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Low-acrylamide French fries and potato chips.

Rommens CM, Yan H, Swords K, Richael C, Ye J - Plant Biotechnol. J. (2008)

Bottom Line: Concerns about the potential health issues associated with the dietary intake of this reactive compound led us to reduce the accumulation of asparagine, one of its main precursors, in the tubers of potato (Solanum tuberosum).This metabolic change coincided with a small increase in the formation of glutamine and did not affect tuber shape or yield.Given the important role of processed potato products in the modern Western diet, a replacement of current varieties with intragenic potatoes could reduce the average daily intake of acrylamide by almost one-third.

View Article: PubMed Central - PubMed

Affiliation: Simplot Plant Sciences, JR Simplot Company, Boise, ID 83706, USA. crommens@simplot.com

ABSTRACT

Summary: Acrylamide is produced in starchy foods that are baked, roasted or fried at high temperatures. Concerns about the potential health issues associated with the dietary intake of this reactive compound led us to reduce the accumulation of asparagine, one of its main precursors, in the tubers of potato (Solanum tuberosum). This metabolic change was accomplished by silencing two asparagine synthetase genes through 'all-native DNA' transformation. Glasshouse-grown tubers of the transformed intragenic plants contained up to 20-fold reduced levels of free asparagine. This metabolic change coincided with a small increase in the formation of glutamine and did not affect tuber shape or yield. Heat-processed products derived from the low-asparagine tubers were also indistinguishable from their untransformed counterparts in terms of sensory characteristics. However, both French fries and potato chips accumulated as little as 5% of the acrylamide present in wild-type controls. Given the important role of processed potato products in the modern Western diet, a replacement of current varieties with intragenic potatoes could reduce the average daily intake of acrylamide by almost one-third.

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Plant transformation with a silencing construct targeting the potato asparagine synthetase genes (StAs1 and StAs2) in tubers. (a) Diagram of vector pSIM1256. St01, potato-derived border-like element resembling the T-DNA border; pAGP, promoter of the potato Agpase gene; 1, StAs1 gene fragment; 2, StAs2 gene fragment; i, inverse complement; S, spacer; pGbss, promoter of the potato Gbss gene; ori, origin of replication; pUbi3, promoter of the potato Ubi3 gene; ipt, Agrobacterium ipt gene; tUbi3, terminator of the potato Ubi3 gene; npt III, kananycin resistance gene from E. coli. Plant-derived sequences are shown in green; vector backbone sequences are shown in grey. (b) P-DNA copy number of nine intragenic lines, as determined with an StAs1/2-derived probe that also visualizes two endogenous fragments (grey arrows).
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fig02: Plant transformation with a silencing construct targeting the potato asparagine synthetase genes (StAs1 and StAs2) in tubers. (a) Diagram of vector pSIM1256. St01, potato-derived border-like element resembling the T-DNA border; pAGP, promoter of the potato Agpase gene; 1, StAs1 gene fragment; 2, StAs2 gene fragment; i, inverse complement; S, spacer; pGbss, promoter of the potato Gbss gene; ori, origin of replication; pUbi3, promoter of the potato Ubi3 gene; ipt, Agrobacterium ipt gene; tUbi3, terminator of the potato Ubi3 gene; npt III, kananycin resistance gene from E. coli. Plant-derived sequences are shown in green; vector backbone sequences are shown in grey. (b) P-DNA copy number of nine intragenic lines, as determined with an StAs1/2-derived probe that also visualizes two endogenous fragments (grey arrows).

Mentions: In an attempt to limit the accumulation of asparagine in potato tubers, a silencing construct was designed that simultaneously targets the expression of StAs1 and StAs2 (Figure 2a). The two genes are quite divergent at the DNA level, with short (approximately 5 bp) stretches of homology interrupted by mismatches. Therefore, 0.4-kb fragments from both StAs1 and StAs2 were fused to create a DNA segment, and two copies of this segment were inserted as an inverted repeat between two convergently orientated promoters. It was our primary intent to reduce the transcription of the StAs1 and StAs2 genes in tubers, whilst limiting the extent of gene silencing in the foliage where the gene products play important roles in both photorespiration (Ta et al., 1985) and ammonium detoxification (Wong et al., 2004). For this reason, promoters were employed that were at least 100-fold more active in tubers than in leaves: the granule-bound starch synthase (Gbss) and a short (2.2-kb) version of the potato ADP-glucose pyrophosphorylase (Agp) (Visser et al., 1991; Muller-Rober et al., 1994; C. Richael, unpubl. data). The resulting silencing construct was positioned within a potato-derived transfer (P-) DNA to create the binary vector pSIM1256.


Low-acrylamide French fries and potato chips.

