The evolutionarily conserved mitogen-activated protein kinase(MAPK)cascades relay extracellular signals into cells,triggering a variety of cellular responses.We previously revealed NtMPK4 as a positive regulator of ni...The evolutionarily conserved mitogen-activated protein kinase(MAPK)cascades relay extracellular signals into cells,triggering a variety of cellular responses.We previously revealed NtMPK4 as a positive regulator of nicotine biosynthesis;however,its upstream regulation remains unclear.Here,we characterized a MAPK cascade,comprising NtMEKK1b,NtMPKK2a,and NtMPK4,that promotes nicotine biosynthesis.This signaling module transduces external cues,including jasmonate and pathogen elicitors such as flg22,into post-translational modifications that enhance transcriptional activity and pathway gene expression.NtMPKK2a physically interacts with and phosphorylates NtMPK4 in vivo,confirming its role as an upstream kinase.RNAi-mediated silencing of NtMPKK2a significantly reduced the expression of nicotine pathway genes and decreased nicotine accumulation,whereas induced-overexpression of NtMPKK2a upregulated nicotine pathway genes and increased nicotine contents in tobacco hairy roots.Overexpression of NtMPKK2a in tobacco cells enhanced the transactivation activity of a NIC2-locus Ethylene Response Factor NtERF221 on Putrescine N-methyltransferase(NtPMT)promotor,further supporting its role in promoting nicotine biosynthesis.Furthermore,we identified NtMEKK1b,a tobacco MEKK that interacts with NtMAPKK2a in yeast cells.Knock-down of NtMEKK1b in transgenic tobacco plants attenuated the expression of nicotine pathway genes and reduced nicotine contents,whereas induced-overexpression of NtMEKK1b upregulated gene expression and nicotine accumulation.Our findings uncover a previously uncharacterized MAPK cascade module,NtMEKK1b-NtMPKK2a-NtMPK4,that regulates nicotine biosynthesis,highlighting the importance of posttranslational regulation in nicotine biosynthesis.展开更多
The yam Dioscorea alata L.is widely cultivated globally.Purple-fleshed varieties of this important crop have enhanced market value due to their high anthocyanin contents,but how anthocyanin biosynthesis in D.alata tub...The yam Dioscorea alata L.is widely cultivated globally.Purple-fleshed varieties of this important crop have enhanced market value due to their high anthocyanin contents,but how anthocyanin biosynthesis in D.alata tubers is regulated remains poorly understood.In this study,we identified and functionally validated key transcription factors that regulate anthocyanin biosynthesis based on a comparative transcriptome and metabolome analysis of three D.alata cultivars with different colored tubers(dark purple,light purple,and white).The anthocyanin glycoside cyanidin-3-O-(2′′-O-glucosyl)glucoside was abundant during early tuber development,and we determined that its accumulation is regulated in opposite manners by two R2R3-MYB transcription factors:DaMYB75 and DaMYB56.Yeast two-hybrid and bimolecular fluorescence complementation assays in Nicotiana benthamiana and co-expression assays in D.alata demonstrated that DaMYB75 promotes anthocyanin biosynthesis by specifically activating the promoter of the late anthocyanin biosynthesis gene DaANS and enhancing its expression through an interaction with DabHLH72.By contrast,DaMYB56 is a negative regulator of anthocyanin biosynthesis that binds to the DaANS promoter together with DabHLH72.Furthermore,the methylation levels of the DaMYB75 promoter were significantly lower in purple tubers than in white tubers.These findings shed light on the regulation of anthocyanin biosynthesis by MYBs and provide the basis for genetically improving anthocyanin content in D.alata.展开更多
Iris domestica,a perennial herb of the Iridaceae family,is widely recognized for its rich isoflavone content and broad therapeutic properties.To elucidate the biosynthetic pathway of these medicinally significant comp...Iris domestica,a perennial herb of the Iridaceae family,is widely recognized for its rich isoflavone content and broad therapeutic properties.To elucidate the biosynthetic pathway of these medicinally significant compounds,we constructed a haplotype-resolved genome assembly of this species.Transcriptomic and metabolomic analyses revealed tissue-specific accumulation of isoflavone,particularly in rhizomes and roots.Functional characterization identified two candidate isoflavone synthase genes,among which IdIFS was confirmed to promote the biosynthesis of key compounds tectorigenin and irisflorentin.The high-quality genome assembly presented here provides a foundational resource for further research into the evolution,secondary metabolite,and environmental adaptation of I.domestica.展开更多
Saikosaponins are the major pharmacologically active components in Bupleurum genus and exhibit significant application potential in multiple fields such as immune regulation and anti-tumor activity.To elucidate the bi...Saikosaponins are the major pharmacologically active components in Bupleurum genus and exhibit significant application potential in multiple fields such as immune regulation and anti-tumor activity.To elucidate the biosynthetic pathway of saikosaponins,we identified two cytochrome P450 monooxygenases,CYP716A41 and CYP716Y4,in Bupleurum chinense.These enzymes catalyze the C-28 oxidation and C-16 hydroxylation of oleanane-type triterpene skeletons,respectively.The catalytic efficiency of CYP716A41 from a southern B.chinense variety was significantly higher than that from a northern variety.Molecular docking and mutagenesis experiments revealed that amino acid residues at sites 9 and 35 may contribute to this difference in catalytic efficiency.Additionally,under cold stress,the expression levels of both CYP450 genes and the saikosaponin contents in the leaves of southern varieties were significantly higher compared to those in northern varieties.The variation in the catalytic efficiency of CYP716A41 and the differential expression of the two CYP450 genes under cold stress during winter are associated with the differences in saikosaponin biosynthesis in the leaves of southern and northern B.chinense varieties.This is consistent with the distinct medicinal usage practices observed between southern and northern China.展开更多
Lignin is a significant secondary metabolite produced through the phenylpropanoid pathway.As a vital component of the plant cell wall,lignin affects various fruit characteristics,including size,seed quantity,and firmn...Lignin is a significant secondary metabolite produced through the phenylpropanoid pathway.As a vital component of the plant cell wall,lignin affects various fruit characteristics,including size,seed quantity,and firmness.In this study,we conducted comprehensive identification and phylogenetic analysis of 265 Caffeic acid O-methyltransferase(COMT)genes across ten different plant species,including Vaccinium corymbosum and four other Vaccinium species.The results reveal that VcCOMT38 is a promising structural gene for the biosynthesis of lignin in blueberry.An in vitro enzymatic assay of VcCOMT38 demonstrated that it is a special enzyme in the lignin biosynthesis pathway and prefers to use caffeic acid as a substrate over 5-hydroxyferulic acid.Transient overexpression and silencing of VcCOMT38 in Vaccinium corymbosum‘Northland’fruits demonstrated that VcCOMT38 participates in lignin biosynthesis and contributes to both an increased number of immature seeds and enhanced fruit firmness.The heterologous overexpression of VcCOMT38 in Nicotiana benthamiana revealed that this gene could increase the lignin content and the syringyl/guaiacyl(S/G)ratio,which determines the maximum monomer yield during lignin depolymerization.These results highlight VcCOMT38 as a crucial gene in lignin biosynthesis and its potential for improving lignin production in industry through genetically modified woody plants.展开更多
