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

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.

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.


Plants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 200 ◽  
Author(s):  
Risky Mulana Anur ◽  
Nurul Mufithah ◽  
Widhi Dyah Sawitri ◽  
Hitoshi Sakakibara ◽  
Bambang Sugiharto

Sucrose phosphate synthase (SPS) is a key enzyme in sucrose synthesis, which controls sucrose content in plants. This study was designed to examine the efficacy of the overexpression of SoSPS1 gene on sucrose accumulation and carbon partitioning in transgenic sugarcane. The overexpression of SoSPS1 gene increased SPS activity and sucrose content in transgenic sugarcane leaves. More importantly, the overexpression enhanced soluble acid invertase (SAI) activity concomitant with the increase of glucose and fructose levels in the leaves, whereas sucrose synthase activity exhibited almost no change. In the stalk, a similar correlation was observed, but a higher correlation was noted between SPS activity and sugar content. These results suggest that SPS overexpression has both direct and indirect effects on sugar concentration and SAI activity in sugarcane. In addition, SPS overexpression resulted in a significant increase in plant height and stalk number in some transgenic lines compared to those in non-transgenic control. Taken together, these results strongly suggest that enhancing SPS activity is a useful strategy for improving sugarcane yield.


2006 ◽  
Vol 33 (6) ◽  
pp. 605 ◽  
Author(s):  
C. P. L. Grof ◽  
C. T. E. So ◽  
J. M. Perroux ◽  
G. D. Bonnett ◽  
R. I. Forrester

Sucrose-phosphate synthase (SPS) is a key enzyme in the pathway of sucrose synthesis. Five different gene families encoding SPS have been reported in the Poaceae [Castleden CK, Aoki N, Gillespie VJ, MacRae EA, Quick WP, Buchner P, Foyer CH, Furbank RT, Lunn JE (2004) Evolution and function of the sucrose-phosphate synthase gene families in wheat and other grasses. Plant Physiology 135, 1753–1764]. Expression of the five families in leaf and stem tissues of Saccharum spp. at different stages of development was determined by quantitative real-time PCR. The type B and C families of SPS genes were predominantly expressed in both immature and mature leaves, whereas the two subfamilies making up the type D family were expressed at similar levels in all tissues examined. In the type A family, expression was lowest in leaves and increased from the meristem region down to internode 7 of the stem.


1997 ◽  
Vol 24 (1) ◽  
pp. 1 ◽  
Author(s):  
John E. Lunn ◽  
Marshall D. Hatch

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.


1984 ◽  
Vol 34 (3) ◽  
pp. 247-252 ◽  
Author(s):  
Thomas W. Rufty ◽  
Steven C. Huber ◽  
Phillip S. Kerr

PLoS ONE ◽  
2017 ◽  
Vol 12 (10) ◽  
pp. e0186650 ◽  
Author(s):  
Juan Wang ◽  
Junjie Du ◽  
Xiaopeng Mu ◽  
Pengfei Wang

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