Sugar Accumulation Research Articles

CLIMATIC FACTORS CHARACTERIZING THE MOISTURE SUPPLY OF THE TERRITORY AND THEIR EFFECT ON THE QUALITY INDICATORS OF GRAPES

The study of scientific problem, to which this research is devoted, is due to planetary climate change, manifested in an increase in the average annual air temperature, rapid changes in winter and summer temperatures, and a lack of precipitation.
 For today, there is a serious problem of adapting plants to climate change due to an increase in water deficiency in many regions of the world. Climate change creates significant uncertainty in the potential adaptability of grape plants, as well as in the prospects for viticulture development in general.
 The study and generalization of territorial distribution of climatic factors that characterize a particular region, as well as their effect on the quality characteristics of raw materials and finished products, are attractive from the point of better understanding and forecasting the potential impact on agricultural systems. The obtained data consumption will allow improving the forecast of climate change consequences in the medium term, and in relation to particular terroirs.
 The goal is to study the effect of climatic factors that characterize the moisture supply of the territory on the quality indicators of grapes.
 Materials and methods. The objects of the study were grapes of white and red cultivars, different in agroecological aspect, and growing in micro regions of Crimea. To identify the effect of factors characterizing the moisture supply of the territory on the quality indicators of raw materials for winemaking products, the amount of precipitation from the beginning of growing season to the harvesting, the amount of precipitation for the last month before harvest, and hydrothermal coefficient of Selyaninov were selected. The assessment of grapes was carried out according to the indicators of carbohydrate-acid complex (mass concentration of sugars, titratable acids, pH value, profile of organic acids), as well as the glucoacidimetric indicator revealing the degree of grape ripeness.
 Results and conclusion. Climatic factors characterizing the moisture supply of viticultural and winemaking regions of Crimea were assessed. The studies carried out made it possible to reveal variations in the concentration of carbohydrate-acid complex components depending on the changing ability of environmental factors. A significant precipitation deficiency was observed on the Peninsula. According to the value of hydrothermal coefficient of Selyaninov (did not exceed 1), most of the territory was classified as an arid or very arid zone. A correlation between the hydrothermal coefficient and mass concentration of grape sugars (r=-0.63) was established for red grapevine cultivars. The data obtained indicate that an increase in the amount of precipitation during growing season contributes to a moderation of sugar accumulation in grapes. Similar pattern was not established for white grapevine cultivars. There was a direct correlation of the mass concentration of malic acid on the amount of precipitation in the last month before harvest (r=0.78).

Genome-Wide Identification and Expression Analysis of the SUT Family from Three Species of Sapindaceae Revealed Their Role in the Accumulation of Sugars in Fruits.

Sapindaceae is an economically important family of Sapindales and includes many fruit crops. The dominant transport and storage form of photoassimilates in higher plants is sucrose. Sucrose transporter proteins play an irreplaceable role in the loading, transportation, unloading, and distribution of sucrose. A few SUT (sugar transporter) family genes have been identified and characterized in various plant species. In this study, 15, 15, and 10 genes were identified in litchi, longan, and rambutan, respectively, via genome-wide screening. These genes were divided into four subgroups based on phylogenetics. Gene duplication analysis suggested these genes underwent potent purifying selection and tandem duplications during evolution. The expression levels of SlSut01 and SlSut08 were significantly increased in the fruits of Sapindaceae members. The homologs of these two genes in longan and rambutan were also highly expressed in the fruits. The expression pattern of SUTs in three organs of the two varieties was also explored. Subcellular colocalization experiments revealed that the proteins encoded by both genes were present in the plasma membrane. This report provides data for the functional study of SUTs in litchi and provides a basis for screening sugar accumulation-related genes in fruits of Sapindaceae.

Transcriptomic and Metabolomic Profiling Reveals the Variations in Carbohydrate Metabolism between Two Blueberry Cultivars.

