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Paul C Bethke - One of the best experts on this subject based on the ideXlab platform.
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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, 2014Co-Authors: Amy E Wiberleybradford, James S Busse, Jiming Jiang, Paul C BethkeAbstract: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.
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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, 2014Co-Authors: Amy E Wiberleybradford, James S Busse, Jiming Jiang, Paul C BethkeAbstract: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.
Amy E Wiberleybradford - One of the best experts on this subject based on the ideXlab platform.
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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, 2014Co-Authors: Amy E Wiberleybradford, James S Busse, Jiming Jiang, Paul C BethkeAbstract: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.
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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, 2014Co-Authors: Amy E Wiberleybradford, James S Busse, Jiming Jiang, Paul C BethkeAbstract: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.
James S Busse - One of the best experts on this subject based on the ideXlab platform.
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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, 2014Co-Authors: Amy E Wiberleybradford, James S Busse, Jiming Jiang, Paul C BethkeAbstract: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.
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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, 2014Co-Authors: Amy E Wiberleybradford, James S Busse, Jiming Jiang, Paul C BethkeAbstract: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.
Jiming Jiang - One of the best experts on this subject based on the ideXlab platform.
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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, 2014Co-Authors: Amy E Wiberleybradford, James S Busse, Jiming Jiang, Paul C BethkeAbstract: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.
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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, 2014Co-Authors: Amy E Wiberleybradford, James S Busse, Jiming Jiang, Paul C BethkeAbstract: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.
Richard N Knowles - One of the best experts on this subject based on the ideXlab platform.
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zebra chip disease enhances respiration and oxidative stress of potato Tubers solanum tuberosum l
Planta, 2017Co-Authors: G Mohan N Kumar, Lisa O Knowles, Richard N KnowlesAbstract:Main conclusion The physiological phenotype of potato Tubers afflicted by zebra chip disease is characterized by increased oxidative stress metabolism and upregulation of systems for its mitigation. Starch catabolism and extensive buildup of reducing sugars render potatoes infected with zebra chip (ZC) pathogen (Candidatus Liberibacter solanacearum) unsuitable for fresh market and processing into chips/fries. Here we show that the disease inflicts considerable oxidative stress, which likely constitutes a substantial sink for metabolic energy, resulting in increased respiration rate of afflicted Tubers. In contrast to healthy Tubers, tissue from diseased Tubers had greater ability to reduce 2,3,5-triphenyl-tetrazolium chloride to formazan, indicating enhanced dehydrogenase activity, probable disease-induced changes in cellular redox potential, and increased respiratory activity. The respiration rate of diseased Tubers (cv. Atlantic) was 2.4-fold higher than healthy Tubers and this correlated with increased activities of glucose-6-phosphate and 6-phosphogluconate dehydrogenases, key enzymes responsible for synthesis of cytosolic reducing equivalents. Wound-induced NADPH oxidase activity was greater for ZC than healthy Tubers, but the resulting superoxide was rapidly catabolized by higher superoxide dismutase activity in ZC Tubers. Peroxidase, catalase, glutathione reductase and ascorbate free radical reductase activities were also higher in diseased Tubers, as was malondialdehyde, a biomarker of peroxidative damage and oxidative stress. Upregulation of the glutathione–ascorbate pathway is a direct response to (and indicator of) oxidative stress, which consumes reducing equivalents (NADPH) to catabolize reactive oxygen species and maintain cellular redox homeostasis. ZC disease substantially altered the oxidative metabolism of Tubers, resulting in a physiological phenotype defined by metabolic changes directed toward mitigating oxidative stress. Paradoxically, the increased respiration rate of ZC Tubers, which fuels the metabolic pathways responsible for attenuating oxidative stress, likely also contributes to oxidative stress.
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low oxygen storage modulates invertase activity to attenuate cold induced sweetening and loss of process quality in potato solanum tuberosum l
Postharvest Biology and Technology, 2016Co-Authors: Derek J Herman, Lisa O Knowles, Richard N KnowlesAbstract:Abstract Russet Burbank and Innovator are mid- to late-season frozen-processing cultivars with inherently different dormancy periods and susceptibilities to low temperature-induced sweetening (LTS). In contrast to Russet Burbank, which is highly prone to accumulation of reducing sugars (Glc + Fru) when stored below 8–9 °C, Innovator Tubers exhibit moderate resistance to LTS and retain process quality longer at lower temperatures (4–6 °C). However, Innovator’s LTS resistance is not robust and often varies across production regions. Here we show that low O2 storage modulates LTS to reveal metabolic differences intrinsic to these cultivars. Changes in tuber respiration, process quality, reducing sugars, sucrose, starch phosphorylase and invertase activities were compared at 4 and 8 °C in 2.5 and 21 kPa O2 over a 212-d storage period. Tuber respiration declined rapidly as O2 level decreased from 21 to 2.5 kPa during acclimation at 8 °C. Respiration rates then fell further as the temperature was lowered from 8 to 4 °C, but this response was greatly muted for Tubers at 2.5 versus 21 kPa O2. Tubers at 21 kPa O2 completed their cold-induced respiratory acclimation response (RAR) within 7 d compared with 13 d at 2.5 kPa O2, and the RAR was much greater for Tubers at 2.5 kPa O2. While reducing sugars increased most rapidly in Tubers over the first 30 d at 4 °C, Innovator Tubers had lower invertase activity and sweetened less than Russet Burbank Tubers, characterizing its LTS-resistant phenotype. Low O2 greatly attenuated these initial LTS responses for both cultivars; however, the effect was only temporary in Innovator. LTS resumed in Innovator Tubers from 93 to 212 d with reducing sugar levels increasing to equal that of Russet Burbank Tubers stored at 4 °C and 21 kPa O2. Activities of α-1,4 glucan phosphorylase (SP) were higher in Russet Burbank than Innovator and increased progressively over the storage period regardless of temperature and oxygen concentration. Innovator Tubers stored at 2.5 kPa O2 had higher SP activities from 30 to 153 d at 4 and 8 °C compared with Tubers stored at 21 kPa O2, which correlated well with increased sucrose buildup and earlier sprouting. The low O2-mediated inhibition of LTS was largely a consequence of reduced invertase activities.
