Transcriptome Sequencing for Sugar and Flavonoid Metabolism in Prunus persica‘Jinxiangyu’

In this study,high performance liquid chromatography(HPLC)and RNA-seq transcriptome sequencing were used to study the changes in soluble sugar components and flavonoids in Prunus persica‘Jinxiangyu’at different developmental stages(20–90 d after flowering)and screen the key genes regulating the formation of soluble sugar and flavonoids in the fruits.The results showed that 60–85 d after flowering was the key stage of quality formation of Prunus persica‘Jinxiangyu’,and the content of soluble sugar,soluble solid,fructose,and sucrose in the fruit increased significantly during this period.The sugar content of ripe fruits was mainly fructose and sucrose.The content of kaempferol glycoside was low in the fruit.Quercetin glycoside content was higher in the young fruit stage and decreased with fruit maturity.There were no anthocyanin compounds in the fruit.The expression levels of genes involved in flavonoid metabolism(ANS,DFR,F3H,FLS,4CL1,etc.)were low in the fruit.A total of 181 differentially expressed genes were identified during fruit development to participate in five sugar metabolism pathways,among which the SDH gene had a higher expression level,which continuously rised in the later stage of fruit development.It mainly promoted the accumulation of fructose content in the later stage of fruit development.The expression levels of SPS1,SS,and SS1 genes were continuously up-regulated,which played a key role in sucrose regulation.The higher expression levels of SUS3 and INVA genes in the early stage of fruit development promoted the degradation of sucrose.

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 diff erent pear cultivars during cold storage using seven major commercial pear cultivars belonging to diff erent 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 fi rmness, 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 signifi cance of diff erent 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.

Effects of Exogenous Trehalose on the Metabolism of Sugar and Abscisic Acid in Tomato Seedlings Under Salt Stress

Salt stress a ects the growth and development of plants, which results in a decrease in crop quality and yield. In this study, we used tomato seedlings treated with salt and trehalose as experimental materials and analyzed them using the technique for order preference by similarity to ideal solution analysis to select the optimal trehalose concentration for treatment. We also determined the contents of sugar and abscisic acid (ABA) and detected the expression of genes involved in the metabolism of sugar and ABA by quantitative real-time PCR. Results showed that the optimal trehalose concentration was 2 mmol/L for tomato seedlings under salt stress. Exogenous trehalose decreased the starch content and increased the soluble sugar con- tent by a ecting the expression of genes related to the metabolism of starch and soluble sugar. Exogenous trehalose altered the accumulation and distribution of sugar by inducing the upregulation of sugar transporter genes. Furthermore, trehalose increased the ABA content to induce salt stress response by regulating the expression of genes related to the synthesis and metabolism of ABA. In conclusion, trehalose can e ectively alleviate salt stress and enhance salt tolerance of tomato. These ndings provide a novel perspective and a better resource to investigate the salt tolerance mechanism and a new method for alleviating salt stress in tomato.

Identification of key gene networks controlling organic acid and sugar metabolism during watermelon fruit development by integrating metabolic phenotypes and gene expression profiles

The organoleptic qualities of watermelon fruit are defined by the sugar and organic acid contents,which undergo considerable variations during development and maturation.The molecular mechanisms underlying these variations remain unclear.In this study,we used transcriptome profiles to investigate the coexpression patterns of gene networks associated with sugar and organic acid metabolism.We identified 3 gene networks/modules containing 2443 genes highly correlated with sugars and organic acids.Within these modules,based on intramodular significance and Reverse Transcription Quantitative polymerase chain reaction(RT-qPCR),we identified 7 genes involved in the metabolism of sugars and organic acids.Among these genes,Cla97C01G000640,Cla97C05G087120 and Cla97C01G018840(r^(2)=0.83 with glucose content)were identified as sugar transporters(SWEET,EDR6 and STP)and Cla97C03G064990(r^(2)=0.92 with sucrose content)was identified as a sucrose synthase from information available for other crops.Similarly,Cla97C07G128420,Cla97C03G068240 and Cla97C01G008870,having strong correlations with malic(r^(2)=0.75)and citric acid(r^(2)=0.85),were annotated as malate and citrate transporters(ALMT7,CS,and ICDH).The expression profiles of these 7 genes in diverse watermelon genotypes revealed consistent patterns of expression variation in various types of watermelon.These findings add significantly to our existing knowledge of sugar and organic acid metabolism in watermelon.