Blueberry is a high-quality fruit tree with significant nutritional and economic value, but the intricate mechanism of sugar accumulation in its fruit remains unclear. In this study, the ripe fruits of blueberry cultivars 'Anna' and 'Misty' were utilized as experimental materials, and physiological and multi-omics methodologies were applied to analyze the regulatory mechanisms of the difference in sugar content between them. The results demonstrated that the 'Anna' fruit was smaller and had less hardness than the 'Misty' fruit, as well as higher sugar content, antioxidant capability, and lower active substance content. A total of 7067 differentially expressed genes (DEGs) (3674 up-regulated and 3393 down-regulated) and 140 differentially abundant metabolites (DAMs) (82 up-regulated and 58 down-regulated) were identified between the fruits of the two cultivars. According to KEGG analysis, DEGs were primarily abundant in phenylpropanoid synthesis and hormone signal transduction pathways, whereas DAMs were primarily enriched in ascorbate and aldarate metabolism, phenylpropanoid biosynthesis, and the pentose phosphate pathway. A combined multi-omics study showed that 116 DEGs and 3 DAMs in starch and sucrose metabolism (48 DEGs and 1 DAM), glycolysis and gluconeogenesis (54 DEGs and 1 DAM), and the pentose phosphate pathway (14 DEGs and 1 DAM) were significantly enriched. These findings suggest that blueberries predominantly increase sugar accumulation by activating carbon metabolism network pathways. Moreover, we identified critical transcription factors linked to the sugar response. This study presents new understandings regarding the molecular mechanisms underlying blueberry sugar accumulation and will be helpful in improving blueberry fruit quality through breeding.

QUALITY CONTROL METHODS OF SHORTCRUST BISCUITS USING HIGHLY NON-TRADITIONAL RAW MATERIALS

Butter cookies refer to products obtained on the basis of visco-plastic dough, which is characterized by a significant amount of fat components, sugar, and the use of wheat flour with an average gluten content. Such a formulation makes the finished product high-calorie and low biological value. The results of research aimed at enriching butter cookies by replacing wheat flour with amaranth flour and a mixture of sprouted cereals with simultaneous regulation of its sugar content by introducing polydextrose are presented in the article. Based on theoretical and experimental studies, it was established that the addition of amaranth flour contributed to the development of springy deformations in the dough and reduced the development of plastic deformations, led to friability, which is associated with a decrease in the content of gluten proteins, the heterogeneity of starch grains, including a significant increase in the amylopectin fraction of starch. It was found that maximum possible replacement was 50% of wheat flour with amaranth flour, which did not impair the taste and aroma of the finished product, but coused dark color both of the dough and the finished product. More amount of replacement of wheat flour with a crushed mixture of sprouted cereals deepened the negative effect on the structural and mechanical properties of the dough, namely, the general deformation of the samples increased, the relative plasticity decreased, and the relative springiness increased. Such regularities are caused by the introduction of a significant amount of dietary fibers into the mixture, as well as low molecular weight water-soluble compounds accumulated due to hydrolytic processes during germination. In the finished products, the baking index increased, there was also an increase in friability. The possibility of adding polydextrose to replace 50% of powdered sugar was experimentally confirmed to improve the structural and mechanical characteristics of dough based on a mixture of amaranth flour, germinated cereal and wheat flour, but the effect on the plastic characteristics of such a replacement was insignificant. In order to achieve the necessary quality indicators, it was proposed to introduce the cellulolytic enzyme preparation Alhamalt HCF from the manufacturer "Stern Ingredients" LLC. It was established that significant changes occurred in the consistency of the dough that was left to rest at a temperature of 35°C, it acquired the plasticity necessary for forming, did not tear, the dough blanks were not characterized by deformation of the seams, and the finished cookies had a smooth, uncracked surface. In the technological scheme for the production of butter cookies with a high content of non-traditional raw materials, it was proposed to introduce a dough resting stage with a temperature of 35 °C, which will allow the enzymatic hydrolysis of cellulose and its derivatives under the action of the introduced enzyme preparation, increase the accumulation of watersoluble sugars, which will lead to the plasticization of the semi-finished product

