The UDP glycosyltransferase gene superfamily: recommended nomenclature update based on evolutionary divergence

An efficient flavonoid glycosyltransferase NjUGT73B1 from Nardostachys jatamansi of alpine Himalayas discovered by structure-based protein clustering

Tilianin and linarin, two rare glycosylated flavonoids in the aromatic endangered medicinal plant Nardostachys jatamansi (D.on)DC., play an important role in the fields of medicine, cosmetics, food and dye industries. However, there remains a lack of comprehensive understanding regarding their biosynthetic pathway. In this study, the phytochemical investigation of N. jatamansi resulted in the isolation of linarin. With help of AlphaFold2 to cluster the entire glycosyltransferase family based on predicted structure similarities, we successfully identified a flavonoid glycosyltransferase NjUGT73B1, which could efficiently catalyze the glucosylation of acacetin at 7-OH to produce tilianin, also the key precursor in the biosynthesis of linarin. Additionally, NjUGT73B1 displayed a high degree of substrate promiscuity, enabling glucosylation at 7-OH of many flavonoids. Molecular modeling and site-directed mutagenesis revealed that H19, H21, H370, F126, and F127 play the crucial roles in the glycosylation ability of NjUGT73B1. Notably, comparation with the wild NjUGT73B1, mutant H19K led to a 50% increase in the activity of producing tilianin from acacetin.

UDP-glucosyltransferase 71C4 controls the flux of phenylpropanoid metabolism to shape cotton seed development

Seeds play a crucial role in plant reproduction, making it essential to identify genes that affect seed development. In this study, we focused on UDP-glucosyltransferase 71C4 (UGT71C4) in cotton, a member of the glycosyltransferase family that shapes seed width and length, thereby influencing seed index and seed cotton yield. Overexpression of UGT71C4 results in seed enlargement owing to its glycosyltransferase activity on flavonoids, which redirects metabolic flux from lignin to flavonoid metabolism. This shift promotes cell proliferation in the ovule via accumulation of flavonoid glycosides, significantly enhancing seed cotton yield and increasing the seed index from 10.66 g to 11.91 g. By contrast, knockout of UGT71C4 leads to smaller seeds through activation of the lignin metabolism pathway and redirection of metabolic flux back to lignin synthesis. This redirection leads to increased ectopic lignin deposition in the ovule, inhibiting ovule growth and development, and alters yield components, increasing the lint percentage from 41.42% to 43.40% and reducing the seed index from 10.66 g to 8.60 g. Our research sheds new light on seed size development and reveals potential pathways for enhancing seed yield.

Four glycosyltransferase genes are responsible for synthesis and accumulation of different flavonol glycosides in apple tissues

Flavonols are widely synthesized throughout the plant kingdom, playing essential roles in plant physiology and providing unique health benefits for humans. Their glycosylation plays significant role in improving their stability and solubility, thus their accumulation and function. However, the genes encoding the enzymes catalyze this glycosylation remain largely unknown in apple. This study utilized a combination of methods to identify genes encoding such enzymes. Initially, candidate genes were selected based on their potential to encode UDP-dependent glycosyltransferases (UGTs) and their expression patterns in response to light induction. Subsequently, through testing the in vitro enzyme activity of the proteins produced in Escherichia coli cells, four candidates were confirmed to encode a flavonol 3-O-galactosyltransferase (UGT78T6), flavonol 3-O-glucosyltransferase (UGT78S1), flavonol 3-O-xylosyltransferase/arabinosyltransferase (UGT78T5), and flavonol 3-O-rhamnosyltransferase (UGT76AE22), respectively. Further validation of these genes' functions was conducted by modulating their expression levels in stably transformed apple plants. As anticipated, a positive correlation was observed between the expression levels of these genes and the content of specific flavonol glycosides corresponding to each gene. Moreover, overexpression of a flavonol synthase gene, MdFLS, resulted in increased flavonol glycoside content in apple roots and leaves. These findings provide valuable insights for breeding programs aimed at enriching apple flesh with flavonols and for identifying flavonol 3-O-glycosyltransferases of other plant species.

