Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Assessment of mutant N19 sugarcane lines for drought tolerance
Thesis (MScAgric)--Stellenbosch University, 2024.
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | English |
| Published: |
Stellenbosch : Stellenbosch University
2024
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613909470412800 |
|---|---|
| access_status_str | Open Access |
| author | Louw, Nicholas |
| author2 | Van der Vyver, Christell |
| author_browse | Louw, Nicholas Van der Vyver, Christell |
| author_facet | Van der Vyver, Christell Louw, Nicholas |
| author_sort | Louw, Nicholas |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2024. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/130466 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:43:38.086Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2024 |
| publishDateRange | 2024 |
| publishDateSort | 2024 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/130466 Assessment of mutant N19 sugarcane lines for drought tolerance Louw, Nicholas Van der Vyver, Christell Stellenbosch University. Faculty of AgriSciences. Department of Genetics & Institute of Plant Biotechnology. Sugarcane -- Mutation breeding Sugarcane -- Effect of stress on Sugarcane -- Drought tolerance Sugarcane -- Effect of drought on Plant biomass Drought-tolerant plants UCTD Thesis (MScAgric)--Stellenbosch University, 2024. ENGLISH ABSTRACT: Sugarcane is an important part of the economy in tropical and subtropical countries where it is used for the extraction of commercially produced sucrose, as well as a biomass resource for biofuel production. Abiotic stress factors such as drought have a significant, negative effect worldwide on sugarcane yield. This has created a demand for novel, drought-resistant sugarcane varieties. Mutation breeding has become a popular way of introducing novel genetic diversity that can potentially lead to drought tolerant phenotypes. This study included a comprehensive morphological, physiological, biochemical and genetic analysis of N19 sugarcane mutants (M23.1, M19.3 and M12.3) produced using ethyl methanesulfonate (EMS) mutagenesis along with in vitro osmotic selection using polyethylene glycol. An analysis of agronomic traits linked to plant growth and yield revealed that most of the mutants were able to maintain similar performance to the parental plants. Glasshouse water deficit pot trials were used to analyse stress related parameters in the mutant compared to the parental plants. No significant differences were found in the relative water content between the genotypes during the stress treatment. However, the M23.1 and M19.3 mutant plants were able to recover better than the parental plants from the water deficit stress. Furthermore, compared with the parental plants, the M23.1 mutant plants were especially able to maintain higher levels of stomatal conductance under mild, chlorophyll content under mild and severe, and lower malondialdehyde levels under severe water deficit stress. In contrast, the M19.3 plants accumulated more superoxide dismutase and proline under severe water deficit stress. Overall, stress tolerance trait indices calculated using the parameters measured during the water deficit pot trials, indicated that the M23.1 mutant only outperformed the parental during mild stress. As for the M19.3 mutant, it showed a higher STTI than its parental counterpart under mild and severe water deficit stressed conditions. The nucleotide sequences and expression of seven genes known to be linked to the sugarcane drought response were analysed and compared to the parental to surmise the potential genetic effects caused by the mutagen. Fifteen putative mutations were found in the mutant nucleotide sequences of the NCED5, P5CS1 and POD genes. These mutations are likely cause by the exposure to EMS and consisted of 12 point mutations, along with one inversion and two base pair deletions, some of which led to premature stop codons. The observed premature stop codons led to major changes in the structure of the predicted protein models with some mutant proteins losing more than half of their amino acid chain. Multiple changes in expression were observed in the seven genes when comparing the parental to the mutant lines. Overall, especially the M19.3 mutant line has the potential to be incorporated in sugarcane breeding programs for the development of drought tolerant genotypes. However, field trials will need to confirm the observed enhanced water deficit stress tolerance and further comprehensive information regarding the genome wide induced mutations will likely have to be obtained through next generation sequencing analysis. AFRIKAANSE OPSOMMING: Suikerriet is 'n belangrike deel van die ekonomie in