Flavonoids are crucial secondary metabolites widely distributed in plants,playing vital roles in diverse biological processes.Although the flavonoid biosynthesis pathway has been extensively characterized,the transcri...Flavonoids are crucial secondary metabolites widely distributed in plants,playing vital roles in diverse biological processes.Although the flavonoid biosynthesis pathway has been extensively characterized,the transcriptional regulatory mechanisms remain poorly understood.In this study,we identify the miR166–ATHB14-LIKE module comprising the miR166 and its target gene ATHB14-LIKE as a key regulator of flavonoid biosynthesis in soybean(Glycine max).Knockdown of miR166 or overexpression of ATHB14-LIKE upregulated multiple flavonoid biosynthesis genes,leading to increased flavonoid accumulation.Conversely,miR166 overexpression suppressed these genes and reduced flavonoid levels.We further show that ATHB14-LIKE directly activates specific flavonoid biosynthesis genes by binding to their promoters.Additionally,ATHB14-LIKE forms homodimers and heterodimers with homologous proteins to regulate downstream flavonoid biosynthesis genes.Together,our findings demonstrate that the miR166–ATHB14-LIKE module controls soybean flavonoid content by coordinating the expression of key biosynthetic genes.展开更多
Locust plagues result in significant agricultural and ecological damage,and the current dependence on broadspectrum chemical pesticides raises serious concerns regarding environmental sustainability and public health....Locust plagues result in significant agricultural and ecological damage,and the current dependence on broadspectrum chemical pesticides raises serious concerns regarding environmental sustainability and public health.In this study,we elucidated the biosynthetic pathway of the locust aggregation pheromone 4-vinylanisole(4VA).Through analysis of the crystal structure of the 4VPMT2-4VA-SAM complex,it was determined that 4-nitrophenol acts as a substrate analogue,effectively inhibiting 4VPMT enzyme activity and thereby preventing the formation of 4VA.This study revealed key enzymatic targets and lead inhibitors for intervention,establishing a molecular foundation for pheromone-based,environmentally sustainable locust control strategies and offering a viable alternative to reduce reliance on conventional chemical pesticides.展开更多
Flavonoids,abundant in the fruits,are pivotal to their growth,development,and storage.In addition,they have significant beneficial effects on human health.Consequently,research is increasingly concentrating on the reg...Flavonoids,abundant in the fruits,are pivotal to their growth,development,and storage.In addition,they have significant beneficial effects on human health.Consequently,research is increasingly concentrating on the regulatory mechanisms governing flavonoid biosynthesis in fruits.Phytohormones are involved in the regulation of flavonoid biosynthesis.The abscisic acid,ethylene,jasmonic acid,cytokinins,and brassinosteroids promote flavonoid biosynthesis,while auxin negatively regulates flavonoid biosynthesis.Subsequently,transcription factors from the MYB,bHLH,WRKY,NAC,and bZIP families are pivotal in regulating flavonoid biosynthesis.In addition,non-coding RNAs(microRNA and lncRNA)also participate in the regulation of flavonoids biosynthesis.MicroRNAs are generally believed to negatively regulate flavonoid metabolism in fruits,while lncRNAs have the opposite effect.Furthermore,the interactions between plant hormones,transcription factors,and non-coding RNAs in fruit flavonoid biosynthesis were analyzed.Ultimately,a foundational regulatory network for fruit flavonoid biosynthesis was hereby established.展开更多
Proanthocyanidins(PAs)are a group of oligomeric flavonoids also known as condensed tannins.PAs in human diet have antioxidant and health-promoting effects.BSISTER(BS)promotes the accumulation of PAs,but its direct tar...Proanthocyanidins(PAs)are a group of oligomeric flavonoids also known as condensed tannins.PAs in human diet have antioxidant and health-promoting effects.BSISTER(BS)promotes the accumulation of PAs,but its direct target gene and regulation mechanism in PAs biosynthesis are not clear.Here,we reported VviBS1 and VviBS2 genes,which bind directly to the promoter of PA synthesis key genes VviANR(ANTHOCYANIDIN REDUCTASE)and VviLAR(LEUCOANTHOCYANIDIN REDUCTASE)and up-regulate their expression to promote the PAs biosynthesis in grapevine.VviBS1 and VviBS2 partially rescued the transparent testa phenotype of an Arabidopsis tt16 mutant.Overexpression of BS1 and BS2 in grapevine callus increased the content of PAs,as well as the expression of specific genes related to PA synthesis.VviBS1 and VviBS2 proteins bound directly to the promoter regions of the key PA synthesis genes VviANR1,VviANR2,and VviLAR1.Overexpression of VviBS1 and VviBS2 promotes VviANR1,VviANR2 and VviLAR1 expression and PAs biosynthesis.Some BS1-and BS2-interacting MADS-box proteins have an effect on PAs biosynthesis.This study provides insight into the regulatory mechanisms of PAs biosynthesis in grapevine,which could be effectively employed for metabolic engineering to increase PA content.展开更多
Lodging is a major constraint limiting oil flax production efficiency in northern China.Crop lodging susceptibility is closely related to stem lignin content,and the regulatory mechanisms by which nitrogen and potassi...Lodging is a major constraint limiting oil flax production efficiency in northern China.Crop lodging susceptibility is closely related to stem lignin content,and the regulatory mechanisms by which nitrogen and potassium fertilization interactively influence lignin biosynthesis in oil flax stems require further investigation.Therefore,this study aimed to enhance lodging resistance and increase grain yield in oil flax.We examined the interactive effects of different nitrogen (75,150,and 225 kg N ha^(–1)) and potassium (60 and 90 kg K_(2)O ha^(–1)) fertilizer rates on lignin metabolism,lodging resistance,and grain yield during the 2022 and 2023 growing seasons.Results indicated that nitrogen and potassium fertilizer levels and their interactions promoted lignin accumulation,improved lodging resistance,and increased grain yield.Compared to the control (CK),the75–150 kg N ha^(–1) combined with 60 kg K_(2)O ha^(–1) treatments significantly enhanced the activities of key lignin-synthesizing enzymes (tyrosine ammonia-lyase (TAL),phenylalanine ammonia-lyase (PAL),cinnamyl alcohol dehydrogenase (CAD),and peroxidase (POD)) and upregulated the expression of 4CL1 and F5H3 genes,leading to a 29.63–43.30%increase in lignin content,improved stem bending strength and lodging resistance index,and a 23.27–32.34%increase in grain yield.Correlation analysis revealed that nitrogen and potassium fertilizers positively regulated enzyme activities and gene expression related to lignin biosynthesis,thereby facilitating lignin accumulation and enhancing stem mechanical strength and lodging resistance.Positive correlations were observed among lignin-related enzyme activities,gene expression,lodging resistance traits,and grain yield.In summary,the application of 75–150 kg N ha^(–1) in conjunction with 60 kg K_(2)O ha^(–1)promoted lignin biosynthesis and accumulation,enhanced lodging resistance,and increased grain yield in oil flax grown in the dryland farming region of central Gansu,China.Furthermore,this treatment provides a technical basis for cultivating stress-tolerant and high-yield oil flax in arid regions.展开更多