Characterization of the UDP-glycosyltransferase UGT33D1 in silkworm Bombyx mori

Uridine diphosphate (UDP)-glycosyltransferases (UGTs) are important metabolizing enzymes functioning by adding a sugar moiety to a small lipophilic substrate molecule and play critical roles in drug/toxin metabolism for all realms of life. In this study, the silkworm Bombyx mori UGT33D1 gene was characterized in detail. UGT33D1 was found localized in the endoplasmic reticulum (ER) compartment just like other animal UGTs and was mainly expressed in the silkworm midgut. We first reported that UGT33D1 was important to BmNPV infection, as silencing UGT33D1 inhibited the BmNPV infection in silkworm BmN cells, while overexpressing the gene promoted viral infection. The molecular pathways regulated by UGT33D1 were analysed via transcriptome sequencing upon UGT33D1 knockdown, highlighting the important role of the gene in maintaining a balanced oxidoreductive state of the organism. In addition, proteins that physically interact with UGT33D1 were identified through immunoprecipitation and mass spectrometry analysis, which includes tubulin, elongation factor, certain ribosomal proteins, histone proteins and zinc finger proteins that had been previously reported for human UGT-interacting proteins. This study provided preliminary but important functional information on UGT33D1 and is hoped to trigger deeper investigations into silkworm UGTs and their functional mechanisms.

Associations of cord serum polybrominated diphenyl ether (PBDE) mixture with birth outcomes and mediating role of thyroid function: Evidence from the Sheyang Mini Birth Cohort Study

BACKGROUND

Polybrominated diphenyl ethers (PBDEs), a series of worldwide applied flame retardants, may influence fetal growth and interfere with thyroid function. The study intended to explore the relationship between in-utero exposure to PBDE mixture and newborn anthropometric indexes and to further examine the potential mediating role of thyroid function.

METHODS

Demographics and laboratory measures of 924 mother-infant pairs were obtained from the database of the Sheyang Mini Birth Cohort Study. We applied gas chromatography-mass spectrometry (GC-MS) and electrochemiluminescence immunoassay to measure nine PBDE congeners and seven thyroid function parameters in umbilical cord serum samples, respectively. We fitted generalized linear models and Bayesian kernel machine regression (BKMR) to evaluate associations of lipid-adjusted cord serum PBDEs, as individuals and as a mixture, with newborn anthropometric and cord serum thyroid function parameters. We applied causal mediation analysis to test our hypothesis that thyroid function parameters act as a mediator between PBDEs and birth outcomes.

RESULTS

The molarity of cord serum ∑9PBDE had a median value of 31.23 nmol/g lipid (IQR 19.14 nmol/g lipid, 54.77 nmol/g lipid). BDE-209 was the most dominant congener. Birth length was positively associated with both single exposure to BDE-28 and cumulative exposure to PBDEs. Correspondingly, ponderal index (PI) was negatively associated with BDE-28 and the total effects of PBDE mixture. Free triiodothyronine had a negative trend with BDE-209 and PBDE mixture. In the sex-stratified analysis, BDE-153 concentrations were positively correlated with PI among males (β = 0.03; 95%CI: 0.01, 0.05; P = 0.01) but not among females. Cord serum thyrotropin mediated 14.92% of the estimated effect of BDE-153 on PI.

CONCLUSIONS

In-utero mixture exposure to PBDEs was associated with birth outcomes and thyroid function. Thyroid function might act as a mediator in the process in which PBDEs impact the growth of the fetus.

