Sugar Metabolism Pathways Research Articles

Phosphorylation of sugar transporter TST2 by protein kinase CPK27 enhances drought tolerance in tomato.

Drought is a major environmental stress threatening plant growth and productivity. Calcium-dependent protein kinases (CPKs) are plant-specific Ca2+ sensors with multifaceted roles in signaling drought responses. Nonetheless, the mechanisms underpinning how CPKs transmit downstream drought signaling remain unresolved. Through genetic investigations, our study unveiled that knocking out CPK27 reduces drought tolerance in tomato (Solanum lycopersicum) plants and impairs abscisic acid (ABA)-orchestrated plant response to drought stress. Proteomics and phosphoproteomics revealed that CPK27-dependent drought-induced proteins were highly associated with the sugar metabolism pathway, which was further verified by reduced soluble sugar content in the cpk27 mutant under drought conditions. Using protein-protein interaction assays and phosphorylation assessments, we demonstrated that CPK27 directly interacts with and phosphorylates Tonoplast Sugar Transporter 2 (TST2), promoting intercellular soluble sugar accumulation during drought stress. Furthermore, Ca2+ and ABA enhanced CPK27-mediated interaction and phosphorylation of TST2, thus revealing a role of TST2 in tomato plant drought tolerance. These findings extend the toolbox of potential interventions for enhancing plant drought stress tolerance and provide a target to improve drought tolerance by manipulating CPK27-mediated soluble sugar accumulation for rendering drought tolerance in a changing climate.

Water saving irrigation mediates bioactive pigments metabolism and storage capacity in tomato fruit

Tomato fruit consumption is influenced by flavor and nutrient quality. In the present study, we investigate the impact of water saving irrigation (WSI) as a pre-harvest management on flavor and nutrient quality of tomato fruit. Our results demonstrate that WSI-treated tomato fruit exhibited improved sensory scores as assessed by a taste panel, accompanied by elevated levels of SlGLK2 expression, sugars, acids, and carotenoid contents compared to non-treated fruit. Notably, WSI treatment significantly enhanced the development of chloroplast and plastoglobulus in chromoplast, which served as carotenoid storage sites and upregulated the expression of carotenoid biosynthetic genes. Furthermore, integrated transcriptome and metabolome analysis revealed heightened expression of sugar and flavonoid metabolism pathways in WSI-treated tomato fruit. Remarkably, the master regulator SlMYB12 displayed a substantially increased expression due to WSI. These findings suggest that WSI is an effective and sustainable approach to enhance the pigments metabolism and storage capacity as well as the organoleptic characteristics and nutritional value of tomato fruit, offering a win-win solution for both water conservation and quality improvement in agro-food production.

Directed Evolution of Escherichia coli Nissle 1917 to Utilize Allulose as Sole Carbon Source.

Sugar substitutes are popular due to their akin taste and low calories. However, excessive use of aspartame and erythritol can have varying effects. While D-allulose is presently deemed a secure alternative to sugar, its excessive consumption is not devoid of cellular stress implications. In this study, the evolution of Escherichia coli Nissle 1917 (EcN) is directed to utilize allulose as sole carbon source through a combination of adaptive laboratory evolution (ALE) and fluorescence-activated droplet sorting (FADS) techniques. Employing whole genome sequencing (WGS) and clustered regularly interspaced short palindromic repeats interference (CRISPRi) in conjunction with compensatory expression displayed those genetic mutations in sugar and amino acid metabolic pathways, including glnP, glpF, gmpA, nagE, pgmB, ybaN, etc., increased allulose assimilation. Enzyme-substrate dynamics simulations and deep learning predict enhanced substrate specificity and catalytic efficiency in nagE A247E and pgmB G12R mutants. The findings evince that these mutations hold considerable promise in enhancing allulose uptake and facilitating its conversion into glycolysis, thus signifying the emergence of a novel metabolic pathway for allulose utilization. These revelations bear immense potential for the sustainable utilization of D-allulose in promoting health and well-being.

