Starch-sugar interconversion in Solanum tuberosum

doi:10.1016/0031-9422(73)85060-5

Phytochemistry

Volume 12, Issue 11, November 1973, Pages 2579-2591

https://doi.org/10.1016/0031-9422(73)85060-5 Get rights and content

Abstract

The changes in starch, sugars, and respiration of both immature and mature potato tubers (variety King Edward) caused by transfer from +10° to +2° and back to +10°, were followed throughout. At each storage temperature the tubers were allowed to reach a steady state before transfer to another temperature. In potatoes transferred from +10° to +2°, the sugar at first rose rapidly and then reached a constant value after 30 days. The respiration showed a characteristic pattern, for the first 5–8 days being below the initial value, then rising to a maximum at 14 days and finally returning to the initial value at 28 days. In potatoes transferred from +2° to +10° the sugar declined steadily, the respiration reaching a maximum after 10 days and then slowly falling to a value slightly above the initial value. Quantitative analysis of the results showed that the sum of starch + sugar + CO₂ expressed in equivalent anhydrohexose units did not change throughout the various changes in temperature. This work provided a quantitative experimental basis for what had hitherto been an assumption. Starch was the only polysaccharide involved in these carbohydrate changes. No change in the amylose/amylopectin ratio was detected either during the breakdown of starch (temperature change +10° to +2°) or during its synthesis (+2° to + 10°). The increased respiration which accompanied any change in temperature was related quantitatively to the formation of sucrose from starch (+10° to +2°) and starch from sugar (+2° to + 10°). The ATP equivalent of the extra CO₂ output was of the same order as that predicted on the basis of known biochemical pathways linking starch and sugar.

References (27)

C.S. Hanes et al.
Proc. R. Soc.
(1931)
S.J. Pirt et al.
J. Sci. Food Agric.
(1951)
H. Muller-Thurgau
Landw. Jbr.
(1882)
B. Arreguin-Lozano et al.
Plant Physiol.
(1949)
J. Barker
New Phytologist
(1965)
J. Barker
New Phytologist
(1968)
J. Barker
New Phytologist
(1968)
H.K. Porter
Biochem. Soc. Symp.
(1953)
W.G. Burton
European Potato J.
(1969)
J. Barker
Proc. R. Soc.
(1936)
G.A. Gilbert et al.

Scheéle C. von et al.

Landw. VerSten

(1937)

W.G. Burton

(1966)

W.J. Whelan

Cited by (151)