Seed priming attenuates the impact of salt stress and enhances lettuce yields

Salt stress is a major factor that contributes to reduced lettuce productivity. Seed priming has emerged as a promising technique to improve crop stress tolerance. In this study, Romaine lettuce seeds were primed with calcium chloride (CaCl2), distilled water (hydro), and potassium nitrate (KNO3) to test their effectiveness in improving salt stress tolerance. Lettuce seeds treated with hydro, 50 mM CaCl2, and 0.5% KNO3 were exposed to 0 or 100 mM sodium chloride (NaCl). Priming treatments significantly increased lettuce's fresh mass by 22%–61% under salt stress. Hydro-primed lettuce showed the most significant increase in root mass (109%), a 38% higher root length, a 35% increase in surface area, and a 25%–40% increase in volume, tips, forks, and crossings of roots. The hydro-primed lettuce had higher gas exchange rates than the non-primed control, followed by the KNO3- and the CaCl2-primed lettuce. Furthermore, hydro-primed seedlings exhibited the highest proline accumulation (105%) under salt stress. The accumulation of sugars (up to 50%) in hydro- and CaCl2-primed lettuce led to a 56% decrease in electrolyte leakage and membrane damage. The correlation network analysis of the traits revealed that hydro-primed seedlings exhibited a higher + ve/-ve edge ratio, which indicates their greater resilience to salt stress than other priming techniques. Priming of seeds before planting offers the potential for improving resilience to stress.

Effects of zinc-nano oxide, salicylic acid and sodium nitroprusside on physiological properties, antioxidant enzyme activities and secondary metabolites of Viola odorata under drought stress

One of the most important abiotic stresses and limiting factors (closing pores, lack of CO2 entry, reduced photosynthesis, and reduced yield) of plant products around the world is water-deficit stress. This study aimed to examine the water deficit stress and foliar application with anti-stress compounds (ASC) on characteristics of Viola odorata. The study was carried out as a factorial experiment based on a randomized complete design. The factors consisted of water deficit and the foliar application of ASC at six levels [zinc-nano oxide (ZnO, 1000 and 1500 mg l–1), salicylic acid (SA, 200 and 300 mg l–1), and sodium nitroprusside (SNP, 200 and 300 μM)], and the control. The water deficit reduced the leaf water potential, cell membrane stability, and the shoot and root fresh weight but increased electrolyte leakage and soluble sugar accumulation. However, foliar applications, particularly SA and SNP, positively affected the measured parameters. The activities of superoxide dismutase and guaiacol peroxidase at all three field capacity levels were higher in the plants treated with SA and SNP than in the control and plants treated with ZnO. In sum, using 200 mg l–1 of SA as a foliar application, in addition to improvement of the growth and developmental conditions of the aromatic violet plant, moderated the adverse effects of water deficit stress and increased the plant resistance to water deficit stress. Based on the results, the application of SA, SNP, and ZnO reduced electrolyte leakage and enhanced the plant’s resistance to water deficit by increasing the compatible osmolyte accumulation and antioxidant enzyme activity.

Exogenous application of ALA enhanced sugar, acid and aroma qualities in tomato fruit.

The content and proportion of sugars and acids in tomato fruit directly affect its flavor quality. Previous studies have shown that 5-aminolevulinic acid (ALA) could promote fruit ripening and improve its aroma quality. In order to explore the effect of ALA on sugar and acid quality during tomato fruit development, 0, 100, and 200 mg L-1 ALA solutions were sprayed on the fruit surface 10 days after pollination of the fourth inflorescence, and the regulation of ALA on sugar, acid metabolism and flavor quality of tomato fruit was analyzed. The results showed that ALA treatment could enhance the activities of acid invertase (AI), neutral invertase (NI), and sucrose synthase (SS), reduce the activity of sucrose phosphate synthase (SPS), up-regulate the expression of SlAI, SlNI and SlSS, change the composition and content of sugar in tomato fruit at three stages, significantly increase the content of sugars in fruit, and promote the accumulation of sugars into flesh. Secondly, ALA treatments increased the activities of phosphoenolpyruvate carboxykinase (PEPC), malic enzyme (ME), and citrate synthase (CS), up-regulated the expression of SlPPC2, SlME1, and SlCS, and reduced the citric acid content at maturity stage, thereby reducing the total organic acid content. In addition, ALA could also increase the number and mass fraction of volatile components in mature tomato fruits. These results indicated that exogenous application of ALA during tomato fruit development could promote the formation of fruit aroma quality and were also conducive to the formation of fruit sugar and acid quality.