Flower color is an essential trait in ornamental plant breeding. Lycoris longituba is a popular ornamental plant native to central eastern China. The decrease in anthocyanin accumulation causes L. longituba petal colo...Flower color is an essential trait in ornamental plant breeding. Lycoris longituba is a popular ornamental plant native to central eastern China. The decrease in anthocyanin accumulation causes L. longituba petal color fading during flower development, which considerably affects the ornamental value of L. longituba. However, mechanisms underlying anthocyanin biosynthesis inhibition during L. longituba petal development remain unclear. In this study, three LlDFR genes were confirmed to be involved in anthocyanin biosynthesis and LlDFRc exerted the strongest promoting effect on anthocyanin accumulation. According to the correlation analysis results, LlbHLH12 exhibited the strongest negative correlation with LlDFRc. Quantitative real-time PCR analysis showed that LlbHLH12 was highly expressed during the medium bud and full bloom stages of flower development. LlbHLH12 was identified as a member of subgroup XII of bHLH transcription factor family. Subcellular localization and transcriptional activation ability assay revealed that LlbHLH12 was located in the nucleus without transcriptional activation activity. Overexpression of LlbHLH12 in Nicotiana tabacum and L. longituba inhibited anthocyanin accumulation by suppressing the expression of anthocyanin biosynthetic pathway genes. Furthermore, yeast one-hybrid, dual-luciferase, and β-glucuronidase activity assays showed that LlbHLH12 directly bound to the promoters of LlPAL and LlDFRc and suppressed their expression to inhibit anthocyanin biosynthesis. Overall, our study identified a novel bHLH repressor negatively regulating anthocyanin biosynthesis and provided new insights into the molecular mechanisms underlying color fading in L. longituba petals.展开更多
Chitin is an abundant aminopolysaccharide found in insect pests and phytopathogenic microorganisms but absent in higher plants and vertebrates. It is crucial for mitigating threats posed by chitin-containing organisms...Chitin is an abundant aminopolysaccharide found in insect pests and phytopathogenic microorganisms but absent in higher plants and vertebrates. It is crucial for mitigating threats posed by chitin-containing organisms to human health, food safety, and agriculture. Therefore, targeting the chitin biosynthesisassociated bioprocess holds a promise for developing human-safe and eco-friendly antifungal agents or pesticides. Chitin biosynthesis requires chitin synthase and associated factors, which are involved in the modification, regulation, organization or turnover of chitin during its biosynthesis. A number of enzymes such as chitinases, hexosaminidases, chitin deacetylases are closely related and therefore are promising targets for designing novel agrochemicals that target at chitin biosynthesis. This review summarizes the advances in understanding chitin biology over the past decade by our research group and collaborates,specifically regarding essential proteins linked to chitin biosynthesis that can be exploited as promising pesticide targets. Examples of small bioactive molecules that against the activity of these targets are given.展开更多
Xylo-oligosaccharides(XOSs)are a category of functional oligosaccharides primarily composed of 2-7 xylose units linked byβ-1,4 glycosidic bonds.They are recognized as soluble dietary fibers with prebiotic properties....Xylo-oligosaccharides(XOSs)are a category of functional oligosaccharides primarily composed of 2-7 xylose units linked byβ-1,4 glycosidic bonds.They are recognized as soluble dietary fibers with prebiotic properties.Recently, there has been significant interest in manufacturing XOSs from xylan extracted from lignocellulosic biomass using enzyme catalysis under mild conditions. In this work, the arabinofuranosidase Abf62A gene was cloned from Aspergillus usamii genomic DNA through sequential molecular processes and expressed in Pichia pastoris X33. The xylan (100 g/L) extracted xylan in wheat straw (WS) was biologically hydrolyzed into 50.32 g/L of XOSs by xylanase Xyn11A (300 U/g substrate) and arabinofuranase Abf62A (20 U/g substrate), which indicated a notable synergistic effect compared to the 34.42 g/L XOSs produced via Xyn11A. The 50.32 g/L of XOSs products comprised xylobiose (31.71 g/L), xylotriose (15.92 g/L), xylotetraose (1.65 g/L) and xylopentaose (1.04 g/L). Notably, the combined content of xylobiose and xylotriose accounted for up to 94.7%. The XOSs purified from the enzyme hydrolysate could effectually scavenge free radicals, and the antioxidant activity was more than 90%. In summary, XOSs were biologically manufactured from wheat straw xylan through the synergistic biocatalysis via xylanase and arabinofuranosidase Abf62A in a green and sustainable way, rending one kind of prebiotic oligosaccharides with substantial positive effects on human and animal health.展开更多
Cyclocarya paliurus(Batalin)Iljinskaja,as a unique and rare monocotyledonous plant in Southern China,is a promising and economical Chinese herbal medicine and functional food.People have conducted a number of research...Cyclocarya paliurus(Batalin)Iljinskaja,as a unique and rare monocotyledonous plant in Southern China,is a promising and economical Chinese herbal medicine and functional food.People have conducted a number of research on C.paliurus because of its rich triterpenoids.However,no comprehensive review has illustrated the composition and pharmacological activity of triterpenoids from C.paliurus.This review summarizes 177 triterpenoids from different parts of C.paliurus.The structures of compounds were elucidated,and their biosynthesis was inferred.The biological activities of compounds and triterpenoid-rich extracts,including anti-diabetes,antihyperlipidemia,anti-inflammatory,anticancer or cytotoxicity,antioxidation,etc.,were discussed.C.paliurus can be an important and valuable supplement to the food market.This review provides a reference for the further research and application of C.paliurus triterpenoids in the fields of foods and pharmaceuticals.展开更多
Camptothecin,a plant-derived pentacyclic pyrroloquinoline alkaloid,and its derivatives like topotecan and irinotecan have been used as clinical anticancer agents for decades.However,the complete biosynthetic pathway o...Camptothecin,a plant-derived pentacyclic pyrroloquinoline alkaloid,and its derivatives like topotecan and irinotecan have been used as clinical anticancer agents for decades.However,the complete biosynthetic pathway of camptothecin still remains unelucidated due to the unknown complex formation processes and corresponding enzymes for the downstream biosynthetic pathway including the committed hydrolysis of glycosides.Herein,a novel glycoside hydrolase(CaGH1)responsible for the deglycosylation of biosynthetic glycoside intermediates including both quinoline-type alkaloids pumiloside(1),(3S)-deoxypumiloside(2)and indole-type alkaloid strictosamide(3)has been functionally identified.Moreover,CaGH1 exhibits the highly strict stereoselectivity towards the substrates with 3S configuration.Furthermore,a combined strategy for the discovery of the unknown biosynthetic enzyme by employing activity-guided enzyme verification,transcriptome-based gene mining,biochemical assay in vitro,and structurally characterizing the unstable enzymatic products by derivatization,is reported.These findings not only provide a better understanding of the deglycosylation in camptothecin biosynthesis,also lay the foundation for the complete elucidation of camptothecin biosynthetic pathway and biological production of camptothecin.展开更多
