Genes In Synthesis Pathway Research Articles

Integrated metabolomic and transcriptomic analysis of anthocyanin metabolism in wheat pericarp

BackgroundWheat seeds display different colors due to the types and contents of anthocyanins, which is closely related to anthocyanin metabolism. In this study, a transcriptomic and metabolomic analysis between white and purple color wheat pericarp aimed to explore some key genes and metabolites involved in anthocyanin metabolism.ResultsTwo wheat cultivars, a white seed cultivar Shiluan02-1 and purple seed cultivar Hengzi151 were used to identify the variations in differentially expressed genes (DEGs) and differentially accumulated flavonoids (DAFs). Based on metabolomic data, 314 metabolites and 191 DAFs were identified. Chalcone, flavonol, pro-anthocyanidin and anthocyanidin were the most differentially accumulated flavonoid compounds in Hengzi151. 2610 up-regulated and 2668 down-regulated DEGs were identified according to transcriptomic data. The results showed that some structural genes in anthocyanin synthesis pathway were prominently activated in Hengzi151, such as PAL, CAD, CHS and so on. Transcription factors (TFs) of MYB, bHLH, WD40 and some other TFs probably involved in regulating anthocyanin biosynthesis were identified. Some genes from hormone synthetic and signaling pathways that may participate in regulating anthocyanin biosynthesis also have been identified.ConclusionsOur results provide valuable information on the candidate genes and metabolites involved in the anthocyanin metabolism in wheat pericarp.

Genetic modifications to push L-tyrosine synthesis in Escherichia coli

L-tyrosine, an aromatic amino acid, has attracted increasing attention owing to its wide application in industrial settings. Nonetheless, to obtain strains with high efficiency in producing L-tyrosine still faces challenges. In this study, a recombinant bacteria with the ability to accumulate L-tyrosine efficiently was identified after analysis of constructed strains obtained by different genetic modifications. For the first strain (TYR02), aroG fbr was up-regulated and tyrR was knocked out to relieve the repression of multiple genes in the L-tyrosine synthesis pathway by TyrR (encoded by tyrR). For the second set of strains (TYR03 and TYR04), the transcription of tyrA fbr B was enhanced by the trc and T7 promoters based on TY02 respectively. In the third set of strains (TYR05 and TYR06), the transcription of tyrA fbr B was enhanced by the trc and T7 promoters respectively, and aroG fbr was up-regulated. TYR02 exhibited relatively efficient on L-tyrosine accumulation in shake flask cultures after 24 h. Notably, up-regulation of the transcript level of tyrA fbr B did not show the predicted effects, while the manifested traits of knocking out tyrR disappeared after up-regulated expression of tyrA fbr B. After 25 h of fed-batch fermentation in a 30 L fermentor, TYR02 accumulated L-tyrosine about 50.2 g/L, representing the highest concentration in such a short fermentation time.

Transcriptomic Analysis Reveals the Opposite Regulatory Effects of WRKY and CAMTA Transcription Factors on Total Tannin Production in Quercus fabri Fruit.

Tannins are prevalent compounds found in plant fruits, contributing to the bitter taste often associated with these fruits and nuts, thereby influencing their overall taste quality. Numerous studies have been conducted to investigate the regulatory factors involved in tannin synthesis. Among these factors, transcription factors exhibit the most significant capacity to regulate tannin production as they can modulate the expression of several key enzyme genes within the tannin synthesis pathway. In this study, we focused on acorns from Quercus fabri, a species abundant in subtropical China. Utilizing transcriptome data from acorns with previously established significant differences in tannin content, we identified novel genes that are capable of regulating tannin synthesis. Specifically, we discovered one transcription factor from the WRKY family and one from the CAMTA family. Promoter response element analysis revealed that the downstream target genes regulated by these two transcription factors are highly similar, and all play crucial roles as enzyme genes in the tannin synthesis pathway. In addition, by detecting the expression levels of two transcription factor genes and target genes, we found that the two transcription factors regulate the target genes in exactly opposite ways. This study not only identifies new transcription factors involved in the regulation of tannin synthesis but also introduces a novel set of molecular biology techniques aimed at effectively modulating tannin content in plant fruits, thereby enhancing fruit quality.

The inhibition effect of high temperature stress on potato tuber skin coloring mainly occurred in the belowground part of the plant.

