scholarly journals Levels and Role of Sucrose Synthase, Sucrose-phosphate Synthase, and Acid Invertase in Sucrose Accumulation in Fruit of Asian Pear

1992 ◽  
Vol 117 (2) ◽  
pp. 274-278 ◽  
Author(s):  
Takaya Moriguchi ◽  
Kazuyuki Abe ◽  
Tetsuro Sanada ◽  
Shohei Yamaki

Soluble sugar content and activities of the sucrose-metabolizing enzymes sucrose synthase (SS) (EC 2.4.1.13), sucrose-phosphate synthase (SPS) (EC 2.4.1.14), and acid invertase (EC 2.4.1.26) were analyzed in the pericarp of fruit from pear cultivars that differed in their potential to accumulate sucrose to identify key enzymes involved in sucrose accumulation in Asian pears. The Japanese pear `Chojuro' [Pyrus pyrifolia (Burro. f.) Nakai] was characterized as a high-sucrose-accumulating type based on the analysis of mature fruit, while the Chinese pear `Yali' (P. bretschneideri Rehd.) was a low-sucrose-accumulating type throughout all developmental stages. The activity of SS and SPS in `Chojuro' increased during maturation concomitant with sucrose accumulation, whereas the activity of these enzymes in `Yali' did not increase during maturation. The activity of SS and SPS in the former were seven and four times, respectively, higher than those in the latter at the mature stage. Further, among 23 pear cultivars, SS activity was closely correlated with sucrose content, while SPS activity was weakly correlated. Soluble acid invertase activity in `Chojuro' and `Yali' decreased with fruit maturation, but the relationships between soluble invertase activity and sucrose content were not significant. The results indicate that SS and SPS are important determinants of sucrose accumulation in Asian pear fruit and that a decrease of soluble acid invertase activity is not absolutely required for sucrose accumulation.

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 540a-540
Author(s):  
R.L. Darnell ◽  
R. Cano-Medrano ◽  
K.E. Koch

Variability in sucrose levels and metabolism in ripe fruit of several Vaccinium species were examined. The objective was to determine if sufficient variability for fruit sucrose accumulation was present in existing populations to warrant attempts to breed for high-sucrose fruit, which potentially would be less subject to bird predation. Three-fold differences in fruit sucrose concentration were found among species, ranging from 19 to 24 mg·(g fw)-1 in V. stamineum and V. arboreum to about 7 mg·(g fw)-1 in cultivated blueberry (V. ashei and V. corymbosum) and V. darrowi. Soluble acid invertase activity was negatively correlated with fruit sucrose concentration. There was no apparent correlation between fruit sugar concentration and either sucrose phosphate synthase or sucrose synthase activities, both of which were low for all species studied. The degree of variability in fruit sucrose accumulation among Vaccinium species supports the feasibility of developing high sucrose fruit, which would be a potentially valuable addition to current strategies of minimizing crop losses to birds.


2000 ◽  
Vol 27 (11) ◽  
pp. 1021 ◽  
Author(s):  
Hongmei Ma ◽  
Henrik H. Albert ◽  
Robert Paull ◽  
Paul H. Moore

Transgenic sugarcane (Saccharum officinarum L.) lines were created to express altered invertase isoform activity to elucidate the role(s) of invertase in the sucrose accumulation process. A sugarcane soluble acid invertase cDNA (SCINVm, AF062734) in the antisense orientation was used to decrease invertase activity. The Saccharomyces cerevisiae invertase gene (SUC2), fused with appropriate targeting elements, was used to increase invertase activity in the apoplast, cytoplasm and vacuole. A callus/liquid culture system was established to evaluate change in invertase activity and sugar concentration in the transgenic lines. Increased invertase activity in the apoplast led to rapid hydrolysis of sucrose and rapid increase of hexose in the medium. The cellular hexose content increased dramatically and the sucrose level decreased. Cells with higher cytoplasmic invertase activity did not show a significant change in the sugar composition in the medium, but did significantly reduce the sucrose content in the cells. Transformation with the sugarcane antisense acid invertase gene produced a cell line with moderate inhibition of soluble acid invertase activity and a 2-fold increase in sucrose accumulation. Overall, intracellular and extracellular sugar composition was very sensitive to the change in invertase activities. Lowering acid invertase activity increased sucrose accumulation.


2000 ◽  
Vol 27 (1) ◽  
pp. 81 ◽  
Author(s):  
Frederik C. Botha ◽  
Kevin G. Black

Sucrose accumulation rates, sucrose-phosphate synthase (SPS, EC 2.4.1.14) and soluble sucrose synthase (SuSy, EC 2.4.1.13) activities were measured in internodal tissue from a sugarcane (Saccharum species hybrids) variety N19. The sucrose accumulation rate sharply increases between internodes 3 to 11. In the older internodes SPS activity was at least three times higher than the SuSy activity. A highly significant positive correlation was found between SPS activity and sucrose content. In contrast, no significant correlation was observed between SuSy and sucrose content. In agreement, when radiolabelled glucose was fed to internodes with a high sucrose accumulation rate, label was equally distributed in the hexose moieties of sucrose. This clearly indicates that SPS is the major sucrose synthesis activity in the culm of sugarcane. Different kinetic forms of SPS apparently exist in the internodal tissue at different stages of development.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 420C-420
Author(s):  
Gene Lester ◽  
Luis Saucedo Arias ◽  
Miguel Gomez-Lim