Gene Expression and Activity of Enzymes Involved in Sugar Metabolism and Accumulation During “Huangguan” and “Yali” Pear Fruit Development

Since the carbohydrate content affects pear flavor during the process of growth, it is necessary to determine the sugar components that accumulate in the fruit. We analyzed the fruit carbohydrate content, and the gene expression and activity ofacid invertase(AI), neutral invertase(NI), sucrose synthase(SS), and sucrose phosphate synthase(SPS) during the development of "Huangguan" and "Yali" pears. The results demonstrate that during development, the fruit sugar metabolism of the "Huangguan" pear follows a typical sorbitol–starch-soluble sugars middle model, whereas the "Yali" pear fruit follows a typical sorbitol–sucrose–starch-soluble sugars middle model. In the "Huangguan" pear, we found the AI and NI gene expressions, as well as AI( P < 0.05) and NI( P < 0.01) enzyme activities, to be positively correlated, whereas we found the NI gene expression and NI enzyme activity of "Yali" pear to be negatively correlated( P < 0.01). We observed the high levels oflate-stage AI and early-stage SS during development to roughly correspond with the gene expression found in the late and early stages, respectively, suggesting their potential regulatory roles in "Huangguan" pear fruit development. Our results indicate that the primary function of SPS during the early developmental stage is to accumulate sucrose, whereas the primary function of AI is to promote hexose accumulation during the late developmental stage ofmature "Yali" pear fruit.

Effects of water stress on quality and sugar metabolism in'Gala'apple fruit

Sugar plays an important role in apple fruit development,appearance and quality as well as contributing to a plant’s water stress response.Trehalose and the trehalose biosynthetic metabolic pathways are part of the sugar signaling system in plants,which are important regulator of water stress response in apple.The effect of water stress treatments applied to apple trees and the corresponding effects of ABA on developmental fruit quality were examined for indicators of fruit quality during fruit development.The results indicated that the severe water stress treatment(W2)occurring after the last stage of fruit cell division caused a decrease in the color and size of fruit.The moderate water stress(W1)occurring after the last stage of fruit cell enlargement(S2)caused an increase in the content of fructose and sorbitol while the apple fruit shape was not affected.These changes in sugar are related to the activity of sugar metabolic enzymes.While the enzymatic activity of vacuolar acid invertase(vAINV)was higher,that of sucrose-phosphate synthase(SPS)was lower in water stress treated fruit throughout the developmental period.This indicates that enhanced sucrose degradation and reduced sucrose synthesis leads to an overall reduced sucrose content during times of drought.Thus,water stress reduced sucrose content.Whereas the content of endogenous trehalose and ABA were the highest in water stress treated fruit.A moderate water stress(W1)imposed on apple trees via water restriction(60%–65%of field capacity)after the fruit cell enlargement phase of fruit development yielded sweeter fruit of higher economic value.

The essential roles of sugar metabolism for pollen development and male fertility in plants

Sugar metabolism plays an essential role in plant male reproduction. Defects in sugar metabolism during anther and pollen development often result in genic male sterility(GMS). In this review, we summarize the recent progresses of the sugar metabolism-related GMS genes and their roles during plant anther and pollen development, including callose wall and primexine formation, intine development, pollen maturation and starch accumulation, anther dehiscence, and pollen germination and tube growth. We predict 112 putative sugar metabolic GMS genes in maize based on bioinformatics and RNA-seq analyses, and most of them have peak expression patterns during middle or late anther developmental stages.Finally, we outline the potential applications of sugar metabolic GMS genes in crop hybrid breeding and seed production. This review will deepen our understanding on sugar metabolic pathways in controlling pollen development and male fertility in plants.

