The Role of Sucrose-Phosphate Synthase in the Control of Photosynthate Partitioning in Zea mays Leaves

1997 ◽  
Vol 24 (1) ◽  
pp. 1 ◽  
Author(s):  
John E. Lunn ◽  
Marshall D. Hatch
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Feedback Inhibition ◽  
Sucrose Phosphate Synthase ◽  
Sucrose Content ◽  
Short Term ◽  
Maize Leaves ◽  
Sucrose Phosphate ◽  
Phosphate Synthase

The influence of light and leaf sucrose content on partitioning of photosynthate and sucrose-phosphate synthase (SPS) activity in maize (Zea mays L.) leaves was investigated. The ratio of partitioning of photosynthate between sucrose and starch shifted from about 17:1 to 2:1 when the irradiance was increased from 180 to 1450 µmol quanta m-2 s-1. Increasing the sucrose content of the leaves had little effect on the partitioning ratio. SPS from illuminated leaves had a higher affinity for its substrates, UDPGlc and Fru6P, and was less inhibited by Pi than the enzyme from darkened leaves but the Vmax was unaffected. SPS was fully light activated at an irradiance of 340 but not 180 µmol quanta m-2 s-1. Increasing the sucrose content of maize leaves more than 3-fold had little or no effect on the activation state of SPS which, together with the partitioning data, suggests that sucrose does not exert significant short-term feedback inhibition of its own synthesis in this species.

Regulation of sucrose-phosphate synthase in wheat (Triticum aestivum) leaves

2004 ◽  
Vol 31 (7) ◽  
pp. 685 ◽  
Author(s):  
Stephen J. Trevanion ◽  
C. Kate Castleden ◽  
Christine H. Foyer ◽  
Robert T. Furbank ◽  
W. Paul Quick ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Feedback Inhibition ◽  
Sucrose Phosphate Synthase ◽  
High Light ◽  
Sucrose Synthesis ◽  
Short Term ◽  
Cereal Species ◽  
Wheat Leaves ◽  
Sucrose Phosphate ◽  
Phosphate Synthase

The regulation of sucrose-phosphate synthase (SPS, E.C. 2.4.1.14), a key enzyme of sucrose synthesis, was investigated in wheat (Triticum aestivum L.) leaves. Wheat SPS was activated in the light, with an increased affinity for its substrates and the activator glucose-6-phosphate, reduced sensitivity to inhibition by Pi, but no change in maximum catalytic activity. Based on these properties, assays to measure the total activity and activation state of the enzyme were established and validated using several different wheat cultivars, grown under different environmental conditions. As found in previous studies on other species, e.g. spinach, activation appeared to be linked to the prevailing rate of photosynthesis rather than light per se. Long-term exposure to higher light levels increased total SPS activity in the leaves, and some experiments indicated that this response could occur within 1 h of exposure of low-light-grown plants to high light. However, activation of pre-existing enzyme was a more common short-term response to high light. Wheat, like many important cereal species, stores a large amount of sucrose in its leaves. In contrast with spinach, which stores more starch in its leaves, accumulation of sucrose in wheat leaves did not lead to inactivation of SPS or inhibition of sucrose synthesis. In conclusion, the mechanisms linking the rates of sucrose synthesis and photosynthetic CO2 fixation in wheat leaves appear to be similar to those in other species, but the mechanisms involved in short-term feedback inhibition of sucrose synthesis by sucrose, found in starch-storing species, are lacking in wheat.

Sucrose phosphate synthase and sucrose synthase activity during maturation of internodal tissue in sugarcane

2000 ◽  
Vol 27 (1) ◽  
pp. 81 ◽  
Author(s):  
Frederik C. Botha ◽  
Kevin G. Black
Keyword(s):  
Sucrose Synthase ◽  
Accumulation Rate ◽  
Sucrose Phosphate Synthase ◽  
Sucrose Accumulation ◽  
Sucrose Content ◽  
Synthesis Activity ◽  
Species Hybrids ◽  
High Sucrose ◽  
Sucrose Phosphate ◽  
Phosphate Synthase

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.

Role of Epigenetic Mechanisms in Regulating the Activity of 2-OGDH and MDH in Maize Leaves (Zea mays L.) during Hypoxia

2021 ◽  
Vol 68 (2) ◽  
pp. 331-336
Author(s):  
A. T. Eprintsev ◽  
D. N. Fedorin ◽  
G. B. Anokhina ◽  
M. O. Gataullina
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Epigenetic Mechanisms ◽  
Maize Leaves

A modified assay method shows leaf sucrose-phosphate synthase activity is correlated with leaf sucrose content across a range of sugarcane varieties

1998 ◽  
Vol 25 (4) ◽  
pp. 499 ◽  
Author(s):  
Christopher P.L. Grof ◽  
Deon P. Knight ◽  
Scott D. McNeil ◽  
John E. Lunn ◽  
James A. Campbell
Keyword(s):  
Sucrose Phosphate Synthase ◽  
Assay Method ◽  
Sucrose Content ◽  
Saccharum Spp ◽  
Sugarcane Varieties ◽  
Controlled Conditions ◽  
The Cross ◽  
First Time ◽  
Sucrose Phosphate ◽  
Phosphate Synthase

Eight different commercial and breeding varieties of sugarcane (Saccharum spp.) grown in controlled conditions were assayed for leaf sucrose-phosphate synthase (SPS) (EC 2.1.4.14) activity and leaf sucrose content. Leaf SPS activity measured at 25˚C ranged between 0.06 and 0.14 nmol sucrose formed mg protein -1 min-1. The cross-varietal average for leaf SPS activity was 0.10 nmol µg protein-1 min-1 (equivalent to 63.4 µmol h-1 g FW-1 or 17.6 nkat g FW-1) which is consistent with previously published leaf SPS activities for sugarcane; however, previous studies have assayed leaf SPS activity at either 30 or 37˚C. The range of leaf sucrose content across varieties (5.5–18.0 mg sucrose g FW-1, average 11.3 mg g FW-1) was consistent with all but one of four previously published reports. Leaf SPS activity and leaf sucrose content were significantly correlated across the eight varieties examined (r2 =0.877, d.f. =7,P<0.001). Whilst previous reports have indicated a co-relationship between leaf SPS activity and leaf sucrose content in single sugarcane varieties both diurnally and with different nutrient regimes, this study shows, for the first time, that this co-relationship also holds true across a range of sugarcane varieties.

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