Increasing Sucrose Concentration Research Articles

Influence of atmospheric and vacuum plasma processing on the organic composition of araça-boi (Eugenia stipitata) juice

Cold plasma is a novel non-thermal technology that is still under development. Cold plasma treatment of food products induces a wide range of chemical changes in food compounds, several of which can improve nutritional quality. Understanding the chemical changes caused during plasma treatment is essential to enhance food quality and avoid the formation of undesired compounds. This investigation addressed the influence of two cold plasma technologies, glow discharge plasma and dielectric barrier discharge plasma, on the organic composition of araça-boi (Eugenia stipitata) juice, which is rich in sugars, organic and amino acids. The chemical composition of the juice was assessed by 1H nuclear magnetic resonance coupled with chemometrics. The effects of excitation frequency, processing time, and plasma flow rate were investigated. Glow discharge plasma and dielectric barrier discharge plasma application tended to decrease the concentration of glucose (33%), fructose (31%), malic acid (25%), and amino acids while increasing sucrose content (23%). Overall, plasma processing changed the juices’ alcohol, sugar, and amino acids content, primarily by reducing the concentration of cysteine (33%), alanine (42%), and methionine (43%). However, the dielectric barrier discharge plasma tended to slightly increase the amino acid content (up to 9%) when operating at 200 Hz.

Soil tillage systems and forms of lime application on soil attribute enhancements in ratoon sugarcane

AbstractCombining deep tillage (DT) with lime application at greater depths may improve sugarcane yield. The objective of this study was to evaluate the impact of conventional tillage (CT) and DT systems and liming on sugarcane productivity and soil physical attributes. The experiment was conducted in a clayey‐textured Rhodic Hapludox soil cultivated with sugarcane for two growing seasons (first and third ratoons) using a randomized block design with four treatments and four repetitions. The treatments consisted of DT without liming (DT0), DT with liming (DT2), CT without liming (CT0) and CT with liming (CT2). In addition to sugarcane stalk and sugar yields, macroporosity (MA), microporosity (MI), total soil porosity (TP), weighted average diameter (WAD), aggregate stability index (ASI), soil penetration resistance (SPR), pH, potential acidity (H + Al), total soil organic carbon (SOC), particulate organic carbon (POC), mineral‐associated organic carbon (MOC), calcium (Ca) and magnesium (Mg) were analysed. DT2 promoted the best soil conservation effect on sugarcane. In general, DT, regardless of lime application, reduced SOC and POC in soil surface layer. Nevertheless, in the long term, localized lime addition resulted in significant reductions in compaction, reaching values below 2 MPa. The soil fertility improvement provided by DT2 promoted increased sucrose concentrations and stalks yield. Considering that there was an improvement in the physical quality and fertility of soil for better plant development, the deep tillage with localized lime addition can be considered an effective alternative for sugarcane cultivation.

Factors affecting in vitro tuberization of potato

BackgroundPotato (Solanum tuberosum L.) is one of the most economically important annual vegetable crops. Microtubers can be produced, stored around year and directly transported to market without transferring to fresh media and without acclimatization. Thus reducing the field cycle to obtain sufficient number of seed potatoes and a high level of healthy materials. The aim of this study was to investigate effects of different combinations and concentrations of growth regulators i.e., kinetin (2.5 mg/l) and coumarin (20, 40 and 60 mg/l) alone or in addition to varied concentrations of sucrose (30, 60 and 90 g/l) on in vitro tuberization of potato (Solanum tuberosum) cv. Diamount.ResultsThe plantlets were propagated using single-node cuttings cultured on Murashige and Skoog medium containing 0.04 mg/l kinetin and 1.0 mg/l IAA. Shoots (6–7 nodes) from the previous step were cultured into medium supplemented with a factorial combination of sucrose concentrations (30, 60 and 90 g/l), coumarin concentrations (0, 20, 40, and 60 mg/l) and two concentrations of kinetin (0 and 2.5 mg/l). Our results showed that kinetin – induced medium have slightly effect to improve tuberization in vitro. But when kinetin was combined with sucrose, this effect was better when raised sucrose concentration from 30 or 60 to 90 g/l. The highest percentage of tuberization after 8 weeks, highest number of microtuber were obtained with high concentration of sucrose (90 g/l) together with dark condition, at 18–20 °C. Also, the highest concentration of sucrose significantly increased the fresh weight of microtuber. In case of coumarin, results revealed that it has important effect on tuber initiation especially with concentrations 20 mg/l and 40 mg/l; otherwise, the initiation period was minimized after adding kinetin. So, the plantlets must be continuously incubated in coumarin –induce medium plus kinetin for 8 weeks to affect the tuberization response. Also, all the other characters of tuberization process on coumarin-inducing medium could be improved by increasing sucrose concentration to 9 g/l.ConclusionsGenerally, results pointed out that the treatment which consists of kinetin (2.5 mg/l) plus 90 g/l sucrose and 20 mg/l coumarin has the best characteristics of in vitro micro-tuberization.