Strawberry soluble solids QTL with inverse effects on yield.

Sugars are the main drivers of strawberry sweetness, and understanding their genetic control is of critical importance for breeding. Large-scale genome-wide association studies were performed in two populations totaling 3399 individuals evaluated for soluble solids content (SSC) and fruit yield. Two stable quantitative trait loci (QTL) on chromosome 3B and 6A for SSC were identified. Favorable haplotypes at both QTL for SSC decreased yield, though optimal allelic combinations were identified with reduced impacts on yield. Metabolites in the starch and sucrose metabolism pathway were characterized and quantified for 23 contrasting genotypes in leaves, white fruit, and red fruit. Variations in sucrose concentrations/efflux indicated genetic variation underlying sucrose accumulation and transportation during fruit ripening. Integration of genome-wide association studies and expression quantitative locus mapping identified starch synthase 4 (FxaC_10g00830) and sugar transporter 2-like candidate genes (FxaC_21g51570) within the respective QTL intervals. These results will enable immediate applications in genomics-assisted breeding for flavor and further study of candidate genes underlying genetic variation of sugar accumulation in strawberry fruit.

Cytokinin promotes anthocyanin biosynthesis via regulating sugar accumulation and MYB113 expression in Eucalyptus.

Anthocyanins are flavonoid-like substances that play important roles in plants' adaptation to various environmental stresses. In this research, we discovered that cytokinin (CK) alone could effectively induce the anthocyanin biosynthesis in Eucalyptus and many other perennial woody plant species, but not in tobacco and Arabidopsis, suggesting a diverse role of CK in regulating anthocyanin biosynthesis in different species. Transcriptomic and metabolomic strategies were used to further clarify the specific role of CK in regulating anthocyanin biosynthesis in Eucalyptus. The results showed that 801 and 2241 genes were differentially regulated at 6 and 24h, respectively, after CK treatment. Pathway analysis showed that most of the differentially expressed genes were categorized into pathways related to cellular metabolism or transport of metabolites, including amino acids and sugars. The metabolomic results well supported the transcriptome data, which showed that most of the differentially regulated metabolites were related to the metabolism of sugar, amino acids and flavonoids. Moreover, CK treatment significantly induced the accumulation of sucrose in the CK-treated leaves, while sugar starvation mimicked by either defoliation or shading treatment of the basal leaves significantly reduced the sugar increase of the CK-treated leaves and thus inhibited CK-induced anthocyanin biosynthesis. The results of in vitro experiment also suggested that CK-induced anthocyanin in Eucalyptus was sugar-dependent. Furthermore, we identified an early CK-responsive transcription factor MYB113 in Eucalyptus, the expression of which was significantly upregulated by CK treatment in Eucalyptus, but was inhibited in Arabidopsis. Importantly, the overexpression of EgrMYB113 in the Eucalyptus hairy roots was associated with significant anthocyanin accumulation and upregulation of most of the anthocyanin biosynthetic genes. In conclusion, our study demonstrates a key role of CK in the regulation of anthocyanin biosynthesis in Eucalyptus, providing a molecular basis for further understanding the regulatory mechanism and diversity of hormone-regulated anthocyanin biosynthesis in different plant species.

Exogenous methylglyoxal alleviates drought-induced 'plant diabetes' and leaf senescence in maize.