tropiese en subtropiese lande waar dit gebruik word vir die ekstraksie van kommersieel geproduseerde sukrose, sowel as 'n biomassa-hulpbron vir bio-brandstof produksie. Abiotiese faktore soos droogte het ‘n beduidende, negatiewe uitwerking wêreldwyd op die opbrengs van suikerriet. Dit het ‘n behoefte geskep vir nuwe, droogte-bestande suikerrietvariëteite. Mutasieteling het 'n gewilde manier geword om nuwe genetiese diversiteit te induseer in plantgenome wat potensieel kan lei tot droogte-bestande fenotipes. Hierdie studie het 'n omvattende morfologiese, fisiologiese, biochemiese en genetiese analise van N19-suikerrietmutante (M23.1, M19.3 en M12.3) ingesluit wat deur etielmetaansulfonaat (EMS)-mutagenese vervaardig is, saam met in vitro osmotiese seleksie deur gebruik te maak van poliëtileenglikol. 'n Analise van agronomiese eienskappe gekoppel aan plantgroei en opbrengs het getoon dat die meeste mutante in staat was om soortgelyke prestasie as die ouerplante te handhaaf. Glashuis water tekort pot-toetse is gebruik om stres-verwante parameters in die mutant te analiseer in vergelyking met die ouerplante. Geen beduidende verskille is gevind in die relatiewe waterinhoud tussen die genotipes tydens die stresbehandeling nie. Die M23.1 en M19.3 mutantplante was egter instaat om beter te herstel as die ouerplante van die water tekort stres. Verder kon die M23.1-mutantplante, in vergelyking met die ouerplante, veral hoër vlakke van stomatale geleiding handhaaf onder matige, chlorofielinhoud onder matige en ernstige, en laer malondialdehiedvlakke onder ernstige water tekort stres. In teenstelling hiermee het die M19.3-plante meer superoksied dismutase en prolien opgehoop onder erge water tekort stres. Algeheel het stresverdraagsaamheidsindekse wat bereken is met behulp van die parameters wat gemeet is gedurende die water tekort-potproewe, aangedui dat die M23.1 mutant slegs beter presteer het as die ouer tydens ligte stress. Wat die M19.3 mutasie betref, het dit 'n hoër STTI as sy ouer eweknie getoon onder ligte en ernstige water gestresde toestande. Die nukleotiedvolgordes en uitdrukking van sewe gene wat bekend is om gekoppel te wees aan die suikerriet droogte-reaksie, is geanaliseer en vergelyk met die ouer om die potensiële genetiese effekte wat deur die mutageen veroorsaak is, te bepaal. Vyftien vermeende mutasies is gevind in die mutant-nukleotiedvolgordes van die NCED5, P5CS1 en POD-gene. Hierdie mutasies is waarskynlik veroorsaak deur blootstelling aan EMS en het bestaan uit 12 puntmutasies, tesame met een inversie en twee basispaar-uitskakelings, waarvan sommige tot vroegtydige stopkodons gelei het. Die waargenome vroegtydige stopkodons het tot groot veranderinge in die struktuur van die voorspelde proteïenmodelle gelei, met sommige mutantproteïene wat meer as die helfte van hul aminosuursamestelling verloor het. Verskeie veranderinge in uitdrukking is waargeneem in die sewe gene wanneer die ouer met die mutantlyne vergelyk word. Oor die algemeen het veral die M19.3 mutante lyn, die potensiaal om ingesluit te word in suikerriet-telingsprogramme vir die ontwikkeling van droogte-bestande genotipes. Dit sal egter nodig wees om veldtoetse te doen om die waargenome verbeterde water tekort stres-toleransie te bevestig, en verdere omvattende inligting oor die genoomwye geïnduseerde mutasies sal waarskynlik deur nuwe-generasie volgordebepalingsanalise verkry moet word. Masters 2024-02-29T12:33:19Z 2024-04-26T18:38:07Z 2024-02-29T12:33:19Z 2024-04-26T18:38:07Z 2024-03 Thesis https://scholar.sun.ac.za/handle/10019.1/130466 en Stellenbosch University xxi, 115 pages : illustrations (some color) application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Sugarcane -- Mutation breeding Sugarcane -- Effect of stress on Sugarcane -- Drought tolerance Sugarcane -- Effect of drought on Plant biomass Drought-tolerant plants UCTD Louw, Nicholas Assessment of mutant N19 sugarcane lines for drought tolerance |
| title | Assessment of mutant N19 sugarcane lines for drought tolerance |
| title_full | Assessment of mutant N19 sugarcane lines for drought tolerance |
| title_fullStr | Assessment of mutant N19 sugarcane lines for drought tolerance |
| title_full_unstemmed | Assessment of mutant N19 sugarcane lines for drought tolerance |
| title_short | Assessment of mutant N19 sugarcane lines for drought tolerance |
| title_sort | assessment of mutant n19 sugarcane lines for drought tolerance |
| topic | Sugarcane -- Mutation breeding Sugarcane -- Effect of stress on Sugarcane -- Drought tolerance Sugarcane -- Effect of drought on Plant biomass Drought-tolerant plants UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/130466 |
| work_keys_str_mv | AT louwnicholas assessmentofmutantn19sugarcanelinesfordroughttolerance |