Optimasi Konsentrasi Sukrosa dan Propilen Glikol dalam Formulasi Chewable Gummy Tablet Ekstrak Daun Kelor (Moringa oleifera L)

Latar Belakang: Moringa leaves extract is promising to develop into nutraceutical products, especially a chewable gummy. The desirable characteristics of chewable gummies are soft, elastic, springy, and flexible. Gelatin is a widely used gelling agent which has been proven to maintain gel structure during storage. The other ingredients which also determine the chewable gel structure are filler and plasticizer. The aim of this study was to determine the effect of sucrose and propylene glycol concentration on Moringa leaves extract based chewable gummy. Metode: The preparation of chewable gummy tablets was conducted by the pour method. Factorial design study (22) was applied in this study to analyze the effect of two factors herein filler and plasticizer. Two levels of concentration were optimized in each factor, herein sucrose (30% and 35% concentration) and propylene glycol (2% and 4% concentration) on the physical characteristics of the gummy tablet. Hasil: The results of the factorial analysis showed that the increase in sucrose concentration will produce a longer dispersion time and lower swelling ratio. Meanwhile, the increase in propylene glycol decreases the syneresis potency. The alteration of physical characteristics was observed during 14 days of storage, particularly in dispersion time, swelling ratio, and syneresis percentage. Kesimpulan: Based on the results of feasible design space, sucrose concentration (30-35%) and propylene glycol concentration (2-4%) optimized in this study produce the desirable characteristics of chewable gummy.

A chromosome 16 deletion conferring a high sucrose phenotype in soybean.

Sucrose in soybean seeds is desirable for many end-uses. Increased sucrose contents were discovered to associate with a chromosome 16 deletion resulting from fast neutron irradiation. Soybean is one of the most economically important crops in the United States. A primary end-use of soybean is for livestock feed. Therefore, genetic improvement of seed composition is one of the most important goals in soybean breeding programs. Sucrose is desired in animal feed due to its role as an easily digestible energy source. An elite soybean line was irradiated with fast neutrons and the seed from plants were screened for altered seed composition with near-infrared spectroscopy (NIR). One mutant line, G15FN-54, was found to have higher sucrose content (8-9%) than the parental line (5-6%). Comparative genomic hybridization (CGH) revealed three large deletions on chromosomes (Chrs) 10, 13, and 16 in the mutant, which were confirmed through whole genome sequencing (WGS). A bi-parental population derived from the mutant G15FN-54 and the cultivar Benning was developed to conduct a bulked segregant analysis (BSA) with SoySNP50K BeadChips, revealing that the deletion on Chr 16 might be responsible for the altered phenotype. The mapping result using the bi-parental population confirmed that the deletion on Chr 16 conferred elevated sucrose content and a total of 21 genes are located within this Chr 16 deletion. NIR and high-pressure liquid chromatography (HPLC) were used to confirm the stability of the phenotype across generations in the bi-parental population. The mutation will be useful to understand the genetic control of soybean seed sucrose content.

