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The volatile tale of arabidopsis thaliana: enhancing plant growth and salinity stress tolerance by overexpressing α-acetolactate decarboxylase to produce acetoin in planta
Thesis (MScAgric)--Stellenbosch University, 2021.
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Stellenbosch : Stellenbosch University
2021
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| _version_ | 1867614098161664000 |
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| access_status_str | Open Access |
| author | Rust, Catharina Magdalena (Carlien) |
| author2 | Hills, Paul N. |
| author_browse | Hills, Paul N. Rust, Catharina Magdalena (Carlien) |
| author_facet | Hills, Paul N. Rust, Catharina Magdalena (Carlien) |
| author_sort | Rust, Catharina Magdalena (Carlien) |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2021. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/110557 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:46:38.139Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/110557 The volatile tale of arabidopsis thaliana: enhancing plant growth and salinity stress tolerance by overexpressing α-acetolactate decarboxylase to produce acetoin in planta Rust, Catharina Magdalena (Carlien) Hills, Paul N. Van der Vyver, Christell Stellenbosch University. Faculty of AgriSciences. Dept. of Genetics. Institute for Plant Biotechnology. Acetoin in planta Plant growth promoting rhizobacteria Plants -- Effect of stress on Arabidopsis thaliana -- Effect of salt on Transgenic plants UCTD Thesis (MScAgric)--Stellenbosch University, 2021. ENGLISH ABSTRACT: The greater need for food security, along with increased abiotic stress (salinity and drought) associated with climate changes, has intensified pressure on agriculture to develop effective and eco-friendly methods to continuously increase crop yields. Moreover, particularly salinity affects an estimated 20% of irrigated land and increased salt concentrations in the soil can cause the death of vegetation and negatively affect crop production. Plant growth promoting rhizobacteria (PGPR) that live in symbiosis with plant roots were suggested as a potential source of new alternative methods to enhance plant growth and induce tolerance to stress. In particular, volatile compounds, such as acetoin produced by certain PGPR, have been shown to enhance plant growth and induce salinity stress tolerance in different plant species. The aim of this study was to investigate the effect of acetoin on plant growth and salinity stress tolerance via the application of the pure compound, and, as a volatile organic compound, produced by transgenic Escherichia coli bacteria and transgenic Arabidopsis thaliana plants. Both transgenic bacteria and plants were generated by transforming the ALDC gene encoding α-acetolactate decarboxylase, responsible for converting α-acetolactate to acetoin, into the respective genome. A transformed E. coli BL21-CodonPlus(DE3)-RIPL strain that can produce the volatile acetoin was successfully generated. Although the ALDC protein could not be detected in transformed E. coli cells through protein analysis, including immunoblotting, acetoin was detected via GC-MS analysis. Arabidopsis plants were further exposed to transgenic E. coli in growth and salinity tolerance experiments to determine the effect of bacterially-produced acetoin. A significant increase of fresh mass of plants exposed to the transgenic bacteria producing acetoin was found in both growth and salinity tolerance experiments when compared to plants exposed to non-engineered E. coli. No significant increase was found for dry mass between plants exposed to the different treatments, indicating a probable link between growth enhancement and relative water content. Two independent homozygous T3 acetoin-producing plants were further characterized. The expression of the ALDC transgene was demonstrated via RT-sqPCR in planta, and as a major novel achievement, the production of acetoin in both independent homozygous A-line Arabidopsis plants via GC-MS analysis was also shown. The presence of the transgene enhanced plant growth in one transgenic line (A6.8 line) grown ex vitro when compared to wild-type Arabidopsis plants, while neither of the two transgenic Arabidopsis lines had in vitro enhanced growth or salinity tolerance. The exposure of plants to the transgenic acetoin-producing bacteria was further in vitro more successful regarding increase of plant growth and eliciting salinity tolerance when compared to in planta acetoin production. The in vitro studies with transgenic Arabidopsis were not highly successful to demonstrate better plant growth and salt tolerance due to acetoin production. However, the transgenic bacteria and transgenic plants might have a greater potential to enhance plant growth and salinity stress tolerance ex vitro. This view is supported by the significant increase in average fresh and dry mass for the ex vitro grown A6.8 plants. AFRKAANSE OPSOMMING: Die groter behoefte aan voedselsekuriteit, tesame met verhoogde abiotiese stres (soutstres en droogte) wat verband hou met klimaatsverandering, het die druk op die landbou sektor verhoog om doeltreffende en omgewingsvriendelike metodes te ontwikkel om oesopbrengse deurlopend te bevorder. Boonop beïnvloed soutstres ongeveer 20% van land onder besproeiing, en die verhoogde soutkonsentrasies in grond kan die dood van vegetasie veroorsaak en oesopbrengs negatief affekteer. Plantegroei-bevorderende rhizobakterieë (PGPR) wat in simbiose met plantwortels leef, is voorgestel as moontlike bron van nuwe alternatiewe metodes om plantegroei te bevorder en stresverdraagsaamheid te induseer. In die besonder is getoon dat vlugtige verbindings soos asetoïen wat deur sekere PGPR geproduseer word, die groei van plante en die soutverdraagsaamheid by verskillende plantsoorte bevorder. Die doel van hierdie studie was om die effek van asetoïen op die groei van plante en soutverdraagsaamheid deur die gebruik van die suiwer verbinding te ondersoek, en as 'n vlugtige organiese verbinding wat geproduseer word deur transgeniese Escherichia coli bakterieë en transgeniese Arabidopsis thaliana plante. Beide transgeniese bakterieë en plante is gegenereer deur die ALDC-geen wat α-asetolaktaat dekarboksilase kodeer, verantwoordelik vir die omskakeling van α-asetolaktaat na asetoïen, in die onderskeie genoomkonteks in te voeg. ‘n Getransformeerde E. coli BL21-CodonPlus (DE3)-RIPL-stam wat die vlugtige asetoïen kan produseer, is suksesvol gegenereer. Alhoewel die ALDC-proteïen nie deur proteïen- uitdrukkingsanalise, insluitend immunoklad-analise, opgespoor kon word in transgeniese E. coli nie, is asetoïen deur GC-MS-ontleding opgespoor. Arabidopsis plante is blootgestel aan die transgeniese bakterieë in groei- en soutverdraagsaamheidsproewe om die effek van bakteriële geproduseerde asetoïen te bepaal. 'n Beduidende toename in gemiddelde vars plantmassa vir plante wat blootgestel is aan die transgeniese bakterieë wat asetoïen produseer, in vergelyking met plante wat blootgestel is aan wilde-tipe E. coli, is waargeneem vir beide groei- en soutverdraagsaamheidsproewe. Daar is egter geen noemenswaardige toename in droë massametings tussen die plante van die verskillende behandelings gesien nie, wat dui op moontlike verband tussen die bevordering van plantegroei en relatiewe waterinhoud. Twee onafhanklike homosigotiese T3 asetoïen-produserende plante is verder gevestig. Daarbenewens is die uitdrukking van die ALDC-transgeen via RT-sqPCR en, as 'n beduidende nuwe resultaat, is in planta produksie van asetoïen in Arabidopsis in beide onafhanklike homosigotiese A- lyn plante getoon via GC-MS-analise. Die aanwesigheid van die transgeen het die groei van plante in een transgeniese lyn (A6.8-lyn) verhoog wat ex vitro gegroei is, in vergelyking met die wilde-tipe Arabidopsis-plante, maar nie een van die twee transgeniese A-lyn Arabidopsis het egter groei of soutverdraagsaamheid in vitro verbeter nie. Die blootstelling van plante aan die transgeniese asetoïen-produserende bakterieë was verder in vitro meer suksesvol met betrekking tot toename in plantegroei en die verkryging van soutverdraagsaamheid in vergelyking met die produksie van asetoïen in planta. Die in vitro-studies met transgeniese Arabidopsis was oor die algemeen nie baie suksesvol om beter plantegroei en soutverdraagsaamheid as gevolg van asetoïen produksie te toon nie. Alhoewel, die transgeniese bakterieë en transgeniese plante 'n groter potensiaal kan hê om die plantegroei en soutverdraagsaamheid ex vitro te verbeter. Hierdie siening word ondersteun deur die beduidende toename in die gemiddelde vars en droë massa vir die ex vitro gekweekte A6.8 plante. Masters 2021-06-07T10:58:16Z 2021-06-07T10:58:16Z 2021-03 Thesis http://hdl.handle.net/10019.1/110557 en_ZA Stellenbosch University xxix, 123 pages : illustrations (some color) application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Acetoin in planta Plant growth promoting rhizobacteria Plants -- Effect of stress on Arabidopsis thaliana -- Effect of salt on Transgenic plants UCTD Rust, Catharina Magdalena (Carlien) The volatile tale of arabidopsis thaliana: enhancing plant growth and salinity stress tolerance by overexpressing α-acetolactate decarboxylase to produce acetoin in planta |
| title | The volatile tale of arabidopsis thaliana: enhancing plant growth and salinity stress tolerance by overexpressing α-acetolactate decarboxylase to produce acetoin in planta |
| title_full | The volatile tale of arabidopsis thaliana: enhancing plant growth and salinity stress tolerance by overexpressing α-acetolactate decarboxylase to produce acetoin in planta |
| title_fullStr | The volatile tale of arabidopsis thaliana: enhancing plant growth and salinity stress tolerance by overexpressing α-acetolactate decarboxylase to produce acetoin in planta |
| title_full_unstemmed | The volatile tale of arabidopsis thaliana: enhancing plant growth and salinity stress tolerance by overexpressing α-acetolactate decarboxylase to produce acetoin in planta |
| title_short | The volatile tale of arabidopsis thaliana: enhancing plant growth and salinity stress tolerance by overexpressing α-acetolactate decarboxylase to produce acetoin in planta |
| title_sort | volatile tale of arabidopsis thaliana enhancing plant growth and salinity stress tolerance by overexpressing α acetolactate decarboxylase to produce acetoin in planta |
| topic | Acetoin in planta Plant growth promoting rhizobacteria Plants -- Effect of stress on Arabidopsis thaliana -- Effect of salt on Transgenic plants UCTD |
| url | http://hdl.handle.net/10019.1/110557 |
| work_keys_str_mv | AT rustcatharinamagdalenacarlien thevolatiletaleofarabidopsisthalianaenhancingplantgrowthandsalinitystresstolerancebyoverexpressingaacetolactatedecarboxylasetoproduceacetoininplanta AT rustcatharinamagdalenacarlien volatiletaleofarabidopsisthalianaenhancingplantgrowthandsalinitystresstolerancebyoverexpressingaacetolactatedecarboxylasetoproduceacetoininplanta |