Physiological basis for enhanced sucrose accumulation in an engineered sugarcane cell line

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.

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.


2007 ◽  
Vol 12 (2) ◽  
pp. 137-143
Author(s):  
Miswar Miswar ◽  
Bambang Sugiharto ◽  
Joedoro Soedarsono ◽  
Sukarti Moeljapawiro

Sucrose phosphate synthase (SPS EC 2.3.1.14) plays an important role in partition of assimilated carbon in most plants. SPS catalyses the penultimate reaction in the pathway of sucrose synthesis, in which sucrose-6-phosphate (Suc6P) is synthesized from UDPglucose (UDPG) and fructose-6-P (Fru6P). To increase the capacity of sugarcane in sucrose synthesis, spindle leaves of sugarcane cv R579 were transformed with cDNA SoSPS1 from sugarcane under the control of constitutive promoter (35S CaMV) that constructed in pBI 121 (pKYS) using Agrobacterium tumefaciens. Based on PCR analysis, we have detected the existence of SPS transgene in some lines of transformed sugarcane, called line 4, 5, 6, and 7. The SPS transgene in transformed sugarcane could be expressed into translation level and increased the amount of leaves SPS protein, so the activity of leaves SPS was higher than wild type sugarcane as control. The transformed sugarcane line 4, 5, 6, and 7 showed 1.4–2.9 fold increases in SPS activity and 1,76–2,2 fold increases in leaves sucrose content. Increasing in SPS activity in transgenic sugarcane was coupled by the increase in invertase activity and ratio between sucrose and starch content.


2001 ◽  
Vol 126 (6) ◽  
pp. 676-680 ◽  
Author(s):  
Yasuyoshi Hayata ◽  
Xin-Xian Li ◽  
Yutaka Osajima

To clarify the cause of low sucrose accumulation in seedless `Crest Earl's' netted muskmelon [Cucumis melo L. (Reticulatus Group)] fruit induced by CPPU, the activity level of sucrose metabolizing enzymes was compared between seeded and seedless fruit. CPPU promoted growth of the ovary in both pollinated and nonpollinated flowers until 10 days after anthesis (DAA), and thereafter the growth rate of nonpollinated fruit was lower than in the controls. Sucrose accumulation of seedless fruit remained lower than in seeded fruit, but there was no difference in fructose and glucose content between seeded and seedless fruit. Acid invertase activity declined sharply 20 DAA in seeded and seedless fruit, and was hardly detectable at 35 DAA, when sucrose accumulation began. Neutral invertase (NI) activity in both seeded and seedless fruit decreased from 20 DAA until 35 DAA; thereafter, NI activity in seeded fruit remained relatively constant, with a small but insignificant increase in maturity. Sucrose synthase (SS-c: sucrose cleavage direction) activity in seeded fruit decreased from 20 to 30 DAA, and then increased as fruit matured, while SS-c activity in seedless fruit did not change during development. Sucrose phosphate synthase (SPS) activity in seeded fruit increased from 25 to 30 DAA and remained relatively constant until harvest. SPS activity in seedless fruit declined gradually from 30 to 45 DAA, then remained at a low level. Sucrose synthase (SS-s: sucrose synthesis direction) activity in seeded fruit increased rapidly after 30 DAA, concomitant with sucrose accumulation. In contrast, SS-s activity in seedless fruit increased only slightly after 30 DAA indicating levels of SS-s activity are closely related to sucrose accumulation in parthenocarpic seedless muskmelons. Chemical name used: [1-(2-chloro-4-pyridyl)-3-phenylurea] (CPPU).


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.


2021 ◽  
Vol 23 (1) ◽  
pp. 176
Author(s):  
Lin Chen ◽  
Fenghua Zheng ◽  
Zili Feng ◽  
Yue Li ◽  
Muxuan Ma ◽  
...  

Vacuolar invertase (VI) can irreversibly degrade sucrose into glucose and fructose and involve in plants abiotic-stress-tolerance. Cucumber (Cucumis sativus L.) is susceptible to drought stress, especially during the seedling stage. To date, the involvement of VI in drought tolerance in cucumber seedlings is in urgent need of exploration. In the present study, a cucumber vacuolar invertase gene, CsVI2, was isolated and functionally characterized. The results showed that (1) CsVI2 showed vacuolar invertase activity both in vivo and in vitro; (2) the transcript level of CsVI2, along with VI activity, was significantly induced by drought stress. Moreover, the expression of sucrose synthase 3 (CsSUS3) was increased and that of sucrose phosphate synthase 1 (CsSPS1) was decreased after exposure to drought stress, which was followed by an increase in sucrose synthase activity and a decrease in sucrose phosphate synthase activity; (3) CsVI2-overexpressing transformed cucumber seedlings showed enhanced vacuolar invertase activity and drought tolerance and 4) protein–protein interaction modelling indicated that a cucumber invertase inhibitor, CsINVINH3, can interact with CsVI2. In summary, the results indicate that CsVI2 as an invertase can regulate sucrose metabolism and enhance drought stress in cucumber seedlings.


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.


1990 ◽  
Vol 115 (2) ◽  
pp. 278-281 ◽  
Author(s):  
Takaya Moriguchi ◽  
Tetsuro Sanada ◽  
Shohei Yamaki

Sugar levels and composition were determined in developing `Hakuto' peach (Prunus persica Batsch var. vulgaris Maxim.) fruit. Glucose and fructose in nearly equal amounts were the predominant sugars detected during the early stage of development. Sucrose subsequently began to accumulate and was the predominant sugar in mature fruit. Sorbitol remained at a low level throughout development. The large increase in the amount of sucrose was accompanied by a rapid increase in sucrose synthase (EC 2.4.1.13) activity. Sucrose phosphate synthase (EC 2.4.1.14) was also detected in flesh extracts, but the activities were low throughout development. Acid invertase (EC 3.2.1.26) activity was highest in young fruit and declined with development. Activity, however, increased again at a later stage of development. Peach fruit contained appreciable sorbitol oxidase activity, while other sorbitol-related enzymes were barely detectable, suggesting that transported sorbitol was predominantly converted to glucose. These results suggest that the supply of glucose and fructose depends on acid invertase and sorbitol oxidase, and that accumulation of sucrose depends on-sucrose synthase.


1994 ◽  
Vol 21 (3) ◽  
pp. 255 ◽  
Author(s):  
IF Wardlaw ◽  
J Willenbrink

Wheat plants grown under non-stress conditions at a dayhight temperature of 18/13�C under glasshouse conditions from head emergence to maturity showed a maximum accumulation of water-soluble, non-structural carbohydrates 20-25 days after anthesis. This storage was largely as fructans with the timing and amount of storage and mobilisation varying between cultivars, although the maximum concentration (fructose equivalents per unit stem fresh weight) was similar in all cultivars. The main storage in the culm was located in the lower part of the peduncle enclosed by the flag leaf sheath, in the penultimate internode and for one cultivar also in the flag leaf sheath. 14CO2 pulse-chase studies showed that there was a considerable delay in the incorporation of flag leaf assimilates into stem fructans, a delay probably associated with transfer and metabolic processes in the stem itself. At anthesis, when soluble carbohydrates were rapidly accumulating in the culm, the level of activity of sucrose synthase (SS) in the penultimate internode was much greater than that of sucrose phosphate synthase (SPS). The activity of SS declined rapidly as active storage ceased. This pattern was the reverse of that found in the leaf where SPS, rather than SS, was initially high and declined towards maturity. These changes are discussed in relation to the possible role of sucrose synthesising enzymes, particularly SS, in the accumulation and mobilisation of stem reserves in wheat.


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