Comparative proteomic analysis of seed germination between allotetraploid cotton Gossypium hirsutum and Gossypium barbadense

Seed germination, a key initial event in the plant life cycle, directly affects cotton yield and quality. Gossypium barbadense and Gossypium hirsutum gradually evolved through polyploidization, resulting in different characteristics, and this interspecific variation lacks genetic and molecular explanation. This work aimed to compare the proteomes between G. barbadense and G. hirsutum during seed germination. Here, we identified 2740 proteins for G. barbadense and 3758 for G. hirsutum. In the initial state, proteins in two cotton involved similar bioprocess, such as sugar metabolism, DNA repairing, and ABA signaling pathway. However, in the post-germination stage, G. hirsutum expressed more protein related to redox homeostasis, peroxidase activity, and pathogen interactions. Analyzing the different expression patterns of 915 single-copy orthogroups between the two kinds of cotton indicated that most of the differentially expressed proteins in G. barbadense were related to carbon metabolism. In contrast, most proteins in G. hirsutum were associated with stress response. Besides that, by proteogenomic analysis, we found 349 putative non-canonical peptides, which may be involved in plant development. These results will help to understand the different characteristics of these two kinds of cotton, such as fiber quality, yield, and adaptability. Significance statementCotton is the predominant natural fiber crop worldwide; Gossypium barbadense and Gossypium hirsutum have evolved through polyploidization to produce differing traits. However, given their specific features, the divergence of mechanisms underlying seed germination between G. hirsutum and G. barbadense has not been discussed. Here, we explore what protein contributes to interspecific differences between G. barbadense and G. hirsutum during the seed germination period. This study helps to elucidate the evolution and domestication history of cotton polyploids and may allow breeders to understand their domestication history better and improve fiber quality and adaptability.

Integrative Analyses of Transcriptomics and Metabolomics in Immune Response of Leguminivora glycinivorella Mats to Beauveria bassiana Infection.

This study utilized Beauveria bassiana to infect Leguminivora glycinivorella, analyzed the effects on the transcriptome and metabolome, and further investigated the antibacterial function of L. glycinivorella. We performed transcriptome and metabolome sequencing on the L. glycinivorella infected with B. bassiana and its control groups, and performed a joint analysis of transcriptome and metabolome results. Upon screening, 4560 differentially expressed genes were obtained in the transcriptome and 71 differentially expressed metabolites were obtained in the metabolome. On this basis, further integration of the use of transcriptomics and metabonomics combined an analysis of common enrichments of pathways of which there were three. They were glutathione S-transferase (GSTs) genes, heat shock protein (HSP) genes, and cytochrome P450 (CYP450) genes. These three pathways regulate the transport proteins, such as ppars, and thus affect the digestion and absorption of sugars and fats, thus regulating the development of pests. The above conclusion indicates that B. bassiana can affect the sugar metabolism, lipid metabolism, and amino acid metabolism pathways of L. glycinivorella, and can consume the necessary energy, protein, and lipids of L. glycinivorella. The research on the immune response mechanism of pests against pathogens can provide an important scientific basis and target for the development of immunosuppressants. This study laid an information foundation for the application of entomogenous fungi to control soybean borer at the molecular level.

Transcriptional Analysis of Antrodin C Synthesis in Taiwanofungus camphoratus (Syn. Antrodia camphorate, Antrodia cinnamomea) to Understand Its Biosynthetic Mechanism

Antrodin C, a bioactive component of Taiwanofungus camphoratus, exhibits good immunophysiological and antitumour activities, including a broad spectrum of anticancer effects. Exogenous additives can bind to metabolites during the submerged culture of T. camphoratus and affect secondary metabolite yields. However, the lack of molecular genetic studies on T. camphoratus has hindered the study of the antrodin C biosynthetic pathway. In this study, we conducted a ribonucleic acid-sequencing-based transcriptional analysis to identify the differentially expressed genes involved in the synthesis of antrodin C by T. camphoratus, using inositol and maleic acid (MAC) as exogenous additives. The addition of inositol significantly upregulated carbohydrate and sugar metabolism pathway genes (E3.2.1.14, UGDH, and IVD). When MAC was used, amino and nucleotide sugar metabolism and starch and sucrose metabolism pathways were significantly inhibited, and the associated genes (E3.2.1.14 and E3.2.1.58) were also significantly downregulated. The biosynthesis pathway genes for ubiquinone and other terpene quinones (COQ2, ARO8, and wrbA), which may play an important role in antrodin C synthesis, were significantly downregulated. This study advances our understanding of how the additives inositol and MAC affect metabolite biosynthesis in T. camphorates. This could be beneficial in proposing potential strategies for improving antrodin C production using a genetic approach.