Reformulation and Thermal Stability of a Therapeutic Anti-Cocaine mAb

We concentrated and reformulated the anti-cocaine mAb, h2E2, to reduce the amount of sucrose and histidine buffer infused with the mAb, to satisfy FDA maximum exposure levels for those components for use in clinical trials. After concentration of the original 20 mg/ml mAb, 4 reformulation buffers were evaluated for suitability. The concentration of histidine was reduced from 10 mM to 3 or 0 mM, and the concentration of sucrose reduced from 10% to 2, 4, or 6%. The approximately 100 mg/ml reformulated mAb samples were analyzed for oligomer formation, aggregation, concentration of the emulsifier polysorbate 80, and thermal stability. These reformulated mAb samples were also assessed for their stability at 40°C from 1 day to 12 weeks. As expected, long term thermal resistance to oligomer formation increased as a function of increasing sucrose concentration. Interestingly, unbuffered reformulated mAb displayed a less than or equal to tendency to form oligomers and aggregates, compared to the histidine buffered samples. Importantly, even after 12 weeks at 40°C, all the reformulated samples displayed little aggregation, and bound their antigen (cocaine) with identical affinities and thermodynamics, as measured by isothermal titration calorimetry (ITC). These ITC thermodynamic binding parameters are consistent with recently published values for the original formulation of this mAb. In all reformulated samples there was a slight decrease in the number of cocaine binding sites after 12 weeks at 40°C, likely due to the parallel small increase in soluble oligomeric antibody, suggesting that soluble oligomeric mAb may no longer bind cocaine with high affinity.

Potato tonoplast sugar transporter 1 controls tuber sugar accumulation during postharvest cold storage.

Cold-induced sweetening (CIS), the undesirable sugar accumulation in cold-stored potato (Solanum tuberosum L.) tubers, is a severe postharvest issue in the potato processing industry. Although the process of sucrose hydrolysis by vacuolar invertase during potato CIS is well understood, there is limited knowledge about the transportation of sucrose from the cytosol to the vacuole during postharvest cold storage. Here, we report that among the three potato tonoplast sugar transporters (TSTs), StTST1 exhibits the highest expression in tubers during postharvest cold storage. Subcellular localization analysis demonstrates that StTST1 is a tonoplast-localized protein. StTST1 knockdown decreases reducing sugar accumulation in tubers during low-temperature storage. Compared to wild-type, potato chips produced from StTST1-silenced tubers displayed significantly lower acrylamide levels and lighter color after cold storage. Transcriptome analysis manifests that suppression of StTST1 promotes starch synthesis and inhibits starch degradation in cold-stored tubers. We further establish that the increased sucrose content in the StTST1-silenced tubers might cause a decrease in the ABA content, thereby inhibiting the ABA-signaling pathway. We demonstrate that the down-regulation of β-amylase StBAM1 in StTST1-silenced tubers might be directly controlled by ABA-responsive element-binding proteins (AREBs). Altogether, we have shown that StTST1 plays a critical role in sugar accumulation and starch metabolism regulation during postharvest cold storage. Thus, our findings provide a new strategy to improve the frying quality of cold-stored tubers and reduce the acrylamide content in potato chips.

Long-Term Soil Drought Limits Starch Accumulation by Altering Sucrose Transport and Starch Synthesis in Sweet Potato Tuberous Root.

