Isoquinoline Alkaloid Biosynthesis Research Articles

Physiological responses and transcriptome analysis of Spirodela polyrhiza under red, blue, and white light.

Red light (RL) accelerated starch accumulation in S. polyrhiza, but higher protein content under blue light (BL) was associated with the upregulation of most DEGs enriched for specific GO terms and KEGG pathways. Red light (RL) and blue light (BL) greatly influence the growth and physiological processes of duckweed. Physiological and molecular mechanisms underlying the response of duckweed to different light qualities remain unclear. This study employed physiological and transcriptomic analyses on duckweed, Spirodela polyrhiza "5510", to elucidate its differential response mechanisms under RL, BL, and white light conditions. Changes in growth indicators, ultrastructure alterations, metabolite accumulations, and differentially expressed genes (DEGs) were measured. The results showed that BL promoted both biomass and protein accumulations, while RL promoted starch accumulation. A total of 633, 518, and 985 DEGs were found in white-vs-red, white-vs-blue, and red-vs-blue comparison groups, respectively. In Gene Ontology (GO) enrichment analysis, the DEGs in all three comparison groups were significantly enriched in two GO terms, carboxylic acid metabolic process and lyase activity. In Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, the DEGs were greatly enriched in two pathways, histidine metabolism and isoquinoline alkaloid biosynthesis. Higher protein content under BL was associated with the upregulation of most DEGs enriched with the GO terms and KEGG pathways. Furthermore, the light qualities influenced the gene expression patterns of other metabolic pathways, like carotenoid biosynthesis, and the regulation of these genes may explain the level of photosynthetic pigment content. The results revealed the physiological changes and transcriptome-level responses of duckweed to three light qualities, thereby providing bases for further research studies on the ability of duckweed as a biomass energy source.

Comprehensive Analysis of Secondary Metabolites in the Extracts from Different Lily Bulbs and Their Antioxidant Ability.

The genus Lilium contains more than 100 wild species and numerous hybrid varieties. Some species of them have been used as medicine and food since ancient times. However, the research on the active components and the medical properties of lilies has only focused on a few species. In this study, the total phenolic acid content (TPC), total flavonoid content (TFC), and antioxidant capacity of 22 representative lilies were systematically investigated. The results showed that the TPC, TFC and antioxidant activity were highly variable among different lilies, but they were significantly positively correlated. Hierarchical cluster analysis indicated that L. henryi and L. regale were arranged in one group characterized by the highest TPC, TFC and antioxidant capacity, followed by Oriental hybrids and Trumpet and Oriental hybrids. The traditional edible and medicinal lilies were clustered in low TPC, TFC and antioxidant capacity group. A total of 577 secondary metabolites, including 201 flavonoids, 153 phenolic acids, were identified in the five species with great differences in antioxidant capacity by extensive targeted metabonomics. Differentially accumulated metabolites (DAMs) analysis reviewed that the DAMs were mainly enriched in secondary metabolic pathways such as isoflavonoid, folate, flavonoid, flavone, flavonol, phenylpropanoid, isoquinoline alkaloid biosynthesis, nicotinate and nicotinamide metabolism and so on. Correlation analysis identified that 64 metabolites were significantly positively correlated with antioxidant capacity (r ≥ 0.9 and p < 0.0001). These results suggested that the genus Lilium has great biodiversity in bioactive components. The data obtained greatly expand our knowledge of the bioactive constituents of Lilium spp. Additionally, it also highlights the potential application of Lilium plants as antioxidants, functional ingredients, cosmetic products and nutraceuticals.