Transcriptomics-based identification and characterization of genes related to sugar metabolism in‘Hongshuijing’pitaya

Sugar composition not only affects fruit flavor but is also an important determinant of fruit taste and consumer preference.In this study,changes in the sugar content and sugar-metabolizing enzymes were investigated from different sections of various fruit development phases of‘Hongshuijing’pitaya(Hylocereus monacanthus).Genes related to sugar metabolism were also screened by transcriptome analyses.The results indicated that glucose was the major sugar in mature pitaya fruit,and was mainly regulated by vacuolar acid invertase(VAI)and sucrose synthase(SS)(degradative direction).Sugar accumulation varied in pulp between different sections of the pitaya fruit.VAI,neutral invertase(NI)and SS(degradative direction)are crucial enzymes for sugar accumulation in pitaya.The expression of 17 genes related to sucrose metabolism obtained from seven databases[NCBI non-redundant protein database(Nr),NCBI non-redundant nucleotide sequence database(Nt),EuKaryotic Orthologous Groups(KOG),The Protein Families(Pfam),Kyoto Encyclopedia of Genes and Genomes(KEGG),Swiss-prot,and Gene Ontology(GO)]were analyzed in different pitaya pulp sections.HpVAI1 had the highest relative expression level on the 29th day after pollination(DAP).Positive correlations were found between HpVAI1 expression and VAI activity;HpNI4 and NI activity;HpSS2,HpSS5,and SS activity(synthetic direction),indicating that HpVAI1,HpNI4,and HpSS2 and HpSS5 were involved in the regulation of VAI,NI,and SS(synthetic direction),respectively.HpVAI1 and HpNI4 regulated sucrose degradation and the accumulation of glucose and fructose,while HpSS2 and HpSS5 regulated sucrose synthesis.These results suggest that HpVAI1 plays a key role in sugar metabolism during fruit development of‘Hongshuijing’pitaya.The results of this study provide new information about sugar metabolism in pitaya fruit that could help improve fruit quality and the breeding of new cultivars.

Potassium deficiency inhibits steviol glycosides synthesis by limiting leaf sugar metabolism in stevia(Stevia rebaudiana Bertoni)plants

The steviol glycosides(SGs)in stevia(Stevia rebaudiana Bertoni)leaves are becoming increasingly valuable due to its high sweetness but low calorific value,which is driving the development of stevia commercial cultivation.Optimizing fertilization management can effectively increase SGs productivity,but knowledge on the relationship between potassium(K)fertilization and SGs production is still lacking.In this study,pot experiments were conducted in order to investigate the effect of K deficiency on SGs synthesis in stevia leaves,as well as the underlying mechanisms.Our results showed that when compared with standard K fertilization,K deficiency treatment has no significant effect on the biomass of stevia plant grown in a given soil with high K contents.However,K deficiency critically decreased leaf SGs contents as well as the expression of SGs synthesis-related genes.The contents of different sugar components decreased and the activities of sugar metabolism-related enzymes were inhibited under the K deficiency condition.Moreover,spraying sucrose on the leaves of stevia seedlings diminished the inhibitory effect caused by K deficiency.Our results also revealed the significant positive correlations between sucrose,glucose and SGs contents.Overall,our results suggest that K deficiency would suppress the synthesis of SGs in stevia leaves,and this effect may be mediated by the leaf sugar metabolism.Our findings provide new insights into the improvement of SGs production potential.