In this study, the influences of long-term soil drought with three levels [soil-relative water content (SRWC) (75 ± 5)%, as the control; SRWC (55 ± 5)%, mild drought; SRWC (45 ± 5)%, severe drought] were investigated on sucrose-starch metabolism in sweet potato tuberous roots (TRs) by pot experiment. Compared to the control, drought stress increased soluble sugar and sucrose content by 4-60% and 9-75%, respectively, but reduced starch accumulation by 30-66% through decreasing the starch accumulate rate in TRs. In the drought-treated TRs, the inhibition of sucrose decomposition was attributed to the reduced activities of acid invertase (AI) and alkaline invertase (AKI) and the IbA-INV3 expression, rather than sucrose synthase (SuSy), consequently leading to the increased sucrose content in TRs. In addition, starch synthesis was inhibited mainly by reducing ADP-glucose pyrophosphorylase (AGPase), granular starch synthase (GBSS) and starch branching enzyme (SBE) activities in TRs under drought stress, and AGPase was the rate-limiting enzyme. Furthermore, soil drought remarkably up-regulated the IbSWEET11, IbSWEET605, and IbSUT4 expressions in Jishu 26 TRs, while it down-regulated or had no significant differences in Xushu 32 and Ningzishu 1 TRs. These results suggested that the sucrose-loading capability in Jishu 26 TRs were stronger than that in Xushu 32 and Ningzishu 1 TRs. Moreover, IbA-INV3, IbAGPS1, IbAGPS2, IbGBSSI and IbSBEII play important roles in different drought-tolerant cultivars under drought stress.

Structural characterization of protein-DNA complexes using small angle X-ray scattering (SAXS) with contrast variation.

Molecular and atomic level characterization of transcription factor (TF)-DNA complexes is critical for understanding DNA-binding specificity and potentially structural changes that may occur in protein and/or DNA upon complex formation. Often TFs are large, multidomain proteins or contain disordered regions that contribute to DNA recognition and/or binding affinity but are difficult to structurally characterize due to their high molecular weight and intrinsic flexibility. This results in challenges to obtaining high resolution structural information using Nuclear Magnetic Resonance (NMR) spectroscopy due to the relatively large size of the protein-DNA complexes of interest or macromolecular crystallography due to the difficulty in obtaining crystals of flexible proteins. Small angle X-ray scattering (SAXS) offers a complementary method to NMR and X-ray crystallography that allows for low-resolution structural characterization of protein, DNA, and protein-DNA complexes in solution over a greater size range and irrespective of interdomain flexibility and/or disordered regions. One important caveat to SAXS data interpretation, however, has been the inability to distinguish between scattering coming from the protein versus DNA component of the complex of interest. Here, we present a protocol using contrast variation via increasing sucrose concentrations to distinguish between protein and DNA using the model protein bovine serum albumin (BSA) and DNA and the LUX ARRYTHMO TF-DNA complex. Examination of the scattering curves of the components individually and in combination with contrast variation allows the differentiation of protein and DNA density in the derived models. This protocol is designed for use on high flux SAXS beamlines with temperature-controlled sample storage and sample exposure units.

Combined effect of elevated temperature and drought stress on carbohydrate metabolism of cotton (Gossypium hirsutum L.) subtending leaves.

High temperatures and drought are expected to become more frequent in the future and last longer than ever before. To investigate their combined effect on cotton subtending leaves (LSCB), an experiment was conducted from 2016 to 2018 using a non-heat-tolerant cotton cultivar and a heat-tolerant cultivar. Two temperature regimes with ambient temperature (AT, 31.0/26.4 °C) and elevated temperature (ET, 33.4/28.9 °C, 2.5 °C higher than AT) and three drought treatments with a soil relative water content (SRWC) of 75 ± 5%, 60 ± 5%, and 45 ± 5% were established repeatedly. ET decreased Pn, initial rubisco activity (4.1.1.39, RuBP) and cy-FBPase (3.1.3.11) activity, upregulated GhSuSyA, and GhSuSyD expressions, and increased SuSy (2.4.1.13) activity, which led to the decline of the final starch and sucrose contents. Moreover, RuBP, Pn, and starch content all decreased with drop in SRWC levels, but the cy-FBPase and SPS (2.4.1.14) activity increased, which in turn increased sucrose content. Under combined stresses, when the changing trends of ET and drought effects were the same, the decrease of Pn, RuBP, and starch content was greater than under single stress exposure. However, when the changing trends of ET and drought effects were adverse, the combined effects on indicators such as cy-FBPase, SuSy, sucrose content were mostly similar to drought stress. These results indicate that the effect of drought on carbohydrate metabolism in LSCB is more prominent than ET. Thus, the drought effect for carbohydrate metabolism in LSCB may need more attention than ET under combined heat and drought stress. This article is protected by copyright. All rights reserved.