Exogenous GR24 Inhibits Strawberry Tillering by Affecting the Phytohormone Signaling and Sugar Metabolism Pathways

Tillering is an important part in strawberry growth, and strawberries can reproduce nutritionally through stolons to generate genetically stable offspring. However, excessive tillering during the fruit-growing stage can negatively impact fruit yield and quality. In this study, different concentrations of exogenous rac-GR24 (GR24) are used to treat the strawberry plants. It was found that GR24 effectively inhibited the sprouting of strawberry stolons, while promoting the growth of the stems and leaves. Among the treatments, the most effective concentration was found to be 5 μmol/L GR24. This treatment resulted in a decrease in the glucose content in the strawberry crowns and also caused changes in the contents of two endogenous phytohormones, gibberellic acid (GA3) and trans-zeatin riboside (tZR). Transcriptome data further suggested that exogenous GR24 may inhibit strawberry plant tillering by affecting various phytohormone signaling pathways and the sugar metabolism pathway. In 5 μmol/L GR24-treated plants, the expression level of type-B response regulator (B-ARR) was down-regulated and the expression level of CYTOKININ RESPONSE 1 (CRE1), histidine-containing phosphotransfer protein (AHP), and type-A response regulator (A-ARR) were up-regulated, suggesting the inhibition of the cytokinin (CTK) signaling pathway. The down-regulation of auxin (AUX) and auxin response factor (ARF), as well as the up-regulation of auxin/indole-3-acetic acid (AUX/IAA), led to the inhibition of the indole-3-acetic acid (IAA) signaling pathway. Additionally, the up-regulation of pyrabactin resistance 1/ pyrabactin resistance 1-like (PYR/PYL), non-fermenting 1-related protein kinase 2 (SnRK2), and ABRE binding factors (ABF) and the down-regulation of protein phosphatase 2C (PP2C) were observed in the up-regulated abscisic acid (ABA) signaling pathways. In the sugar metabolism pathway, the up-regulation of invertase (INV), hexokinase (HK), and fructokinase (FRK) and the down-regulation of trehalase (TREH) and beta-amylase (BMY) led to a decreased glucose synthesis and an increased glucose consumption. Therefore, GR24 can effectively inhibit strawberry plant tillering through these pathways, making it an effective reagent for tillering inhibition.

Loss function of NtGA3ox1 delays flowering through impairing gibberellins metabolite synthesis in Nicotiana tabacum.

Flowering time, plays a crucial role in tobacco ecological adaptation besides its substantial influence on tobacco production and leaf quality. Meanwhile, it is sensitive to biotic or abiotic challenges. The plant hormones Gibberellins (GAs), controlling a number of metabolic processes, govern plants growth and development. In this study, we created a late flowering mutant HG14 through knocking out NtGA3ox1 by CRISPR/Cas9. It took around 13.0 and 12.1 days longer to budding and flowering compared to wild type Honghuadajinyuan. Nearly all of the evaluated agronomic characters deteriorated in HG14, showing slower growth and noticeably shorter and narrower leaves. We found that NtGA3ox was more prevalent in flowers through quantitative reverse transcription PCR analysis. Transcriptome profiling detected 4449, 2147, and 4567 differently expressed genes at the budding, flowering, and mature stages, respectively. The KEGG pathway enrichment analysis identified the plant-pathogen interaction, plant hormone signal transduction pathway, and MAPK signaling pathway are the major clusters controlled by NtGA3ox1 throughout the budding and flowering stages. Together with the abovementioned signaling pathway, biosynthesis of monobactam, metabolism of carbon, pentose, starch, and sucrose were enriched at the mature stage. Interestingly, 108 up- and 73 down- regulated DEGs, impairing sugar metabolism, diterpenoid biosynthesis, linoleic and alpha-linolenic acid metabolism pathway, were continuously detected accompanied with the development of HG14. This was further evidenced by the decreasing content of GA metabolites such as GA4 and GA7, routine chemicals, alkaloids, amino acids, and organic acids Therefore, we discovered a novel tobacco flowering time gene NtGA3ox1 and resolved its regulatory network, which will be beneficial to the improvement of tobacco varieties.

The Prebiotic Activity of a Novel Polysaccharide Extracted from Huangshui by Fecal Fermentation In Vitro.