The surface macromolecules of probiotic bacteria play crucial roles in modulating immune responses in the host.Exopolysaccharide(EPS)from lactic acid bacteria(LAB)have been widely reported to exhibit immunomodulatory ...The surface macromolecules of probiotic bacteria play crucial roles in modulating immune responses in the host.Exopolysaccharide(EPS)from lactic acid bacteria(LAB)have been widely reported to exhibit immunomodulatory activity.In this study,the EPS biosynthesis gene cluster of Lacticaseibacillus paracasei S-NB was analyzed and a deletion mutant S-NBΔ7576(two genes S-NB_2175/wze and S-NB_2176/wzd were responsible for the chain length determination and export of EPS)was successfully constructed,resulting a 40.02%decrease in the production of EPS.The deletion of wze and wzd had little effect on the monosaccharide composition and major groups of the two EPS fractions(BEPS1 and BEPS2).Both BEPS1 and BEPS2 could inhibit the transcriptional level of tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),inducible nitric oxide synthase(i NOS)and cyclooxygenase-2(COX-2)mRNA in RAW 264.7 cells induced by lipopolysaccharide(LPS),and enhance host immune tolerance via suppressing NF-κB and MAPK signaling.Notably,the S-NBΔ7576 mutant supplied with the BEPS1/BEPS2 exhibited more significant inhibition of cytokines production and the phosphorylation of p65 and c-Jun N-terminal kinase(JNK)in LPS-stimulated cells compared with the S-NBΔ7576 mutant alone.Our study provided the immunomodulatory effect of BEPS1 and BEPS2 from L.paracasei S-NB,in which the wze and wzd genes associated with EPS biosynthesis may play an important role.展开更多
Mammalian scent glands mediate species-specific chemical communication,yet the mechanistic basis for convergent musk production remain incompletely understood.Forest musk deer and muskrat have independently evolved sp...Mammalian scent glands mediate species-specific chemical communication,yet the mechanistic basis for convergent musk production remain incompletely understood.Forest musk deer and muskrat have independently evolved specialized musk-secreting glands,representing a striking case of convergent evolution.Through an integrated multi-omics approach,this study identified cyclopentadecanone as a shared key metabolic precursor in musk from both forest musk deer and muskrat,although downstream metabolite profiles diverged between the two lineages.Single-cell RNA sequencing revealed that these specialized apocrine glands possessed unique secretory architecture and exhibited transcriptional profiles associated with periodic musk production,distinct from those in conventional apocrine glands.Convergent features were evident at the cellular level,where acinar,ductal,and basal epithelial subtypes showed parallel molecular signatures across both taxa.Notably,acinar cells in both species expressed common genes involved in fatty acid and glycerolipid metabolism(e.g.,ACSBG1,HSD17B12,HACD2,and HADHA),suggesting a conserved molecular framework for musk precursor biosynthesis.Metagenomic analysis of musk samples further revealed parallel microbial community structures dominated by Corynebacterium and enriched in lipid metabolic pathways.These findings suggest multi-level convergence in musk biosynthesis,from molecular pathways to microbial communities,providing novel insights into mammalian chemical signaling and artificial musk production.展开更多
In plants, transcription factor (TF) family LATERAL ORGAN BOUNDARIES DOMAIN (LBD) has been identified to be involved in the ripening and senescence processes of fruits. However, the function of LBD in Hylocereus undat...In plants, transcription factor (TF) family LATERAL ORGAN BOUNDARIES DOMAIN (LBD) has been identified to be involved in the ripening and senescence processes of fruits. However, the function of LBD in Hylocereus undatus (Haw.) Britton & Rose (H. undatus) has not been reported yet. Through transcriptomic analysis, virus-induced gene silencing (VIGS) technology, and RT-qPCR validation, we investigated the role of the LBD TFs in the senescence of H. undatus. Transcriptomic analysis revealed that HuLBD1 is a key transcription factor of the LBD family regulating H. undatus senescence. After silencing HuLBD1, 5075 differentially expressed genes (DEGs) were identified. GSEA results showed that these DEGs were mainly enriched in the phenylpropanoids and flavonoid biosynthesis pathway. The leading subset of genes in these two pathways included 16 DEGs, with four upregulated genes, HuCHS1-2, HuFLS1, HuCYP75B2, and HuCHS5-2 being central in the Protein-Protein Interaction (PPI) network. H. undatus phenotypic experiments confirmed that silencing HuLBD1 significantly increased the flavonoid content in the fruit peel, and RT-qPCR validation showed that the gene expression trends were consistent with the RNA-seq data. The study indicated that HuLBD1 likely delays the fruit senescence process by negatively regulating the expression of four key genes, including HuCHS1-2, thus promoting the synthesis of phenylpropanoids such as flavonoids. In conclusion, our findings suggest that the HuLBD1 TF plays an important role in the senescence of H. undatus fruit, providing a theoretical basis for postharvest senescence control.展开更多
Starch is an essential commodity for humans and other animals.Future demands require qualitative and quantitative improvement by crop and post-harvest engineering that calls for comprehensive actions requiring increas...Starch is an essential commodity for humans and other animals.Future demands require qualitative and quantitative improvement by crop and post-harvest engineering that calls for comprehensive actions requiring increased fundamental knowledge on starch biosynthesis,development of advanced breeding strategies,efficient farming,and well-adapted and up scalable extraction protocols for diverse starch products.Recent staggering progress in molecular breeding techniques,especially genome editing,have enabled generation of higher starch yield and special functional qualities required to support such advancement.However,this necessitates fundamental biochemical and mechanistic understanding of starch biosynthesis and the variegated starch crop germplasms,all of which are closely linked to the relationships between starch molecular structures and functionality of various starch types as directed by the different capabilities of starch crop genotypes.We here review starch biosynthesis and its genetic foundation with a focus on increasing nutritional and health-promoting value of starch especially through bioengineering of the high amylose trait.展开更多
In recent years,cellulose-based fluorescent polymers have received considerable attention.However,conventional modification methods face challenges such as insolubility in most solvents,fluorescence instability,and en...In recent years,cellulose-based fluorescent polymers have received considerable attention.However,conventional modification methods face challenges such as insolubility in most solvents,fluorescence instability,and environmental risks.In this study,a novel biosynthesis strategy was developed to fabricate fluorescent cellulose by adding fluorescent glucose derivatives to a bacterial fermentation broth.The metabolic activity of bacteria is utilized to achieve in situ polymerization of glucose and its derivatives during the synthesis of bacterial cellulose.Owing to the structural similarity between triphenylamine-modified glucose(TPA-Glc N)and glucose monomers,the TPA-Glc N were efficiently assimilated by the bacterial cells and incorporated into the cellulose matrix,resulting in a uniform distribution of fluorescence.The fluorescence color and intensity of the obtained cellulose could be adjusted by varying the amount of the fluorescent glucose derivatives.Compared to the fluorescent cellulose synthesized through physical dyeing,the fluorescence of the products obtained by in situ polymerization showed higher intensity and stability.Furthermore,fluorescent bacterial cellulose can be hydrolyzed into nanocellulose-based ink,which demonstrates exceptional anti-counterfeiting capabilities under UV light.This biosynthesis method not only overcomes the limitations of traditional modification techniques but also highlights the potential of microbial systems as platforms for synthesizing functional polymers.展开更多
基金supported partially by the Kentucky Tobacco Research and Development Center(KTRDC),University of Kentucky.