Duplications and Losses of the Detoxification Enzyme Glycosyltransferase 1 Are Related to Insect Adaptations to Plant Feeding

Insects have developed sophisticated detoxification systems to protect them from plant secondary metabolites while feeding on plants to obtain necessary nutrients. As an important enzyme in the system, glycosyltransferase 1 (GT1) conjugates toxic compounds to mitigate their harm to insects. However, the evolutionary link between GT1s and insect plant feeding remains elusive. In this study, we explored the evolution of GT1s across different insect orders and feeding niches using publicly available insect genomes. GT1 is widely present in insect species; however, its gene number differs among insect orders. Notably, plant-sap-feeding species have the highest GT1 gene numbers, whereas blood-feeding species display the lowest. GT1s appear to be associated with insect adaptations to different plant substrates in different orders, while the shift to non-plant feeding is related to several losses of GT1s. Most large gene numbers are likely the consequence of tandem duplications showing variations in collinearity among insect orders. These results reveal the potential relationships between the evolution of GT1s and insect adaptation to plant feeding, facilitating our understanding of the molecular mechanisms underlying insect-plant interactions.

Genome-wide investigation of UDP-Glycosyltransferase family in Tartary buckwheat (Fagopyrum tataricum)

BACKGROUND

Tartary buckwheat (Fagopyrum tataricum) belongs to Polygonaceae family and has attracted increasing attention owing to its high nutritional value. UDP-glycosyltransferases (UGTs) glycosylate a variety of plant secondary metabolites to control many metabolic processes during plant growth and development. However, there have been no systematic reports of UGT superfamily in F. tataricum.

RESULTS

We identified 173 FtUGTs in F. tataricum based on their conserved UDPGT domain. Phylogenetic analysis of FtUGTs with 73 Arabidopsis UGTs clustered them into 21 families. FtUGTs from the same family usually had similar gene structure and motif compositions. Most of FtUGTs did not contain introns or had only one intron. Tandem repeats contributed more to FtUGTs amplification than segmental duplications. Expression analysis indicates that FtUGTs are widely expressed in various tissues and likely play important roles in plant growth and development. The gene expression analysis response to different abiotic stresses showed that some FtUGTs were involved in response to drought and cadmium stress. Our study provides useful information on the UGTs in F. tataricum, and will facilitate their further study to better understand their function.

CONCLUSIONS

Our results provide a theoretical basis for further exploration of the functional characteristics of FtUGTs and for understanding the growth, development, and metabolic model in F. tataricum.

Cloning, Expression, and Functional Characterization of Two Highly Efficient Flavonoid-di-O-glycosyltransferases ZmUGT84A1 and ZmUGT84A2 from Maize (Zea mays L.)

The maize (Zea mays L.) glycosyltransferase family 1 comprises many uridine diphosphate glycosyltransferase (UGT) members. However, UGT activities and biochemical functions have seldom been revealed. In this study, the genes of two flavonoid di-O-glycosyltransferases ZmUGT84A1 and ZmUGT84A2 were cloned from maize plant and expressed in Escherichia coli. Phylogenetic analysis showed that the two enzymes were homologous to AtUGT84A1 and AtUGT84A3. The two recombinant enzymes showed a high conversion rate of luteolin to its glucosides, mainly 4',7-di-O-glucoside and minorly 3',7-di-O-glucoside in two-step glycosylation reactions in vitro. Moreover, the recombinant ZmUGT84A1 and ZmUGT84A2 had a broad substrate spectrum, converting eriodictyol, naringenin, apigenin, quercetin, and kaempferol to monoglucosides and diglucosides. The highly efficient ZmUGT84A1 and ZmUGT84A2 may be used as a tool for the effective synthesis of various flavonoid O-glycosides and as markers for crop breeding to increase O-glycosyl flavonoid content in food.