Stress response to oxytetracycline and microplastic-polyethylene in wheat (Triticum aestivum L.) during seed germination and seedling growth stages

Much efforts have been devoted to clarify the phytotoxicity of individual contaminants in plants, such as individual antibiotic and microplastic; however, little is known about the phytotoxicity of their combined exposure. Here, we investigated the effects of individual and combined exposure of wheat (Triticum aestivum L.) (Xiaoyan 22) to oxytetracycline (OTC) and polyethylene (PE) microplastics using physiological and metabolic profilings. During the seed germination stage, OTC induced phytotoxicity, as observed through the changes of root elongation, sprout length, fresh weight and the vitality index, with significant effect at the 50 and 150 mg·L−1 levels; the effect of PE microplastics depended on the OTC level in the combined exposure groups. During seedling cultivation, catalase (CAT) and ascorbate peroxidase (APX), as antioxidant enzyme indices, were sensitive to OTC exposure stress, although OTC was not determined in leaves. Untargeted metabolomics of wheat leaves revealed OTC concentration-, metabolite class- and PE-dependent metabolic responses. Dominant metabolites included carboxylic acids, alcohols, and amines in the control group and all treatment groups. Compared to only OTC treatment, PE reprogrammed carboxylic acid and alcohol profiles in combined exposure groups with obvious separation in PLS-DA. Combined exposure induced fewer metabolites than OTC exposure alone at the 5 and 50 mg·L−1 levels. The shared metabolite numbers were higher in the OTC groups than in the PE-OTC groups. Pathway enrichment analysis showed a drift in metabolic pathways between individual and combined exposure to OTC and PE, which included glyoxylate and dicarboxylate metabolism, amino acid metabolism and isoquinoline alkaloid biosynthesis. Among metabolites, aromatic acids and amino acids were more sensitive to combined exposure than individual exposure. These results contribute to clarifying the underlying mechanisms of phytotoxicity of individual and combined exposure to OTC and PE.

Metabolomics analysis of grains of wheat infected and noninfected with Tilletia controversa K\xfchn

Dwarf bunt caused by the pathogen Tilletia controversa Kühn is one of the most serious quarantine diseases of winter wheat. Metabolomics studies provide detailed information about the biochemical changes at the cell and tissue levels of plants. In the present study, a liquid chromatography/mass spectrometry (LC/MS) metabolomics approach was used to investigate the changes in the grain metabolomics of infected and noninfected with T. controversa samples. PCA suggested that T. controversa-infected and noninfected samples were separated during the interaction. LC/MS analysis showed that 62 different metabolites were recorded in the grains, among which a total of 34 metabolites were upregulated and 28 metabolites were downregulated. Prostaglandins (PGs) and 9-hydroxyoctadecadienoic acids (9-HODEs) are fungal toxin-related substances, and their expression significantly increased in T. controversa-infected grains. Additionally, the concentrations of cucurbic acid and octadecatrienoic acid changed significantly after pathogen infection, which play a large role in plant defense. The eight different metabolic pathways activated during T. controversa and wheat plant interactions included phenylalanine metabolism, isoquinoline alkaloid biosynthesis, starch and sucrose metabolism, tyrosine metabolism, sphingolipid metabolism, arginine and proline metabolism, alanine, aspartate, and glutamate metabolism, and tryptophan metabolism. In conclusion, we found differences in the metabolic profiles of wheat grains after T. controversa infection. To our knowledge, this is the first study to evaluate the metabolites in wheat grains after T. controversa infection.

Root Endophytes and Ginkgo biloba Are Likely to Share and Compensate Secondary Metabolic Processes, and Potentially Exchange Genetic Information by LTR-RTs.

Ginkgo biloba is a pharmaceutical resource for terpenes and flavonoids. However, few insights discussed endophytes’ role in Ginkgo, and whether genetic exchange happens between Ginkgo and endophytes remains unclear. Herein, functional gene profiles and repetitive sequences were analyzed to focus on these issues. A total of 25 endophyte strains were isolated from the Ginkgo root and distributed in 16 genera of 6 phyla. Significant morphological diversities lead to the diversity in the COG functional classification. KEGG mapping revealed that endophytic bacteria and fungi potentially synthesize chalcone, while endophytic fungi might also promote flavonoid derivatization. Both bacteria and fungi may facilitate the lignin synthesis. Aspergillus sp. Gbtc_1 exhibited the feasibility of regulating alcohols to lignans. Although Ginkgo and the endophytes have not observed the critical levopimaradiene synthase in ginkgolides synthesis, the upstream pathways of terpenoid precursors are likely intact. The MVK genes in Ginkgo may have alternative non-homologous copies or be compensated by endophytes in long-term symbiosis. Cellulomonas sp. Gbtc_1 became the only bacteria to harbor both MEP and MVA pathways. Endophytes may perform the mutual transformation of IPP and DMAPP in the root. Ginkgo and bacteria may lead to the synthesis and derivatization of the carotenoid pathway. The isoquinoline alkaloid biosynthesis seemed lost in the Ginkgo root community, but L-dopa is more probably converted into dopamine as an essential signal-transduction substance. So, endophytes may participate in the secondary metabolism of the Ginkgo in a shared or complementary manner. Moreover, a few endophytic sequences predicted as Ty3/Gypsy and Ty1/Copia superfamilies exhibited extremely high similarity to those of Ginkgo. CDSs in such endophytic LTR-RT sequences were also highly homologous to one Ginkgo CDS. Therefore, LTR-RTs may be a rare unit flowing between the Ginkgo host and endophytes to exchange genetic information. Collectively, this research effectively expanded the insight on the symbiotic relationship between the Ginkgo host and the endophytes in the root.

