Identifying the closest wild relative of sweet potato (Ipomoea batatas (L.) Lam.)
<p>Thanks to its relative resilience, nutritional value, and high dry-matter content, sweet potato (<i>Ipomoea batatas</i> (L.) Lam.) is a vital staple food around the world, especially for small-scale farmers in drought-prone areas. The development and distribution of Vitamin A-ri...
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| Format: | Thesis |
| Language: | English |
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2023
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| _version_ | 1826311336151220224 |
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| author | Wells, T |
| author2 | Scotland, R |
| author_facet | Scotland, R Wells, T |
| author_sort | Wells, T |
| collection | OXFORD |
| description | <p>Thanks to its relative resilience, nutritional value, and high dry-matter content, sweet potato (<i>Ipomoea batatas</i> (L.) Lam.) is a vital staple food around the world, especially for small-scale farmers in drought-prone areas. The development and distribution of Vitamin A-rich, orange-fleshed varieties has proved a particularly valuable tool in combatting malnutrition and mineral deficiency, and made sweet potato an increasingly popular health food. Despite this agricultural and dietary importance however, sweet potato’s origin and domestication are still relatively poorly understood. Several outstanding questions remain about how sweet potato evolved, including <i>whether sweet potato is an auto or allohexaploid, why it possesses two independent chloroplast lineages, and how it developed its thickened storage roots</i>. Answering these inter-related questions is integral to assembling sweet potato’s complex hexaploid genome; understanding the development of key traits; identifying, classifying and utilising wild and cultivated diversity; and assessing how geneflow and introgression have shaped all three.</p>
<p>Central to answering these questions is the need for an improved understanding of the systematics and taxonomy of sweet potato’s immediate crop wild relatives (CWRs), and in particular the identification of its closest wild ancestor, or “progenitor”. Given current knowledge of the likely genomic structure of hexaploid <i>I. batatas</i>, this progenitor is thought to be autotetraploid – with two identical subgenomes – but no such taxon has yet been identified. The lack of previous progress in identifying this tetraploid progenitor of cultivated sweet potato is largely the result of extensive taxonomic confusion over nomenclature and species delimitation for sweet potato CWRs, which has been exacerbated by a complex evolutionary history for <i>I. batatas</i> involving polyploidy and potential hybridisation and introgression.</p>
<p>In this thesis, I provide a comprehensive review of all putatively wild tetraploid material resembling or previously associated with <i>I. batatas</i>, before placing them within the phylogenetic and taxonomic framework established by the recent Foundation Monograph of the genus <i>Ipomoea</i> L. in the Americas. I identify and describe sweet potato’s closest CWR <i>I. aequatoriensis</i> T.Wells & P.Muñoz, providing a complete systematic account of its diversity and exploring its relationship to the cultivated crop. I have been able to achieve this by integrating material from germplasm and natural history (herbarium) collections – two data sources that are generally treated separately – and by the application of a combination of analytic approaches that include the latest in high-throughput sequencing technologies, bioinformatics, and rigorous morphological analysis. Doing so provides vital new insights into the origin of one of the world’s most important food crops.</p> |
| first_indexed | 2024-03-07T08:06:44Z |
| format | Thesis |
| id | oxford-uuid:832345e4-7a3b-4b7b-bc13-09157caa6a81 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T08:06:44Z |
| publishDate | 2023 |
| record_format | dspace |
| spelling | oxford-uuid:832345e4-7a3b-4b7b-bc13-09157caa6a812023-11-03T12:28:46ZIdentifying the closest wild relative of sweet potato (Ipomoea batatas (L.) Lam.)Thesishttp://purl.org/coar/resource_type/c_db06uuid:832345e4-7a3b-4b7b-bc13-09157caa6a81Biology--Classification--Molecular aspectsBiology--ClassificationBotanyBiologyEnglishHyrax Deposit2023Wells, TScotland, R<p>Thanks to its relative resilience, nutritional value, and high dry-matter content, sweet potato (<i>Ipomoea batatas</i> (L.) Lam.) is a vital staple food around the world, especially for small-scale farmers in drought-prone areas. The development and distribution of Vitamin A-rich, orange-fleshed varieties has proved a particularly valuable tool in combatting malnutrition and mineral deficiency, and made sweet potato an increasingly popular health food. Despite this agricultural and dietary importance however, sweet potato’s origin and domestication are still relatively poorly understood. Several outstanding questions remain about how sweet potato evolved, including <i>whether sweet potato is an auto or allohexaploid, why it possesses two independent chloroplast lineages, and how it developed its thickened storage roots</i>. Answering these inter-related questions is integral to assembling sweet potato’s complex hexaploid genome; understanding the development of key traits; identifying, classifying and utilising wild and cultivated diversity; and assessing how geneflow and introgression have shaped all three.</p> <p>Central to answering these questions is the need for an improved understanding of the systematics and taxonomy of sweet potato’s immediate crop wild relatives (CWRs), and in particular the identification of its closest wild ancestor, or “progenitor”. Given current knowledge of the likely genomic structure of hexaploid <i>I. batatas</i>, this progenitor is thought to be autotetraploid – with two identical subgenomes – but no such taxon has yet been identified. The lack of previous progress in identifying this tetraploid progenitor of cultivated sweet potato is largely the result of extensive taxonomic confusion over nomenclature and species delimitation for sweet potato CWRs, which has been exacerbated by a complex evolutionary history for <i>I. batatas</i> involving polyploidy and potential hybridisation and introgression.</p> <p>In this thesis, I provide a comprehensive review of all putatively wild tetraploid material resembling or previously associated with <i>I. batatas</i>, before placing them within the phylogenetic and taxonomic framework established by the recent Foundation Monograph of the genus <i>Ipomoea</i> L. in the Americas. I identify and describe sweet potato’s closest CWR <i>I. aequatoriensis</i> T.Wells & P.Muñoz, providing a complete systematic account of its diversity and exploring its relationship to the cultivated crop. I have been able to achieve this by integrating material from germplasm and natural history (herbarium) collections – two data sources that are generally treated separately – and by the application of a combination of analytic approaches that include the latest in high-throughput sequencing technologies, bioinformatics, and rigorous morphological analysis. Doing so provides vital new insights into the origin of one of the world’s most important food crops.</p> |
| spellingShingle | Biology--Classification--Molecular aspects Biology--Classification Botany Biology Wells, T Identifying the closest wild relative of sweet potato (Ipomoea batatas (L.) Lam.) |
| title | Identifying the closest wild relative of sweet potato (Ipomoea batatas (L.) Lam.) |
| title_full | Identifying the closest wild relative of sweet potato (Ipomoea batatas (L.) Lam.) |
| title_fullStr | Identifying the closest wild relative of sweet potato (Ipomoea batatas (L.) Lam.) |
| title_full_unstemmed | Identifying the closest wild relative of sweet potato (Ipomoea batatas (L.) Lam.) |
| title_short | Identifying the closest wild relative of sweet potato (Ipomoea batatas (L.) Lam.) |
| title_sort | identifying the closest wild relative of sweet potato ipomoea batatas l lam |
| topic | Biology--Classification--Molecular aspects Biology--Classification Botany Biology |
| work_keys_str_mv | AT wellst identifyingtheclosestwildrelativeofsweetpotatoipomoeabatatasllam |