High temperature stress leads to a dramatic reduction of both the anthocyanin concentration and the appearance quality of colored potatoes. However, it remains uncertain if the high temperature impacts potato tuber skin coloring through only the aerial or belowground parts of the plant, or through their interaction; and it's underlying reason is still unclear. In this study, the red-skin cultivar Qingshu9 (Qs9) was exposed to the high-temperature (30°C) treatment on the belowground part alone (BH), aerial part alone (AH) and entire plant (EH), and the normal-temperature treatment on entire plant (EN) as control. The results indicated that the total anthocyanin content in tuber skin of the BH treatment was significantly lower than the EN and AH treatment, and there was no accumulation of cyanidin and pelargonidin in BH treatment, only peonidin. Compared with the EN treatment, the decrease rate of total anthocyanin content of the AH treatment was much smaller than the BH treatment, and the composition of anthocyanin did not change. Transcriptome analysis showed the downregulated DEGs of BH vs EN, BH vs AH and AH vs EN were significantly associated with the anthocyanin synthesis and metabolism pathway. High temperature inhibited anthocyanin synthesis by reducing the expression of key genes (StPAL, StF3H, StF3'H, StF3'5'H, StDFR and StANS) in the anthocyanin synthesis pathway. In summary, high temperature inhibits anthocyanin synthesis in tuber skin by downregulating key genes, and this inhibitory effect mainly occurs through the belowground part of the plant.

Highly efficient biosynthesis of 6′-sialyllactose in a metabolically engineered plasmid-free Escherichia coli using a novel α2,6-sialyltransferase from Nicoletella semolina

6′-Sialyllactose (6′-SL), one of the most prevalent sialylated human milk oligosaccharides (HMOs), has recently garnered significant attention due to its promising health effects for infants. In this study, the 6′-SL biosynthetic pathway in EZAK (E. coli BL21(DE3) ΔlacZΔnanAΔnanK) was initially constructed by introducing a plasmid expressing the precursor CMP-Neu5Ac synthesis pathway genes neuBCA. A novel α2,6-sialyltransferase Ev6ST (NCBI Reference Sequence: WP_132500470) was selected by introducing plasmids expressing various α2,6-sialyltransferase-encoding genes and subsequent comparisons of the yields of 6′-SL. Subsequently, by integrating neuBCA and ev6st individually or in combination on the chromosome of EZAK, the high-yielding plasmid-free strain EZAKBEP with an extracellular yield of 5.68 g/L. In the 5 L bioreactor, fed-batch fermentation resulted in an extracellular yield of 15.35 g/L of 6′-SL. This work successfully screened a high-efficiency α2,6-sialyltransferase Ev6ST and constructed a high-yielding strain EZAKBEP under plasmid-free conditions, which is the highest yield of shake flask fermentation to date, and provides some reference significance for subsequent research.

Multi-Omics Analysis Uncovers the Mechanism for Enhanced Organic Acid Accumulation in Peach (Prunus persica L.) Fruit from High-Altitude Areas.

The early-ripening peach industry has undergone rapid development in the Panxi region of the Sichuan Basin in recent years. However, after the introduction of some new peach varieties to the high-altitude peach-producing areas in Panxi, the titratable acid content in peach fruit has significantly increased. This study compared the fruit quality indicators of early-ripening peach varieties cultivated in Xide County (a high-altitude peach-producing area) and Longquanyi District (a low-altitude peach-producing area) in Sichuan Province and analyzed the differences in organic acid metabolism by combining primary metabolomic and transcriptomic approaches. The results showed that the 'Zhongtaohongyu' fruit from the high-altitude peach-producing area had a much higher accumulation of malic acid and, accordingly, a significantly higher organic acid content than the other samples. The lower annual average temperature and stronger ultraviolet radiation in high-altitude peach-producing areas may lead to the increased expression of genes (PpNAD-ME1, PpNADP-ME3, and PpPEPC1) in the organic acid synthesis pathway and the decreased expression of genes (PpACO2, PpNAD-MDH2/3/4/5, and PpPEPCK2) in the organic acid degradation pathway in peach fruit, ultimately resulting in the accumulation of more organic acids. Among them, the downregulation of the key genes PpNAD-MDH3/4/5 involved in malic acid metabolism may be the main reason for the higher malic acid accumulation in peach fruit from high-altitude peach-producing areas. Overall, this study elucidates the mechanism by which environmental factors enhance the accumulation of organic acids in peach fruit from high-altitude peach-producing areas from a multi-omics perspective, as well as providing a theoretical basis for screening key genes involved in organic acid metabolism in peach fruit.