Effects of phosphorus application on carbohydrate metabolism in cottonseed kernel during the key development period provided a new insight for phosphorus management in cotton production

Cottonseed provides abundant and high-quality raw materials for biodiesel, fine chemical, and other industries due to its rich oil, but phosphorus-deficient farmland and finite phosphate resource hinder its production. Cottonseed development is based on its carbohydrate, and exploring the response of cottonseed carbohydrate metabolism to phosphorus could contribute to optimizing phosphorus management in cotton production and continuously obtaining high-quality cottonseed. Here, the experiment on phosphorus rates [0 (phosphorus deficient), 100 (phosphorus critical), and 200 (phosphorus excess) kg P2O5 ha−1] was conducted using Lu 54 (low-phosphorus sensitive) and Yuzaomian 9110 (low-phosphorus tolerant) in a field containing 16.9 mg kg−1 available phosphorus to assess the effects of phosphorus on cottonseed yield, cottonseed total phosphorus, ash, and oil contents, carbohydrate metabolism related carbohydrate contents, and enzymes activities. The results showed that phosphorus application increased cottonseed yield and oil content by 32.4%−54.2% and 14.8%−20.1% on average, respectively, which could be attributed to the improvements in sucrose transport and hydrolysis in cottonseed kernel during 18–26 days post anthesis induced by higher total phosphorus content (17.1%−26.7%). During the key development period of cottonseed kernel, phosphorus application increased sucrose content (13.0%−19.4%) by increasing the expression of sucrose transporter genes, and promoted sucrose hydrolysis by elevating enzymes activities, especially sucrose synthase (11.2%−19.1%) in cottonseed kernel. Consequently, phosphorus application increased hexose levels in cottonseed kernel and thus provided more substrates for its development, which promoted the formation of cottonseed kernel biomass (6.2%−10.6%), cottonseed and oil yields. Additionally, carbohydrate metabolism in Lu 54 was more sensitive to phosphorus than Yuzaomian 9110 during the key development period, resulting in greater increases in cottonseed kernel biomass, cottonseed yield, and oil content for Lu 54. Notably, the increments generated by unit phosphate fertilizer on the above indicators attenuated markedly with phosphorus application. Based on sucrose content, the key substance, the critical phosphorus concentration in the subtending leaf to cotton boll (LPC) needed by the efficient operation of the key carbohydrate metabolic pathway was 0.38% for Lu 54 versus 0.34% for Yuzaomian 9110. This report first unveiled the key carbohydrate metabolic pathway regulated by phosphorus for cottonseed and oil yield formation and its demand for LPC during the key development period, providing a new insight for diagnosing and regulating phosphorus in cotton production.

Effect of sweeteners and carbonation on aroma partitioning and release in beverage systems

The effect of monosaccharides (glucose, fructose and galactose) and disaccharides (sucrose and lactose) at 10, 20 and 30 % w/v on the in-vitro aroma partitioning of C4 – C10 aldehydes and ethyl esters, as well as limonene (concentration of aroma compounds at 1 μg mL−1), was studied using atmospheric pressure chemical ionisation–mass spectrometry. An increase in sugar concentration from 0 to 30 % w/v resulted in a significant increase in partitioning under static headspace conditions for the majority of the compounds (p < 0.05), an effect generally not observed when 10 % w/v sucrose was substituted with low-calorie sweeteners (p > 0.05). The complexity of the system was increased to model a soft drink design – comprising water, sucrose (10, 20 and 30 % w/v), acid (0.15 % w/v), carbonation (∼7.2 g/L CO2) and aroma compounds representative of an apple style flavouring, namely ethyl butanoate and hexanal (10 μg mL−1 each). Although the addition of sucrose had no significant in-vivo effect, carbonation significantly decreased breath-by-breath (in-vivo) aroma delivery (p < 0.05). To understand the physical mechanisms behind aroma release from the beverage matrix, the effect of sucrose on the kinetics of the matrix components was explored. An increase in sucrose concentration from 0 to 30 % w/v resulted in a significant decrease in water activity (p < 0.05), which accounted for the significantly slower rate of self-diffusion of aroma compounds (p < 0.05), measured using diffusion-ordered spectroscopy–nuclear magnetic resonance spectroscopy. No significant effect of sucrose on carbon dioxide volume flux was found (p > 0.05).

