Abstract
Due to the large amount of nutritional benefits of the common bean (Phaseolus vulgaris L.), it is considered an important diet for human intake. Conventional plant breeding brought important advancements in the cultivated common bean. New plant breeding techniques could help speed up this proces. However plant transformation and regeneration of the common bean can still not be achieved efficiently. Therefore, in this study, we have optimized an in vitro transformation protocol for P. vulgaris cv. CIAP7247F. The indirect organogenesis pathway has been utilized for efficient callus induction and proliferation, followed by the A. tumefaciens mediated transformation. Different transformation combinations were tested to evaluate the best combination for the transformation of P. vulgaris cv. CIAP7247F.The explant type and A. tumefaciens strains used in this study influenced the transformation. The primary proliferative calli were successfully transformed by all three A. tumefaciens strains. The highest transformation efficiency (75%) was observed with A. tumefaciens EHA105 (pGFPGUSPLUS) whereas A. tumefaciens LBA4404 (pGFPGUSPLUS) and A. tumefaciens C58C1 RifR(pMP90) (pGFPGUSPLUS) could only transform 14% of the callus. The transformation of the wounded cotyledons, as well as the secondary proliferative callus explants, was not successful with any agrobacterium strains because no GUS staining was observed in both of them when visualized under a stereomicroscope. The primary proliferative callus transformed with A. tumefaciens EHA105 (pGFPGUSPLUS) was observed as an effective combination for transformation.
Antinutritional factors such as the raffinose family oligosaccharides (RFOs) present in the common bean seeds lead to flatulence and lower uptake of essential nutrients in humans upon consumption. To investigate this disturbance in more detail, we have measured the expression of the genes associated with these RFOs in P. vulgaris cv. CIAP7247F at different developmental stages of the seed development. The up and downregulation of the gene expression was measured via comparative gene expression analysis. The highest gene expression was observed at the late maturation phase of the seed development (30-35 days after flowering). Focusing on the research based on the importance of these RFOs , the seed specific gene encoding the raffinose synthase enzyme can be targeted to create a knockout mutant in order to reduce the RFO content in the common bean seeds and enhance the nutrient uptake.
| Date of Award | 28 Jan 2021 |
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| Original language | English |
| Supervisor | Geert Angenon (Promotor), Ramon De Koning (Advisor) & Mary Esther Muyoka Toili (Advisor) |