A novel polysaccharide, HSP80-2, with an average molecular weight of 13.8 kDa, was successfully isolated by the gradient ethanol precipitation (GEP) method from Huangshui (HS), the by-product of Chinese Baijiu. It was mainly composed of arabinose, xylose, and glucose with a molar ratio of 4.0:3.1:2.4, which was completely different from the previous reported HS polysaccharides (HSPs). Morphological observations indicated that HSP80-2 exhibited a smooth but uneven fragmented structure. Moreover, HSP80-2 exerted prebiotic activity evaluated by in vitro fermentation. Specifically, HSP80-2 was utilized by gut microbiota, and significantly regulated the composition and abundance of beneficial microbiota such as Phascolarctobacterium, Parabacteroides, and Bacteroides. Notably, KEGG pathway enrichment analysis illustrated that HSP80-2 enriched the pathways of amino sugar and nucleotide sugar metabolism (Ko00520), galactose metabolism (ko00052), and the citrate cycle (TCA cycle) (ko00020). Meanwhile, the contents of short-chain fatty acids (SCFAs) mainly including acetic acid, propionic acid, and butyric acid in the HSP80-2 group were remarkably increased, which was closely associated with the growth of Lachnoclostridium and Parabacteroides. These results showed that HSP80-2 might be used as a potential functional factor to promote human gut health, which further extended the high value utilization of HS.

The potentiality of Wickerhamomyces anomalus against postharvest black spot disease in cherry tomatoes and insights into the defense mechanisms involved

Our previous study revealed that Wickerhamomyces anomalus effectively inhibited Botrytis cinerea disease in cherry tomatoes. However, the potentiality of W. anomalus against black spot disease in cherry tomatoes as well as possible mechanisms related to this efficacy remain unclear. In our current study, we investigated the efficacy of W. anomalus against black spot disease in cherry tomatoes, and the molecular mechanisms related to disease-resistance response of W. anomalus treated cherry tomatoes were also investigated by transcriptome analysis. The results exhibited that W. anomalus successfully controlled postharvest black spot disease of cherry tomatoes caused by Alternaria alternata. Furthermore, W. anomalus vigorously controlled the spore germination and reduced the germ tube elongation of A. alternata. The physiological mechanisms by which W. anomalus inhibited the black spot decay in cherry tomatoes mainly through enhancing the ascorbate peroxidase (APX) and chitinase (CHI), and reducing the content of malondialdehyde (MDA). In addition, based on transcriptome technology, W. anomalus could up-regulate genes involved in several important KEGG pathways, including amino sugar and nucleotide sugar metabolism pathway, selenocompound metabolism pathway, linoleic acid metabolism pathway, and galactose metabolism pathway. These genes may help the fruit to enhance the enzyme activities and nutritional values of cherry tomatoes, synthesize the regulatory molecules in plant disease response as well as plant growth and development, increase the defense and oxidation resistance of the fruit during and after harvesting, and trigger ROS induced resistance in cherry tomatoes. Ultimately, W. anomalus has been proved as a biocontrol agent which could effectively control black spot disease in cherry tomatoes caused by A. alternata. This study can provide theoretical reference for the practical application of antagonistic yeasts in the biological control of postharvest diseases of cherry tomatoes.

Comparative Transcriptome Analysis Reveals the Underlying Response Mechanism to Salt Stress in Maize Seedling Roots.

Crop growth and development can be impeded by salt stress, leading to a significant decline in crop yield and quality. This investigation performed a comparative analysis of the physiological responses of two maize inbred lines, namely L318 (CML115) and L323 (GEMS58), under salt-stress conditions. The results elucidated that CML115 exhibited higher salt tolerance compared with GEMS58. Transcriptome analysis of the root system revealed that DEGs shared by the two inbred lines were significantly enriched in the MAPK signaling pathway-plant and plant hormone signal transduction, which wield an instrumental role in orchestrating the maize response to salt-induced stress. Furthermore, the DEGs' exclusivity to salt-tolerant genotypes was associated with sugar metabolism pathways, and these unique DEGs may account for the disparities in salt tolerance between the two genotypes. Meanwhile, we investigated the dynamic global transcriptome in the root systems of seedlings at five time points after salt treatment and compared transcriptome data from different genotypes to examine the similarities and differences in salt tolerance mechanisms of different germplasms.