Genome-Wide Analysis and Identification of UDP Glycosyltransferases Responsive to Chinese Wheat Mosaic Virus Resistance in Nicotiana benthamiana

Glycosylation, a dynamic modification prevalent in viruses and higher eukaryotes, is principally regulated by uridine diphosphate (UDP)-glycosyltransferases (UGTs) in plants. Although UGTs are involved in plant defense responses, their responses to most pathogens, especially plant viruses, remain unclear. Here, we aimed to identify UGTs in the whole genome of Nicotiana benthamiana (N. benthamiana) and to analyze their function in Chinese wheat mosaic virus (CWMV) infection. A total of 147 NbUGTs were identified in N. benthamiana. To conduct a phylogenetic analysis, the UGT protein sequences of N. benthamiana and Arabidopsis thaliana were aligned. The gene structure and conserved motifs of the UGTs were also analyzed. Additionally, the physicochemical properties and predictable subcellular localization were examined in detail. Analysis of cis-acting elements in the putative promoter revealed that NbUGTs were involved in temperature, defense, and hormone responses. The expression levels of 20 NbUGTs containing defense-related cis-acting elements were assessed in CWMV-infected N. benthamiana, revealing a significant upregulation of 8 NbUGTs. Subcellular localization analysis of three NbUGTs (NbUGT12, NbUGT16 and NbUGT17) revealed their predominant localization in the cytoplasm of N. benthamiana leaves, and NbUGT12 was also distributed in the chloroplasts. CWMV infection did not alter the subcellular localization of NbUGT12, NbUGT16, and NbUGT17. Transient overexpression of NbUGT12, NbUGT16, and NbUGT17 enhanced CWMV infection, whereas the knockdown of NbUGT12, NbUGT16 and NbUGT17 inhibited CWMV infection in N. benthamiana. These NbUGTs could serve as potential susceptibility genes to facilitate CWMV infection. Overall, the findings throw light on the evolution and function of NbUGTs.

Analysis of the UDP-Glucosyltransferase (UGT) Gene Family and Its Functional Involvement in Drought and Salt Stress Tolerance in Phoebe bournei

Uridine diphosphate glycosyltransferases (UDP-GTs, UGTs), which are regulated by UGT genes, play a crucial role in glycosylation. In vivo, the activity of UGT genes can affect the availability of metabolites and the rate at which they can be eliminated from the body. UGT genes can exert their regulatory effects through mechanisms such as post-transcriptional modification, substrate subtype specificity, and drug interactions. Phoebe bournei is an economically significant tree species that is endemic to southern China. Despite extensive studies on the UGT gene family in various species, a comprehensive investigation of the UGT family in P. bournei has not been reported. Therefore, we conducted a systematic analysis to identify 156 UGT genes within the entire P. bournei genome, all of which contained the PSPG box. The PbUGT family consists of 14 subfamilies, consistent with Arabidopsis thaliana. We observed varying expression levels of PbUGT genes across different tissues in P. bournei, with the following average expression hierarchy: leaf > stem xylem > stem bark > root xylem > root bark. Covariance analysis revealed stronger covariance between P. bournei and closely related species. In addition, we stressed the seedlings with 10% NaCl and 10% PEG-6000. The PbUGT genes exhibited differential expression under drought and salt stresses, with specific expression patterns observed under each stress condition. Our findings shed light on the transcriptional response of PbUGT factors to drought and salt stresses, thereby establishing a foundation for future investigations into the role of PbUGT transcription factors.

Overexpression and nonsynonymous mutations of UDP-glycosyltransferases are potentially associated with pyrethroid resistance in Anopheles funestus

UDP-glycosyltransferases (UGTs) enzymes are pivotal in insecticide resistance by transforming hydrophobic substrates into more hydrophilic forms for efficient cell elimination. This study provides the first comprehensive investigation of Anopheles funestus UGT genes, their evolution, and their association with pyrethroid resistance. We employed a genome-wide association study using pooled sequencing (GWAS-PoolSeq) and transcriptomics on pyrethroid-resistant An. funestus, along with deep-targeted sequencing of UGTs in 80 mosquitoes Africa-wide. UGT310B2 was consistently overexpressed Africa-wide and significant gene-wise Fst differentiation was observed between resistant and susceptible populations: UGT301C2 and UGT302A3 in Malawi, and UGT306C2 in Uganda. Additionally, nonsynonymous mutations in UGT genes were identified. Gene-wise Tajima's D density curves provide insights into population structures within populations across these countries, supporting previous observations. These findings have important implications for current An. funestus control strategies facilitating the prediction of cross-resistance to other UGT-metabolised polar insecticides, thereby guiding more effective and targeted insecticide resistance management efforts.