Drought-induced leaf senescence is associated with high sugar levels, which bears some resemblance to the syndrome of diabetes in humans; however, the underlying mechanisms of such 'plant diabetes' on carbon imbalance and the corresponding detoxification strategy are not well understood. Here, we investigated the regulatory mechanism of exogenous methylglyoxal (MG) on 'plant diabetes' in maize plants under drought stress applied via foliar spraying during the grain-filling stage. Exogenous MG delayed leaf senescence and promoted photoassimilation, thereby reducing the yield loss induced by drought by 14%. Transcriptome and metabolite analyses revealed that drought increased sugar accumulation in leaves through inhibition of sugar transporters that facilitate phloem loading. This led to disequilibrium of glycolysis and overaccumulation of endogenous MG. Application of exogenous MG up-regulated glycolytic flux and the glyoxalase system that catabolyses endogenous MG and glycation end-products, ultimately alleviating 'plant diabetes'. In addition, the expression of genes facilitating anabolism and catabolism of trehalose-6-phosphate was promoted and suppressed by drought, respectively, and exogenous MG reversed this effect, implying that trehalose-6-phosphate signaling in the mediation of 'plant diabetes'. Furthermore, exogenous MG activated the phenylpropanoid biosynthetic pathway, promoting the production of lignin and phenolic compounds, which are associated with drought tolerance. Overall, our findings indicate that exogenous MG activates defense-related pathways to alleviate the toxicity derived from 'plant diabetes', thereby helping to maintain leaf function and yield production under drought.

Rapid Dilute Sulfuric Acid Hydrolysis of Soy Flour to Amino Acids for Microbial Processes and Biorefining

Amino acids have relevance in biorefining as fermentation nutrients but also as valued coproducts obtainable from plant biomass. Soy flour was studied as a representative low-cost protein source requiring hydrolysis to free primary amino acids for utilization. Within the context of biorefining, process schemes, reactant concentrations, times, and temperatures were varied to explore the efficiency of dilute sulfuric acid hydrolysis of soy flour to release amino acids. Two process strategies were optimized. Either soy flour was co-processed with switchgrass biomass using a dilute-acid pretreatment, or it was hydrolyzed alone with dilute acid. Significant improvement to hydrolysate fermentability was accomplished by adding 2.5–10 g/L soy flour to switchgrass pretreatment with dilute sulfuric acid (0.936% v/v) for 15 min at 160 °C. This practice optimized accumulation of neutral sugars and resulted in a 25% reduction in furfural while boosting xylose 7% and up to doubling primary amino nitrogen (PAN), as compared to no soy flour addition to switchgrass pretreatment. When soy flour was hydrolyzed alone, PAN titers were optimized to 1588 mg N/L (9.9 g amino acids/L) and yield to 0.0529 g PAN/g flour (61% of theoretical) using a 10% (v/v) (1.8 M) sulfuric acid hydrolysis 30 min at 160 °C.

Effects of Different Forms and Proportions of Nitrogen on the Growth, Photosynthetic Characteristics, and Carbon and Nitrogen Metabolism in Tomato.

Optimal plant growth in many species is achieved when the two major forms of N are supplied at a particular ratio. This study investigated optimal nitrogen forms and ratios for tomato growth using the 'Jingfan 502' tomato variety. Thirteen treatments were applied with varying proportions of nitrate nitrogen (NN), ammonium nitrogen (AN), and urea nitrogen (UN). Results revealed that the combination of AN and UN inhibited tomato growth and photosynthetic capacity. Conversely, the joint application of NN and UN or NN and AN led to a significant enhancement in tomato plant growth. Notably, the T12 (75%UN:25%NN) and T4 (75%NN:25%AN) treatments significantly increased the gas exchange and chlorophyll fluorescence parameters, thereby promoting the accumulation of photosynthetic products. The contents of fructose, glucose, and sucrose were significantly increased by 121.07%, 206.26%, and 94.64% and by 104.39%, 156.42%, and 61.40%, respectively, compared with those in the control. Additionally, AN favored starch accumulation, while NN and UN favored fructose, sucrose, and glucose accumulation. Gene expression related to nitrogen and sugar metabolism increased significantly in T12 and T4, with T12 showing greater upregulation. Key enzyme activity in metabolism also increased notably. In summary, T12 enhanced tomato growth by upregulating gene expression, increasing enzyme activity, and boosting photosynthesis and sugar accumulation. Growers should consider using NN and UN to reduce AN application in tomato fertilization.

