Sucrose Synthetase Research Articles

Drought-induced disturbance of carbohydrate metabolism in anthers and male abortion of two Gossypium hirsutum cultivars differing in drought tolerance.

Cotton pollen abortion, under drought stress, was closely associated with changes in anther carbohydrate metabolism, and pollen abortion rate due to drought was higher in drought-sensitive cultivars than drought-tolerant cultivars. Cotton reproductive failure under drought stress is intrinsically connected with altered male fertility, however, studies investigating the effect of drought stress on cotton male fertility are nonexistent. Thus, a drought stress experiment was conducted with two cotton cultivars, differing in drought tolerance, to study pollen fertility and anthers' physiology. Results indicated that drought stress reduced pollen fertility of both cultivars due to decreases in anther starch and adenosine triphosphate (ATP) synthesis. Lower assimilate supply capacity in conjunction with impaired activities of ADP-glucose pyrophosphorylase and soluble starch synthase were the main reasons for the decreased starch levels in drought-stressed anthers. The decreased activities of sucrose synthetase and acid invertase were responsible for the higher sucrose level in drought-stressed anthers than well-watered anthers and the changing trend of sucrose was intensified by the decreased expressions of sucrose synthase genes (GhSusA, GhSusB, GhSusD) and acid invertase genes (GhINV1, GhINV2). However, despite sucrose degradation being limited in drought-stressed anthers, glucose level was higher in droughted anthers than well-watered ones, and that might be attributed to the down-regulated respiration since decreased anther ATP levels were detected in drought-stressed plants. Furthermore, compared to the drought-tolerant cultivar, pollen fertility was more suppressed by drought stress for the drought-sensitive cultivar, and that was attributed to the larger decrease in starch and ATP contents.

Rapid Effect of Nitrogen Supply for Soybean at the Beginning Flowering Stage on Biomass and Sucrose Metabolism

Nitrogen application at the beginning flowering stage (R1 stage) increased the soybean grain yield, however, the rapid effect of enriched nitrogen at R1 growth stage on soybean dry matter accumulation and sugar metabolism is still unclear. Continuous high nitrogen (CHN), Continuous low nitrogen (CLN), Enriched nitrogen supply at R1 stage (ENS) treatments were applied on two soybean cultivars (Liaodou11, Liaodou14), to investigate the effect of enriched nitrogen on plant biomass accumulation and sucrose metabolism. After 12 h of ENS treatment, the root/shoot rate of both cultivars were lower than that of CLN, but at 24 h it was no significant difference between ENS and CLN. Enriched N at R1 stage, soybean kept a balance of sucrose synthesis and decomposition in leaf by affecting sucrose synthetase (SS) and sucrose phosphate synthase (SPS) activities. Under N limitation condition the plant dry matter accumulation supported root growth priority. Enriched N at R1 stage resulted in the rapid shoot biomass accumulation. In high yield cultivar, the shoot growth was priority to root growth, the common yield cultivar was on the contrary. Our result suggest that enrich N at R1 stage resulted in the accumulation of biomass in shoot rapidly.

Regulation Network of Sucrose Metabolism in Response to Trivalent and Hexavalent Chromium in Oryza sativa.

The presence of chromium (Cr) in cultivated fields affects carbohydrate metabolism of rice (Oryza sativa L.) and weakens its productivity. Little is known about the molecular mechanism of sucrose metabolism underlying Cr stress response in rice plants. In the present study, the transcriptome map of sucrose metabolism in rice seedlings exposed to both trivalent and hexavalent chromium was investigated using Agilent 4 × 44K rice microarray analysis. Results indicated that Cr exposure (3 days) significantly (p < 0.05) improved sucrose accumulation, and altered the activities of sucrose synthetase, sucrose phosphate phosphatase, and amylosynthease in rice tissues. We identified 119 differentially regulated genes involved in 17 sucrose metabolizing enzymes and found that gene responses in roots were significantly (p < 0.05) stronger than in shoots under both Cr(III) and Cr(VI) treatment. The network maps of gene regulation responsible for sucrose metabolism in rice plants provide a theoretical basis for further cultivating Cr-resistant rice cultivars through molecular genetic improvement.