Carbon starvation drives biosynthesis of high mannose-composition polysaccharides in Ganoderma lucidum

Polysaccharides with high mannose composition exhibit favorable antitumor activity, but there is currently a lack of well-defined and practical approaches to efficiently manufacture this type of polysaccharide. This study explores the impact of carbon utilization on exopolysaccharide (EPS) production and monosaccharide composition in Ganoderma lucidum, aiming to promote the biosynthesis of polysaccharides with high mannose composition. Sucrose supply significantly increased the mannose proportion to 35.52 % in EPS via carbon starvation. To enhance polysaccharide production with high mannose composition, a joint control by carbon starvation and glucose feeding strategy was developed, achieving 0.42 g/L EPS and 18.67 % mannose with 5 g/L glucose supplementation on day 6 in an initial 10 g/L glucose medium. Using this approach, G. lucidum mycelia exhibited normal growth patterns similar to those in sucrose culture. Essentially, carbon starvation upregulated key genes in the GDP-mannose synthesis pathway, including phosphomannose isomerase (PMI), phosphomannose mutase (PMM), and GDP-mannose pyrophosphorylase (GMP), by over 2-fold, facilitating high mannose-composition polysaccharide synthesis in both sucrose and carbon starvation conditions. This work provides insights into the biosynthesis of structurally specific polysaccharides in G. lucidum and offers a foundation for developing polysaccharides with diverse applications in food, medicine, and other fields.

NAT10-mediated mRNA N4-acetylcytidine reprograms serine metabolism to drive leukaemogenesis and stemness in acute myeloid leukaemia

RNA modification has emerged as an important epigenetic mechanism that controls abnormal metabolism and growth in acute myeloid leukaemia (AML). However, the roles of RNA N4-acetylcytidine (ac4C) modification in AML remain elusive. Here, we report that ac4C and its catalytic enzyme NAT10 drive leukaemogenesis and sustain self-renewal of leukaemic stem cells/leukaemia-initiating cells through reprogramming serine metabolism. Mechanistically, NAT10 facilitates exogenous serine uptake and de novo biosynthesis through ac4C-mediated translation enhancement of the serine transporter SLC1A4 and the transcription regulators HOXA9 and MENIN that activate transcription of serine synthesis pathway genes. We further characterize fludarabine as an inhibitor of NAT10 and demonstrate that pharmacological inhibition of NAT10 targets serine metabolic vulnerability, triggering substantial anti-leukaemia effects both in vitro and in vivo. Collectively, our study demonstrates the functional importance of ac4C and NAT10 in metabolism control and leukaemogenesis, providing insights into the potential of targeting NAT10 for AML therapy.

PhAN2 regulated Ph3GT silencing changes the flower color and anthocyanin content in petunias.

Anthocyanins are important secondary metabolites in plants. After the formation of anthocyanidins, Flavonoid 3-O-glucosyltransferase (3GT) mediated glycosylation first occurs at the C-3 site, forming a stable anthocyanin 3-O-glucoside. Several studies have investigated the function of 3GT using biochemical methods. However, it is necessary to provide further genetic evidence for the role of Ph3GT in petunia (Petunia hybrida). In addition, there is no information regarding the subcellular localization of Ph3GT and the regulation of transcription factors on Ph3GT. In this study, the full-length Ph3GT gene from petunia (Petunia hybrida) was isolated. We found that Ph3GT is localized in the cytoplasm. Ph3GT exhibited high expression levels in the corollas during the coloring period of petunia flowers. VIGS-mediated Ph3GT silencing resulted in a lighter corolla color and a significant decrease in the anthocyanin content in six petunia cultivars. The silencing of Ph3GT affected the expression levels of eight key genes in the anthocyanin synthesis pathway. Additionally, dual luciferase and yeast one-hybrid assays showed that R2R3-MYB transcription factor PhAN2 directly regulates the transcript of Ph3GT.

'140R' Rootstock Regulates Resveratrol Content in 'Cabernet Sauvignon' Grapevine Leaves Through miRNA.