Transcriptome profiling of Jerusalem artichoke seedlings (Helianthus tuberosus L.) under polyethylene glycol-simulated drought stress

Drought stress is one of the most important abiotic stresses affecting crop growth and development, which leads to huge production and economics losses. Jerusalem artichoke (Helianthus tuberosus L.) is a perennial crop with high drought tolerance that can be used in ecological management. In this study, Jerusalem artichoke seedlings under polyethylene glycol (PEG) 6000-simulated drought stress were used for analysis of malonaldehyde, proline, and soluble sugar content, then the differentially expressed unigenes were identified by RNA-sequencing. A total number of 172,291 unigenes were generated from the leaves of Jerusalem artichoke and 17,612 unigenes were identified as differentially expressed unigenes. Gene Ontology enrichment showed that differential expression genes were classified in plastoglobules, photosystem II, and photosystem. Kyoto Encyclopedia of Genes and Genomes enrichment showed that differential expression genes were mainly classified in metabolic pathways; biosynthesis of secondary metabolites; photosynthesis - antenna proteins; circadian rhythm-plant; porphyrin and chlorophyll metabolism; phenylpropanoid biosynthesis; ABC transporters; flavonoid biosynthesis; carotenoid biosynthesis; stilbenoid, diarylheptanoid, and gingerol biosynthesis; cutin, suberin, and wax biosynthesis; and isoquinoline alkaloid biosynthesis. A transcription factor analysis showed that NAC, MYB, WRKY, homeobox-leucine zipper (HD-ZIP) and basic leucine-zipper (bZIP) were considered to be closely related to the response to PEG-simulated drought stress. These findings suggest that transcription factors may respond to drought stress by regulating structural genes expression level in metabolic pathways and then regulating the accumulation of related metabolites. Results obtained in this study will be helpful for cloning and analysis of drought-resistant genes of Jerusalem artichoke in the future, and also lay the foundation for the explanation of the drought resistance mechanism of Jerusalem artichoke and are helpful for the identification of drought tolerant Jerusalem artichoke varieties.

The color difference of rubus fruits is closely related to the composition of flavonoids including anthocyanins

Blackberry and raspberry flavonoid compounds, including anthocyanins, are known for their nutritional and health benefits. Five representative Rubus fruits (blackberry, red raspberry, yellow raspberry, black raspberry, Rubus hybrid ‘Young’ fruit) were examined. The yellow raspberry ‘Colde Summit’ had the brightest color. The Rubus hybrid ‘Young’ had the highest brix and ‘Colde Summit’ the lowest solidity-acid ratio. In total, 2118 and 1089 known metabolites were identified from five representative Rubus fruits by LC-MS in positive and negative ion modes. Isoquinoline alkaloid biosynthesis was the most enriched pathway in the biosynthesis of other secondary metabolites, followed by flavonoid and anthocyanin biosynthesis. Fewer pathways differed between red raspberry and yellow raspberry than among other Rubus fruits. Significant differences among groups occurred in cyanidin-3-sambubioside content in the anthocyanin pathway, which may be predominantly responsible for color differences. This study provides a theoretical basis for the comprehensive utilization and quality improvement of Rubus.