New Insights on ‘GALA’ Apple Fruit Development: Sugar and Acid Accumulation: A Transcriptomic Approach

Apple (Malus domestica, L. Borkh.) is an economically important fruit tree in the world and the quality of apple is vital for better economic returns. Components that determine apple fruit quality may accumulate at different developmental stages. To elucidate molecular mechanisms of compositional change, we performed a comprehensive transcriptomic analysis of apple fruit at five developmental stages, from young fruit to maturity, coupled with metabolic profiling. Correlating the transcriptomic and metabolic processes in apple is important for the understanding of apple fruit quality. We identified 7404 differentially expressed genes (DEGs) and divided them into 9 clusters. This transcriptomic dataset presents a global view of the critical pathways involved in apple fruit development and metabolism at different developmental stages. Physiological quality indices, including firmness, soluble solids content, total titratable acid, sugar content, and acid content, were also characterized during five periods of the apple. The main KEGG pathways, such as starch and sucrose metabolism, glycolysis/gluconeogen metabolism, and the tricarboxylic acid cycle, were analyzed. The activity of enzymes corresponding to DEGs, including sucrose synthetase, sucrose-phosphate synthase, and malate dehydrogenase, involved in the starch and sucrose metabolism and tricarboxylic acid cycle, were analyzed. Moreover, our findings imply that the probable reason of increases in sugar content during apple fruit development is related to a synthesis of trehalose-6-phosphate and trehalose, which are mainly regulated by Trehalose-6-phosphate synthase, trehalose-6-phosphate phosphatase, and trehalase. These analyses using the transcriptomic approach lay the foundation for understanding of apple fruit sugar and acid accumulation during growth and development.

Selenium impedes cadmium and arsenic toxicity in potato by modulating carbohydrate and nitrogen metabolism

Past studies have already determined that selenium (Se) is very effective in alleviating cell oxidative damage caused by various abiotic stresses in plants. Past studies have also indicated other physiological pathways by which Se may benefit plants. In order to better understand the full array of potential applications for Se in agriculture, this study investigated the influence of Se on carbohydrate and nitrogen (N) metabolism in potato plants (Solanum tuberosum L. cv. Sante) grown under cadmium (Cd) and/or arsenic (As) toxicity. Potato plants were grown in a growth chamber and fertigated with Hoagland nutrient solution with or without Se (9 μM). After 48-d of growth under Cd (40 μM) and/or As (40 μM) stress, carbohydrate and N metabolism in leaves, roots and stolons were measured. For carbohydrate metabolism, various sugars—i.e., sucrose, starch, glucose, fructose, and total soluble sugar contents (TSSC)—and the activities of enzymes associated with sucrose metabolism and glycolysis—i.e., acid invertase (AI), neutral invertase (NI), sucrose-synthetase (SS), sucrose phosphatesynthetase (SPS), fructokinase (FK), hexokinase (HK), phosphofructokinase (PFK), and pyruvatekinase (PK)—were measured. For N metabolism, NO3−, NO2− and NH4+ contents along with the enzymatic activities of nitrate reductase (NRA), nitrite reductase (NiRA), glutamine-synthetase (GS), and glutamate-synthetase (GOGAT) were measured. Overall, Cd and/or As treatments had reduced plant growth relative to those plants grown without heavy metal toxicity, due to hindered photosynthesis and alterations in N metabolism and glycolysis. Regarding N metabolism, heavy metal toxicity caused a reduction in NO3− and NO2− content and NRA and NiRA enzymatic activity and enhanced NH4+ content and GDH activity in leaves, roots and stolons. Regarding glycolysis, the activity of enzymes of glycolysis—i.e., FK, HK, PFK, and PK—were also reduced. In the C metabolism study, plants combatted Cd and As toxicity naturally by an adaptation mechanism which caused an increase in soluble sugars (fructose, glucose, sucrose) by increasing NI, SS and SSP enzymatic activity. Supplementation with Se in the Cd and/or As treatments in the carbohydrate and N metabolism studies improved plant growth. Selenium supplementation in the Cd and As treatments decreased Cd and/or As content in the plant tissue and alleviating the Cd- and/or As-induced toxicity by enhancing the C-metabolism adaptation mechanism. Applying Se to Cd and As treatments also decreased nitrogen losses by hindering Cd- and As-induced changes in the N-metabolism. Se also limited Cd and As accumulation in the plant tissue by the antagonistic effect between Cd/Se and As/Se in the roots. The results of this study indicate that in the presence of Cd and/or As. soil toxicity, Se may be a powerful tool for promoting plant growth.