Grafting is important for increasing the resistance of grapevines to environmental stress, improving fruit quality, and shortening the reproductive period. In this study, 'Cabernet Sauvignon' (CS) grafted on the resistant rootstock 140R (CS/140R), self-grafted grapevines of the resistant rootstock 140R (140R/140R), and self-grafted grapevines of CS (CS/CS) were subjected to high-throughput sequencing; small RNA (sRNA) libraries were constructed, and miRNAs responsive to the grafting process were identified. A total of 177 known miRNAs and 267 novel miRNAs were identified. Many miRNAs responsive to the grafting process were significantly down-regulated in CS/140R leaves relative to CS/CS leaves, such as vvi-miR171c, vvi-miR171e, et al., suggesting that the expression of these miRNAs might be affected by grafting. Kyoto Encyclopedia of Genes and Genomes analysis revealed that the differentially expressed miRNAs regulated the expression of genes in the phenylpropanoid synthesis pathway. Grapevine leaves transiently overexpressing vvi-miR171c were assayed, and the expression of the target gene, VvMYB154, and the resveratrol content were decreased, indicating that vvi-miR171c negatively regulates the expression of VvMYB154. In sum, 140R increased the resveratrol content of the scion by grafting, down-regulating the expression of vvi-miR171c. These results provide new information that will aid future analyses of the effects of grafting on the content of secondary metabolites.

A neurotransmitter atlas of C. elegans males and hermaphrodites

Mapping neurotransmitter identities to neurons is key to understanding information flow in a nervous system. It also provides valuable entry points for studying the development and plasticity of neuronal identity features. In the Caenorhabditis elegans nervous system, neurotransmitter identities have been largely assigned by expression pattern analysis of neurotransmitter pathway genes that encode neurotransmitter biosynthetic enzymes or transporters. However, many of these assignments have relied on multicopy reporter transgenes that may lack relevant cis-regulatory information and therefore may not provide an accurate picture of neurotransmitter usage. We analyzed the expression patterns of 16 CRISPR/Cas9-engineered knock-in reporter strains for all main types of neurotransmitters in C. elegans (glutamate, acetylcholine, GABA, serotonin, dopamine, tyramine, and octopamine) in both the hermaphrodite and the male. Our analysis reveals novel sites of expression of these neurotransmitter systems within both neurons and glia, as well as non-neural cells, most notably in gonadal cells. The resulting expression atlas defines neurons that may be exclusively neuropeptidergic, substantially expands the repertoire of neurons capable of co-transmitting multiple neurotransmitters, and identifies novel sites of monoaminergic neurotransmitter uptake. Furthermore, we also observed unusual co-expression patterns of monoaminergic synthesis pathway genes, suggesting the existence of novel monoaminergic transmitters. Our analysis results in what constitutes the most extensive whole-animal-wide map of neurotransmitter usage to date, paving the way for a better understanding of neuronal communication and neuronal identity specification in C. elegans.

A neurotransmitter atlas of C. elegans males and hermaphrodites.

Mapping neurotransmitter identities to neurons is key to understanding information flow in a nervous system. It also provides valuable entry points for studying the development and plasticity of neuronal identity features. In the Caenorhabditis elegans nervous system, neurotransmitter identities have been largely assigned by expression pattern analysis of neurotransmitter pathway genes that encode neurotransmitter biosynthetic enzymes or transporters. However, many of these assignments have relied on multicopy reporter transgenes that may lack relevant cis-regulatory information and therefore may not provide an accurate picture of neurotransmitter usage. We analyzed the expression patterns of 16 CRISPR/Cas9-engineered knock-in reporter strains for all main types of neurotransmitters in C. elegans (glutamate, acetylcholine, GABA, serotonin, dopamine, tyramine, and octopamine) in both the hermaphrodite and the male. Our analysis reveals novel sites of expression of these neurotransmitter systems within both neurons and glia, as well as non-neural cells, most notably in gonadal cells. The resulting expression atlas defines neurons that may be exclusively neuropeptidergic, substantially expands the repertoire of neurons capable of co-transmitting multiple neurotransmitters, and identifies novel sites of monoaminergic neurotransmitter uptake. Furthermore, we also observed unusual co-expression patterns of monoaminergic synthesis pathway genes, suggesting the existence of novel monoaminergic transmitters. Our analysis results in what constitutes the most extensive whole-animal-wide map of neurotransmitter usage to date, paving the way for a better understanding of neuronal communication and neuronal identity specification in C. elegans.