Rommens CM, Yan H, Swords K, Richael C, Ye J - Plant Biotechnol. J. (2008)

Plant transformation with a silencing construct targeting the potato asparagine synthetase genes (StAs1 and StAs2) in tubers. (a) Diagram of vector pSIM1256. St01, potato-derived border-like element resembling the T-DNA border; pAGP, promoter of the potato Agpase gene; 1, StAs1 gene fragment; 2, StAs2 gene fragment; i, inverse complement; S, spacer; pGbss, promoter of the potato Gbss gene; ori, origin of replication; pUbi3, promoter of the potato Ubi3 gene; ipt, Agrobacterium ipt gene; tUbi3, terminator of the potato Ubi3 gene; npt III, kananycin resistance gene from E. coli. Plant-derived sequences are shown in green; vector backbone sequences are shown in grey. (b) P-DNA copy number of nine intragenic lines, as determined with an StAs1/2-derived probe that also visualizes two endogenous fragments (grey arrows).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2607532&req=5

fig02: Plant transformation with a silencing construct targeting the potato asparagine synthetase genes (StAs1 and StAs2) in tubers. (a) Diagram of vector pSIM1256. St01, potato-derived border-like element resembling the T-DNA border; pAGP, promoter of the potato Agpase gene; 1, StAs1 gene fragment; 2, StAs2 gene fragment; i, inverse complement; S, spacer; pGbss, promoter of the potato Gbss gene; ori, origin of replication; pUbi3, promoter of the potato Ubi3 gene; ipt, Agrobacterium ipt gene; tUbi3, terminator of the potato Ubi3 gene; npt III, kananycin resistance gene from E. coli. Plant-derived sequences are shown in green; vector backbone sequences are shown in grey. (b) P-DNA copy number of nine intragenic lines, as determined with an StAs1/2-derived probe that also visualizes two endogenous fragments (grey arrows).
Mentions: In an attempt to limit the accumulation of asparagine in potato tubers, a silencing construct was designed that simultaneously targets the expression of StAs1 and StAs2 (Figure 2a). The two genes are quite divergent at the DNA level, with short (approximately 5 bp) stretches of homology interrupted by mismatches. Therefore, 0.4-kb fragments from both StAs1 and StAs2 were fused to create a DNA segment, and two copies of this segment were inserted as an inverted repeat between two convergently orientated promoters. It was our primary intent to reduce the transcription of the StAs1 and StAs2 genes in tubers, whilst limiting the extent of gene silencing in the foliage where the gene products play important roles in both photorespiration (Ta et al., 1985) and ammonium detoxification (Wong et al., 2004). For this reason, promoters were employed that were at least 100-fold more active in tubers than in leaves: the granule-bound starch synthase (Gbss) and a short (2.2-kb) version of the potato ADP-glucose pyrophosphorylase (Agp) (Visser et al., 1991; Muller-Rober et al., 1994; C. Richael, unpubl. data). The resulting silencing construct was positioned within a potato-derived transfer (P-) DNA to create the binary vector pSIM1256.

Bottom Line: Concerns about the potential health issues associated with the dietary intake of this reactive compound led us to reduce the accumulation of asparagine, one of its main precursors, in the tubers of potato (Solanum tuberosum).This metabolic change coincided with a small increase in the formation of glutamine and did not affect tuber shape or yield.Given the important role of processed potato products in the modern Western diet, a replacement of current varieties with intragenic potatoes could reduce the average daily intake of acrylamide by almost one-third.

View Article: PubMed Central - PubMed

Affiliation: Simplot Plant Sciences, JR Simplot Company, Boise, ID 83706, USA. crommens@simplot.com

ABSTRACT

Summary: Acrylamide is produced in starchy foods that are baked, roasted or fried at high temperatures. Concerns about the potential health issues associated with the dietary intake of this reactive compound led us to reduce the accumulation of asparagine, one of its main precursors, in the tubers of potato (Solanum tuberosum). This metabolic change was accomplished by silencing two asparagine synthetase genes through 'all-native DNA' transformation. Glasshouse-grown tubers of the transformed intragenic plants contained up to 20-fold reduced levels of free asparagine. This metabolic change coincided with a small increase in the formation of glutamine and did not affect tuber shape or yield. Heat-processed products derived from the low-asparagine tubers were also indistinguishable from their untransformed counterparts in terms of sensory characteristics. However, both French fries and potato chips accumulated as little as 5% of the acrylamide present in wild-type controls. Given the important role of processed potato products in the modern Western diet, a replacement of current varieties with intragenic potatoes could reduce the average daily intake of acrylamide by almost one-third.

Show MeSH
Related in: MedlinePlus