Role of alkaline/neutral invertases in postharvest storage of potato
2022, Postharvest Biology and Technology
Potatoes stored at cold temperatures undergo undesirable sweetening due to the cleavage of sucrose into reducing sugars by invertases. Although significant research has focused on vacuolar invertase (StVAC) during cold storage of potatoes, little is known about the role of alkaline/neutral invertases (StNI). We identified eight members in the NI family from the potato genome, and phylogenetic analysis suggested their probable subcellular location as plastid/mitochondria (group α) or cytosol (group β). Using three commercially important potato cultivars with known differences in cold storage responses (‘Russet Burbank’, ‘Bintje’, and ‘Shepody’), we compared the expression of the eight StNI genes to StVAC and vacuolar invertase inhibitor (StINH2) genes during harvest, and after one and five months of storage at 4 °C or 22 °C. The activity of neutral invertase (NI), soluble acid invertase activity (SAI), and the levels of reducing sugars were also determined. Tubers of ‘Russet Burbank’ displayed high transcript abundance of StNI5, high reducing sugar content and more NI activity than SAI activity. This was associated with a high level of StINH2 transcripts and low StVAC transcript levels suggesting the susceptibility of these tubers to cold-induced sweetening could be due to cytoplasmic cleavage of sucrose by NI. In ‘Bintje’, the induction of StNI5 and StVAC transcripts and NI and SAI activities indicate that sucrose degradation is carried out by both NI and SAI. In ‘Shepody’, a higher abundance of the StNI4 and StNI6 transcripts indicates different isoforms of NI are required for sucrose degradation. This study reveals significant contribution of NI in the regulation of reducing sugars and the process of cold-induced sweetening. Additional studies are needed to determine the in vivo function of NI in cold-stored potato tubers.
Comparative transcriptome reveals distinct starch-sugar interconversion patterns in potato genotypes contrasting for cold-induced sweetening capacity
2021, Food Chemistry
Potato accumulates large amounts of soluble sugar during cold storage periods. However, a system based understanding of this process is still largely unknown. Here, we compared the dynamic cold-responded transcriptome of genotypes between cold-induced sweetening resistant (CIS-R) and cold-induced sweetening sensitive (CIS-S) in tubers. Comparative transcriptome revealed that activating the pathways of starch degradation, sucrose synthesis and hydrolysis could be common strategies in response to cold in both genotypes. Moreover, the variation in sugar accumulation between genotypes may be due to genetic differences in cold response, which could be mainly explained: CIS-R genotype was active in starch synthesis and attenuated in sucrose hydrolysis by promoting the coordinate expression of a series of genes involved in starch-sugar interconversion. Additionally, transcription factors, the candidate master regulators of starch-sugar interconversion, were discussed. Taken together, this work has provided an avenue for studying the mechanism involved in the regulation of the CIS resistance.
Developmental and postharvest physiological phenotypes of engineered potatoes (Solanum tuberosum L.) grown in the Columbia Basin
2020, Field Crops Research
Citation Excerpt :
The respiratory and sweetening responses of tubers during cold acclimation, storage at 4 °C, and subsequent reconditioning at 16 °C defined the postharvest physiological phenotypes of Innate® and parental cultivars. Respiration rates are indicative of overall tuber metabolic rates and temperature-dependent starch to sugar interconversion is a sink for metabolic energy (Isherwood, 1973). Changes in tuber respiration rates are driven by changes in “ATP-requiring activities of the cell that pull the process of ATP-yielding catabolism.
The Innate® potato cultivars, Glaciate, Acclimate, and Hibernate are engineered for bruise and cold sweetening resistance, low acrylamide forming potential and increased Late Blight resistance. Phenotyping trials from 2015 to 2017 characterized the in-field performance, postharvest physiology, and process quality of these cultivars in the Columbia Basin of Washington. Plant growth, tuber yields and specific gravities of Acclimate and Hibernate were comparable to their respective parental cultivars, Ranger Russet and Atlantic. Glaciate exhibited lower yield and specific gravity compared with Russet Burbank. All Innate® cultivars had lower reducing sugars at harvest than their conventional counterparts resulting in superior process fry color. Asparagine (Asn) increased many-fold during development of Russet Burbank and Atlantic tubers but remained relatively low in Innate® tubers due to silenced Asn synthetase. Tuber respiration rates during sequential periods of low temperature sweetening (LTS, 4 °C), reconditioning (16 °C), and subsequent cold storage (4 °C) were largely comparable for Acclimate versus Ranger and for Hibernate versus Atlantic. Glaciate tubers, however, maintained significantly higher respiration rates than Russet Burbank tubers. Silenced invertase conferred resistance to reducing sugar buildup at 4 °C, resulting in superior process quality of the Innate® cultivars regardless of storage temperature. However, cold storage (4 °C) induced substantial increases in Suc concentration of Innate® tubers, which was then lowered 43–73 % by reconditioning at 16 °C. Subsequent storage at 4 °C had no further effect on Suc concentrations, demonstrating the efficacy of reconditioning as a management technique to reduce and minimize Suc levels during prolonged cold storage of Innate® tubers. While heat stress exacerbated the cold-induced buildup of Suc in Innate® tubers and reducing sugars in the parental cultivars, the increases in total sugar (Suc + Glc + Fru) concentrations remained equal, indicating similar elevated levels of starch catabolism during LTS of heat-stressed tubers. However, by virtue of silenced invertase, Innate® tubers were highly tolerant of heat stress for retention of process quality.
Combined transcriptomic and proteomic analysis of cold stress induced sugar accumulation and heat shock proteins expression during postharvest potato tuber storage
2019, Food Chemistry
