Tags

Type your tag names separated by a space and hit enter

Sugar metabolism, chip color, invertase activity, and gene expression during long-term cold storage of potato (Solanum tuberosum) tubers from wild-type and vacuolar invertase silencing lines of Katahdin.
BMC Res Notes. 2014 Nov 16; 7:801.BR

Abstract

BACKGROUND

Storing potato tubers at low temperatures minimizes sprouting and disease but can cause an accumulation of reducing sugars in a process called cold-induced sweetening. Tubers with increased amounts of reducing sugars produce dark-colored, bitter-tasting fried products with elevated amounts of acrylamide, a possible carcinogen. Vacuolar invertase (VInv), which converts sucrose produced by starch breakdown to glucose and fructose, is the key determinant of reducing sugar accumulation during cold-induced sweetening. In this study, wild-type tubers and tubers in which VInv expression was reduced by RNA interference were used to investigate time- and temperature-dependent changes in sugar contents, chip color, and expression of VInv and other genes involved in starch metabolism in tubers during long-term cold storage.

RESULTS

VInv activities and tuber reducing sugar contents were much lower, and tuber sucrose contents were much higher, in transgenic than in wild-type tubers stored at 3-9°C for up to eight months. Large differences in VInv mRNA accumulation were not observed at later times in storage, especially at temperatures below 9°C, so differences in invertase activity were likely established early in the storage period and maintained by stability of the invertase protein. Sugar contents, chip color, and expression of several of the studied genes, including AGPase and GBSS, were affected by storage temperature in both wild-type and transgenic tubers. Though transcript accumulation for other sugar-metabolism genes was affected by storage temperature and duration, it was essentially unaffected by invertase silencing and altered sugar contents. Differences in stem- and bud-end sugar contents in wild-type and transgenic tubers suggested different compartmentalization of sucrose at the two ends of stored tubers.

CONCLUSIONS

VInv silencing significantly reduced cold-induced sweetening in stored potato tubers, likely by means of differential VInv expression early in storage. Transgenic tubers retained sensitivity to storage temperature, and accumulated greater amounts of sucrose, glucose and fructose at 3°C than at 7-9°C. At each storage temperature, suppression of VInv expression and large differences in tuber sugar contents had no effect on expression of AGPase and GBSS, genes involved in starch metabolism, suggesting that transcription of these genes is not regulated by tuber sugar content.

Authors+Show Affiliations

No affiliation info availableNo affiliation info availableNo affiliation info availableUnited States Department of Agriculture - Agricultural Research Service, Vegetable Crops Research Unit, 1575 Linden Dr,, Madison, WI 53706, USA. pbethke@wisc.edu.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

25399251

Citation

Wiberley-Bradford, Amy E., et al. "Sugar Metabolism, Chip Color, Invertase Activity, and Gene Expression During Long-term Cold Storage of Potato (Solanum Tuberosum) Tubers From Wild-type and Vacuolar Invertase Silencing Lines of Katahdin." BMC Research Notes, vol. 7, 2014, p. 801.
Wiberley-Bradford AE, Busse JS, Jiang J, et al. Sugar metabolism, chip color, invertase activity, and gene expression during long-term cold storage of potato (Solanum tuberosum) tubers from wild-type and vacuolar invertase silencing lines of Katahdin. BMC Res Notes. 2014;7:801.
Wiberley-Bradford, A. E., Busse, J. S., Jiang, J., & Bethke, P. C. (2014). Sugar metabolism, chip color, invertase activity, and gene expression during long-term cold storage of potato (Solanum tuberosum) tubers from wild-type and vacuolar invertase silencing lines of Katahdin. BMC Research Notes, 7, 801. https://doi.org/10.1186/1756-0500-7-801
Wiberley-Bradford AE, et al. Sugar Metabolism, Chip Color, Invertase Activity, and Gene Expression During Long-term Cold Storage of Potato (Solanum Tuberosum) Tubers From Wild-type and Vacuolar Invertase Silencing Lines of Katahdin. BMC Res Notes. 2014 Nov 16;7:801. PubMed PMID: 25399251.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Sugar metabolism, chip color, invertase activity, and gene expression during long-term cold storage of potato (Solanum tuberosum) tubers from wild-type and vacuolar invertase silencing lines of Katahdin. AU - Wiberley-Bradford,Amy E, AU - Busse,James S, AU - Jiang,Jiming, AU - Bethke,Paul C, Y1 - 2014/11/16/ PY - 2014/07/25/received PY - 2014/10/24/accepted PY - 2014/11/17/entrez PY - 2014/11/17/pubmed PY - 2015/7/7/medline SP - 801 EP - 801 JF - BMC research notes JO - BMC Res Notes VL - 7 N2 - BACKGROUND: Storing potato tubers at low temperatures minimizes sprouting and disease but can cause an accumulation of reducing sugars in a process called cold-induced sweetening. Tubers with increased amounts of reducing sugars produce dark-colored, bitter-tasting fried products with elevated amounts of acrylamide, a possible carcinogen. Vacuolar invertase (VInv), which converts sucrose produced by starch breakdown to glucose and fructose, is the key determinant of reducing sugar accumulation during cold-induced sweetening. In this study, wild-type tubers and tubers in which VInv expression was reduced by RNA interference were used to investigate time- and temperature-dependent changes in sugar contents, chip color, and expression of VInv and other genes involved in starch metabolism in tubers during long-term cold storage. RESULTS: VInv activities and tuber reducing sugar contents were much lower, and tuber sucrose contents were much higher, in transgenic than in wild-type tubers stored at 3-9°C for up to eight months. Large differences in VInv mRNA accumulation were not observed at later times in storage, especially at temperatures below 9°C, so differences in invertase activity were likely established early in the storage period and maintained by stability of the invertase protein. Sugar contents, chip color, and expression of several of the studied genes, including AGPase and GBSS, were affected by storage temperature in both wild-type and transgenic tubers. Though transcript accumulation for other sugar-metabolism genes was affected by storage temperature and duration, it was essentially unaffected by invertase silencing and altered sugar contents. Differences in stem- and bud-end sugar contents in wild-type and transgenic tubers suggested different compartmentalization of sucrose at the two ends of stored tubers. CONCLUSIONS: VInv silencing significantly reduced cold-induced sweetening in stored potato tubers, likely by means of differential VInv expression early in storage. Transgenic tubers retained sensitivity to storage temperature, and accumulated greater amounts of sucrose, glucose and fructose at 3°C than at 7-9°C. At each storage temperature, suppression of VInv expression and large differences in tuber sugar contents had no effect on expression of AGPase and GBSS, genes involved in starch metabolism, suggesting that transcription of these genes is not regulated by tuber sugar content. SN - 1756-0500 UR - https://www.unboundmedicine.com/medline/citation/25399251/Sugar_metabolism_chip_color_invertase_activity_and_gene_expression_during_long_term_cold_storage_of_potato__Solanum_tuberosum__tubers_from_wild_type_and_vacuolar_invertase_silencing_lines_of_Katahdin_ DB - PRIME DP - Unbound Medicine ER -