Characterization of CYP303A1 and its potential application based on ZIF-8 nanoparticle-wrapped dsRNA in Nilaparvata lugens (Stål).

RNA interference (RNAi) technology has been put forward as a promising method for pest control and resistance management. Mining highly efficient lethal genes and constructing stable double-stranded RNA (dsRNA) delivery systems are of great significance to improve the application potential of RNAi technology. In this study, we characterized a molting-related gene, NlCYP303A1, in Nilaparvata lugens that was highly expressed in the cuticle and at the end stages of each instar in nymphs. Silencing the expression of NlCYP303A1 in N. lugens resulted in a deformed phenotype and a significant increase in mortality. Furthermore, interfering with NlCYP303A1 changed the relative expression of key genes in the chitin synthesis and degradation pathway. Finally, we used the nanocarrier zeolitic imidazolate framework-8 (ZIF-8) to load dsNlCYP303A1, forming a complex denoted as dsNlCYP303A1@ZIF-8. The results of both feeding and rice-seedling dip experiments indicated that the expression of NlCYP303A1 was dramatically and persistently suppressed by the dsNlCYP303A1@ZIF-8 treatment, compared with treatment with dsNlCYP303A1, suggesting that ZIF-8 can enhance the interference efficiency as well as the stability of dsNlCYP303A1. Our results demonstrate that the lethal gene NlCYP303A1 can be employed as an excellent target for RNAi technology by loading onto a nano-delivery system, and provide new insights into the creation of innovative pest control approaches. © 2024 Society of Chemical Industry.

Transcriptome-based analysis of key functional genes in the triterpenoid saponin synthesis pathway of Platycodon grandiflorum

BackgroundPlatycodon grandiflorum (P. grandiflorum) is a commonly used medicinal plant in China. Transcriptome sequencing studies of different tissues of P. grandiflorum have been widely conducted. However, studies on transcriptome sequencing and expression patterns of key genes in the saponin synthesis pathway of Tongcheng P. grandiflorum, a high-quality medicinal resource of different years, are relatively limited.ResultsThis study involved transcriptome sequencing and bioinformatics analysis of the roots from annual, biennial, and triennial P. grandiflorum in the Tongcheng area. After data filtering and assembly, we obtained 111.44 Gb of clean base data, including 742,880616 clean reads. We identified 5,156 differential expression unigenes between at least two sample groups, with differences noted among annual, biennial, and triennial P. grandiflorum plants. GO enrichment analysis annotated 3509, 1819, and 1393 DEGs in comparison TC1vsTC2, TC1vsTC3, and TC2vsTC3, respectively. Furthermore, KEGG enrichment analysis identified 16 genes encoding key enzymes in the terpene skeleton biosynthesis, sesquiterpene and triterpene biosynthesis pathways, including SE, AACT, FPPS, DXR, HMGR, HMGS, and DXS. The results of qRT-PCR experiments showed that most of the genes were most highly expressed in annual P. grandiflorum.ConclusionsThe present study provided transcriptomic data from the roots of Tongcheng P. grandiflorum of different years, which provides critical bioinformatics data on the growth and development of P. grandiflorum, laying a foundation for further research on saponins and identifying key enzymes involved in this process across different growth stages.

Astaxanthin Alleviates Hepatic Lipid Metabolic Dysregulation Induced by Microcystin-LR.

Microcystin-LR (MC-LR), frequently generated by cyanobacteria, has been demonstrated to raise the likelihood of liver disease. Few previous studies have explored the potential antagonist against MC-LR. Astaxanthin (ASX) has been shown to possess various beneficial effects in regulating lipid metabolism in the liver. However, whether ASX could alleviate MC-LR-induced hepatic lipid metabolic dysregulation is as yet unclear. In this work, the important roles and mechanisms of ASX in countering MC-LR-induced liver damage and lipid metabolic dysregulation were explored for the first time. The findings revealed that ASX not only prevented weight loss but also enhanced liver health after MC-LR exposure. Moreover, ASX effectively decreased triglyceride, total cholesterol, aspartate transaminase, and alanine aminotransferase contents in mice that were elevated by MC-LR. Histological observation showed that ASX significantly alleviated lipid accumulation and inflammation induced by MC-LR. Mechanically, ASX could significantly diminish the expression of genes responsible for lipid generation (Srebp-1c, Fasn, Cd36, Scd1, Dgat1, and Pparg), which probably reduced lipid accumulation induced by MC-LR. Analogously, MC-LR increased intracellular lipid deposition in THLE-3 cells, while ASX decreased these symptoms by down-regulating the expression of key genes in the lipid synthesis pathway. Our results implied that ASX played a crucial part in lipid synthesis and effectively alleviated MC-LR-induced lipid metabolism dysregulation. ASX might be developed as a novel protectant against hepatic impairment and lipid metabolic dysregulation associated with MC-LR. This study offers new insights for further management of MC-LR-related metabolic diseases.