Brassica rapa orphan genes largely affect soluble sugar metabolism

Orphan genes(OGs),which are genes unique to a specific taxon,play a vital role in primary metabolism.However,little is known about the functional significance of Brassica rapa OGs(BrOGs)that were identified in our previous study.To study their biological functions,we developed a BrOG overexpression(BrOGOE)mutant library of 43 genes in Arabidopsis thaliana and assessed the phenotypic variation of the plants.We found that 19 of the 43 BrOGOE mutants displayed a mutant phenotype and 42 showed a variable soluble sugar content.One mutant,BrOG1OE,with significantly elevated fructose,glucose,and total sugar contents but a reduced sucrose content,was selected for indepth analysis.BrOG1OE showed reduced expression and activity of the Arabidopsis sucrose synthase gene(AtSUS);however,the activity of invertase was unchanged.In contrast,silencing of two copies of BrOG1 in B.rapa,BraA08002322(BrOG1A)and BraSca000221(BrOG1B),by the use of an efficient CRISPR/Cas9 system of Chinese cabbage(B.rapa ssp.campestris)resulted in decreased fructose,glucose,and total soluble sugar contents because of the upregulation of BrSUS1b,BrSUS3,and,specifically,the BrSUS5 gene in the edited BrOG1 transgenic line.In addition,we observed increased sucrose content and SUS activity in the BrOG1 mutants,with the activity of invertase remaining unchanged.Thus,BrOG1 probably affected soluble sugar metabolism in a SUS-dependent manner.This is the first report investigating the function of BrOGs with respect to soluble sugar metabolism and reinforced the idea that OGs are a valuable resource for nutrient metabolism.

Regulation of Growth, Antioxidants and Sugar Metabolism in Rice (Oryza sativa L.) Seedlings by NaCl and Its Reversal by Silicon

The effect of NaCl with or without silicon on the growth and metabolism in rice seedlings cv. MTU1010 was studied. In these seedlings, the oxidative stress has been observed with NaCl treatments and the levels of proline, H2O2 and malondialdehyde contents were increased whereas catalase activity was decreased. NaCl exposure at 25 mM, 50 mM and 100 mM concentrations in the test seedlings resulted in an increase in both reducing and non-reducing sugar content. There was a decrease in starch contents and the activity of starch phosphorylase was increased. NaCl stress also affected the activities of different carbohydrate metabolizing enzymes. The activities of sucrose synthase and sucrose phosphate synthase were increased, while the activity of acid invertase was decreased. Joint application of silicon with NaCl showed significant alterations on all parameters tested under the purview of NaCl treatment alone leading to better growth and metabolism in rice seedlings. Thus the use of silicon enriched fertilizers may help to grow healthy rice plants in NaCl rich soil.

EFFECT OF ACUPUNCTURE ON CARBOHYDRATE METABOLISM IN PATIENTS WITH SIMPLE OBESITY

In an attempt to elucidate the effect ofacupuncture on carbohydrate metabolism inpatients with simple obesity and its mecha-nism in reducing excess body fat,obesity in-dexes,fasting blood sugar,insulin contentand activity of lactic dehydrogenase(LDH)were all observed before and afteracupuncture treatment.

High Sugar-Fat Diet Induces Metabolic-Inflammatory Disorders Independent of Obesity Development

Background: The modern dietary habit, which is rich in refined carbohydrates and saturated fats, increases the risk of chronic diseases due to the proinflammatory effect of these nutrients. Aim: To evaluate the impact of high sugar-fat diet in the development of metabolic-inflammatory disorders in non-obese animals. Methods: Male Wistar rats were distributed into two groups according to the diet: control and high sugar-fat for 30 weeks. It was analyzed: dietary efficiency;chow, water and caloric intake;metabolic and hormonal profile in plasma and inflammatory cytokines in epididymal adipose tissue. Data were compared by Student’s t test or by Mann-Whitney U test with p Results: HSF presented lower chow intake, higher water consumption and dietary efficiency with no difference in the caloric intake. The final body weight (FBW) and weight gain (WG) were lower in the HSF group and there was no difference in the adiposity index (AI). HSF diet-induced hyperglycemia and hyperinsulinemia with no difference for Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). Triglycerides, uric acid, adiponectin and leptin levels were higher in the HSF group. The HSF group showed increased interleukin-6 (IL-6) and tumoral necrosis factor-alpha (TNF-α) levels in epidydimal adipose tissue. The urinary protein-creatinine ratio and albuminuria were higher in the HSF group. Conclusion: HSF diet intake is directly involved in the development of metabolic-inflammatory disorders independent of obesity, dissociating the view that increased adiposity is the major risk factor for complications commonly found in obese individuals.