Similarities in Structure and Function of UDP-Glycosyltransferase Homologs from Human and Plants

The uridine diphosphate glycosyltransferase (UGT) superfamily plays a key role in the metabolism of xenobiotics and metabolic wastes, which is essential for detoxifying those species. Over the last several decades, a huge effort has been put into studying human and mammalian UGT homologs, but family members in other organisms have been explored much less. Potentially, other UGT homologs can have desirable substrate specificity and biological activities that can be harnessed for detoxification in various medical settings. In this review article, we take a plant UGT homology, UGT71G1, and compare its structural and biochemical properties with the human homologs. These comparisons suggest that even though mammalian and plant UGTs are functional in different environments, they may support similar biochemical activities based on their protein structure and function. The known biological functions of these homologs are discussed so as to provide insights into the use of UGT homologs from other organisms for addressing human diseases related to UGTs.

Chemoenzymatic indican for light-driven denim dyeing

Blue denim, a billion-dollar industry, is currently dyed with indigo in an unsustainable process requiring harsh reducing and alkaline chemicals. Forming indigo directly in the yarn through indican (indoxyl-β-glucoside) is a promising alternative route with mild conditions. Indican eliminates the requirement for reducing agent while still ending as indigo, the only known molecule yielding the unique hue of blue denim. However, a bulk source of indican is missing. Here, we employ enzyme and process engineering guided by techno-economic analyses to develop an economically viable drop-in indican synthesis technology. Rational engineering of PtUGT1, a glycosyltransferase from the indigo plant, alleviated the severe substrate inactivation observed with the wildtype enzyme at the titers needed for bulk production. We further describe a mild, light-driven dyeing process. Finally, we conduct techno-economic, social sustainability, and comparative life-cycle assessments. These indicate that the presented technologies have the potential to significantly reduce environmental impacts from blue denim dyeing with only a modest cost increase.

Efficient Production of Flavonoid Glucuronides in Escherichia coli Using Flavonoid O-Glucuronosyltransferases Characterized from Marchantia polymorpha

As a model liverwort, Marchantia polymorpha contains various flavone glucuronides with cardiovascular-promoting effects and anti-inflammatory properties. However, the related glucuronosyltransferases have not yet been reported. In this study, two bifunctional UDP-glucuronic acid/UDP-glucose:flavonoid glucuronosyltransferases/glucosyltransferases, MpUGT742A1 and MpUGT736B1, were identified from M. polymorpha. Extensive enzymatic assays found that MpUGT742A1 and MpUGT736B1 exhibited efficient glucuronidation activity for flavones, flavonols, and flavanones and showed promiscuous regioselectivity at positions 3, 6, 7, 3', and 4'. These enzymes catalyzed the production of a variety of flavonoid glucuronides with medicinal value, including apigenin-7-O-glucuronide and scutellarein-7-O-glucuronide. With the use of MpUGT736B1, apigenin-4'-O-glucuronide and apigenin-7,4'-di-O-glucuronide were prepared by scaled-up enzymatic catalysis and structurally identified by NMR spectroscopy. MpUGT742A1 also displayed glucosyltransferase activity on the 7-OH position of the flavanones using UDP-glucose as the sugar donor. Furthermore, we constructed four recombinant strains by combining the pathway for increasing the UDP-glucuronic acid supply with the two novel UGTs MpUGT742A1 and MpUGT736B1. When apigenin was used as a substrate, the extracellular apigenin-4'-O-glucuronide and apigenin-7,4'-di-O-glucuronide production obtained from the Escherichia coli strain BB2 reached 598 and 81 mg/L, respectively. Our study provides new candidate genes and strategies for the biosynthesis of flavonoid glucuronides.