文摘The evolutionarily conserved mitogen-activated protein kinase(MAPK)cascades relay extracellular signals into cells,triggering a variety of cellular responses.We previously revealed NtMPK4 as a positive regulator of nicotine biosynthesis;however,its upstream regulation remains unclear.Here,we characterized a MAPK cascade,comprising NtMEKK1b,NtMPKK2a,and NtMPK4,that promotes nicotine biosynthesis.This signaling module transduces external cues,including jasmonate and pathogen elicitors such as flg22,into post-translational modifications that enhance transcriptional activity and pathway gene expression.NtMPKK2a physically interacts with and phosphorylates NtMPK4 in vivo,confirming its role as an upstream kinase.RNAi-mediated silencing of NtMPKK2a significantly reduced the expression of nicotine pathway genes and decreased nicotine accumulation,whereas induced-overexpression of NtMPKK2a upregulated nicotine pathway genes and increased nicotine contents in tobacco hairy roots.Overexpression of NtMPKK2a in tobacco cells enhanced the transactivation activity of a NIC2-locus Ethylene Response Factor NtERF221 on Putrescine N-methyltransferase(NtPMT)promotor,further supporting its role in promoting nicotine biosynthesis.Furthermore,we identified NtMEKK1b,a tobacco MEKK that interacts with NtMAPKK2a in yeast cells.Knock-down of NtMEKK1b in transgenic tobacco plants attenuated the expression of nicotine pathway genes and reduced nicotine contents,whereas induced-overexpression of NtMEKK1b upregulated gene expression and nicotine accumulation.Our findings uncover a previously uncharacterized MAPK cascade module,NtMEKK1b-NtMPKK2a-NtMPK4,that regulates nicotine biosynthesis,highlighting the importance of posttranslational regulation in nicotine biosynthesis.
基金supported by the National Natural Science Foundation of China(32460767)Jiangxi Provincial Key Research and Development Program(20232BBF60007)Jiangxi Provincial Natural Science Foundation(20224BAB205024).
文摘The yam Dioscorea alata L.is widely cultivated globally.Purple-fleshed varieties of this important crop have enhanced market value due to their high anthocyanin contents,but how anthocyanin biosynthesis in D.alata tubers is regulated remains poorly understood.In this study,we identified and functionally validated key transcription factors that regulate anthocyanin biosynthesis based on a comparative transcriptome and metabolome analysis of three D.alata cultivars with different colored tubers(dark purple,light purple,and white).The anthocyanin glycoside cyanidin-3-O-(2′′-O-glucosyl)glucoside was abundant during early tuber development,and we determined that its accumulation is regulated in opposite manners by two R2R3-MYB transcription factors:DaMYB75 and DaMYB56.Yeast two-hybrid and bimolecular fluorescence complementation assays in Nicotiana benthamiana and co-expression assays in D.alata demonstrated that DaMYB75 promotes anthocyanin biosynthesis by specifically activating the promoter of the late anthocyanin biosynthesis gene DaANS and enhancing its expression through an interaction with DabHLH72.By contrast,DaMYB56 is a negative regulator of anthocyanin biosynthesis that binds to the DaANS promoter together with DabHLH72.Furthermore,the methylation levels of the DaMYB75 promoter were significantly lower in purple tubers than in white tubers.These findings shed light on the regulation of anthocyanin biosynthesis by MYBs and provide the basis for genetically improving anthocyanin content in D.alata.
文摘Iris domestica,a perennial herb of the Iridaceae family,is widely recognized for its rich isoflavone content and broad therapeutic properties.To elucidate the biosynthetic pathway of these medicinally significant compounds,we constructed a haplotype-resolved genome assembly of this species.Transcriptomic and metabolomic analyses revealed tissue-specific accumulation of isoflavone,particularly in rhizomes and roots.Functional characterization identified two candidate isoflavone synthase genes,among which IdIFS was confirmed to promote the biosynthesis of key compounds tectorigenin and irisflorentin.The high-quality genome assembly presented here provides a foundational resource for further research into the evolution,secondary metabolite,and environmental adaptation of I.domestica.
基金supported by CARS(CARS-21),the CAMS Innovation Fund for Medical Sciences(2021-I2M-1-032)the Science and Technology Department of Xizang(XZ202401ZY0020)+2 种基金the Science and Technology Department of Sichuan Province(2023YFH0044,2023YFH0018)the Sichuan Province Science Foundation for Distinguished Young Scholars(2022JDJQ0006)the Doctoral Fund of Southwest University of Science and Technology(19ZX7117,21ZX7116).
文摘Saikosaponins are the major pharmacologically active components in Bupleurum genus and exhibit significant application potential in multiple fields such as immune regulation and anti-tumor activity.To elucidate the biosynthetic pathway of saikosaponins,we identified two cytochrome P450 monooxygenases,CYP716A41 and CYP716Y4,in Bupleurum chinense.These enzymes catalyze the C-28 oxidation and C-16 hydroxylation of oleanane-type triterpene skeletons,respectively.The catalytic efficiency of CYP716A41 from a southern B.chinense variety was significantly higher than that from a northern variety.Molecular docking and mutagenesis experiments revealed that amino acid residues at sites 9 and 35 may contribute to this difference in catalytic efficiency.Additionally,under cold stress,the expression levels of both CYP450 genes and the saikosaponin contents in the leaves of southern varieties were significantly higher compared to those in northern varieties.The variation in the catalytic efficiency of CYP716A41 and the differential expression of the two CYP450 genes under cold stress during winter are associated with the differences in saikosaponin biosynthesis in the leaves of southern and northern B.chinense varieties.This is consistent with the distinct medicinal usage practices observed between southern and northern China.
文摘Lignin is a significant secondary metabolite produced through the phenylpropanoid pathway.As a vital component of the plant cell wall,lignin affects various fruit characteristics,including size,seed quantity,and firmness.In this study,we conducted comprehensive identification and phylogenetic analysis of 265 Caffeic acid O-methyltransferase(COMT)genes across ten different plant species,including Vaccinium corymbosum and four other Vaccinium species.The results reveal that VcCOMT38 is a promising structural gene for the biosynthesis of lignin in blueberry.An in vitro enzymatic assay of VcCOMT38 demonstrated that it is a special enzyme in the lignin biosynthesis pathway and prefers to use caffeic acid as a substrate over 5-hydroxyferulic acid.Transient overexpression and silencing of VcCOMT38 in Vaccinium corymbosum‘Northland’fruits demonstrated that VcCOMT38 participates in lignin biosynthesis and contributes to both an increased number of immature seeds and enhanced fruit firmness.The heterologous overexpression of VcCOMT38 in Nicotiana benthamiana revealed that this gene could increase the lignin content and the syringyl/guaiacyl(S/G)ratio,which determines the maximum monomer yield during lignin depolymerization.These results highlight VcCOMT38 as a crucial gene in lignin biosynthesis and its potential for improving lignin production in industry through genetically modified woody plants.