Effects of light quality on carbon-nitrogen metabolism, growth, and quality of Chinese chives

We examined the effect of white + red (WR), white + blue (WB), white + green (WG), white + purple (WP) on the carbon-nitrogen metabolism, growth and quality of Chinese chives, with &lsquo;Pingjiu 2&rsquo; as the material and white light (W) as the control. The results showed that photosynthetic rate (Pn) in WR treatment was significantly higher than that in the control (CK) and that there was no difference among WB, WG, WP and CK. The activity of RuBPCase in all the four treatments was higher than that in CK. Compared with other treatments, WR showed the highest total sugar content, then WP, with WB and WG showing the lowest. Compared with CK, sucrose phosphate synthase (SPS) activity in WR was higher, and lower in the other three treatments, especially the lowest in WB. WB showed the highest activity of sucrose synthetase (SS) and amylase (AMS), WR displayed the lowest as well as the similar or lower in WG or WP compared with CK. These results implied that the increases of the proportion of red and purple light could improve carbon assimilation and transformation and thus accelerate sugar accumulation of Chinese chives. The content of total nitrogen, protein nitrogen, the activities of NR, GS and GOGAT of WB were the highest among all the treatments. The GDH activity of WB was the lowest and notably lower compared with CK. WR showed the lower contents of total nitrogen, protein nitrogen, the activities of NR and GS, and higher activities of GOGAT and GDH than those in CK, while the GDH activity of WR was the highest. WG showed lower total nitrogen, no-protein nitrogen content, and GDH activity, but higher protein nitrogen, NR and GOGAT activities than those in CK. Compared with the control, WP showed the similar results as WG, besides the higher GS activity, with most of these parameters in WP being better than in WG. These results indicated that blue, purple and green light could promote nitrogen metabolism, while red light might inhibit protein synthesis in Chinese chives. The growth of Chinese chives was much better under red and purple light, but worse under blue light, which led to thinner leaves and lower growth mass. Chinese chives of WP with the lowest crude fiber content showed the optimal comprehensive quality. Therefore, purple light exhibited the best effect on the growth of Chinese chives.

Changes in Sugar Metabolism and Fruit Quality of Different Pear Cultivars During Cold Storage

This study evaluated the changes in sugar metabolism and fruit quality of different pear cultivars during cold storage using seven major commercial pear cultivars belonging to different Pyrus species, such as P. bretschneideri Rehd. (“Huangguan,” “Yali”), P. pyrifolia Nakai. (“Wonhwang,” “Hosui”), P. ussuriensis Maxim. (“Jingbai,” “Nanguo”), and P. communis L. (“Bartlett”). The firmness, respiration rate, titratable acidity, total soluble solids, sugar content, and enzyme activity of the seven pear cultivars were investigated. SPSS was used for analyzing the significance of different indexes. Results showed that fructose was the dominant sugar, accounting for > 60% of total sugars, followed by glucose and sucrose. The respiration peak of almost all cultivars appeared within 60 days. The levels of fructose, glucose, sucrose, and total soluble solids increased within 90 days and then generally decreased. Acid invertase showed the highest activity among all pear cultivars, followed by neutral invertase, sucrose synthetase, and sucrose phosphate synthetase during storage.