Plant species differ greatly in their ability to acclimatise to and survive, cold stress. Normally, potato tubers are stored at low temperatures (below 10 °C) to delay sprouting. In this research, combined transcriptomic and proteomic analysis was conducted on potato tubers stored at 15 °C, 4 °C and 0 °C to investigate the mechanism of cold responses during postharvest storage. Results showed that soluble sugars were accumulated under low temperatures, regulating by granule-bound starch synthase 1, beta-amylase, invertase inhibitor and fructokinase. In addition, fifteen heat shock proteins (Hsps), including three Hsp70s, two Hsp80s, one Hsp90, one Hsp100 and eight small Hsps, were induced by low temperatures, which may act individually or synergistically to prevent physiological or cellular damage from cold stress in postharvest potato tubers. This research provided general information of sugar accumulation and defense response in potato tuber under cold storage.
Respiratory and low-temperature sweetening responses of fresh-cut potato (Solanum tuberosum L.) tubers to low oxygen
2019, Postharvest Biology and Technology
Citation Excerpt :
Refrigeration remains essential to maintaining shelf-life following cutting of these engineered apple and potato cultivars and is legally required by the FDA to control microbial proliferation (https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-industry-guide-minimize-microbial-food-safety-hazards-fresh-cut-fruits-and-vegetables#ch6, accessed June 11, 2019). However, unlike apple, potatoes are susceptible to low temperature sweetening (LTS) (Isherwood, 1973; Sowokinos, 2001), which can negatively affect processing and nutritional qualities. Storage of whole tubers of LTS-susceptible potato cultivars below ca 9 °C induces starch breakdown, resulting in the accumulation of reducing sugars (glc and fru) from sucrose via vacuolar acid invertase (Sowokinos, 2001; Bethke, 2014).
Enzymatic browning (EB) has impeded the commercialization of fresh-cut (FC) potato. However, recently introduced Innate^®-engineered cultivars with silenced polyphenol oxidase (PPO) have overcome this obstacle. As a supplement to refrigeration, low O₂ atmosphere may extend the shelf-life of FC potato by reducing wound-induced respiration, associated dry matter loss, EB, and low-temperature sweetening (LTS). Determining the O₂ concentration that minimizes these deteriorative physiological processes without invoking anaerobic metabolism is prerequisite to designing effective modified atmosphere packaging (MAP). Accordingly, FC tubers of cultivars Russet Burbank (RB), Ranger Russet (RR), and their Innate^® counterparts, CultivATE^®, GenerATE^®, and GlaciATE^®, were stored (4 °C) in ten O₂ atmospheres ranging from 0 to 21 kPa to determine the lower oxygen limit (LOL) for aerobic respiration and effects on LTS and EB. FC tissue stored at 21 kPa O₂ displayed a prominent cold-induced respiratory acclimation response (RAR), characterized by an initial decline in respiration rate followed by a steady increase through 48 h. The RAR decreased with O₂ and was extinguished at ≤1.5 kPa. Lowering O₂ from 21-7 kPa had little effect on tissue respiration; however, rates fell from 4.23 to 3.41 μg kg⁻¹ s⁻¹ as O₂ decreased from 7 to 3.5 kPa, followed by a further 79% reduction to 0.70 μg kg⁻¹ s⁻¹ at 0 kPa O₂. Tissue lactate profiles revealed the onset of anaerobic metabolism at ca 1.5 kPa O₂ for all cultivars. Importantly, lactate and ethanol accumulation were negligible through 16 d at ≥2 kPa O₂ (= LOL) but increased considerably at ≤1 kPa. Low O₂ attenuated the cold-induced synthesis of sucrose and reducing sugars in FC tissue from RB, and sucrose from GlaciATE^® tubers in which acid invertase is silenced. Enzymatic browning of FC RB and RR tubers was inhibited by anoxia, but extensive at ≥0.5 kPa O₂. FC Innate^® tubers exhibited only minor EB at all O₂ concentrations. Collectively, these data inform the further development of MAP for FC potato.
Postharvest temperature has a greater impact on apical dominance of potato seed-tuber than field growing-degree days exposure
2018, Field Crops Research
Citation Excerpt :
Cold-induced sweetening resulting from the accumulation of reducing sugars in cold-stored potato tubers has been mainly studied for its impact on potato processing (Sowokinos, 2001; Dale and Bradshaw, 2003). During cold-induced sweetening, sucrose synthesis increases and some sucrose is transported to the vacuole, where it is hydrolyzed to glucose and fructose (Isherwood, 1973; Isla et al., 1998; Sowokinos, 2001). This step is predominantly controlled by vacuolar acid invertase, an enzyme strongly associated with the accumulation of reducing sugars during cold storage (Matsuura-Endo et al., 2004).
The potato tuber is a swollen stem, which is used as the propagation material for commercial potato crops. At the end of a period of dormancy, the number of sprouts growing from the tuber nodes represent loss of tuber apical dominance (AD) resulting in branching. In Mediterranean countries, seed tubers cannot be kept in cold storage for a long period as it leads to over-branching of the seed tuber after replanting. In order to test the hypothesis that temperature exposure in the field effects dormancy length and/or AD postharvest, we exposed seed tubers to different numbers of growing-degree days (GDD) during their development. Seed tubers were cultivated at 0, 300 and 880 m above sea level (ASL), at three different planting dates. Crops were exposed to 780–1250 GDD and extended growth period induce linear accumulating GDD. For both cultivars, ‘Desiree’ and ‘Nicola’, there was a low correlation between GDD in the field and the number of days of storage at 2 °C before 70% of the tubers were released from dormancy. The main factor affecting the duration of dormancy period was the cultivar. In both cultivars, there was a low correlation between the seed-tuber crop’s exposure to GDD and the number of stems that emerged from the replanted tubers. The number of produced stems was mainly affected by the length of the storage period until replanting. Tubers that were replanted in the fall (following 130–190 d of storage) produced two to four stems each; whereas tubers replanted in the spring (following 210–270 d of storage) produced four to seven stems. There was a low correlation between mother-plant exposure to GDD in the field and total yield of the daughter plants. In both cultivars, exposure of the mother plants to different numbers of GDD did not have any significant effect on the size distribution of the tubers produced by the daughter plants. Extending the storage period did consistently induce yield of smaller sized tubers. We suggest that potato seed-tubers do not “remember” their GDD history and their AD is mainly affected by the duration of cold storage.

View all citing articles on Scopus

View full text

Starch-sugar interconversion in Solanum tuberosum

Abstract

Proc. R. Soc.

J. Sci. Food Agric.

Landw. Jbr.

Plant Physiol.

New Phytologist

New Phytologist

New Phytologist

Biochem. Soc. Symp.

European Potato J.

Proc. R. Soc.

Landw. VerSten