Comparison of Chemical Constituents in Pseudostellariae Radix with Different Dosage Forms Based on HPLC-Q-Exactive Orbitrap/MS Combined with Multivariate Statistical Analysis.

Background Pseudostellariae Radix (PR) is an important traditional Chinese herbal medicine with vast clinical consumptions, which has two different dosage forms, PR decoction pieces and PR formula granules. However, these two forms are bound to have an impact on the accumulation of the effective components in PR, so the effectiveness of clinical use cannot be guaranteed. Objective To determine the effective composition of PR. Methods In this research, PR decoction pieces and formula granules were collected, and their composition was detected by HPLC-Q-Exactive Orbitrap/MS; multivariate statistical analysis was used to distinguish differential metabolites between PR decoction pieces and formula granules. Results A clear cut difference in the composition of the two groups was observed. 98 differential chemical constituents could be identified in the positive mode, while 52 differential chemical compositions could be identified in the negative mode. The differential chemical compositions were mainly concentrated in flavonoids, organic acids, fatty acids, and amino acids and present different change rules, mainly involved in the isoquinoline alkaloid biosynthesis metabolic pathways. Conclusions This study provides basic information to reveal the influence law of different dosage forms on the metabolite synthesis and quality formation mechanism of PR.

Integrated Analysis of the Transcriptome and Metabolome Revealed Candidate Genes Involved in GA3-Induced Dormancy Release in Leymus chinensis Seeds.

Leymus chinensis is a perennial forage grass that has good palatability, high yield and high feed value, but seed dormancy is a major problem limiting the widespread cultivation of L. chinensis. Here, we performed transcriptomic and metabolomic analysis of hulled and de-hulled seeds of L. chinensis treated with or without GA3 to investigate the changes in gene and metabolites associated with dormancy release induced by GA3. The germination test revealed that the optimum concentration of GA3 for disruption of L. chinensis seed dormancy was 577 μM. A total of 4327 and 11,919 differentially expressed genes (DEGs) and 871 and 650 differentially abundant metabolites were identified in de-hulled and hulled seeds treated with GA3, respectively, compared with seeds soaked in sterile water. Most of the DEGs were associated with starch and sucrose metabolism, protein processing in the endoplasmic reticulum, endocytosis and ribosomes. Furthermore, isoquinoline alkaloid biosynthesis, tyrosine metabolism, starch and sucrose metabolism, arginine and proline metabolism, and amino sugar and nucleotide sugar metabolism were significantly enriched pathways. Integrative analysis of the transcriptomic and metabolomic data revealed that starch and sucrose metabolism is one of the most important pathways that may play a key role in providing carbon skeletons and energy supply for the transition of L. chinensis seeds from a dormant state to germination by suppressing the expression of Cel61a, egID, cel1, tpsA, SPAC2E11.16c and TPP2, enhancing the expression of AMY1.1, AMY1.2, AMY1.6 and GLIP5, and inhibiting the synthesis of cellobiose, cellodextrin, and trehalose while promoting the hydrolysis of sucrose, starch, cellobiose, cellodextrin, and trehalose to glucose. This study identified several key genes and provided new insights into the molecular mechanism of seed dormancy release induced by GA3 in L. chinensis. These putative genes will be valuable resources for improving the seed germination rate in future breeding studies.

Comparative Metabolomic Analysis of Multi-Ovary Wheat under Heterogeneous Cytoplasm Suppression

The multi-ovary trait of wheat inbred line DUOII is controlled by a dominant gene whose expression can be suppressed by the heterogeneous cytoplasm of TeZhiI (TZI), another inbred line with the nucleus of common wheat and the cytoplasm of Aegilops. DUOII (♀) × TZI (♂) shows multi-ovary trait, while TZI (♀) × DUOII (♂) shows mono-ovary. To elucidate the molecular mechanism regulating heterogeneous cytoplasmic suppression of the multi-ovary gene, we performed an untargeted metabolomic analysis of 2–6 mm young spikes of reciprocal crosses between DUOII and TZI at the critical stage of additional pistil primordium development. We identified 198 annotated differentially expressed metabolites and analyzed them according to their biological functions. The results showed that these metabolites had obvious functional pathways mainly implicated in amino acid, carbohydrate, nicotinate and nicotinamide, and purine metabolism and isoquinoline alkaloid biosynthesis. We also found that shikimate, phosphoglycolic acid, nicotinamide, guanine, and xanthine might play essential roles in cytoplasmic suppression of multi-ovary trait. Chloroplast metabolism was also implicated in the nuclear-cytoplasmic effect of the multi-ovary gene. The findings provide solid theoretical and empirical foundations for future studies elucidating the mechanisms controlling heterogeneous cytoplasmic suppression of the nuclear multi-ovary gene in wheat.