Heat-responsive microRNAs participate in regulating the pollen fertility stability of CMS-D2 restorer line under high-temperature stress

Anther development and pollen fertility of cytoplasmic male sterility (CMS) conditioned by Gossypium harknessii cytoplasm (CMS-D2) restorer lines are susceptible to continuous high-temperature (HT) stress in summer, which seriously hinders the large-scale application of "three-line" hybrids in production. Here, integrated small RNA, transcriptome, degradome, and hormone profiling was performed to explore the roles of microRNAs (miRNAs) in regulating fertility stability in mature pollens of isonuclear alloplasmic near-isogenic restorer lines NH and SH under HT stress at two environments. A total of 211 known and 248 novel miRNAs were identified, of which 159 were differentially expressed miRNAs (DEMs). Additionally, 45 DEMs in 39 miRNA clusters (PmCs) were also identified, and most highly expressed miRNAs were significantly induced in SH under extreme HT, especially four MIR482 and six MIR6300 family miRNAs. PmC28 was located in the fine-mapped interval of the Rf1 gene and contained two DEMs, gra-miR482_L-2R + 2 and gma-miR2118a-3p_R + 1_1ss18TG. Transcriptome sequencing identified 6281 differentially expressed genes, of which heat shock protein (HSP)-related genes, such as HSP70, HSP22, HSP18.5-C, HSP18.2 and HSP17.3-B, presented significantly reduced expression levels in SH under HT stress. Through integrating multi-omics data, we constructed a comprehensive molecular network of miRNA–mRNA–gene-KEGG containing 35 pairs of miRNA/target genes involved in regulating the pollen development in response to HT, among which the mtr-miR167a_R + 1, tcc-miR167c and ghr-miR390a, tcc-miR396c_L-1 and ghr-MIR169b-p3_1ss6AG regulated the pollen fertility by influencing ARF8 responsible for the auxin signal transduction, ascorbate and aldarate metabolism, and the sugar and lipid metabolism and transport pathways, respectively. Further combination with hormone analysis revealed that HT-induced jasmonic acid signaling could activate the expression of downstream auxin synthesis-related genes and cause excessive auxin accumulation, followed by a cascade of auxin signal transduction, ultimately resulting in pollen abortion. The results provide a new understanding of how heat-responsive miRNAs regulate the stability of fertility restoration for CMS-D2 cotton under heat stress.

Study on the metabolic process of phthalic acid driven proliferation of Rhizoctonia solani.

Continuous cropping obstacle seriously affects the quality and yield of Salvia miltiorrhiza, and the synergistic effect of root exudates and rhizosphere pathogenic microorganisms may be an important cause of continuous cropping obstacle. This study aimed to explore the effects of representative organic acids on the growth and metabolism of specific microorganisms in the S. miltiorrhiza rhizosphere soil under continuous cropping, and clarify its mechanism. The effect of phthalic acid (PA) on the growth and metabolism of Rhizoctonia solani was evaluated by mycelial growth inhibition method. Ultra-high performance liquid chromatography and tandem mass spectrometry were used to identify the differential metabolites of R. solani induced by exogenous PA. PA exerted a concentration-dependent effect on mycelial growth, biomass, intracellular polysaccharides con-tent, and total protein content in R. solani. A total of 1773 metabolites and 1040 differential metabolites were identified in the blank medium (CK), Fungi (CK + fungi), and PA-Fungi (CK + fungi + acid) groups. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the differential metabolites were mainly involved in the sugar, lipid, and protein metabolic pathways related to stable membrane structure and cell growth. The proliferation and metabolism network of R. solani induced by PA was proposed, and the enhancement of sugar, lipid, and amino acid metabolism was presumed to be related to the active resistance of cells to organic acid stress. These results offer new in-sights into the effects of PA metabolism on promoting R. solani proliferation, and provide theoretical support for further optimizing the rhizosphere microecological environment of Salvia miltiorrhiza continuous cropping soil and reducing continuous cropping obstacle.