Foliar Application of dsRNA Targeting Endogenous Potato (Solanum tuberosum) Isoamylase Genes ISA1, ISA2, and ISA3 Confers Transgenic Phenotype

Isoamylase (ISA) is a debranching enzyme found in many plants, which hydrolyzes (1-6)-α-D glucosidic linkages in starch, amylopectin, and β-dextrins, and is thought to be responsible for starch granule formation (ISA1 and ISA2) and degradation (ISA3). Lipid-modified PEI (lmPEI) was synthesized as a carrier for long double-stranded RNA (dsRNA, 250-bp), which targets the three isoamylase isoforms. The particles were applied to the plant via the foliar spray and were differentially effective in suppressing the expressions of ISA1 and ISA2 in the potato leaves, and ISA3 in the tubers. Plant growth was not significantly impaired, and starch levels in the tubers were not affected as well. Interestingly, the treated plants had significantly smaller starch granule sizes as well as increased sucrose content, which led to an early sprouting phenotype. We confirm the proposal of previous research that an increased number of small starch granules could be responsible for an accelerated turnover of glucan chains and, thus, the rapid synthesis of sucrose, and we propose a new relationship between ISA3 and the starch granule size. The implications of this study are in achieving a transgenic phenotype for endogenous plant genes using a systemic, novel delivery system, and foliar applications of dsRNA for agriculture.

Effects of NaCl and sucrose on the structural and functional properties of debranched quinoa starch-oleic acid complexes under baking

The effects of different dosage of NaCl and sucrose on the structural and functional properties of debranched quinoa starch-oleic acid complexes (DQS-OA) under baking were investigated. The results showed that the resistant starch content of the baked DQS-OA increased by 17.15 % than DQS-OA. The addition of NaCl destroyed the thermal stability, short-range molecular order and crystalline structure of the complexes. The results of particle size, SEM and amylose content showed that NaCl accelerated the degradation of starch granules, which reduced the enzyme resistance of starch. In contrast, the enthalpy (7.28 J/g-7.78 J/g) and crystallinity (54.29 %–56.69 %) of the samples with sucrose significantly increased, and the molecular structure of the complexes became more ordered. Furthermore, with the increase of sucrose concentration, the resistant starch content also increased from 28.80 % to 31.41 %.

Meta-Topolin mediated in vitro propagation in an ornamentally important crop Iris × hollandica Tub. cv. professor Blaauw and genetic fidelity studies using SCoT markers

Dutch iris is a commercially important bulbous ornamental crop. Its high demand in global floriculture market necessitates the production of its high-quality planting material. In the present investigation, an efficient in vitro propagation system has been developed for Iris × hollandica Tub. cv. Professor Blaauw (Dutch iris) using meta-Topolin (mT) for the first time. Effect of various concentrations of BAP, Kn, and mT (0, 0.5, 1.0, 1.5 and 2 mg L−1) along with varying photoperiods (16 h light and dark incubation for 1, 2, 3 and 4 weeks) on in vitro shoot induction from the twin scale explants was studied. Of the cytokinins tested, different doses of mT has resulted in better shoot induction response from twin scale explants than BAP and Kn. Photoperiod duration has also affected shoot induction response significantly. Along with dark incubation for 1 week, cytokinin mT at 1.0 mg L−1 in MS medium has resulted in maximum shoot induction response (91.63%) with increased emergence of micro shoots (4.83 shoots/explant with average shoot length of 5.02 cm). Efficacy of BAP and mT alone or in combination with auxins for in vitro shoot multiplication was also compared. The synergistic effect of cytokinin-auxin in multiplication medium comprising MS + 1.0 mg L−1 mT + 0.25 mg L−1 NAA resulted in considerably higher number of shoots (17.53) with mean shoot length (7.06 cm) and maximum number of bulblets (2.74). Positive effect of increased sucrose concentration (90 g L−1) alone or with paclobutrazol (5 mg L−1) on in vitro bulblet formation and bulblet size was observed respectively. The superiority of mT over BAP was also found during in vitro rhizogenesis. Shoots raised on the mT medium were healthy and long enough, thus showed better rooting response (63.83%) on ½ MS medium + 0.5 mg L−1 IAA after 4 weeks of incubation. About 89.16% survival rate was recorded for in vitro raised plantlets under ex vitro conditions. Analysis of clonal fidelity of thirteen in vitro regenerated plants was done using SCoT markers. Out of 36 primers, 13 primers showed clearly scorable monomorphic bands, thus displaying genetic uniformity among in vitro regenerated plantlets. This mT mediated protocol can be routinely used for the rapid large scale production of this valuable floriculture crop.