Metabolic profiling of two medicinal Piper species

Piper sarmentosum Roxb. (PS) and Piper cathayanum M. G. Gilbert & N. H. Xia (PC) are both listed as Traditional Chinese Medicine herbs. In this study, ultra-performance liquid chromatography mass spectrometry (UPLC-MS/MS) was used to analyze secondary metabolites and metabolically profile the leaves, stems and roots in PS and PC. A total of 110 and 92 differential metabolites were shared from various organs of PS and PC, respectively. Compared to the stems and roots of PS or PC, alkaloids and phenols in leaves of PS or PC accounted for 70% and 57% of the total alkaloids and phenols, respectively. An analysis of enriched metabolic pathways demonstrated that L-tyrosine and 4-hydroxycinnamic acid in PS were directly involved in five and three metabolic pathways, which are related to the biosynthesis of isoquinoline alkaloids and phenol backbones, respectively. The L-glutamic acid and oxoglutaric acid in PC were involved in seven and two metabolic pathways, respectively. L-glutamic acid synthesizes heme, tropane, piperidine and pyridine alkaloids, and the type Ⅱ polyketide backbone. Moreover, oxoglutaric acid generated via L-glutamic acid was mainly involved in the citrate cycle and played a fundamental role in determining these important metabolic processes.

Physiological and metabolomics responses of two wheat (Triticum aestivum L.) genotypes differing in grain cadmium accumulation

To reduce cadmium (Cd) pollution of food chains, screening and breeding of low-Cd-accumulating genotypes have received increasing attention. However, the mechanisms involving Cd tolerance and accumulation are not fully understood. Here, we investigated the physiological responses and metabolomics profiling on two wheat (Triticum aestivum L.) genotypes, a low-Cd-accumulating genotype in grains (Aikang58, AK58) and a high-Cd-accumulating genotype in grains (Zhenmai10, ZM10), in hydroponic culture treated without/with Cd for 7 days. The results showed that AK58 was a Cd tolerant genotype with higher capacity of antioxidant systems in root. In addition, the concentrations of Cd bound to root cell walls were higher in AK58 than ZM10, of which pectin and hemicellulose played important roles in Cd binding. Moreover, subcellular distribution manifested that Cd sequestrated in the vacuoles was another tolerance mechanism in AK58. Simultaneously, metabolomics profiling showed that, in AK58, phenylalanine metabolism, alanine, aspartate and glutamate metabolism, isoquinoline alkaloid biosynthesis, arginine and proline metabolism, arginine biosynthesis and glyoxylate and dicarboxylate metabolism are highly related to antioxidant defense system, cell wall biosynthesis and metabolisms of phytochelatins together with other organic ligands, playing crucial roles in Cd tolerance and Cd fixation mechanisms in roots. These novel findings should be useful for molecular assisted screening and breeding of low Cd-accumulating genotypes for wheat crop.

