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Investigating the role of a pyrabactin resistance 1-like abscisic acid receptor gene to improve drought tolerance in sugarcane
Thesis (MScAgric)--Stellenbosch University, 2022.
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Stellenbosch : Stellenbosch University
2022
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| _version_ | 1867613958537478144 |
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| access_status_str | Open Access |
| author | Fischer, Riette Louwrene |
| author2 | Van der Vyver, Christell |
| author_browse | Fischer, Riette Louwrene Van der Vyver, Christell |
| author_facet | Van der Vyver, Christell Fischer, Riette Louwrene |
| author_sort | Fischer, Riette Louwrene |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2022. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/126345 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:44:24.894Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/126345 Investigating the role of a pyrabactin resistance 1-like abscisic acid receptor gene to improve drought tolerance in sugarcane Fischer, Riette Louwrene Van der Vyver, Christell Stellenbosch University. Faculty of AgriSciences. Department of Genetics & Institute of Plant Biotechnology. Sugarcane -- Growth Feedstock Biomass energy Sugarcane -- Drought tolerance -- Genetic aspects Sugarcane -- Water requirements Crops and climate Sugarcane -- Effect of stress on Climatic factors Abscisic acid -- Physiological aspects Plants -- Effect of drought on Transgenes -- Expression UCTD Thesis (MScAgric)--Stellenbosch University, 2022. ENGLISH ABSTRACT: Sugarcane is one of the world's major C4 crops and is mainly grown in tropic and subtropic environments. Sugarcane is primarily used for sugar production and as a bioenergy feedstock. Abiotic factors such as temperature and water availability have a signif icant effect on sugarcane yield worldwide. The production of sugarcane has been negatively impacted and will likely continue to be affected by the increase in the frequency and intensity of extreme environmental conditions such as droughts due to climate change. Abscisic acid (ABA) is a major phytohormone that plays a key role in plant growth and development. It also plays a role in abiotic stresses, such as drought and salinity stress, by controlling stomatal closure and osmotic potential. In general, ABA regulates physiological processes in response to water deficit stress perception. The presence of ABA is sensed by pyrabactin resistance (PYR)/pyr-like (PYL) receptors. The ligation of ABA to a PYR/PYL receptor induces a conformational change in the receptor rendering them to bind and inhibit type 2C protein phosphatases (PP2C). The inhibition of PP2C’s releases the inhibition of sucrose non-fermenting 1-related protein kinase 2 (SnRK2), which are then able to phosphorylate certain transcription factors (TFs) resulting in the regulation of ABA-dependant signalling pathways and the expression of ABA-responsive genes. Previous research has indicated that the Arabidopsis thaliana PYL9 gene plays an import role in promoting drought tolerance by influencing dormancy-like responses and leaf senescence. In this study, sugarcane plants overexpressing the AtPYL9 transgene, both constitutively as well as in a stress-inducible manner, were successfully generated through particle bombardment. Transgene insertion was confirmed in putative transformed sugarcane through PCR analysis and transgene expression was confirmed through semi-quantitative reverse transcription PCR. The effectiveness of the stress-inducible promoter, Rab17, was tested through quantitative real-time PCR. Transgenic sugarcane plantlets were planted ex vitro and drought pot trials were setup. Once plants were deprived of water, phenotypic and biochemical changes in transgenic sugarcane lines were compared to non-transgenic control sugarcane plants. The physiological and biochemical analysis of the plant material indicated that there was no significance enhancement in the drought tolerance of the transgenic sugarcane plants when compared to the wild-type (WT) control plants. To expand on the knowledge known about the sugarcane genome an attempt to identify the orthologue of AtPYL9 was made. A phylogenetic approach was successful in identifying the presumed sugarcane orthologue which was called ShPYL9.1. This ShPYL9.1 gene contains the conserved regions known to play a role in ABA binding and PP2C interaction: CL1-CL4. To functionally annotate the identified orthologue transgenic tobacco plants constitutively overexpressing the transgene were generated and exposed to water deficit stress. The result of the drought trial was that the ShPYL9.1 transgene did not play a similar role as AtPYL9 in the drought tolerance capabilities of the transgenic plants, however ShPYL9,1 can be confidently classified as a PYL receptor and does seem to interact with native SnRK2’s. AFRIKAANSE OPSOMMING: Suikerriet is een van die wêreld se belangrikste C4-gewasse en word hoofsaaklik in tropiese en subtropiese omgewings verbou. Suikerriet word hoofsaaklik vir suikerproduksie en ook as 'n bio-energie voer gebruik. Abiotiese faktore soos temperatuur- en