Changes in sucrose and the VcADR gene induced sugar accumulation in blueberries during ripening and after chitosan treatment

BACKGROUND: The sweetness of highbush blueberries (Vaccinium corymbosum L.) is related to changes in sucrose and other primary sugar metabolites. OBJECTIVE: This study compared the fruit quality and sugar metabolism in the blueberry cultivars Brigitta and Elizabeth at three ripening stages and with a postharvest chitosan treatment to determine which factors are important in sugar metabolism in the two cultivars. METHODS: Blueberries were harvested at three ripening stages. Fully ripe fruit was treated with chitosan and kept at room temperature for 5 and 10 days. GC-MS was used to measure organic acids, individual sugars, and sugar derivatives. Gene expression was analysed using qPCR. RESULTS: Elizabeth fruit was less firm than Brigitta fruit, but contained more soluble solids. The sweeter taste of Elizabeth versus Brigitta was due to down-regulated VcINV, VcSPS, and VcADR transcription and increased sucrose concentration. Chitosan inhibited VcADR and VcINV transcription in Elizabeth, but activated these genes in Brigitta after 5 days of storage. CONCLUSIONS: Aldose reductase might be an essential enzyme in blueberry sugar metabolism. These findings support research on the mechanism of sugar accumulation in fruit during maturation and after postharvest treatments in blueberries.

Arabidopsis sucrose transporter 4 (AtSUC4) is involved in high sucrose-mediated inhibition of root elongation

Sucrose transporters (SUCs/SUTs) play crucial roles in apoplast transport and long-distance distribution of sucrose throughout the whole plant. However, whether and how the Arabidopsis AtSUC4 modulates sucrose import from apoplast to cytosol remains unclear. In the present study, we found that AtSUC4 protein was localized to the plasma membrane in the root. Expression of AtSUC4 in roots was gradually induced with the increasing sucrose concentrations (0%, 2%, 4% and 6%). When feeding high concentrations (4% and 6%) of sucrose, the primary root growth of seedling was inhibited. Interestingly, atsuc4 mutants exhibited longer primary root than the wild type under these conditions, indicating that atsuc4 mutants were less sensitive to excess sucrose. Moreover, the root of atsuc4 mutants accumulated less sucrose and abscisic acid (ABA) and more indole-3-acetic acid (IAA) on 4% and 6% sucrose supplementation. Transcriptomic analysis revealed that numerous genes associated with sugar transport and metabolism, as well as ABA signalling were down-regulated, whereas many IAA signaling-related genes were up-regulated in mutant plants relative to the wild type under 6% sucrose treatment. Collectively, our finding demonstrated that the deficiency of AtSUC4 reduced the inhibition of primary root growth under high sucrose condition, probably through reducing the sucrose transportation and metabolism, and subsequent alteration in IAA and ABA signalling.

Defoliation, wounding, and methyl jasmonate induce expression of the sucrose lateral transporter LpSUT1 in ryegrass (Lolium perenne L.)