Transcriptome analysis and differential gene expression profiling of two contrasting quinoa genotypes in response to salt stress

BackgroundSoil salinity is one of the major abiotic stress factors that affect crop growth and yield, which seriously restricts the sustainable development of agriculture. Quinoa is considered as one of the most promising crops in the future for its high nutrition value and strong adaptability to extreme weather and soil conditions. However, the molecular mechanisms underlying the adaptive response to salinity stress of quinoa remain poorly understood. To identify candidate genes related to salt tolerance, we performed reference-guided assembly and compared the gene expression in roots treated with 300 mM NaCl for 0, 0.5, 2, and 24 h of two contrasting quinoa genotypes differing in salt tolerance.ResultsThe salt-tolerant (ST) genotype displayed higher seed germination rate and plant survival rate, and stronger seedling growth potential as well than the salt-sensitive (SS) genotype under salt stress. An average of 38,510,203 high-quality clean reads were generated. Significant Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were identified to deeper understand the differential response. Transcriptome analysis indicated that salt-responsive genes in quinoa were mainly related to biosynthesis of secondary metabolites, alpha-Linolenic acid metabolism, plant hormone signal transduction, and metabolic pathways. Moreover, several pathways were significantly enriched amongst the differentially expressed genes (DEGs) in ST genotypes, such as phenylpropanoid biosynthesis, plant-pathogen interaction, isoquinoline alkaloid biosynthesis, and tyrosine metabolism. One hundred seventeen DEGs were common to various stages of both genotypes, identified as core salt-responsive genes, including some transcription factor members, like MYB, WRKY and NAC, and some plant hormone signal transduction related genes, like PYL, PP2C and TIFY10A, which play an important role in the adaptation to salt conditions of this species. The expression patterns of 21 DEGs were detected by quantitative real-time PCR (qRT-PCR) and confirmed the reliability of the RNA-Seq results.ConclusionsWe identified candidate genes involved in salt tolerance in quinoa, as well as some DEGs exclusively expressed in ST genotype. The DEGs common to both genotypes under salt stress may be the key genes for quinoa to adapt to salinity environment. These candidate genes regulate salt tolerance primarily by participating in reactive oxygen species (ROS) scavenging system, protein kinases biosynthesis, plant hormone signal transduction and other important biological processes. These findings provide theoretical basis for further understanding the regulation mechanism underlying salt tolerance network of quinoa, as well establish foundation for improving its tolerance to salinity in future breeding programs.

Antifungal potential evaluation and alleviation of salt stress in tomato seedlings by a halotolerant plant growth-promoting actinomycete Streptomyces sp. KLBMP5084

Salt stress affects plant growth and crop yield reduction, thus how to improve the salt tolerance of plants is full of challenges. Plant growth-promoting rhizobacteria (PGPR), as an environment-friendly treatment to improve salt stress tolerance of plants is widely accepted and has big potential in field application. In this study, a halotolerant actinomycete Streptomyces sp. KLBMP5084 obtained from the root of halophyte Limonium sinense was evaluated for antifungal activity in vitro and applied for the growth promoting of tomato seedlings under salt stress. Results demonstrated that the fermentation broth and the volatile organic compounds (VOCs) of strain KLBMP5084 could inhibit a variety of plant pathogenic fungi, including tomato early blight disease pathogenic fungi Alternaria solani. In particular, the KLBMP5084 inoculation significantly enhance the growth of tomato seedlings compared with the control after irrigating with 200 mM NaCl, with increased fresh weight, shoot length, and the number of fibrous roots. Further, the antioxidant enzymes activity, soluble sugar and proline contents in leaf and stem were also effectively increased, and malondialdehyde (MDA) was decreased. KLBMP5084 inoculation also increased the contents of K+ and Ca2+, reduced the Na+ accumulation in leaf. A total of 191 genes were also observed differentially expressed after KLBMP5084 treatment under salt stress in leaves by transcriptome analysis. Genes involved in the photosynthesis-antenna proteins pathway, isoquinoline alkaloid biosynthesis, zeatin biosynthesis and protein processing of endoplasmic reticulum pathway were enriched to the highest degree, indicating their significance and effects in response to salt stress in tomato seedlings. Collectively, these findings indicate that strain Streptomyces sp. KLBMP5084 has the potential as the biological fertilizer for promoting the tomato seedlings growth under salinity stress.

A comparative UPLC-Q-Orbitrap-MS untargeted metabolomics investigation of different parts of Clausena lansium (Lour.) Skeels.