基金the Projects of Science and Technology of Shanghai(22N11900400)Key Projects of Beijing Institute of Life Science and Technology(2024400CB0050)+1 种基金National Natural Science Foundation of China(32488102)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA24030303)。
文摘Flavonoids are crucial secondary metabolites widely distributed in plants,playing vital roles in diverse biological processes.Although the flavonoid biosynthesis pathway has been extensively characterized,the transcriptional regulatory mechanisms remain poorly understood.In this study,we identify the miR166–ATHB14-LIKE module comprising the miR166 and its target gene ATHB14-LIKE as a key regulator of flavonoid biosynthesis in soybean(Glycine max).Knockdown of miR166 or overexpression of ATHB14-LIKE upregulated multiple flavonoid biosynthesis genes,leading to increased flavonoid accumulation.Conversely,miR166 overexpression suppressed these genes and reduced flavonoid levels.We further show that ATHB14-LIKE directly activates specific flavonoid biosynthesis genes by binding to their promoters.Additionally,ATHB14-LIKE forms homodimers and heterodimers with homologous proteins to regulate downstream flavonoid biosynthesis genes.Together,our findings demonstrate that the miR166–ATHB14-LIKE module controls soybean flavonoid content by coordinating the expression of key biosynthetic genes.
基金support of the National Natural Science Foundation of China(32472594).
文摘Locust plagues result in significant agricultural and ecological damage,and the current dependence on broadspectrum chemical pesticides raises serious concerns regarding environmental sustainability and public health.In this study,we elucidated the biosynthetic pathway of the locust aggregation pheromone 4-vinylanisole(4VA).Through analysis of the crystal structure of the 4VPMT2-4VA-SAM complex,it was determined that 4-nitrophenol acts as a substrate analogue,effectively inhibiting 4VPMT enzyme activity and thereby preventing the formation of 4VA.This study revealed key enzymatic targets and lead inhibitors for intervention,establishing a molecular foundation for pheromone-based,environmentally sustainable locust control strategies and offering a viable alternative to reduce reliance on conventional chemical pesticides.
基金supported by the China Agricultural Research System(Grant No.CARS-09)the Central Government Guiding Local Science and Technology Development Project(Grant No.YDZX2023029)the Gansu Planning Projects on Science and Technology(Grant No.23CXNJ0013).
文摘Flavonoids,abundant in the fruits,are pivotal to their growth,development,and storage.In addition,they have significant beneficial effects on human health.Consequently,research is increasingly concentrating on the regulatory mechanisms governing flavonoid biosynthesis in fruits.Phytohormones are involved in the regulation of flavonoid biosynthesis.The abscisic acid,ethylene,jasmonic acid,cytokinins,and brassinosteroids promote flavonoid biosynthesis,while auxin negatively regulates flavonoid biosynthesis.Subsequently,transcription factors from the MYB,bHLH,WRKY,NAC,and bZIP families are pivotal in regulating flavonoid biosynthesis.In addition,non-coding RNAs(microRNA and lncRNA)also participate in the regulation of flavonoids biosynthesis.MicroRNAs are generally believed to negatively regulate flavonoid metabolism in fruits,while lncRNAs have the opposite effect.Furthermore,the interactions between plant hormones,transcription factors,and non-coding RNAs in fruit flavonoid biosynthesis were analyzed.Ultimately,a foundational regulatory network for fruit flavonoid biosynthesis was hereby established.
基金funded by the Key R&D Program of Shaanxi province(Grant Nos.2023-ZDLNY-23 and 2023XCZX2-18)the National Key R&D Program of China(Grant No.2019YFD1001405).
文摘Proanthocyanidins(PAs)are a group of oligomeric flavonoids also known as condensed tannins.PAs in human diet have antioxidant and health-promoting effects.BSISTER(BS)promotes the accumulation of PAs,but its direct target gene and regulation mechanism in PAs biosynthesis are not clear.Here,we reported VviBS1 and VviBS2 genes,which bind directly to the promoter of PA synthesis key genes VviANR(ANTHOCYANIDIN REDUCTASE)and VviLAR(LEUCOANTHOCYANIDIN REDUCTASE)and up-regulate their expression to promote the PAs biosynthesis in grapevine.VviBS1 and VviBS2 partially rescued the transparent testa phenotype of an Arabidopsis tt16 mutant.Overexpression of BS1 and BS2 in grapevine callus increased the content of PAs,as well as the expression of specific genes related to PA synthesis.VviBS1 and VviBS2 proteins bound directly to the promoter regions of the key PA synthesis genes VviANR1,VviANR2,and VviLAR1.Overexpression of VviBS1 and VviBS2 promotes VviANR1,VviANR2 and VviLAR1 expression and PAs biosynthesis.Some BS1-and BS2-interacting MADS-box proteins have an effect on PAs biosynthesis.This study provides insight into the regulatory mechanisms of PAs biosynthesis in grapevine,which could be effectively employed for metabolic engineering to increase PA content.
基金funded by the National Natural Science Foundation of China (31760363)the Earmarked Fund for CARS (CARS-14-1-16)+1 种基金the Gansu Education Science and Technology Innovation Industry Support Program,China (2021CYZC-38)the Gansu Provincial Key Laboratory of Arid Land Crop Science,Gansu Agricultural University,China (GSCS-2020-Z6)。
文摘Lodging is a major constraint limiting oil flax production efficiency in northern China.Crop lodging susceptibility is closely related to stem lignin content,and the regulatory mechanisms by which nitrogen and potassium fertilization interactively influence lignin biosynthesis in oil flax stems require further investigation.Therefore,this study aimed to enhance lodging resistance and increase grain yield in oil flax.We examined the interactive effects of different nitrogen (75,150,and 225 kg N ha^(–1)) and potassium (60 and 90 kg K_(2)O ha^(–1)) fertilizer rates on lignin metabolism,lodging resistance,and grain yield during the 2022 and 2023 growing seasons.Results indicated that nitrogen and potassium fertilizer levels and their interactions promoted lignin accumulation,improved lodging resistance,and increased grain yield.Compared to the control (CK),the75–150 kg N ha^(–1) combined with 60 kg K_(2)O ha^(–1) treatments significantly enhanced the activities of key lignin-synthesizing enzymes (tyrosine ammonia-lyase (TAL),phenylalanine ammonia-lyase (PAL),cinnamyl alcohol dehydrogenase (CAD),and peroxidase (POD)) and upregulated the expression of 4CL1 and F5H3 genes,leading to a 29.63–43.30%increase in lignin content,improved stem bending strength and lodging resistance index,and a 23.27–32.34%increase in grain yield.Correlation analysis revealed that nitrogen and potassium fertilizers positively regulated enzyme activities and gene expression related to lignin biosynthesis,thereby facilitating lignin accumulation and enhancing stem mechanical strength and lodging resistance.Positive correlations were observed among lignin-related enzyme activities,gene expression,lodging resistance traits,and grain yield.In summary,the application of 75–150 kg N ha^(–1) in conjunction with 60 kg K_(2)O ha^(–1)promoted lignin biosynthesis and accumulation,enhanced lodging resistance,and increased grain yield in oil flax grown in the dryland farming region of central Gansu,China.Furthermore,this treatment provides a technical basis for cultivating stress-tolerant and high-yield oil flax in arid regions.