Anti-Müllerian hormone deficiency leads to two distinct ovarian phenotypes with different alterations of sex hormones in gynogenetic carp

Anti-Müllerian hormone (Amh) plays conserved roles in gonadal development and function in vertebrates. Previous studies have demonstrated that amh deficiency results in severe gonadal hypertrophy in teleost. Here, we report a novel phenotype of gonadal atrophy caused by amh knockout in fish. Firstly, it was found that the amh gene had three alleles and was expressed in the cytoplasm of follicle cells in gynogenetic amphiploid gibel carp (Carassius gibelio). Subsequently, we constructed a mutant line of amh and identified two distinct ovarian abnormalities in gibel carp. Most mutants exhibited hypertrophic ovaries with increased proliferation and decreased differentiation of early germ cells, which is consistent with previously reported findings. Intriguingly, a small number of mutants displayed atrophic ovaries with decreased proliferation and premature differentiation of germ cells, which represents a novel phenotype in fish species. Transcriptome analysis revealed that these two distinct ovaries of amh mutants showed different alterations in the sex hormone biosynthesis pathway, when compared with wild-type ovaries. Furthermore, diverse gonadal sex hormone levels were also detected in these two abnormal ovaries, which were consistent with the transcriptional expressions of corresponding genes in the sex hormone synthesis pathway. These findings identify a novel atrophic ovarian phenotype of amh mutants and confirm the amh function in controlling the balance between proliferation and differentiation of germ cells in fish.

Influence of exogenous 24-epibrassinolide on improving carotenoid content, antioxidant capacity and gene expression in germinated maize seeds.

Carotenoids have various physiological functions, such as immune regulation and cancer prevention. Germination could further improve the content of carotenoids in maize seeds. In this study, yellow maize seeds (Suyu 29) were soaked and germinated with different concentrations of 24-epibrassinolide. The changes of germination percentage, sprout length, bioactive components, antioxidant capacity and carotenoid content of the maize seeds were analyzed. Additionally, the relative expression of key genes in the carotenoid synthesis pathway was investigated. The results showed that the sprout length, germination percentage, soluble protein, free amino acids, proline, endogenous abscisic acid, vitamin C, total phenolics and carotenoids displayed a significant increasing trend compared with the control group (P < 0.05). The activity of superoxide dismutase and peroxidase increased by 55.1% and 58.5% versus the control group, and the antioxidant capacity of 2,2-diphenyl-1-picrylhydrazyl, 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) and ferric reducing antioxidant power was 19.8%, 13.4% and 44.1% higher than that of the control group (P < 0.05). Compared with the control group, the expression of genes was significantly up-regulated (P < 0.05). Under the treatment of 0.1 mg L-1 of 24-epibrassinolide, carotenoid content reached the highest value. The carotenoids showed a positive correspondence with antioxidant enzyme activity, antioxidant capacity and total phenolics content (P < 0.05). This study showed that 0.1 mg L-1 of exogenous 24-epibrassinolide promoted the accumulation of carotenoids and improved the antioxidant capacity and the quality of germinated maize seeds. It could provide a method for the development of germinated maize products enriched in carotenoids. © 2024 Society of Chemical Industry.

Heterologous Expression of Sunflower HaHPT and HaTMT Genes Enhances Rice-Grain Vitamin E Content.