Bunch transpiration is involved in the hastening of grape berry ripening under elevated temperature and low relative humidity conditions

The present study aimed: i) to evaluate the impact of the changes in temperature and relative humidity (RH), projected by the year 2100, on grape ripening, and ii) to assess if bunch transpiration is a key physiological process involved in the advancement in grape development under future climate conditions. Fruit-bearing cuttings of Vitis vinifera L. cv. ‘Tempranillo’ were grown, from fruit set to maturity, in glasshouses under two conditions: 24°C/14°C and 55%/70% RH (day/night) (T) vs 28°C/18°C and 43%/58% RH (T+4). To elucidate the role of bunch transpiration in grape development in a future climate scenario, the bunches of half of the plants in the T+4 glasshouse were sprayed with an antitranspirant (AT+4). T+4 increased bunch transpiration, hastened the ripening process, increasing the rate of total soluble solid (TSS) accumulation and malic acid degradation, and reduced the concentration of total anthocyanins. The application of antitranspirant partially alleviated the effects of combined high temperature and low RH on maturation times, through lower TSS accumulation rates. Berries in AT+4 had the lowest concentrations of anthocyanins and color, likely related to a reduction in light transmittance by the antitranspirant film and to higher anthocyanin degradation due to the longer exposure to elevated temperatures. The results show a negative impact of elevated temperature and low RH on grape composition. The increased bunch transpiration under these conditions played an important role in the changes observed in phenology and sugar accumulation.

High daily light integral positively regulate photosynthetic capacity through mediating nitrogen partitioning and leaf anatomical characteristic in flowering Chinese cabbage

In controlled environment agriculture, optimization of lighting regimes, i.e. daily light integral (DLI, photosynthetic photon flux density (PPFD) x photoperiod duration), plays vital roles to maximize harvestable yield and reduce lighting costs. Regulating PPFD or photoperiod have been widely used for energy-efficient cultivation, while the mechanisms of multiple DLI contributing to photosynthesis capacity are poorly understood. Hence, the treatment of 16/8 h light/dark compared with 24 h continuous lighting (CL), at 200 and 300 μmol m−2 s−1 PPFD, with the DLI from 11.52 to 25.92 mol m−2 d−1, were conducted in flowering Chinese cabbage respectively. The results showed that higher DLI significantly promoted relative growth rate and dry matter accumulation, irrespective of the combination of PPFD and photoperiod, consequently facilitated faster harvest compared to the lower DLI of 11.52 mol m−2 d−1 treatment. Under higher DLI, the increase in Rubisco content was the primary factor accelerating photosynthetic capacity, followed by the increases in gm. Additionally, the enhancement of Rubisco was ascribed to the increased allocation of nitrogen to the carboxy system. Furthermore, the increase of gm under higher DLI was largely resulted from the increase in Sm/S and Sc/S caused by increased accumulation of soluble sugar and starch. Unexpectedly, at the same DLI of 17.28 mol m−2 d−1, extending photoperiod from 16 to 24 h d−1 had no influence on photosynthetic capacity, although 24 h 200 μmol m−2 s−1 treatment reduced the abaxial stomatal density and light-saturated stomatal conductance, and increased the thickness of cell walls and the contents of chlorophyll and Rubisco, compared with 16 h 300 μmol m−2 s−1 treatment. To summarize, plant growth and ripening were promoted as the DLI increased. And optimized nitrogen allocation accounted for the promotion of photosynthetic capacity. Increasing photoperiod at the same DLI had no promotion on photosynthetic capacity.