Muskmelon [Cucumis melo L. (Reticulatus Group)] fruit sugar content is the single most important consumer preference attribute. During fruit ripening, sucrose accumulates when soluble acid invertase (AI) activity is less then sucrose phosphate synthase (SPS) activity. To genetically heighten fruit sugar content, knowledge of sugar accumulation during fruit development in conjunction with AI and SPS enzyme activities and their peptide immunodetection profiles is needed. Two netted muskmelon cultivars [`Valley Gold' (VG), a high sugar accumulator, and `North Star' (NS), a low sugar accumulator] with similar maturity indices were assayed for fruit sugars, AI, and SPS activity and immunodetection of AI and SPS polypeptides following 2, 5, 10, 15, 20, 25, 30, 35, and 40 (abscission) days after anthesis (DAA). Both cultivars, grown in spring and fall, showed similar total sugar accumulation profiles. Total sugars increased 1.5 fold, from 2 through 5 DAA and then remained unchanged until 30 DAA. From 30 DAA until abscission, total sugar content increased, with VG accumulating significantly more sugar then NS. In both cultivars, during both seasons, sucrose was detected at 2 DAA, which coincided with higher SPS activity than AI activity. At 5 through 25 DAA, SPS activity was less then AI activity resulting in little or no sucrose detection. It was not until 30 DAA that SPS activity was greater than AI activity resulting in increased sucrose accumulation. VG at abscission had higher total sugar content and SPS activity and lower AI activity than NS. Total polypeptides from both cultivars 2 through 40 DAA, were immunodetected with antibodies: anti-AI and anti-SPS. NS had Al isoforms bands at 75, 52, 38, and 25 kDa that generally decreased wtih DAA. One isoform at 52 kDa remained detectable up to anthesis (40 DAA) VG had the same four Al isoforms, all decreased with DAA and became undetectable by 20 DAA. It is unclear if one or all AI isoforms correspond with detected enzyme activity. VG and NS had one SPS band at 58 kDa that increased with DAA and concomitantly with SPS activity. VG had a more intense SPS polypeptide band at abscission then did NS. Thus, netted muskmelon sugar accumulation may be increased by selecting for cultivars with a specific number of AI isoforms, which are down-regulated, and with high SPS activity during fruit ripening.


2010 ◽  
Vol 37 (12) ◽  
pp. 1161 ◽  
Author(s):  
Luguang Wu ◽  
Robert G. Birch

Transgenic sugarcane (Saccharum officinarum L. interspecific hybrids) line N3.2 engineered to express a vacuole-targeted sucrose isomerase was found to accumulate sucrose to twice the level of the background genotype Q117 in heterotrophic cell cultures, without adverse effects on cell growth. Isomaltulose levels declined over successive subcultures, but the enhanced sucrose accumulation was stable. Detailed physiological characterisation revealed multiple processes altered in line N3.2 in a direction consistent with enhanced sucrose accumulation. Striking differences from the Q117 control included reduced extracellular invertase activity, slower extracellular sucrose depletion, lower activities of symplastic sucrose-cleavage enzymes (particularly sucrose synthase breakage activity), and enhanced levels of symplastic hexose-6-phosphate and trehalose-6-phosphate (T6P) in advance of enhanced sucrose accumulation. Sucrose biosynthesis by sucrose phosphate synthase (SPS) and sucrose phosphate phosphatase (SPP) was substantially faster in assays conducted to reflect the elevation in key allosteric metabolite glucose-6-phosphate (G6P). Sucrose-non-fermenting-1-related protein kinase 1 (SnRK1, which typically activates sucrose synthase breakage activity while downregulating SPS in plants) was significantly lower in line N3.2 during the period of fastest sucrose accumulation. For the first time, T6P is also shown to be a negative regulator of SnRK1 activity from sugarcane sink cells, hinting at a control circuitry for parallel activation of key enzymes for enhanced sucrose accumulation in sugarcane.


2002 ◽  
Vol 24 (4) ◽  
pp. 441-446 ◽  
Author(s):  
Federico A. Gutiérrez-Miceli ◽  
Martha A. Rodríguez-Mendiola ◽  
Neftalí Ochoa-Alejo ◽  
Ricardo Méndez-Salas ◽  
Luc Dendooven ◽  
...  

1992 ◽  
Vol 22 (4) ◽  
pp. 442-446 ◽  
Author(s):  
J. Brad Murphy ◽  
Mark R. Rutter ◽  
Mark F. Hammer

The developmental pattern and relative activities of sucrose synthase (EC 2.4.1.13) and soluble acid invertase (EC 3.2.1.26), and the associated contents of sucrose and hexoses, were analyzed in the cotyledons, hypocotyl, and radicle of pinyon (Pinusedulis Engelm.) seedlings following radicle emergence. Sucrose synthase activity did not appear to be correlated with organ growth, but showed a close association with sucrose content. Conversely, there was a high degree of correlation between soluble acid invertase activity and growth of the various organs. Hexose content also was correlated with the level of invertase activity. Thus, soluble acid invertase appeared to be directly involved in providing respiratory and biosynthetic substrates in growing organs, while the role of sucrose synthase was less clear, being more active in tissues that are involved in sucrose import and transport and possibly sucrose to starch conversion.


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