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Identification and expression analysis of putative NLR genes in avocado, Persea americana, during infection by the oomycete, Phytophthora cinnamomi
Dissertation (MSc (Genetics))--University of Pretoria, 2021.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2022
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| _version_ | 1867613436982067201 |
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| access_status_str | Open Access |
| author2 | Van den Berg, Noelani |
| author_browse | Van den Berg, Noelani |
| author_facet | Van den Berg, Noelani |
| collection | Thesis |
| dc_rights_str_mv | © 2019 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. |
| description | Dissertation (MSc (Genetics))--University of Pretoria, 2021. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/83476 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:36:07.570Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| 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:2263/83476 Identification and expression analysis of putative NLR genes in avocado, Persea americana, during infection by the oomycete, Phytophthora cinnamomi Van den Berg, Noelani alicia.fick@up.ac.za Swart, Velushka Fick, Alicia Avocado Resistance genes UCTD Dissertation (MSc (Genetics))--University of Pretoria, 2021. Avocado production in South Africa is significantly affected by the pathogen Phytophthora cinnamomi. This pathogen causes root necrosis in infected rootstocks, which may ultimately lead to plant death and thus economic losses. The complex molecular interactions between avocado and P. cinnamomi are not well understood and might be the key to breeding P. cinnamomi resistant rootstocks. Understanding the molecular mechanisms behind successful immune responses against P. cinnamomi is thus of utmost importance. Nucleotide binding-Leucine rich repeat (NLR) proteins play an important role in activating the Effector triggered immune (ETI) response after pathogen effector recognition. This immune response leads to a Hypersensitive response and cell death, which restricts P. cinnamomi growth during the pathogen’s biotrophic stage. Furthermore, previous studies have shown that differential expression patterns of NLR genes influences the amplitude of the ETI response. The importance of NLR proteins during P. cinnamomi infection and whether they play a role in rootstock resistance levels remain unclear. Chapter 1 of this thesis provides a detailed review of NLR proteins. The structure of these proteins is described, together with the molecular mechanisms which regulate the expression of NLR genes. Various examples are given regarding how NLR gene expression changes after pathogen infection in other plant species, and how NLR gene sequence variations within a plant species influence resistance levels towards various pathogens. Furthermore, methods for NLR identification and characterization using a genomic approach are discussed. Lastly, a summary is given on NLR sequences found in woody tree species and how this knowledge can be applied to avocado trees. Chapter 2 reports on the PaNLRs identified in avocado using a bioinformatic approach and the VC75 avocado genome. Gene clusters were identified, and phylogenetic analysis was performed to investigate possible PaNLR gene duplication events. PaNLR expression analysis was done using dual RNA-seq data obtained from a partially resistant and susceptible rootstock inoculated with P. cinnamomi. The expression data was used to indicate which PaNLRs are potentially important for the detection of P. cinnamomi infection, and to assess whether a difference in PaNLR expression was evident between the two rootstocks. The Hans Merensky Foundation Genetics MSc (Genetics) Unrestricted 2022-01-27T06:57:07Z 2022-01-27T06:57:07Z 2022-05-09 2021 Dissertation Fick, A 2022, Identification and expression analysis of putative NLR genes in avocado, Persea americana, during infection by the oomycete, Phytophthora cinnamomi, University of Pretoria, Pretoria http://hdl.handle.net/2263/83476 A2022 http://hdl.handle.net/2263/83476 en © 2019 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. application/pdf University of Pretoria |
| spellingShingle | Avocado Resistance genes UCTD Identification and expression analysis of putative NLR genes in avocado, Persea americana, during infection by the oomycete, Phytophthora cinnamomi |
| title | Identification and expression analysis of putative NLR genes in avocado, Persea americana, during infection by the oomycete, Phytophthora cinnamomi |
| title_full | Identification and expression analysis of putative NLR genes in avocado, Persea americana, during infection by the oomycete, Phytophthora cinnamomi |
| title_fullStr | Identification and expression analysis of putative NLR genes in avocado, Persea americana, during infection by the oomycete, Phytophthora cinnamomi |
| title_full_unstemmed | Identification and expression analysis of putative NLR genes in avocado, Persea americana, during infection by the oomycete, Phytophthora cinnamomi |
| title_short | Identification and expression analysis of putative NLR genes in avocado, Persea americana, during infection by the oomycete, Phytophthora cinnamomi |
| title_sort | identification and expression analysis of putative nlr genes in avocado persea americana during infection by the oomycete phytophthora cinnamomi |
| topic | Avocado Resistance genes UCTD |
| url | http://hdl.handle.net/2263/83476 |