Dietary phytosterols supplementation improves the growth performance and decreases the abdominal fat of broiler chickens by regulating intestinal epithelial structure and microbiota

Phytosterols, plant-derived fatty compounds, were reported to be bioactive for animals and promote the growth of broilers. Whether dietary phytosterols could improve the growth performance of broilers by regulating intestinal morphology and microbiota is still unclear and limited. Thus, our experiment aimed to evaluate the effects of dietary phytosterols on the growth performance, intestinal morphology, and microbiota of broilers. A total of 200 male Arbor Acres broiler chickens (1 day old) were randomly assigned to 2 treatment groups with 5 replicates of 20 birds each, (1) basic corn-soybean diet; (2) basic corn-soybean diet supplemented with 25 mg/kg phytosterols. Dietary supplementation of phytosterols at 25 mg/kg increased the average daily gain and reduced the feed conversion rate of broilers (P < 0.05), but did not affect average daily feed intake (P > 0.05). It reduced the abdominal fat yield and serum triglyceride and low-density lipoprotein cholesterol levels in broilers (P < 0.05). Phytosterols treatment increased villus height to crypt depth ratio and up-regulated the mRNA expression of tight junction-related genes in both jejunal (i.e., ZO-2, ZO-3, and claudin-3) and ileal (i.e., claudin-1 and claudin-2) tissues (P < 0.05). Additionally, dietary phytosterols significantly down-regulated the mRNA expression of pro-inflammatory cytokine (IL-1β and IL-6) in the jejunal tissues (P < 0.05), and up-regulated that of anti-inflammatory cytokine (IL-4 and IL-10) in the ileal tissues (P < 0.05). Moreover, broilers fed with dietary phytosterols had a higher concentration of lactic acid in the caecal digesta (P < 0.05). Dietary supplementation with phytosterols decreased the alpha diversity of the bacterial community (P < 0.05) and increased the relative abundance of probiotics (i.e., Lactobacillus) in the intestinal digesta of broilers (P < 0.05). PICRUSt2 analyses revealed that phytosterols enhanced the bacterial metabolic pathways of amino sugar and nucleotide sugar metabolism and fatty acid metabolism. Dietary supplementation of phytosterols could improve the growth performance and reduce the abdominal fat yield of broilers by altering their intestinal epithelial structure, lipid metabolism and bacterial community.

Integrated Analysis of Metabolome and Transcriptome Reveals Insights for Low Phosphorus Tolerance in Wheat Seedling.

Low phosphorus (LP) stress leads to a significant reduction in wheat yield, primarily in the reduction of biomass, the number of tillers and spike grains, the delay in heading and flowering, and the inhibition of starch synthesis and grouting. However, the differences in regulatory pathway responses to low phosphorus stress among different wheat genotypes are still largely unknown. In this study, metabolome and transcriptome analyses of G28 (LP-tolerant) and L143 (LP-sensitive) wheat varieties after 72 h of normal phosphorus (CK) and LP stress were performed. A total of 181 and 163 differentially accumulated metabolites (DAMs) were detected for G28CK vs. G28LP and L143CK vs. L143LP, respectively. Notably, the expression of pilocarpine (C07474) in G28CK vs. G28LP was significantly downregulated 4.77-fold, while the expression of neochlorogenic acid (C17147) in L143CK vs. L143LP was significantly upregulated 2.34-fold. A total of 4023 differentially expressed genes (DEGs) were acquired between G28 and L143, of which 1120 DEGs were considered as the core DEGs of LP tolerance of wheat after LP treatment. The integration of metabolomics and transcriptomic data further revealed that the LP tolerance of wheat was closely related to 15 metabolites and 18 key genes in the sugar and amino acid metabolism pathway. The oxidative phosphorylation pathway was enriched to four ATPases, two cytochrome c reductase genes, and fumaric acid under LP treatment. Moreover, PHT1;1, TFs (ARFA, WRKY40, MYB4, MYB85), and IAA20 genes were related to the Pi starvation stress of wheat roots. Therefore, the differences in LP tolerance of different wheat varieties were related to energy metabolism, amino acid metabolism, phytohormones, and PHT proteins, and precisely regulated by the levels of various molecular pathways to adapt to Pi starvation stress. Taken together, this study may help to reveal the complex regulatory process of wheat adaptation to Pi starvation and provide new genetic clues for further study on improving plant Pi utilization efficiency.

Screening of Lactiplantibacillus plantarum 67 with Strong Adhesion to Caco-2 Cells and the Effects of Protective Agents on Its Adhesion Ability during Vacuum Freeze Drying.

