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Molecular characterisation of RNA interference in Fusarium circinatum

Dissertation (MSc (Genetics))--University of Pretoria, 2024.

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Other Authors: Steenkamp, Emma Theodora
Format: Thesis
Language:English
Published: University of Pretoria 2024
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access_status_str Open Access
author2 Steenkamp, Emma Theodora
author_browse Steenkamp, Emma Theodora
author_facet Steenkamp, Emma Theodora
collection Thesis
dc_rights_str_mv © 2023 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, 2024.
format Thesis
id oai:repository.up.ac.za:2263/96579
institution University of Pretoria (South Africa)
language English
last_indexed 2026-06-10T12:38:23.596Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2024
publishDateRange 2024
publishDateSort 2024
publisher University of Pretoria
publisherStr University of Pretoria
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source_str UPSpace — University of Pretoria Institutional Repository
spelling oai:repository.up.ac.za:2263/96579 Molecular characterisation of RNA interference in Fusarium circinatum Steenkamp, Emma Theodora boitshokorammuki@gmail.com Santana, Quentin Wingfield, Brenda D. Motaung, Thabiso Eric Rammuki, Boitshoko Mercia Fusarium circinatum RNA interference Spray-induced gene silencing (SIGS) Dicer Argonaute RNA-dependent RNA polymerase UCTD Natural and agricultural sciences theses SDG-08 SDG-08: Decent work and economic growth Dissertation (MSc (Genetics))--University of Pretoria, 2024. RNA interference is an important biological pathway that can be induced to control plant pathogens. Methods of application include host-, virus- and spray-induced gene silencing. While earlier research concentrated on host-induced gene silencing (HIGS), recent studies indicate that spray-induced gene silencing is now considered the more effective approach. This study focused on using spray-induced gene silencing (SIGS) to induce silencing in Fusarium circinatum which causes pitch canker on Pinus species. This work first determined whether RNAi pathways are functional in F. circinatum. The protein sequences of Neurospora crassa RNAi genes were used to identify the 7 RNAi-related genes in 21 Fusarium species including F. circinatum and 13 other fungal species. All the species had the core RNAi genes including Argonaute, Dicer and RNA-dependent RNA polymerase (RdRP). An additional Argonaute gene was found, forming a sister clade to SMS-2 (suppressor of meiotic silencing 2, an argonaute protein in N. crassa) containing clade. A total of 99 Argonaute, 70 Dicer, 120 RdRP, 38 RecQ helicase, 68 RPA, 34 QIP and MRPL3 genes were found in the 34 species. Most species possessed 3 Argonaute, 2 Dicer, 4 RdRP, 2 RPA, 1 QIP, RecQ helicase and MRPL3 genes. The greatest variation in gene copy number was observed with regards to Argonaute and RdRP genes. Gene phylogenies were also generated for comparison to the species tree. The congruency between the gene trees and species tree suggests that the RNAi genes are conserved. InterProScan was used to determine the protein domain organisation in each gene. All the identified putative proteins had the necessary domains associated with RNAi proteins. In a subsequent pilot study, application of double-stranded RNA (dsRNA) to F. circinatum GFP (green fluorescent protein) mutants reduced the expression of GFP. This was reflected by a significant difference in GFP fluorescence compared to the control. In a bigger study, this was not observed, potentially due to use of growth medium containing rifampicin, which have been shown to affect eukaryotic RNA dependent RNase activity. Additional studies are thus needed to decipher the impact of rifampicin on RNAi, and the original experiment should be repeated without rifampicin. Furthermore, Reverse Transcriptase-quantitative PCR (RT-qPCR) and small RNA-Seq analyses should be performed to validate the efficacy of the applied dsRNA in gene silencing. Overall, the work presented in this dissertation presents a valuable first step towards the development of SIGS or some other RNAi-based approach for controlling F. circinatum. Genetics MSc (Genetics) Unrestricted Faculty of Natural and Agricultural Sciences SDG-08: Decent work and economic growth 2024-06-21T07:55:33Z 2024-06-21T07:55:33Z 2024-09 2024-02 Dissertation * S2024 http://hdl.handle.net/2263/96579 DOI: https://doi.org/10.25403/UPresearchdata.26001067.v1 10.25403/UPresearchdata.26001067 en © 2023 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 Fusarium circinatum
RNA interference
Spray-induced gene silencing (SIGS)
Dicer
Argonaute
RNA-dependent RNA polymerase
UCTD
Natural and agricultural sciences theses SDG-08
SDG-08: Decent work and economic growth
Molecular characterisation of RNA interference in Fusarium circinatum
title Molecular characterisation of RNA interference in Fusarium circinatum
title_full Molecular characterisation of RNA interference in Fusarium circinatum
title_fullStr Molecular characterisation of RNA interference in Fusarium circinatum
title_full_unstemmed Molecular characterisation of RNA interference in Fusarium circinatum
title_short Molecular characterisation of RNA interference in Fusarium circinatum
title_sort molecular characterisation of rna interference in fusarium circinatum
topic Fusarium circinatum
RNA interference
Spray-induced gene silencing (SIGS)
Dicer
Argonaute
RNA-dependent RNA polymerase
UCTD
Natural and agricultural sciences theses SDG-08
SDG-08: Decent work and economic growth
url http://hdl.handle.net/2263/96579