In this study, the non‐targeted large‐scale plant metabolomics (UPLC‐Q‐Orbitrap‐MS) was performed for the comparison of chemical profiling of the leaves, barks, flowers, peels, pulps, and seeds of Clausena lansium (Lour.) Skeels (called “wampee”). A total of 364 metabolites were identified, and 62 potential biomarkers were selected by the multivariate statistical analysis. Hierarchical cluster analysis suggested that the selected biomarkers were significant differential metabolites among various parts of wampee. Metabolic pathway analysis showed a significant enrichment of the “Flavone and flavonol synthesis” and “Isoquinoline alkaloid biosynthesis” pathway. This study provides important information for the isolation and identification of functional components from different tissues of wampee and the metabolic biosynthesis pathway elucidation in detail.

Association of high-risk human papillomavirus infection duration and cervical lesions with vaginal microbiota composition.

BackgroundCervical cancer is reportedly caused by the synergistic effects of persistent high-risk human papillomavirus (HPV) infection. Cervical microbiota represent a unique and dynamically changing microecological system that is directly exposed to the vagina. The relationship between HPV and the composition of the cervical microbiome has long been a primary focus of research.MethodsTo determine the specific differential florae throughout the process of cervical cancer development, in the present study, 16S rRNA sequencing was combined with KEGG pathway enrichment analysis to analyse five groups of cervical scraping samples with increasing durations of HPV infection and cervical intraepithelial neoplasia pathological classification.ResultsThe findings revealed that decreasing levels of probiotics, including Shuttleworthia, Prevotella, Lactobacillus, and Sneathia, and increasing levels of pathogenic bacteria, including Dispar, Streptococcus, and Faecalibacterium prausnitzii, could be the direct result of early HPV infection. Other pathogenic bacteria, such as Bifidobacteriaceae, might represent key factors in cancer progression. Additionally, KEGG pathway enrichment analysis indicated that HPV infection directly inhibits multiple pathways, including those of sporulation, porphyrin and chlorophyll metabolism, arginine and proline metabolism, isoquinoline alkaloid biosynthesis, and ansamycin biosynthesis, which may lead to the development of early symptoms of cervical cancer. Biomarkers were predicted based on operational taxonomic unit (OTU) abundance data, and OTU851726 and OTU715913 were undoubtedly the best potential indicators of cervical cancer.ConclusionsThe findings of the present study could assist with the development of a guideline for screening new clinical drugs for cervical cancer.

Comparative Transcriptome Analysis Reveals Candidate Genes Involved in Isoquinoline Alkaloid Biosynthesis in Stephania tetrandra

The roots of Stephania tetrandra are used as a traditional Chinese medicine. Isoquinoline alkaloids are considered to be the most important and effective components in this herb, but little is known about the molecular mechanism underlying their biosynthesis. In this context, this study aimed to reveal candidate genes related to isoquinoline alkaloid biosynthesis in S.tetrandra. Determination of tetrandrine and fangchinoline in the roots and leaves of S. tetrandra by HPLC showed that the roots had much higher contents of the two isoquinoline alkaloids than the leaves. Thus, a comparative transcriptome analysis of the two tissues was performed to uncover candidate genes involved in isoquinoline alkaloid biosynthesis. A total of 71 674 unigenes was obtained and 31 994 of these were assigned putative functions based on BLAST searches against 6 annotation databases. Among the 79 isoquinoline alkaloid-related unigenes, 51 were differentially expressed, with 42 and 9 genes upregulated and downregulated, respectively, when the roots were compared with the leaves. The upregulated differentially expressed genes were consistent with isoquinoline alkaloid accumulation in roots and thus were deemed key candidate genes for isoquinoline alkaloid biosynthesis in the roots. Moreover, the expression profiles of 10 isoquinoline alkaloid-related differentially expressed genes between roots and leaves were validated by quantitative real-time polymerase chain reaction, which indicated that our transcriptome and gene expression profiles were reliable. This study not only provides a valuable genomic resource for S. tetrandra but also proposes candidate genes involved in isoquinoline alkaloid biosynthesis and transcription factors related to the regulation of isoquinoline alkaloid biosynthesis. The results lay a foundation for further studies on isoquinoline alkaloid biosynthesis in this medicinal plant.