干旱胁迫下紫花苜蓿幼苗非结构性碳水化合物代谢对NO的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 干旱胁迫下紫花苜蓿幼苗非结构性碳水化合物代谢对NO的响应 DOI: 10.5846/stxb201807231573 作者: 作者单位: 甘肃农业大学,甘肃农业大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31560663） Responses of non-structural carbohydrate metabolism of Medicago sativa seedlings to nitric oxide under drought stress Author: Affiliation: Gansu Agricultural University,Gansu Agricultural University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以紫花苜蓿（Medicago sativa）为材料，采用盆栽试验方法，用聚乙二醇（PEG-6000）作为渗透介质模拟干旱胁迫，外源喷施NO供体硝普钠，NO清除剂（carboxy-PTIO，cPTIO），对紫花苜蓿幼苗叶片、根系中非结构性碳水化合物含量及相关酶活性的变化进行研究，探讨NO对紫花苜蓿耐旱机制的作用。结果表明：外源NO促进了紫花苜蓿叶片中淀粉的分解、根系中淀粉的积累，提高叶片及根系中可溶性糖（蔗糖、果糖和葡萄糖）含量，降低了渗透势，促进细胞吸水，缓解干旱造成的损伤。此外，外源NO能提高干旱胁迫下紫花苜蓿叶片中蔗糖合成酶（SS）、酸性转化酶（AI）和中性转化酶（NI）活性，降低了蔗糖磷酸合成酶（SPS）的活性，提高根系中SS、SPS和转化酶活性，使蔗糖的合成与分解处于高水平的动态平衡，增强了紫花苜蓿的抗旱性。而NO清除剂cPTIO则会不同程度的抑制紫花苜蓿幼苗中非结构性碳水化合物（NSC）及其相关酶活性。因此，NO可以通过调控NSC的代谢响应干旱胁迫，缓解干旱胁迫造成的不利影响，在紫花苜蓿的抗旱中扮演着重要的角色。 Abstract:The effects of nitric oxide on non-structural carbohydrate metabolism of Medicago sativa seedlings leaves and roots under drought stress by 10% PEG were investigated. Solutions with:(i) osmotic potentials obtained using polyethylene-glycol-6000 (PEG-6000); (ii) a nitric oxide donor sodium nirorpusside (SNP); (iii) an NO scavenger (carboxy-PTIO, cPTIO); were sprayed onto the leaves of alfalfa seedlings in pot experiment at different combinations. The results showed that exogenous nitric oxide promoted the starch decomposition of leaves, the accumulation of starch in roots and increased the content of soluble sugar (sucrose, fructose and glucose) in leaves and roots in Medicago sativa seedlings under drought stress, which decreased the osmotic potential, promoted cell water absorption and alleviated damage caused by drought. Furthermore, under drought stress exogenous nitric oxide can increase the activity of sucrose synthetase (SS), acid invertase (AI), neatral invertase (NI), reduce the activity of Sucrose phosphate synthase(SPS) in leaves and can increase the activity of SS, SPS, invertase in roots, so that make the synthesis and decomposition of sucrose at a high level of dynamic balance. It enhances the drought resistance of alfalfa. The metabolism of NSC and related enzymes were inhibited by NO scavenger cPTIO. Therefore, nitric oxide played an important role in the drought resistance of Medicago sativa. It can regulate the metabolic of NSC response to drought stress and alleviate the adverse effects caused by drought stress. 参考文献 相似文献 引证文献

Effect of exogenous α-naphthaleneacetic acid on carbon metabolism of soybean under drought stress at flowering stage

With pot experiment, two soybean (Glycine max) varieties, Jindou 21 (drought-tole-rant) and Xudou 22 (drought-sensitive), were used to examine the effects of α-naphthaleneacetic acid (NAA) on carbon metabolism of soybean under drought stress at flowering stage. The results showed that under drought stress, compared to Xudou 22, Jindou 21 had smaller decrease in net photosynthetic rate (Pn), smaller increase in photorespiration rate (Pr) and soluble sugar content of leaves, while a greater increase in the activities of sucrose phosphate synthase (SPS) and sucrose synthetase (SS) (synthesis) of leaves and sucrose content of roots. NAA treatment increased Pn and decreased Pr under drought stress, and thus obviously alleviated the growth inhibition of drought stress on plants. NAA treatment reduced the activities of starch-degrading enzymes, acid invertase (AI) and SS (cleavage), thereby inhibited the accumulation of soluble sugar induced by drought stress. In addition, NAA treatment increased SPS and SS (synthesis) activities of leaves, sucrose content of roots and shoot-root ratio, indicating that NAA treatment improved the transportation of sucrose from leaf blade to root under drought stress. In conclusion, exogenous NAA could enhance drought tolerance in soybean by regulating carbon metabolism.