Enhanced antioxidant activity and quality of olecranon peach fruits (Prunus persica L.) through synergistic application of exogenous nano-selenium and melatonin

Olecranon peach, a significant economic crop in southern China, faces quality degradation due to pests, diseases, and pesticide residues. Melatonin (MT) and nano-selenium (Nano-Se) applied individually have been found to improve crop growth and abiotic stress resistance. However, the impact of different Nano-Se and MT ratios on olecranon peach quality remains uncertain. Plants were foliar sprayed with varying Nano-Se and MT ratios during the fruit set phase. A combined 5 mg/L Nano-Se and 10 mg/L MT (Nano-Se5 + MT10) effect outperformed individual treatments and the control in enhancing fruit quality. Nano-Se5 + MT10 notably increased peroxidase (190.3%) and superoxide dismutase (112.2%) activities, and reduced polyphenol oxidase activity (-13.2%), raised total sugars (33.3%), soluble protein (18.5%), and phenolic contents like apigenin (51.9%), vanillic acid (21.4%), ferulic acid (29.4%), and p-hydroxybenzoic acid (317.2%) compared to the control. Correlation analysis linked antioxidant enzymes and phenolics in olecranon peach fruits to nutrient accumulation. Nano-Se5 + MT10 improves sweetness and quality by enhancing antioxidant ability (increased peroxidase and superoxide dismutase, decreased polyphenol oxidase and phenolics), and promoting soluble protein, total sugar, and phenolic accumulation. In conclusion, Nano-Se5 + MT10 application shows promise in enhancing olecranon peach quality and antioxidant attributes.Graphical

Source-sink manipulation does not mitigate the effects of grapevine red blotch virus (GRBV) infection on fruit sugar and flavonoid accumulation in Cabernet-Sauvignon

Source-sink manipulation does not mitigate the effects of grapevine red blotch virus (GRBV) infection on fruit sugar and flavonoid accumulation in Cabernet-Sauvignon

Disrupted sugar transport and continued sugar consumption lead to sugar decline in ripe ‘Shixia’ longan fruit

Longan fruit pulp sugar content and sweetness decline after ripening, which affects fruit quality and postharvest storage. Fruit sugar decline research has focused mainly on fruit physiology and biochemistry. To explore the molecular mechanism underlying sugar decline, we conducted transcriptome and metabolome analyses of ‘Shixia’ longan fruit aril (pulp) tissues at different stages of development. In total, 873 metabolites and 26584 annotated unigenes were identified. Sugar content changes in aril tissues were closely related to gene expression patterns related to starch and sucrose metabolism, such as sucrose phosphate synthase (SPS), invertase (INV), sucrose synthase (SUS), and glucose-6-phosphate isomerase (GPI). Notably, glycolytic pathway gene expression and cellulose and lignin contents increased during the sugar decline stage compared to the sugar accumulation stage. Conversely, sucrose transporter genes, such as DlSWEET2b, DlSWEET10, and DlSWEET12, showed the opposite expression pattern, pointing to reduced sucrose transport during sugar decline. These results indicate that longan fruit sugar decline is likely related to an interruption of sugar input (cessation of sucrose transport to the aril) and continued glycolysis and cellulose/lignin biosynthesis. This provides a new way to delay longan fruit sugar decline, by regulating sugar transport instead of inhibiting respiration.

