Silencing of vacuolar invertase and asparagine synthetase genes and its impact on acrylamide formation of fried potato products

Authors: ZHU, XIAOBIAO - University Of Wisconsin; GONG, HUILING - University Of Wisconsin; HE, QUNYAN - University Of Wisconsin; ZENG, ZIXIAN - University Of Wisconsin; Busse, James; JIN, WEIWEI - China Agricultural University; Bethke, Paul; JIMING, JIANG - University Of Wisconsin

Submitted to: Plant Biotechnology Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2015
Publication Date: 2/1/2016
Publication URL: http://handle.nal.usda.gov/10113/4806048
Citation: Zhu, X., Gong, H., He, Q., Zeng, Z., Busse, J.S., Jin, W., Bethke, P.C., Jiming, J. 2016. Silencing of vacuolar invertase and asparagine synthetase genes and its impact on acrylamide formation of fried potato products. Plant Biotechnology Journal. 14(2):709-718. doi: 10.1111/pbi.12421.

Interpretive Summary: Acrylamide is produced in a wide variety of foods during high temperature cooking. Dietary acrylamide is a suspected human carcinogen, and health concerns related to dietary acrylamide have been raised worldwide. French fries and potato chips contribute a significant proportion to daily intake of acrylamide, especially in developed countries. One way to reduce health concerns related to acrylamide is to develop potato varieties that produce less acrylamide when cooked. For this research we made many genetically modified lines of potato that had reduced amounts of glucose, fructose and asparagine, the compounds that give rise to acrylamide during cooking. Fried potato products from these lines had as little as one-fifteenth of the acrylamide content of controls. Interestingly, the extent of acrylamide reduction was similar to that seen when tuber glucose and fructose contents alone were reduced. These results show that an acrylamide mitigation strategy focused on developing potato cultivars with low glucose and fructose is likely to be an effective and sufficient approach for minimizing the acrylamide-forming potential of fry processing potatoes. This finding will benefit potato breeders and the potato industry as they develop and evaluate new varieties of potato. Consumers will benefit if concerns about acrylamide in foods are confirmed.

Technical Abstract: Acrylamide is produced in a wide variety of carbohydrate-rich foods during high temperature cooking. Dietary acrylamide is a suspected human carcinogen, and health concerns related to dietary acrylamide have been raised worldwide. French fries and potato chips contribute a significant proportion to the average daily intake of acrylamide, especially in developed countries. One way to mitigate health concerns related to acrylamide is to develop potato cultivars with that have reduced contents of the acrylamide precursors asparageine, glucose and fructose in tubers. We generated a large number of silencing lines of cultivar Russet Burbank by targeting the vacuolar invertase gene VInv and the asparagine synthetase genes StAS1 and StAS2 with a single RNA-interference construct. The transcription levels of these three genes were correlated with reducing sugar (glucose and fructose) and asparagine content in tubers. Fried potato products from the best triple-gene-silencing lines had one-fifteenth of the acrylamide content of controls. Interestingly, the extent of acrylamide reduction of the best VInv/StAS1/StAS2-triple silencing lines was similar to that of the best VInv-single silencing lines developed previously from cultivar Russet Burbank. These results show that an acrylamide mitigation strategy focused on developing potato cultivars with low reducing sugars is likely to be an effective and sufficient approach for minimizing the acrylamide-forming potential of French fry processing potatoes.