Ploidy level of citrus rootstocks affects the carbon and nitrogen metabolism in the leaves of Chromium-stressed Kinnow mandarin plants

This study compared the effects of chromium toxicity on the carbon and nitrogen metabolism in Kinnow mandarin (Citrus nobilis Lour x Citrus deliciosa Ten) plants grafted on the diploid (2x) and tetraploid (4x) of Poncirus trifoliata [L.], Citrus reshni, and Citrus limonia Osbeck. Plants were grown under controlled conditions and fertigated with complete nutrient solution supplemented with chromium (0.75 mM). After 120-d of growth under chromium (Cr) stress, carbon (C) and nitrogen (N) metabolism in leaves were studied. In the C metabolism study sucrose, glucose, fructose, starch contents, and the enzymatic activities of acid invertase (AI), neutral invertase (NI), sucrose synthetase (SS), sucrose phosphatesynthetase (SPS), fructokinase (FK), hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK) were investigated. Nitrogen metabolism study was comprised of determination of nitrate, nitrite and ammonium content and the nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate synthetase (GOGAT), and glutamate dehydrogenase (GDH) activities. Basically, in the C metabolism study the Cr enhanced the enzymatic activities and sugar contents, and decreased starch. Chromium stress caused a decrease in nitrate and nitrite, and an increase in ammonia; it also inhibited all measured enzymatic activities except GDH which was increased. The responses of Kinnow mandarin plants grafted on 2x or 4x for any rootstock followed a similar pattern, although the effects of Cr toxicity were more drastic in 2x grafted plants. Glycolysis was the only metabolic process which had a different behavior between 2x and 4x grafted plants under Cr stress: FK and HK activities under Cr stress were significantly increased in 4x grafted plants than in 2x grafted plants. These data suggest that in Kinnow mandarin plants grafted on 4x rootstocks the C metabolism is modified thereby strengthening the plants to adapt Cr stress, but N metabolism was inhibited by Cr toxicity.

Relationship between cellulose accumulation and lodging resistance in the stem of relay intercropped soybean [Glycine max (L.) Merr.

Stem lodging is the most important constraint for soybean at seedling stage in maize–soybean intercropping in China. This study was conducted to determine whether cellulose accumulation and lodging resistance of soybean was affected by different cropping systems and soybean varieties with different shading tolerance at seedling stage. Three soybean varieties – Nandou 032-4 (shade susceptible), Jiuyuehuang (moderately shade tolerant) and Nandou 12 (shade tolerant) – were used to investigate the effect of intercropping on soybean lodging behavior and cellulose accumulation in stems and its relationship to lodging resistance. Shading by maize significantly reduced cellulose accumulation and the stem breaking strength of the soybean, which were significantly negatively correlated with the lodging rate. In the maize–soybean intercropping system, shading inhibited sucrose transportation and degradation into cellulose in the soybean stem. Less content of cellulose in soybean stem at the seedling stage resulted in lodging in the intercropping system. Compared with shade susceptible varieties, Nandou 12 had higher cellulose accumulation and related enzyme activities in the stem, and thus the stem breaking strength and lodging resistance of the basal stem increased. The higher activities of sucrose phosphate synthase and sucrose synthetase in the stem were associated with shade tolerance and lodging resistance. Thus, we concluded that the high physical strength and high cellulose contents of the stem of shade tolerant soybean reduced the rate of lodging in the maize–soybean intercropping system.

Down-regulation of nitrogen/carbon metabolism coupled with coordinative hormone modulation contributes to developmental inhibition of the maize ear under nitrogen limitation.

Developmental inhibition of the maize ear by nitrogen limitation is due to overall down-regulation of nitrogen/carbon metabolism, coordinative hormonal modulation, and probable early senescence. The kernel number is primarily determined from 2weeks pre-silking to 3weeks post-silking, largely depending on dynamic nitrogen (N) and carbohydrate metabolism and accumulation in the maize ear. Underlying physiological and molecular mechanisms of kernel abortion caused by N limitation needs to be further investigated. Using a widely grown maize hybrid ZD958, we found that the N deficient ear was shorter, with less biomass accumulation, lower N concentrations, and overall lower concentrations of N assimilates and soluble sugars at 1- or 2-week after silking. Such negative alterations were probably due to significant decreases in activities of nitrate reductase, glutamine synthetase, sucrose phosphate synthetase, and sucrose synthetase in the N deficient maize ear especially after silking. Compensatory up-regulation of corresponding gene expression, together with co-downregulation of gene expression and enzyme activities in certain circumstances, suggested regulatory complexity and mechanistic differentiation from gene expression to functioning at physiological and molecular levels in quickly developing maize ear in counteracting N deficiency. Importantly, auxin, gibberellin, cytokinin, and abscisic acid may act in a coordinative manner to negatively modulate ear development under N limitation, as indicated by their concentration variations and substantial up-regulation of IAA14, GA2-ox1, and CKX12. Lastly, early senescence may occur in the low-N ear driven by interplay of hormone functioning and senescence-related gene regulation.