Auxin response factor 6A regulates photosynthesis,sugar accumulation,and fruit development in tomato

Auxin response factors(ARFs)are involved in auxin-mediated transcriptional regulation in plants.In this study,we performed functional characterization of SlARF6A in tomato.SlARF6A is located in the nucleus and exhibits transcriptional activator activity.Overexpression of SlARF6A increased chlorophyll contents in the fruits and leaves of tomato plants,whereas downregulation of SlARF6A decreased chlorophyll contents compared with those of wild-type(WT)plants.Analysis of chloroplasts using transmission electron microscopy indicated increased sizes of chloroplasts in SlARF6A-overexpressing plants and decreased numbers of chloroplasts in SlARF6A-downregulated plants.Overexpression of SlARF6A increased the photosynthesis rate and accumulation of starch and soluble sugars,whereas knockdown of SlARF6A resulted in opposite phenotypes in tomato leaves and fruits.RNA-sequence analysis showed that regulation of SlARF6A expression altered the expression of genes involved in chlorophyll metabolism,photosynthesis and sugar metabolism.SlARF6A directly bound to the promoters of SlGLK1,CAB,and RbcS genes and positively regulated the expression of these genes.Overexpression of SlARF6A also inhibited fruit ripening and ethylene production,whereas downregulation of SlARF6A increased fruit ripening and ethylene production.SlARF6A directly bound to the SAMS1 promoter and negatively regulated SAMS1 expression.Taken together,these results expand our understanding of ARFs with regard to photosynthesis,sugar accumulation and fruit development and provide a potential target for genetic engineering to improve fruit nutrition in horticulture crops.

Change in ^(14)C-soluble Sugar Involved in the Photosynthate Translocation Pathway of Tomato

Liaoyuanduoli tomato was planted in pots in a solar greenhouse. The first leaf below the second cluster was labeled by ^14CO2 with a dose of 0.555 MBq 30 days after the second cluster anthesis. Mesophyll, midrib, petiole vascular of the fed leaf, internode vascular below the fed leaf （adjacent to the fed leaf）, peduncle vascular of the second cluster, sepal, fruit pedicle, pulp, pectinic, and dissepiment were taken 2, 4, 8, 12, 20, 24, 48, and 72 h, respectively, after ^14CO2 feed to determinate the composition and specific activity of carbohydrate at different sites and different time after the labeling. The results indicated that almost all of the photosynthates resulting from 1 h of photosynthesis could be transported out of the leaf within 72 h and more than 85% of them were exported within 24 h. The greatest amount of sucrose transport occurred in the internode pedicel vascular bundle 8 h after the start of photosynthesis. Assimilates entering the fruit through the internode and pedicel vascular bundles were detectable but in small quantities 2 h after photosynthesis. Only the radio activity of sucrose but not that of glucose and fructose was detected, suggesting that some of the sucrose in the fruit came directly through the phloem at an early stage of fruit development, not through the synthesis of glucose and fructose. Fruit vascular may be the part where sucrose first metabolized after it entered the fruit.