Ryegrass (Lolium perenne L.) regrowth after defoliation results from the mobilization of sugar reserves (mainly fructans) and, simultaneously, the efficient lateral transport of sucrose towards growing tissues. However, as for grasses overall, it is not yet known if the induction of this transport is solely linked to the sugar demand of growing tissues via the modification of sugar content at the tissue or cellular level or if it could be triggered by a wounding signal due to the defoliation itself. Ryegrass plants were therefore submitted to total or partial defoliation, pinning of the leaf blades to simulate wounding, or to leaf spraying with 100 μM methyl jasmonate (MeJA), a phytohormone related to wounding. As a response to total or partial defoliation, fructans were mobilized, and the expression of the sucrose lateral transporter LpSUT1 was induced. This highlights an efficient intra-plant compensatory partitioning of sugar resources between defoliated and intact tillers, resulting in the adaptation to regrow after moderate to severe defoliation. The MeJA treatment strongly decreased fructan content. Pinning and especially MeJA largely and quickly increased sucrose content and LpSUT1 transcript levels in leaf sheaths and elongating leaf bases, suggesting a direct effect of wounding on the up-regulation of the sucrose lateral transporter. The overall results suggest that sucrose transport capacity and fructan degradation are induced by defoliation through the modification of source-sink relationships for sugars at the plant level and are mediated by phytohormones associated with wounding, such as jasmonates. This article is protected by copyright. All rights reserved.

Exogenous Hemin alleviates cadmium stress in maize by enhancing sucrose and nitrogen metabolism and regulating endogenous hormones

Cadmium (Cd) stress restricts maize growth and productivity severely. We aimed to investigate the effects of Hemin on the metabolism of sucrose and nitrogen and endogenous hormones in maize under cadmium stress. Maize varieties ‘Tiannong 9’ (cadmium tolerant) and ‘Fenghe 6’ (cadmium sensitive) were grown in nutrient solutions to study the effects of Hemin on maize physiological and ecological mechanisms under cadmium stress. The results showed that Hemin mediated the increase of sucrose content and the activities of key enzymes sucrose phosphate synthase (SPS) and sucrose synthase (SS) in maize leaves under cadmium stress. Soluble acid invertase (SAInv) and basic/neutral invertase (A/N-Inv) enzyme activities in leaves were decreased significantly, and sucrose accumulation in leaves was increased. Hemin also mediated the increase of NO3 − content in leaves, the decrease of NH4 + content and the increase of nitrate reductase (NR), glutamine synthetase (GS), glutamate synthase activity (GOGAT) and glutamate dehydrogenase (GDH) enzyme activities under cadmium stress. The contents of IAA, ZR, and GA in leaves and roots increased, ABA, MeJA, and SA decreased, and IAA/ABA, ZR/ABA, and GA/ABA increased under cadmium stress. Our study showed Hemin can alleviate cadmium stress in maize by enhancing sucrose and nitrogen metabolism and regulating endogenous hormones.

Candidate Acetic Acid Bacteria Strains for Levan Production.

In this study, twelve strains of acetic acid bacteria (AAB) belonging to five different genera were tested for their ability to produce levan, at 70 and 250 g/L of sucrose concentration, respectively. The fructan produced by the bacterial strains was characterized as levan by NMR spectroscopy. Most of the strains produced levan, highlighting intra- and inter-species variability. High yield was observed for Neoasaia chiangmaiensis NBRC 101099 T, Kozakia baliensis DSM 14400 T and Gluconobacter cerinus DSM 9533 T at 70 g/L of sucrose. A 12-fold increase was observed for N. chiangmaiensis NBRC 101099 T at 250 g/L of sucrose concentration. Levan production was found to be affected by glucose accumulation and pH reduction, especially in Ko. baliensis DSM 14400 T. All the Gluconobacter strains showed a negative correlation with the increase in sucrose concentration. Among strains of Komagataeibacter genus, no clear effect of sucrose on levan yield was found. Results obtained in this study highlighted the differences in levan yield among AAB strains and showed interdependence between culture conditions, carbon source utilization, and time of incubation. On the contrary, the levan yield was not always related to the sucrose concentration.