Identification and transcriptomic profiling of genes involved in increasing sugar content during salt stress in sweet sorghum leaves.

BackgroundSweet sorghum is an annual C4 crop considered to be one of the most promising bio-energy crops due to its high sugar content in stem, yet it is poorly understood how this plant increases its sugar content in response to salt stress. In response to high NaCl, many of its major processes, such as photosynthesis, protein synthesis, energy and lipid metabolism, are inhibited. Interestingly, sugar content in sweet sorghum stems remains constant or even increases in several salt-tolerant species.ResultsIn this study, the transcript profiles of two sweet sorghum inbred lines (salt-tolerant M-81E and salt-sensitive Roma) were analyzed in the presence of 0 mM or 150 mM NaCl in order to elucidate the molecular mechanisms that lead to higher sugar content during salt stress. We identified 864 and 930 differentially expressed genes between control plants and those subjected to salt stress in both M-81E and Roma strains. We determined that the majority of these genes are involved in photosynthesis, carbon fixation, and starch and sucrose metabolism. Genes important for maintaining photosystem structure and for regulating electron transport were less affected by salt stress in the M-81E line compared to the salt-sensitive Roma line. In addition, expression of genes encoding NADP+-malate enzyme and sucrose synthetase was up-regulated and expression of genes encoding invertase was down-regulated under salt stress in M-81E. In contrast, the expression of these genes showed the opposite trend in Roma under salt stress.ConclusionsThe results we obtained revealed that the salt-tolerant genotype M-81E leads to increased sugar content under salt stress by protecting important structures of photosystems, by enhancing the accumulation of photosynthetic products, by increasing the production of sucrose synthetase and by inhibiting sucrose decomposition.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1760-5) contains supplementary material, which is available to authorized users.

Spermine alleviates drought stress in white clover with different resistance by influencing carbohydrate metabolism and dehydrins synthesis.

The objective of this research was to analyse whether ameliorating drought stress through exogenously applied spermine (Spm) was related to carbohydrate metabolism, dehydrins accumulation and the transcription of genes encoding dehydrins in two white clovers (drought-susceptible cv. ‘Ladino’ and drought-resistant cv. ‘Haifa’) under controlled drying conditions for 10 days. The results show that the application of Spm effectively alleviates negative effects caused by drought stress in both cultivars. Exogenous Spm led to accumulation of more water-soluble carbohydrates (WSC), sucrose, fructose and sorbitol in both cultivars under drought stress, and also significantly elevated glucose content in leaves of drought-resistant cv. ‘Haifa’, but had no effect on drought-susceptible cv. ‘Ladino’. Accordingly, the key enzyme activities of sucrose and sorbitol metabolism changed along with the application of Spm under drought stress. Spm induced a significant increase in sucrose phosphate synthase (SPS) or sorbitol dehydrogenase (SDH) activity, but decrease in sucrose synthetase (SS) activity when two cultivars were subjected to drought. In addition, the improved accumulation of dehydrins induced by exogenous Spm coincided with three genes expression which was responsible for dehydrins synthesis. But Spm-induced transcript level of dehydrin genes increased earlier in cv. ‘Ladino’ than that in cv. ‘Haifa’. Thus, these results suggest that ameliorating drought stress through exogenously applied Spm may be associated with increased carbohydrate accumulation and dehydrins synthesis. There are differences between drought-susceptible and -resistant white clover cultivars related to Spm regulation of WSC metabolism and dehydrins expression.

An-Overview on invertase in sugarcane.