Characterization of full-length transcriptome and mechanisms ofsugar accumulation in Annona squamosa fruit

Annona squamosa is a multipurpose fruit tree employed in nutritional,medicinal,and industrial fields.Its fruit is significantly enriched in sugars,making it an excellent species to study sugar accumulation in fruit.However,the scarcity of genomic resources hinders genetic studies in this species.This study aimed at generating large-scale genomic resources in A.squamosa and deciphering the molecular basis of its high sugar content.Herein,we sequenced and characterized the full-length transcriptome of A.squamosa fruit using PacBio Iso-seq.In addition,we analyzed the changes in sugar content over five fruit growth and ripening stages,and we applied RNA-sequencing technology to investigate the changes in gene expression related to sugar accumulation.A total of 783,647 circular consensus sequences were generated,from which we obtained 48,209 high-quality,full-length transcripts.Additionally,1,838 transcription factors and 1,768 long non-coding RNAs were detected.Furthermore,we identified 10,400 alternative splicing events from 2,541 unigenes having on average 2–4 isoforms.A total of 15,061 simple sequence repeat(SSR)motifs were discovered and up to three primer pairs were designed for each SSR locus.Sugars mainly accumulate during the ripening stage in A.squamosa.Most of the genes involved in sugar transport and metabolism in the fruit were progressively repressed overgrowth and ripening stages.However,sucrose phosphate synthase involved in sucrose synthesis and more importantly,isoamylase,alpha-amylase,beta-amylase,4-alphaglucanotransferase genes involved in starch degradation displayed positive correlations with sugar accumulation in fruit.Overall,we provide here a high-quality,full-length transcriptome assembly which will facilitate gene discovery and molecular breeding of A.squamosa.We found that starch degradation during fruit ripening was the main channel for sugar accumulation in A.squamosa fruit,and the key genes positively linked to sugar accumulation could be further studied to identify targets for controlling sugar content in A.squamosa fruit.

个性化营养干预联合快速康复对妊娠期糖尿病孕妇剖宫产术后恢复、并发症和糖代谢的影响

目的:探讨个性化营养干预联合快速康复(FTS)对妊娠期糖尿病(GDM)孕妇剖宫产术后恢复、并发症和糖代谢的影响。方法:根据护理方式不同将120例GDM剖宫产孕妇分为A组、B组、C组,每组各40例。A组给予饮食教育和常规护理;B组给予饮食教育及FTS护理;C组给予个性化营养干预及FTS护理,各组均从入院干预至出院。比较各组术后恢复指标(泌乳始动时间、首次排气时间、首次下床时间、血性恶露持续时间、术后住院时间及切口愈合情况)及糖代谢指标[入组时、术后1 d及术后3 d空腹血糖(FBG)、餐后2 h血糖(2hPG),产后42 d的75 g糖耐量试验(OGTT)],记录各组术后并发症发生情况及出院时护理满意度。结果:各组泌乳始动时间、首次排气时间、首次下床时间、血性恶露持续时间、术后住院时间比较:C组<B组<A组(P<0.05)。术后1 d及术后3d,各组FBG及2hPG比较:C组<B组<A组(P<0.05)。产后42d,各组 0GTT比较:C组<B组<A组(P<0.05)。C 组总并发症发生率低于A组(P<0.05),A组与B组、B组与 C组比较差异均无统计学意义(P>0.05)。C组护理满意度高于A组和B组(97.50%vs.80.00%;97.50%vs.87.50%,P<0.05)。结论:个性化营养干预联合FTS能缩短GDM剖宫产术恢复时间,利于患者产后血糖稳定,值得临床推广。