The effectiveness of non-root fertilizers during cultivation white cabbage in the Non-Chernozem zone

Relevance. Foliar feeding when growing vegetables is due to its positive effect on quality and yield indicators. The use of microfertilizers for foliar feeding allows optimizing the absorption of nutrients by plants, which can not only reduce economic costs, but also regulate the accumulation of biologically active substances. Identifying the optimal fertilizing system for different varieties and hybrids of vegetables is especially important in risky farming areas, where the main factor regulating yield indicators is weather.Methodology. The purpose of the work is to conduct a comparative assessment of the effectiveness of foliar feeding of the white cabbage variety Zimovka 1474 different agrochemicals. In a field experiment for three years (2018-2020), the effect of microfertilizers, humate, chelates and a biostimulator on the yield, biochemical and microelement composition of white cabbage variety Zimovka 1434 was studied.Results. It has been shown that the biometric characteristics of cabbage are best influenced by foliar fertilization with microfertilizer Aquarin and the biostimulator BIS-65, and the total and marketable yield is influenced by microfertilizer in chelate form Helaton. The greatest accumulation of dry matter, sugars, and vitamin C was typical for variants using the biological product BIS-65 and chelated fertilizers (Tiaton, Helaton). Chelated fertilizers also contributed to an increase in the accumulation of elements such as potassium, calcium, iron, zinc and manganese in cabbage heads.

PbrbZIP15 promotes sugar accumulation in pear via activating the transcription of the glucose isomerase gene PbrXylA1.

The composition and abundance of soluble sugars in mature pear (Pyrus) fruit are important for its acceptance by consumers. However, our understanding of the genes responsible for soluble sugar accumulation remains limited. In this study, a S1-group member of bZIP gene family, PbrbZIP15, was characterized from pear genome through the combined analyses of metabolite and transcriptome data followed by experimental validation. PbrbZIP15, located in nucleus, was found to function in fructose, sucrose, and total soluble sugar accumulation in pear fruit and calli. After analyzing the expression profiles of sugar-metabolism-related genes and the distribution of cis-acting elements in their promoters, the glucose isomerase 1 gene (PbrXylA1), whose corresponding protein catalyzed the isomerization of glucose and fructose in vitro, was identified as a downstream target gene of PbrbZIP15. PbrbZIP15 could directly bind to the G-box element in PbrXylA1 promoter and activate its transcription, as evidenced by chromatin immunoprecipitation-quantitative PCR, yeast one-hybrid, electrophoretic mobility shift assay, and dual-luciferase assay. PbrXylA1, featuring a leucine-rich signal peptide in its N-terminal, was localized to the endoplasmic reticulum. It was validated to play a significant role in fructose, sucrose, and total soluble sugar accumulation in pear fruit and calli, which was associated with the upregulated fructose/glucose ratio. Further studies revealed a positive correlation between the sucrose content and the expression levels of several sucrose-biosynthesis-related genes (PbrFRK3/8, PbrSPS1/3/4/8, and PbrSPP1) in PbrbZIP15-/PbrXylA1-transgenic fruit/calli. In conclusion, our results suggest that PbrbZIP15-induced soluble sugar accumulation during pear development is at least partly attributed to the activation of PbrXylA1 transcription.

Pulsed light treatment enhances starch hydrolysis and improves starch physicochemical properties of germinated brown rice.

Recently, germinated brown rice (GBR) has gained substantial attention as a functional food because of its nutritional attributes. Notably, pulsed light technology (PLT) has emerged as a promising tool for enhancing rice germination and, consequently, has improved the nutritional and functional qualities of GBR-derived products. However, further research is required to comprehensively understand the impact of PLT on GBR physicochemical properties. The present study aimed to investigate the stimulating effects of PLT on starch hydrolysis, starch structure and functional properties of GBR. The PLT substantially boosted α-amylase activity during brown rice germination, leading to a 10.9% reduction in total starch content and a 17.3% increase in reducing sugar content, accompanied by elevated free water levels. Structural analysis indicated no changes in starch crystalline types, whereas gelatinization temperature slightly increased. Pasting properties exhibited a significant drop in peak viscosity. Scanning electron microscopy showed surface erosion of starch granules with microstructural changes. Furthermore, correlation analysis established positive links between α-amylase activity, reducing sugar accumulation, starch structure and functional properties in GBR. The present study demonstrates that PLT enhanced the physicochemical properties of GBR starch, significantly improving the stability of GBR products, thereby contributing to expanded applicability of rice starch in the food industry. © 2023 Society of Chemical Industry.