Saccharum officinarum is one of the most cultivated hybrid varieties among the sugarcane varieties. In sugarcane plant sucrose is the major carbohydrate which can be stored and transported. Different physiological and biochemical studies on this crop report that invertase activity and sucrose concentration some how are key limiting step in the process of sucrose accumulation. Significant efforts have been made in relation to the sucrose cycle by altering the sucrose phosphate synthetase, sucrose synthetase and invertase. In sugarcane two types of invertase enzymes have been reported on the basis of pH and cellular localization. Invertase breaks the sucrose into hexoses as a source of energy and carbon. It has also been reported that this enzyme is involved in the process of cell differentiation and plant development. Progress has been made for the understanding of invertase activity and its role in sugarcane plant. With the help of biotechnology it is possible to target the desired gene with genetic engineering approach to increase sucrose content by careful manipulation of invertase (enzyme) gene to increase the sucrose yield in sugarcane. Purpose of this mini review is to high-light the role of invertase in sugarcane and how to overcome sucrose recovery in sugarcane.

Effects of Heat Stress During Grain Filling on Sugar Accumulation and Enzyme Activity Associated with Sucrose Metabolism in Sweet Corn

With the trends of global warming,the extreme high temperature stress often happens during crop grain filling in the world.Heat stress has been an important factor limiting grain yield and quality.To determine the effects of heat stress on fresh kernel yield,quality and enzyme activities of sucrose metabolism,we carried out an experiment in artificial phytotron using two sweet corn cultivars(Xiatian 1 and Yuetian 16) with two typical temperature treatments(high temperature,HT and control,CK) during grain filling.The results indicated that the growth process of sweet corn was accelerated,but the weight and quality of kernel was decreased seriously under high temperature.The weight of 100-fresh-kernel and kernel water content were markedly reduced,but content of pericarp was increased.At the optimum harvest stage of fresh ear(with kernel water content 68%–74%),the fresh kernel weight of the two cultivars was reduced significantly by 20.8%(Xiatian 1) and 16.4%(Yuetian 16) under higher temperature respectively.The contents of soluble sugar and sucrose first increased and then decreased during the grain filling stage.High temperature was not favorable to sugar accumulation,resulting in sucrose content decrease and starch content increase.Sucrose phosphate synthetase(SPS) and sucrose synthetase(SS) play an important role in sucrose synthesis and degradation.SS catalyzes the interconversion of sucrose.Heat stress decreased the activities of SPS and SS(synthetic) and increased the activity of SS(cleavage),which inevitably leads to a depression in sucrose content and a reduction in kernel quality.The maximum SS(synthetic) activity in process of grain filling of two sweet corns appeared earlier under high temperature,while that of SPS activity appeared earlier in Xiatian 1 and did not in Yuetian 16.

Sucrose phosphate synthase plays a key role in boron‐promoted sucrose synthesis in tobacco leaves

AbstractBoron (B) is essential for plant growth. The mechanism of B interacting with sucrose transport is not fully understood. In detached tobacco leaves treated with increasing B concentrations, the concentrations of sucrose, glucose, fructose, and starch as well as the activities of sucrose phosphate synthetase (SPS), sucrose synthetase (SS), and α‐amylase were quantified. In addition, the expression levels of sucrose transporters (SUT1 and SUT4) were determined. The data presented here suggest that B promotes the sucrose concentration and transport via elevation of SPS activity, decrease of SS activity, and increase of SUT4 expression level.

密度和种植方式对夏玉米酶活性和产量的影响

Effects of different planting densities and modes on activities of key enzymes related to carbon-nitrogen metabolism in summer maize in two cultivars,Zhengdan 958 and Xundan 20,were studied under the condition of Northern Henan Province.The results showed that the activities of nitrate reductase(NR),glutamine synthetase(GS),sucrose phosphate synthetase(SPS) and sucrose synthetase(SS) in leaves increased first and decreased later during tasseling and silking stages.The activities of NR and GS in leaves reached the peak at silking stage,and the maximum of activities of SPS and SS in grains occurred at 15d after filling.Genotype,density and planting mode had significant effects on the activities of NR,GS in leaves and SPS,SS in grains during the later-growth period,but the interaction between them was indistinctive.The activities of NR,GS in leaves and SPS,SS in grains of Zhengdan 958 were higher than those of Xundan 20(5.02%,7.40%,6.25% and 4.43% increases,respectively) during the later-growth period.Within the range of 67500—90000 plants per hm2,the activities of these enzymes decreased significantly with the increasing of planting density.A comparison between two planting modes indicated that activities of NR,GS in leaves and SPS,SS in grains of wide-narrow row mode were higher than those of equidistant row mode(6.23%,9.25%,6.87% and 2.84% increases,respectively).The yield reached highest in the test plots with 82 500 plants per hm2 and wide-narrow row mode.