Adhesion to the intestinal tract provides the foundation for Lactobacillus to exert its benefits. Vacuum freeze-drying (VFD) is currently one of the main processing methods for Lactobacillus products. Therefore, the effects of VFD on the adhesion and survival of Lactiplantibacillus plantarum 67 were investigated in this study. The results show that L. plantarum 67 exhibits remarkable tolerance following successive exposure to simulated saliva, gastric juice and intestinal juice, and also has a strong adhesion ability to Caco-2 cells. The adhesion and survival rates of L. plantarum 67 significantly decreased after VFD in phosphate-buffered saline (PBS), whereas they significantly increased in protective agents (PAs) (p < 0.05). Scanning electron microscope observations show that L. plantarum 67 aggregated more to Caco-2 cells in PAs than in PBS, and its shape and size were protected. Proteomics detection findings indicated that differentially expressed proteins (DEPs) related to adhesins and vitality and their pathways in L. plantarum 67 were significantly affected by VFD (p < 0.05). However, the expression of DEPs (such as cold shock protein, cell surface protein, adherence protein, chitin-binding domain and extracellular transglycosylase, membrane-bound protein) was improved by PAs. Compared with PBS, the PAs significantly adjusted the phosphotransferase system and amino sugar and nucleotide sugar metabolism pathways (p < 0.05). VFD decreased the adhesion and vitality of L. plantarum 67, while the PAs could exert protective effects by regulating proteins and pathways related to adhesion and vitality.

Transcriptomic and targeted metabolomic unravelling the molecular mechanism of sugar metabolism regulating heteroblastic changes in Pinus massoniana seedlings

Pine seedling leaf characteristics show a distinct transition from primary to secondary needles, known as heteroblastic change. However, the underlying regulatory mechanism is poorly understood. The molecular mechanism of sugar metabolism involved in regulating heteroblastic changes in Pinus massoniana seedlings was investigated via transcriptomics and targeted metabolomics. The results identified 12 kinds of sugar metabolites in the foliage. Three types of sugar accumulated at the highest levels: sucrose, glucose and fructose. Compared to seedlings with only primary needles (PN), the contents of these soluble sugars were lower in seedlings with developing secondary needle buds (SNB). RNA-seq analysis highlighted 1086 DEGs between PN and SNB seedlings, revealing significant enrichment in KEGG pathways including starch and sucrose metabolism, plant hormone signal transduction and amino sugar and nucleic acid sugar metabolism. Combined transcriptomic and metabolomic analysis revealed that HK, MDH, and ATPase could potentially enhance sugar availability by stimulating the glycolytic/TCA cycle and oxidative phosphorylation. These processes may lead to a reduced sugar content in the foliage of SNB seedlings. We also identified 72 transcription factors, among which the expression levels of MYB, WRKY, NAC and C2H2 family genes were closely related to those of DEGs in the sugar metabolism pathway. In addition, we identified alternative splicing (AS) events in one NAC gene leading to two isoforms, PmNAC5L and PmNAC5S. PmNAC5L was significantly upregulated, while PmNAC5S was significantly downregulated in SNB seedlings. Overall, our results provide new insights into how sugar metabolism is involved in regulating heteroblastic changes in pine seedlings.

Molecular mechanism of Osthole against chitin synthesis of Ustilaginoidea virens based on combined transcriptome and metabolome analyses

Rice false smut, caused by the fungus Ustilaginoidea virens, is a destructive grain disease in rice-producing areas worldwide. To reveal the action mechanism of osthole against U. virens, the mycelial morphology, differential genes and metabolites of osthole-treated U. virens were determined using electron microscopy and multi-omics, respectively. The hyphae of osthole-treated U. virens were severely wrinkled and distorted with rough cell walls, uneven thickness, and protoplast aggregation. Calcium fluorescent white staining showed that osthole affected chitin synthesis in U. virens. The differential genes and metabolites in U. virens were significantly enriched in amino sugar and nucleotide sugar metabolism pathway. The expression of the acetylglucosamine phosphate mutase (AGM) gene (UvAGM1) and UDP-N-acetylglucosamine was significantly down regulated. The AGM of osthole-treated U. virens was 133.43 ng/mL, which was significantly lower than that of the control group (205.67 ng/mL). Osthole combined with the amino acid residue THR334 of AGM via hydrogen bonding. These results indicate that UvAGM1 may be a key candidate gene of osthole against U. virens. Overall, the results provide valuable information for the application of osthole to control rice false smut.