基金supported by the National Natural Science Foundation of China(Grant Nos.31870695,32071828)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Flower color is an essential trait in ornamental plant breeding. Lycoris longituba is a popular ornamental plant native to central eastern China. The decrease in anthocyanin accumulation causes L. longituba petal color fading during flower development, which considerably affects the ornamental value of L. longituba. However, mechanisms underlying anthocyanin biosynthesis inhibition during L. longituba petal development remain unclear. In this study, three LlDFR genes were confirmed to be involved in anthocyanin biosynthesis and LlDFRc exerted the strongest promoting effect on anthocyanin accumulation. According to the correlation analysis results, LlbHLH12 exhibited the strongest negative correlation with LlDFRc. Quantitative real-time PCR analysis showed that LlbHLH12 was highly expressed during the medium bud and full bloom stages of flower development. LlbHLH12 was identified as a member of subgroup XII of bHLH transcription factor family. Subcellular localization and transcriptional activation ability assay revealed that LlbHLH12 was located in the nucleus without transcriptional activation activity. Overexpression of LlbHLH12 in Nicotiana tabacum and L. longituba inhibited anthocyanin accumulation by suppressing the expression of anthocyanin biosynthetic pathway genes. Furthermore, yeast one-hybrid, dual-luciferase, and β-glucuronidase activity assays showed that LlbHLH12 directly bound to the promoters of LlPAL and LlDFRc and suppressed their expression to inhibit anthocyanin biosynthesis. Overall, our study identified a novel bHLH repressor negatively regulating anthocyanin biosynthesis and provided new insights into the molecular mechanisms underlying color fading in L. longituba petals.
基金supported by the National Key Research and Development Program of China (No. 2022YFD1700200)the National Natural Science Foundation of China (Nos. 32161133010, 3230170969)+1 种基金the Innovation Program of Chinese Academy of Agricultural Sciences, the Shenzhen Science and Technology Program (No. KQTD20180411143628272)the Special Funds for Science Technology Innovation and Industrial Development of Shenzhen Dapeng New District (No. PT202101–02)。
文摘Chitin is an abundant aminopolysaccharide found in insect pests and phytopathogenic microorganisms but absent in higher plants and vertebrates. It is crucial for mitigating threats posed by chitin-containing organisms to human health, food safety, and agriculture. Therefore, targeting the chitin biosynthesisassociated bioprocess holds a promise for developing human-safe and eco-friendly antifungal agents or pesticides. Chitin biosynthesis requires chitin synthase and associated factors, which are involved in the modification, regulation, organization or turnover of chitin during its biosynthesis. A number of enzymes such as chitinases, hexosaminidases, chitin deacetylases are closely related and therefore are promising targets for designing novel agrochemicals that target at chitin biosynthesis. This review summarizes the advances in understanding chitin biology over the past decade by our research group and collaborates,specifically regarding essential proteins linked to chitin biosynthesis that can be exploited as promising pesticide targets. Examples of small bioactive molecules that against the activity of these targets are given.
文摘Xylo-oligosaccharides(XOSs)are a category of functional oligosaccharides primarily composed of 2-7 xylose units linked byβ-1,4 glycosidic bonds.They are recognized as soluble dietary fibers with prebiotic properties.Recently, there has been significant interest in manufacturing XOSs from xylan extracted from lignocellulosic biomass using enzyme catalysis under mild conditions. In this work, the arabinofuranosidase Abf62A gene was cloned from Aspergillus usamii genomic DNA through sequential molecular processes and expressed in Pichia pastoris X33. The xylan (100 g/L) extracted xylan in wheat straw (WS) was biologically hydrolyzed into 50.32 g/L of XOSs by xylanase Xyn11A (300 U/g substrate) and arabinofuranase Abf62A (20 U/g substrate), which indicated a notable synergistic effect compared to the 34.42 g/L XOSs produced via Xyn11A. The 50.32 g/L of XOSs products comprised xylobiose (31.71 g/L), xylotriose (15.92 g/L), xylotetraose (1.65 g/L) and xylopentaose (1.04 g/L). Notably, the combined content of xylobiose and xylotriose accounted for up to 94.7%. The XOSs purified from the enzyme hydrolysate could effectually scavenge free radicals, and the antioxidant activity was more than 90%. In summary, XOSs were biologically manufactured from wheat straw xylan through the synergistic biocatalysis via xylanase and arabinofuranosidase Abf62A in a green and sustainable way, rending one kind of prebiotic oligosaccharides with substantial positive effects on human and animal health.
基金financially supported by the National Natural Science Foundation of China(31960090,32160562)the Natural Science Foundation of Jiangxi Province(20224BAB215046)the Project Program of State Key Laboratory of Food Science and Resources,Nanchang University(SKLF-ZZB-202129,SKLF-ZZB-202324,SKLF-KF-202216)。
文摘Cyclocarya paliurus(Batalin)Iljinskaja,as a unique and rare monocotyledonous plant in Southern China,is a promising and economical Chinese herbal medicine and functional food.People have conducted a number of research on C.paliurus because of its rich triterpenoids.However,no comprehensive review has illustrated the composition and pharmacological activity of triterpenoids from C.paliurus.This review summarizes 177 triterpenoids from different parts of C.paliurus.The structures of compounds were elucidated,and their biosynthesis was inferred.The biological activities of compounds and triterpenoid-rich extracts,including anti-diabetes,antihyperlipidemia,anti-inflammatory,anticancer or cytotoxicity,antioxidation,etc.,were discussed.C.paliurus can be an important and valuable supplement to the food market.This review provides a reference for the further research and application of C.paliurus triterpenoids in the fields of foods and pharmaceuticals.
基金financially supported by the National Key Research and Development Program of China(No.2020YFA0908000)CAMS Innovation Fund for Medical Sciences(No.CIFMS-2023I2M-2–006)。
文摘Camptothecin,a plant-derived pentacyclic pyrroloquinoline alkaloid,and its derivatives like topotecan and irinotecan have been used as clinical anticancer agents for decades.However,the complete biosynthetic pathway of camptothecin still remains unelucidated due to the unknown complex formation processes and corresponding enzymes for the downstream biosynthetic pathway including the committed hydrolysis of glycosides.Herein,a novel glycoside hydrolase(CaGH1)responsible for the deglycosylation of biosynthetic glycoside intermediates including both quinoline-type alkaloids pumiloside(1),(3S)-deoxypumiloside(2)and indole-type alkaloid strictosamide(3)has been functionally identified.Moreover,CaGH1 exhibits the highly strict stereoselectivity towards the substrates with 3S configuration.Furthermore,a combined strategy for the discovery of the unknown biosynthetic enzyme by employing activity-guided enzyme verification,transcriptome-based gene mining,biochemical assay in vitro,and structurally characterizing the unstable enzymatic products by derivatization,is reported.These findings not only provide a better understanding of the deglycosylation in camptothecin biosynthesis,also lay the foundation for the complete elucidation of camptothecin biosynthetic pathway and biological production of camptothecin.