waterbeskikbaarheid het 'n beduidende uitwerking op suikerrietopbrengs wêreldwyd. Die produksie van suikerriet word ook negatief beïnvloed en sal waarskynlik steeds beïnvloed word deur die toename in die frekwensie en intensiteit van uiterste omgewingstoestande soos droogtes as gevolg van klimaatsverandering. Absisiensuur (ABA) is 'n belangrike fitohormoon wat 'n sleutelrol speel in plantgroei en - ontwikkeling. Dit speel ook 'n rol in abiotiese stremmings, soos droogte en soutgehaltestres, deur die stomatale sluiting en osmotiese potensiaal te beheer. Oor die algemeen reguleer ABA fisiologiese prosesse in reaksie op die persepsie van die spanning van watertekort. Die teenwoordigheid van ABA word waargeneem deur pyrabaktienweerstand (PYR)/pyr-like (PYL) reseptore. Die afbinding van ABA aan 'n PYR/PYL-reseptor veroorsaak 'n konformasieverandering in die reseptor wat dit lewer om aan tipe 2C proteïenfosfatase (PP2C) te bind en te belemmer. Die remming van PP2C's stel die remming van sukrose nie-gierende 1-verwante proteïen kinase 2 (SnRK2) vry wat dan in staat is om transkripsiefaktore (TF's) te fosforileer wat lei tot die regulering van die uitdrukking van ABA-responsiewe gene. Vorige navorsing het aangedui dat die Arabidopsis thaliana PYL9 geen 'n belangrike rol speel in die bevordering van droogteverdraagsaamheid deur dormansie en blaarveroudering te beinvloed. In hierdie studie was suikerrietplante wat die AtPYL9-transgeen beide konstitutief sowel as in 'n stres-induseerbare manier uitdruk, suksesvol deur deeltjiebombardement gegenereer. Transgene-invoeging is bevestig in die geplaasde getransformeerde suikerriet deur polimerase kettingreaksie (PCR) analise en transgene-uitdrukking is bevestig deur semi- kwantitatiewe omgekeerde transkripsie PCR. Die doeltreffendheid van die stres-induseerbare promotor, Rab17, is getoets deur kwantitatiewe omgekeerde transkripsie PCR. Transgeniese suikerrietplantette is ex vitro geplant en droogtepotproewe is opgestel. Sodra plante van water ontneem is, is fenotipiese en biochemiese veranderinge in transgeniese suikerrietlyne vergelyk met die nie-transgeniese kontrole suikerrietplante. Die fisiologiese en biochemiese ontleding van die plantmateriaal het aangedui dat daar geen betekenis in die droogtetoleransie van die transgeniese suikerrietplante was in vergelyking met die wildtipe (WT) kontroleplante nie. Om die kennis wat oor die suikerrietgenoom bekend is, uit te brei, is 'n poging aangewend om die ortoloog van AtPYL9 te identifiseer. 'n Filogenetiese benadering was suksesvol met die identifisering van die veronderstelde ortoloog van AtPYL9, wat ShPYL9.1 genoem is. Hierdie ShPYL9.1-geen bevat die gekonserveerde streke wat bekend is dat dit 'n rol speel in ABA- binding en PP2C-interaksie: CL1-CL4. Om die geïdentifiseerde ortoloog funksioneel te annoteer, is transgeniese tabakplante wat die transgene uitdruk gegenereer en blootgestel aan ‘n watertekort periode. Die resultaat van die droogtepotproef was dat die ShPYL9.1- transgene nie 'n soortgelyke rol as AtPYL9 speel in die droogteverdraagsaamheidsvermoëns nie, maar ShPYL9.1 kan met vertroue as 'n PYL-reseptor geklassifiseer word en het ‘n interaksie met inheemse SnRK2’s. Masters 2022-11-23T15:58:10Z 2023-01-23T06:53:15Z 2022-11-23T15:58:10Z 2022-12 Thesis http://hdl.handle.net/10019.1/126345 en_ZA Stellenbosch University xxix, 156 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Sugarcane -- Growth Feedstock Biomass energy Sugarcane -- Drought tolerance -- Genetic aspects Sugarcane -- Water requirements Crops and climate Sugarcane -- Effect of stress on Climatic factors Abscisic acid -- Physiological aspects Plants -- Effect of drought on Transgenes -- Expression UCTD Fischer, Riette Louwrene Investigating the role of a pyrabactin resistance 1-like abscisic acid receptor gene to improve drought tolerance in sugarcane |
| title | Investigating the role of a pyrabactin resistance 1-like abscisic acid receptor gene to improve drought tolerance in sugarcane |
| title_full | Investigating the role of a pyrabactin resistance 1-like abscisic acid receptor gene to improve drought tolerance in sugarcane |
| title_fullStr | Investigating the role of a pyrabactin resistance 1-like abscisic acid receptor gene to improve drought tolerance in sugarcane |
| title_full_unstemmed | Investigating the role of a pyrabactin resistance 1-like abscisic acid receptor gene to improve drought tolerance in sugarcane |
| title_short | Investigating the role of a pyrabactin resistance 1-like abscisic acid receptor gene to improve drought tolerance in sugarcane |
| title_sort | investigating the role of a pyrabactin resistance 1 like abscisic acid receptor gene to improve drought tolerance in sugarcane |
| topic | Sugarcane -- Growth Feedstock Biomass energy Sugarcane -- Drought tolerance -- Genetic aspects Sugarcane -- Water requirements Crops and climate Sugarcane -- Effect of stress on Climatic factors Abscisic acid -- Physiological aspects Plants -- Effect of drought on Transgenes -- Expression UCTD |
| url | http://hdl.handle.net/10019.1/126345 |
| work_keys_str_mv | AT fischerriettelouwrene investigatingtheroleofapyrabactinresistance1likeabscisicacidreceptorgenetoimprovedroughttoleranceinsugarcane |