid and methyl jasmonate signalling pathways in Eucalyptus grandis |
| title_full_unstemmed | Expression profiling marker genes of the salicylic acid and methyl jasmonate signalling pathways in Eucalyptus grandis |
| title_short | Expression profiling marker genes of the salicylic acid and methyl jasmonate signalling pathways in Eucalyptus grandis |
| title_sort | expression profiling marker genes of the salicylic acid and methyl jasmonate signalling pathways in eucalyptus grandis |
| topic | Eucalyptus species UCTD Salicylic acid Methyl jasmonate Eucalyptus grandis |
| url | http://hdl.handle.net/2263/31151 http://upetd.up.ac.za/thesis/available/etd-08102012-160146/ |