Effect of Heat Stress on Sargassum fusiforme Leaf Metabolome

Temperature is a major environmental factor affecting the growth, development, and productivity of Sargassum fusiforme. We aimed to assess the metabolic processes and regulatory mechanisms in S. fusiforme during a 7-day high-temperature (27 °C and 32 °C) experiment. Changes in chlorophyll content and electrolyte leakage after high-temperature treatment were investigated. Metabolic changes in the leaves of S. fusiforme were analysed using gas chromatography–mass spectrometry. High temperatures suppressed chlorophyll content and increased electrolyte leakage. Further, a strong modulation of various metabolisms was observed: organic acids, amino acids, sugars or sugar alcohols, esters, and amines. These metabolisms were significantly enriched in ten pathways under the 27 °C treatment: aminoacyl-tRNA biosynthesis; glycine, serine, and threonine metabolism; alanine, aspartate, and glutamate metabolism; valine, leucine, and isoleucine biosynthesis; cyanoamino acid metabolism; cysteine and methionine metabolism; arginine and proline metabolism; tyrosine metabolism; citrate cycle (TCA cycle); and glucosinolate biosynthesis. The various metabolisms significantly enriched seven pathways under the 32 °C treatment, namely, alanine, aspartate, and glutamate metabolism; aminoacyl-tRNA biosynthesis; phenylalanine metabolism; tyrosine metabolism; arginine and proline metabolism; nitrogen metabolism; and isoquinoline alkaloid biosynthesis. These changes in metabolic pathways may contribute to the tolerance and adaptability of S. fusiforme to high-temperature stress.

Metabolic regulations in lettuce root under combined exposure to perfluorooctanoic acid and perfluorooctane sulfonate in hydroponic media

Per- and polyfluoroalkyl substances (PFASs) have been detected in many agricultural products in contaminated fields and in supply chains. Roots are the main organ in plants to uptake and bio-accumulate PFASs, but the changes of metabolic regulation in roots by PFASs are largely unexplored. Here, lettuce exposed to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) at different concentrations (500, 1000, 2000 and 5000 ng/L) was investigated via metabolomics. Many key metabolites, such as antioxidants, lipids, amino acids, fatty acids, carbohydrates, linolenic acid derivatives, purine and nucleosides, were significantly altered. Tyrosine metabolism, purine metabolism, isoquinoline alkaloid biosynthesis and terpenoid backbone biosynthesis were altered in roots by PFOA and PFOS. Tricarboxylic acid cycle was perturbed by 5000 ng/L exposure. Activation of antioxidant defense pathways, reallocation of carbon and nitrogen metabolism, regulation of energy metabolism and purine metabolism were reprogrammed in roots. Lettuce employed multiple strategies to increase tolerance to PFOA and PFOS, which includes the adjustment of membrane composition, elevation of inorganic nitrogen fixation and respiration, accumulation of sucrose and regulation of signaling molecules. The results of this study offer insights into the molecular reprogramming of plant roots in response to PFAS exposure and provide important information for the risk assessment of PFASs in environment.

Metabolic profiles of moso bamboo in response to drought stress in a field investigation

An increasing number of moso bamboo habitats are suffering severe drought events. The improvement in our understanding of the mechanisms of drought-resistance in moso bamboo benefits their genetic improvement and maintenance of forest sustainability. Here, we investigated the metabolic changes across the annual growth cycle of moso bamboo in the field under drought stress using liquid chromatography coupled to mass spectrometry (LC-MS) based on untargeted metabolomic profiling. Our results showed that the metabolic profiles induced by drought stress were relatively consistent among the three growth stages. Specifically, most responsive metabolites exhibited enhanced accumulation under drought stress, including anthocyanins, glycosides, organic acids, amino acids, and sugars and sugar alcohols. The potential metabolism pathways involved in the response to drought stress were mainly included into amino acid metabolism and sugar metabolism pathways. Five common responsive metabolic pathways were found among three growth stages, including linoleic acid metabolism, ubiquinone and other terpenoid-quinone biosynthesis, tyrosine metabolism, starch and sucrose metabolism and isoquinoline alkaloid biosynthesis. Overall, our findings provide new insights into the responsive mechanisms of the moso bamboo under drought stress in terms of metabolic profiles.