Transcriptome Analysis Reveals Association of Photosynthesis and Phytohormone Pathways with Leaf Color in Chinese Cabbage

Chinese cabbage (Brassica rapa L. ssp. Pekinensis) in the genus Brassica of the family Brassicaceae (Cruciferae) originates from China and is one of the most consumed leafy vegetables in East Asian countries. The leaf color is tightly linked with its growth, development, and yield. By screening an EMS mutagenized population of Chinese cabbage inbred line A03, we identified a yellowgreen leaf mutant ygl. This mutant developed abnormal ultrastructure in chloroplasts. Transcriptome and Gene Ontology (GO) analyses unveiled that abiotic stress response and glucan metabolism pathways were enriched in ygl compared to A03. A Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis reveals that differentially expressed genes were mainly associated with plant hormone signal transduction, photosynthesis, and starch and sucrose metabolism. In ygl, the expression of some photosynthetic pathway genes was significantly up-regulated, while the transcription of key genes related to carbon fixation, starch syntheses, and sugar metabolism pathways, such as RBCS1A, APS1, APL3, and SUS1, was markedly down-regulated. We also found a similar reduction trend in mRNA levels of IAA19, IAA29, and ARR4 associated with auxin and cytokinin pathways. Taken together, we uncovered transcriptional profiles for some important genes that may be responsible for leaf color development, and such gene expression repertoire may be useful for further investigation into the phenotype-to-genotype link in the ygl mutant Chinese cabbage.

Combined analysis of the proteome and metabolome provides insight into microRNA-1174 function in Aedes aegypti mosquitoes

BackgroundPathogenic viruses can be transmitted by female Aedes aegypti (Ae. aegypti) mosquitoes during blood-meal acquisition from vertebrates. Silencing of mosquito- and midgut-specific microRNA (miRNA) 1174 (miR-1174) impairs blood intake and increases mortality. Determining the identity of the proteins and metabolites that respond to miR-1174 depletion will increase our understanding of the molecular mechanisms of this miRNA in controlling blood-feeding and nutrient metabolism of mosquitoes.MethodsAntisense oligonucleotides (antagomirs [Ant]) Ant-1174 and Ant-Ct were injected into female Ae. aegypti mosquitoes at 12–20 h posteclosion, and depletion of miR-1174 was confirmed by reverse transcription quantitative real-time PCR (RT-qPCR). Ant-1174-injected and control mosquitoes were collected before the blood meal at 72 h post-injection for tandem mass tag-based proteomic analysis and liquid chromatography-tandom mass spectrometry non-target metabolomic analysis to identify differentially expressed proteins and metabolites, respectively. RNA interference (RNAi) using double-stranded RNA (dsRNA) injection was applied to investigate the biological roles of these differentially expressed genes. The RNAi effect was verified by RT-qPCR and western blotting assays. Triglyceride content and ATP levels were measured using the appropriate assay kits, following the manufacturers’ instructions. Statistical analyses were conducted with GraphPad7 software using the Student’s t-test.ResultsUpon depletion of mosquito- and midgut-specific miR-1174, a total of 383 differentially expressed proteins (DEPs) were identified, among which 258 were upregulated and 125 were downregulated. Functional analysis of these DEPs using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment suggested that miR-1174 plays important regulatory roles in amino acid metabolism, nucleotide metabolism, fatty acid metabolism and sugar metabolism pathways. A total of 292 differential metabolites were identified, of which 141 were upregulated and 151 were downregulated. Integrative analysis showed that the associated differential proteins and metabolites were mainly enriched in a variety of metabolic pathways, including glycolysis, citrate cycle, oxidative phosphorylation and amino acid metabolism. Specifically, the gene of one upregulated protein in miR-1174-depleted mosquitoes, purine nucleoside phosphorylase (PNP; AAEL002269), was associated with the purine, pyrimidine and niacin-nicotinamide metabolism pathways. PNP knockdown seriously inhibited blood digestion and ovary development and increased adult mortality. Mechanically, PNP depletion led to a significant downregulation of the vitellogenin gene (Vg); in addition, some important genes in the ecdysone signaling and insulin-like peptide signaling pathways related to ovary development were affected.ConclusionsThis study demonstrates differential accumulation of proteins and metabolites in miR-1174-depleted Ae. aegypti mosquitoes using proteomic and metabolomic techniques. The results provide functional evidence for the role of the upregulated gene PNP in gut physiological activities. Our findings highlight key molecular changes in miR-1174-depleted Ae. aegypti mosquitoes and thus provide a basis and novel insights for increased understanding of the molecular mechanism involved in a lineage-specific miRNA in mosquito vectors.Graphical