Insufficient dietary vitamin intake can lead to severe health conditions in humans. Improving the vitamin E (VE) content of food crops such as rice through breeding is an economical and effective means to alleviate this problem. In this study, Homogentisate phytyltransferase (HPT) and γ-tocopherol methyltransferase (γ-TMT), two genes derived from sunflower (Helianthus annuus L., a high VE species), were introduced into an elite rice (Oryza sativa L.) cultivar "Ningjing 7" for biofortification. We verified the successful expression of the two genes in multiple transformation events. High-performance liquid chromatography revealed that transgenic plants expressing either HaHPT alone or HaHPT and HaTMT accumulate more VE compared with the wild type. We also revealed that the level of α-tocopherol, the form of VE with the highest biological activity, had increased to 2.33 times in transgenic HaTMT plants compared with the wild type. Transcriptome analysis revealed that the expression levels of some chlorophyll synthesis pathway genes related to VE precursor synthesis significantly increased during grain filling in transgenic rice grains. No difference in agronomic traits was observed between the transgenic plants and their wild type except for a slightly reduced plant height associated with the transgenic plants. These data demonstrate that the heterologous expression of HaHPT gene is effective in increasing the total VE content, while HaTMT plays an important role in the relative abundance of α-tocopherol in rice grains. This study demonstrates a promising strategy for breeding rice with elevated VE content via metabolic engineering.

Little alginates synthesized in EPS: Evidences from high-throughput community and metagenes

As a significant structure in activated sludge, extracellular polymeric substances (EPS) hold considerable value regarding resource recovery and applications. The present study aimed to elucidate the relationship between the microbial community and the composition and properties of EPS. A biological nutrient removal (BNR) reactor was set up in the laboratory and controlled under different solid retention times (SRT), altering microbial species within the system. Then EPS was extracted from activated and analyzed by chemical and spectroscopic methods. High-throughput sequencing and metagenomic approaches were employed to investigate bacterial community and metabolic pathways. The results showed that lower SRT with a higher abundance of the family-level Proteobacteria (27.7%-53.5%) favored EPS synthesis, while another dominant group Bacteroidetes (20.0%-32.6%) may not significantly affect EPS synthesis. Furthermore, the abundance of alginates-producing bacteria including Pseudomonas spp. and Azotobacter vinelandii was only 2.53%-6.76% and 1.98%-6.34%, respectively. The alginate synthesis pathway genes Alg8 and Alg44 were also present at very low levels (0.05‱-0.11‱, 0.01‱-0.02‱, respectively). Another important gene related to alginates operons, AlgK, was absent across all the SRT-operated reactors. These findings suggest an impossible and incomplete alginate synthesis pathway within sludge. In light of these results, it can be concluded that EPS does not necessarily contain alginate components.

Transcriptomic Analyses Reveal the Mechanism by Which Different Light Qualities and Light Duration Induce Anthocyanin Biosynthesis in ‘Kyoho’ Grapes

The light plays a key role in regulating anthocyanin biosynthesis in plants. However, the molecular basis of anthocyanin synthesis in grape skins irradiated at night with supplemental white light (W), red light (R), blue light (B), and blue light for 3 h, 6 h, 9 h, and 12 h (B3, B6, B9, and B12) is not known. In the present study, the total anthocyanin content in grape skins was significant under different light (DL) and blue-light time (DT) treatments, and the best result was obtained with B9. Analysis of RNA-seq data determined that the key genes in the anthocyanin synthesis pathway, PAL, CHS, DFR, GT, CFIP, VIT_14s0068g00920, VIT_06s0009g02860, and VIT_06s0004g08150, were significantly up-regulated under night-time supplemental light treatments, which led to the significant expression of the phenylpropanoid biosynthesis, phenylalanine metabolism, flavonoid biosynthesis, flavone and flavonol biosynthesis, and the anthocyanin biosynthesis pathway, which were significantly expressed, promoting the accumulation of anthocyanin. The B caused significant expression of PAL (VIT_08s0040g01710), CFIP (VIT_13s0067g03820, VIT_13s0067g02870) and DFR (VIT_18s0001g12800), which may be one of the reasons for the better effect of B compared to W anthocyanin enrichment in grape skins. The DT treatment resulted in significant expression of GT (VIT_11s0052g01600), Peroxidase, VIT_09s0018g01190, and VIT_11s0037g00570. In addition, many TFs such as bHLH, MYB, ERF, WRKY, C2H2, MYB-related, and NAC were found to be involved in the synthesis of anthocyanins under light regulation. These results provide new insights into plants’ nocturnal supplemental-light regulation of anthocyanin accumulation.