基金co-financed by the International Science&Technology Cooperation Program of Hainan Province(GHYF2023009)Jiangsu Provincial Key Research and Development Program(BE2022325)+1 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_0777)Qing Lan Project of Jiangsu Province and Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘The surface macromolecules of probiotic bacteria play crucial roles in modulating immune responses in the host.Exopolysaccharide(EPS)from lactic acid bacteria(LAB)have been widely reported to exhibit immunomodulatory activity.In this study,the EPS biosynthesis gene cluster of Lacticaseibacillus paracasei S-NB was analyzed and a deletion mutant S-NBΔ7576(two genes S-NB_2175/wze and S-NB_2176/wzd were responsible for the chain length determination and export of EPS)was successfully constructed,resulting a 40.02%decrease in the production of EPS.The deletion of wze and wzd had little effect on the monosaccharide composition and major groups of the two EPS fractions(BEPS1 and BEPS2).Both BEPS1 and BEPS2 could inhibit the transcriptional level of tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),inducible nitric oxide synthase(i NOS)and cyclooxygenase-2(COX-2)mRNA in RAW 264.7 cells induced by lipopolysaccharide(LPS),and enhance host immune tolerance via suppressing NF-κB and MAPK signaling.Notably,the S-NBΔ7576 mutant supplied with the BEPS1/BEPS2 exhibited more significant inhibition of cytokines production and the phosphorylation of p65 and c-Jun N-terminal kinase(JNK)in LPS-stimulated cells compared with the S-NBΔ7576 mutant alone.Our study provided the immunomodulatory effect of BEPS1 and BEPS2 from L.paracasei S-NB,in which the wze and wzd genes associated with EPS biosynthesis may play an important role.
基金supported by the National Natural Science Foundation of China(32225009,32370452,82274046)Jilin Agricultural University High-level Talent Introduction Fund(202020218)。
文摘Mammalian scent glands mediate species-specific chemical communication,yet the mechanistic basis for convergent musk production remain incompletely understood.Forest musk deer and muskrat have independently evolved specialized musk-secreting glands,representing a striking case of convergent evolution.Through an integrated multi-omics approach,this study identified cyclopentadecanone as a shared key metabolic precursor in musk from both forest musk deer and muskrat,although downstream metabolite profiles diverged between the two lineages.Single-cell RNA sequencing revealed that these specialized apocrine glands possessed unique secretory architecture and exhibited transcriptional profiles associated with periodic musk production,distinct from those in conventional apocrine glands.Convergent features were evident at the cellular level,where acinar,ductal,and basal epithelial subtypes showed parallel molecular signatures across both taxa.Notably,acinar cells in both species expressed common genes involved in fatty acid and glycerolipid metabolism(e.g.,ACSBG1,HSD17B12,HACD2,and HADHA),suggesting a conserved molecular framework for musk precursor biosynthesis.Metagenomic analysis of musk samples further revealed parallel microbial community structures dominated by Corynebacterium and enriched in lipid metabolic pathways.These findings suggest multi-level convergence in musk biosynthesis,from molecular pathways to microbial communities,providing novel insights into mammalian chemical signaling and artificial musk production.
基金supported by the National Key Research and Development Program of China(2017YFC1600802)Henan Provincial Science and Technology Research Project,China(No.232102110134)the National and Local Joint Engineering Laboratory of High Efficiency and Superior-Quality Cultivation and Fruit Deep Processing Technology of Characteristic Fruit Trees in South Xinjiang of China(No.FE202303).
文摘In plants, transcription factor (TF) family LATERAL ORGAN BOUNDARIES DOMAIN (LBD) has been identified to be involved in the ripening and senescence processes of fruits. However, the function of LBD in Hylocereus undatus (Haw.) Britton & Rose (H. undatus) has not been reported yet. Through transcriptomic analysis, virus-induced gene silencing (VIGS) technology, and RT-qPCR validation, we investigated the role of the LBD TFs in the senescence of H. undatus. Transcriptomic analysis revealed that HuLBD1 is a key transcription factor of the LBD family regulating H. undatus senescence. After silencing HuLBD1, 5075 differentially expressed genes (DEGs) were identified. GSEA results showed that these DEGs were mainly enriched in the phenylpropanoids and flavonoid biosynthesis pathway. The leading subset of genes in these two pathways included 16 DEGs, with four upregulated genes, HuCHS1-2, HuFLS1, HuCYP75B2, and HuCHS5-2 being central in the Protein-Protein Interaction (PPI) network. H. undatus phenotypic experiments confirmed that silencing HuLBD1 significantly increased the flavonoid content in the fruit peel, and RT-qPCR validation showed that the gene expression trends were consistent with the RNA-seq data. The study indicated that HuLBD1 likely delays the fruit senescence process by negatively regulating the expression of four key genes, including HuCHS1-2, thus promoting the synthesis of phenylpropanoids such as flavonoids. In conclusion, our findings suggest that the HuLBD1 TF plays an important role in the senescence of H. undatus fruit, providing a theoretical basis for postharvest senescence control.
文摘Starch is an essential commodity for humans and other animals.Future demands require qualitative and quantitative improvement by crop and post-harvest engineering that calls for comprehensive actions requiring increased fundamental knowledge on starch biosynthesis,development of advanced breeding strategies,efficient farming,and well-adapted and up scalable extraction protocols for diverse starch products.Recent staggering progress in molecular breeding techniques,especially genome editing,have enabled generation of higher starch yield and special functional qualities required to support such advancement.However,this necessitates fundamental biochemical and mechanistic understanding of starch biosynthesis and the variegated starch crop germplasms,all of which are closely linked to the relationships between starch molecular structures and functionality of various starch types as directed by the different capabilities of starch crop genotypes.We here review starch biosynthesis and its genetic foundation with a focus on increasing nutritional and health-promoting value of starch especially through bioengineering of the high amylose trait.
基金supported by the National Natural Science Foundation of China(No.22376111)Shandong Provincial Natural Science Foundation(No.ZR2024YQ026)+2 种基金for Excellent Young Scholars,Taishan Scholar Foundation of Shandong Province(No.tsqn202408237)Youth Innovation Team Project for Talent Introduction and Cultivation in Universities of Shandong Province(No.096-1622002)the Research Foundation for Distinguished Scholars of Qingdao Agricultural University(No.663-1117015)。
文摘In recent years,cellulose-based fluorescent polymers have received considerable attention.However,conventional modification methods face challenges such as insolubility in most solvents,fluorescence instability,and environmental risks.In this study,a novel biosynthesis strategy was developed to fabricate fluorescent cellulose by adding fluorescent glucose derivatives to a bacterial fermentation broth.The metabolic activity of bacteria is utilized to achieve in situ polymerization of glucose and its derivatives during the synthesis of bacterial cellulose.Owing to the structural similarity between triphenylamine-modified glucose(TPA-Glc N)and glucose monomers,the TPA-Glc N were efficiently assimilated by the bacterial cells and incorporated into the cellulose matrix,resulting in a uniform distribution of fluorescence.The fluorescence color and intensity of the obtained cellulose could be adjusted by varying the amount of the fluorescent glucose derivatives.Compared to the fluorescent cellulose synthesized through physical dyeing,the fluorescence of the products obtained by in situ polymerization showed higher intensity and stability.Furthermore,fluorescent bacterial cellulose can be hydrolyzed into nanocellulose-based ink,which demonstrates exceptional anti-counterfeiting capabilities under UV light.This biosynthesis method not only overcomes the limitations of traditional modification techniques but also highlights the potential of microbial systems as platforms for synthesizing functional polymers.