Post-Anthesis Changes in Concentrations of Polyamines in Superior and Inferior Spikelets and Their Relation with Grain Filling of Super Rice

Success in super rice breeding has been considered a great progress in rice production in China. However, many un-filled inferior spikelets limit the realization of great yield. As polyamines have been frequently described as endogenous plant growth regulators or intracellular messengers mediating physiological processes, this study investigated whether and how poly-amines are involved in the regulating post-anthesis development of rice spikelets. Four super rice cultivars, Liangyoupeijiu and II you 084 (indica hybrids), Huaidao 9 and Wujing 15 (japonica), and two high-yielding check cultivars, Shanyou 63 (indica hybrid) and Yangfujing 8 (japonica), were field grown. Concentrations of putrescine (Put), spermidine (Spd) and spermine (Spm) in both inferior and superior spikelets during the grain filling period and grain filling rate were determined. The relationship between polyamine concentrations and grain filling rate were analyzed, and chemical regulators were applied to verify the roles of poly-amines in grain filling. The results showed that the maximum grain filling rate, mean grain filling rate, and brown rice weight for superior spikelets showed small difference between the super rice and check rice, but those of inferior spikelets were significantly lower for super rice than for check rice cultivars. Changes in concentrations of polyamines in grains exhibited single peak during the grain filling period. The peak and mean concentrations of Put were greater in inferior than in superior spikelets. The peak and mean concentrations of Spd and Spm were greater in the superior than in the inferior, and greater in the check rice than in the su-per rice. The mean grain filling rate and brown rice weight were negatively and very significantly correlated with the Put concen-trations, and positively and very significantly correlated with Spd and Spm concentrations, Spd/Put, and Spm/Put. Application of Spd or Spm to panicle at the early grain filling stage significantly enhanced activities of sucrose synthetase, adenine di-phosphoglucose pyrophosphorylase, and soluble starch synthetase in inferior spikelets, and significantly increased grain filling rate, seed setting rate and grain weight of inferior spikelets. Application of Put or methylglyoxal-bis (guanylhydrazone) (MGBG, an inhibitor of S-adenosyl-L-methionine decarboxylase) exhibited an opposite effect. The results suggest that polyamines play a role in regulating grain filling. Low concentrations of Spd and Spm and low Spd/Put and Spm/Put may be an important physiological reason for the small grain filling rate and low grain weight of inferior spikelets in super rice.

Post-Anthesis Changes in Concentration of Polyamine in Superior and Inferior Spikelets and Their Relationship with Grain Filling of Super Rice

To reveal the physiological role of polyamines and the mechanism involved in grain-filling of rice ( Oryza sativa L.) superior and inferior spikelets, the relationship between grain-filling rate and polyamine concentrations was analyzed and verified using 4 super rice cultivars and 2 high-yielding cultivars (controls). Compared with the controls, super rice had similar maximum grain-filling rate, mean grain-filling rate, and brown rice weight in superior spikelets and significantly lower values in inferior spikelets. The concentrations of putrescine (Put), spermidine (Spd), and spermine (Spm) varied in single-peak curves in both inferior and superior spikelets during grain-filling period. The peak and mean concentrations of Put were greater in inferior spikelets than in superior spikelets. However, the peak and mean concentrations of Spd and Spm were greater in superior spikelets than in inferior spikelets. The control cultivars had higher concentrations of polyamines than super rice. The mean grain-filling rate and brown rice weight were negatively correlated with Put concentration, and positively correlated with Spd and Spm concentrations and the ratios of Spd/Put and Spm/Put. Spraying of Spd or Spm to panicle at early grain-filling stage significantly enhanced activities of sucrose synthetase, adenine diphosphoglucose pyrophosphorylase, and soluble starch synthetase in inferior spikelets, resulting in improvement of grain-filling rate, seed-setting rate, and grain weight. Application of Put or methylglyoxal-bis (guanylhydrazone) (MGBG, an inhibitor of S-adenosyl- L-methioninedecarboxylase) exhibited an opposite effect. These results indicated a regulative function of polyamines during grain filling. The low grain-filling rate and grain weight in inferior spikelets of super rice are probably in relation to the low concentrations of Spd and Spm and the small ratios of Spd/Put and Spm/Put in inferior spikelets.