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Developing novel potato properties using gene editing

Ly, Diem Nguyen Phuoc (2021) Developing novel potato properties using gene editing. PhD thesis, Murdoch University.

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Abstract

Potato (Solanum tuberosum L.) is the most important tuber food crop worldwide and a significant component of food security. A major use of potato is their processing into crisps and French fries. Potato tubers that accumulate hexose sugars and exhibit browning after frying are rejected, causing economic losses and waste. Acrylamide formation when potato tubers are deep-fried also presents a health risk for consumers because acrylamide is a potential neurotoxin/ carcinogen. The aim of this project was to upgrade existing potato cultivars (Atlantic and Desiree) using gene editing (CRISPR/Cas9) to reduce the expression of the vacuolar invertase and asparagine synthetase 1 genes, to minimise cold-induced sweetening and acrylamide formation in fried potato products.

The Cas9 and gRNAs were delivered into plant cells either as expression vectors using Agrobacterium tumefaciens or directly by particle bombardment as a ribonucleoprotein complex. A total of 20 transgenic edited events and one transgene-free edited event were obtained. Ten transgenic events were further analysed, and small insertions and deletions that ranged from 1 bp to 35 bp accounted for 67.9% of mutation frequency. Biochemical analysis from cold-stored, edited tubers (four months at 4°C) revealed that hexose sugars in cold-stored tubers and acrylamide levels in crisps were significantly reduced, accompanied by a noticeably improved colour intensity of fried crisps. Hexose sugar in edited events was reduced up to 21 times and was extremely low in one event; only 0.02 mg/gfw glucose and 0.13 mg/gfw fructose were detected. The acrylamide content was decreased up to 3.7 times in Atlantic-derived events and 6.8 times in Desiree-derived events, and the lowest recorded acrylamide level was 332.9 ng/g. Overall, gene-edited events generated in this project exhibited better properties for human consumption/health. This research successfully demonstrated that CRISPR/Cas9 can be used to improve economically important potato cultivars.

Item Type: Thesis (PhD)
Murdoch Affiliation(s): College of Science, Health, Engineering and Education
Centre for Crop and Food Innovation
Food Futures Institute
Supervisor(s): Jones, Michael, Iqbal, Sadia and Milroy, Stephen
URI: http://researchrepository.murdoch.edu.au/id/eprint/63604
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