阳光玫瑰葡萄冬果品质及糖代谢响应光质机理

【目的】探索光质条件改变对阳光玫瑰葡萄冬果品质及糖类物质代谢变化的影响,为提高葡萄冬季果实品质提供参考依据。【方法】在冬果发育阶段对阳光玫瑰葡萄植株进行LED灯照射补光处理,分别为红光、蓝光和白光,以不补光处理为对照;分别在硬果期(E-L33)、果实膨大期(E-L35)、果实未完全成熟期(E-L37)和果实完全成熟期(E-L38)各采样1次,对果实样品的纵径、单粒重,可溶性固形物、可滴定酸、果糖、葡萄糖和蔗糖含量,蔗糖合成酶(SS)、蔗糖磷酸合成酶(SPS)和中性转化酶(NI)活性及其基因相对表达量进行测定。【结果】白光对果粒纵径的伸长影响较大,在E-L38时期较对照显著提高4.94%(P<0.05,下同)。红光处理促进果实可溶性固形物含量增加,在E-L38时期较对照显著提高11.26%。蓝光处理对果实可滴定酸含量的降低有促进作用,在E-L37时期较对照显著降低15.54%。在E-L37和E-L38时期红光处理促进果实果糖含量增加,分别较对照显著提高11.14%和22.93%。红光处理对果实葡萄糖含量积累有促进作用,在E-L38时期较对照显著提高17.51%。在E-L35和E-L37时期,红光处理的SS活性分别较对照显著提高18.50%和13.39%。在E-L38时期,红光、蓝光和白光处理均对果实SS和SPS活性有促进作用,红光处理的NI活性较对照显著降低17.71%。红光处理使VvSS和VvNI基因相对表达量在E-L35和E-L38时期分别较对照降低10.54%、20.90%和11.57%、28.50%。果实成熟期,蓝光处理的VvSPS基因相对表达量较对照显著降低22.74%。【结论】红光显著促进阳光玫瑰葡萄冬果的可溶性固形物、果糖和葡萄糖含量的积累,蓝光有助于可滴定酸含量的降低。红光、蓝光和白光在果实成熟期对SS和SPS活性均有促进作用。可根据阳光玫瑰葡萄冬果对光照环境及果实品质的需求选择合适的人工光源进行补光。

胁迫性和非胁迫性低温贮藏番石榴果实糖代谢差异分析

为探究胁迫低温与非胁迫低温对采后番石榴果实糖代谢、糖积累的响应特征和规律,比较分析了‘红香'番石榴果实在4℃(冷害胁迫)和10℃(非冷害胁迫)贮藏过程中可溶性总糖、还原糖、蔗糖、果糖和葡萄糖含量以及蔗糖合成酶(SS)、蔗糖磷酸合成酶(SPS)、酸性转化酶(S-AI)和中性转化酶(NI)活性的变化。结果表明,与10℃相比,4℃同时抑制了贮藏期间番石榴果实S-AI和NI活性的升高、贮藏后期SS(SS-Ⅰ和SS-Ⅱ)活性的升高以及SPS活性的降低,从而显著降低胁迫性低温贮藏下番石榴果实可溶性总糖、贮藏中期果糖与葡萄糖含量,提高贮藏中前期蔗糖以及贮藏后期果糖与葡萄糖的含量。以上结果说明胁迫低温使番石榴糖代谢失衡,糖含量降低,易发生冷害,而非胁迫低温下番石榴果实可进行正常的糖代谢,各糖组分含量充足,保障果实的正常成熟和衰老。

枇杷叶提取物对高糖饮食诱导的黑腹果蝇代谢紊乱的缓解作用

为了探究枇杷叶提取物对高糖饮食诱导的代谢紊乱的缓解作用,以黑腹果蝇为研究对象,设置基础培养基、高糖培养基和分别添加1%、5%、10%枇杷叶提取物的含药培养基对黑腹果蝇进行培养,对各组黑腹果蝇的寿命、运动能力、生长发育指标、抗氧化能力、肠道完整性、肠道微生物多样性进行检测。结果表明,高糖饮食能造成黑腹果蝇代谢紊乱,在饮食中添加10%的枇杷叶提取物能通过延长黑腹果蝇寿命、提高老年黑腹果蝇的运动能力、提高黑腹果蝇卵的蛹化率和羽化率来提高黑腹果蝇的生长性能;通过提高黑腹果蝇体内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性,降低脂质过氧化物丙二醛(MDA)含量来提高黑腹果蝇的抗氧化能力;通过肠道菌群16S rRNA测序和分析发现,高糖饮食能导致黑腹果蝇肠道菌群失调,在饮食中添加10%枇杷叶提取物能通过提高菌群丰度、抑制肠炎相关菌群增殖、改变菌群组成等方式缓解菌群失调。结果显示,枇杷叶提取物可在一定程度上缓解高糖饮食造成的代谢紊乱。