Map-based cloning and functional analysis of a major quantitative trait locus, BolC.Pb9.1, controlling clubroot resistance in a wild Brassica relative (Brassica macrocarpa)

KEY MESSAGE

A causal gene BoUGT76C2, conferring clubroot resistance in wild Brassica oleracea, was identified and functionally characterized. Clubroot is a devastating soil-borne disease caused by the obligate biotrophic pathogen Plasmodiophora brassica (P. brassicae), which poses a great threat to Brassica oleracea (B. oleracea) production. Although several QTLs associated with clubroot resistance (CR) have been mapped in cultivated B. oleracea, none have been cloned in B. oleracea. Previously, we found that the wild B. oleracea B2013 showed high resistance to clubroot. In this study, we constructed populations using B2013 and broccoli line 90196. CR in B2013 is quantitatively inherited, and a major QTL, BolC.Pb9.1, was identified on C09 using QTL-seq and linkage analysis. The BolC.Pb9.1 was finely mapped to a 56 kb genomic region using F2:3 populations. From the target region, the candidate BoUGT76C2 showed nucleotide variations between the parents, and was inducible in response to P. brassicae infection. We generated BoUGT76C2 overexpression lines in the 90196 background, which showed significantly enhanced resistance to P. brassicae compared to the WT line, suggesting that BoUGT76C2 corresponds to the resistance gene BolC.Pb.9.1. This is the first report on the CR gene map-based cloning and functional analysis from wild relatives, which provides a theoretical basis to the understanding of the molecular mechanism of CR, and lays a foundation to improve the CR of cultivated B. oleracea.

Gestational exposure to bisphenol AF causes endocrine disorder of corpus luteum by altering ovarian SIRT-1/Nrf2/NF-kB expressions and macrophage proangiogenic function in mice

Bisphenol AF (BPAF) is extensively used in industrial production as an emerging substitute for the earlier-used bisphenol A (BPA). Studies have found that BPAF had stronger estrogenic activities than BPA. However, the effects of BPAF on the luteal function of pregnancy and its possible mechanisms are largely unknown. In this study, pregnant mice were orally administered 3.0 and 30 mg/kg/day of BPAF from gestational day (GD) 1 to 8, and samples were collected on GD 8 and GD 19. Results showed that maternal exposure to BPAF impaired embryo implantation and reduced ovarian weight, and interfered with steroid hormone secretion, and decreased the numbers and areas of corpus luteum. BPAF treatment significantly down-regulated expression levels of ovarian Star, Cyp11a, Hsd3b1, and Cyp19a1 mRNA and CYP19a1 and ERα proteins. BPAF also disrupted markers of redox/inflammation key, including silent information regulator of transcript-1 (SIRT-1), nuclear factor erythroid 2-related factor 2 (Nrf2), and nuclear factor kappa-B (NF-ĸB) expressions along with reduced ovarian antioxidant (CAT and SOD) capacity, enhanced oxidant (H2O2 and MDA) and inflammatory factor (Il6 and Tnfa) activities. Furthermore, BPAF exposure inhibited macrophages with a pro-angiogenic phenotype that specifically expressed TIE-2, accompanied by inhibition of angiogenic factors (HIF1a, VEGFA, and Angpt1) and promotion of anti-angiogenic factor Ang-2 to suppress luteal angiogenesis. In addition, BPAF administration also induced luteolysis and apoptosis by up-regulation of COX-2, BAX/BCL-2, and Cleaved-Caspase-3 protein. Collectively, our current data demonstrated that gestational exposure to BPAF caused luteal endocrine disorder by altering ovarian SIRT-1/Nrf2/NF-kB expressions and macrophage proangiogenic function in mice.

UGT89AC1-mediated quercetin glucosylation is induced upon herbivore damage and enhances Camellia sinensis resistance to insect feeding

Quercetin is a key flavonol in tea plants (Camellia sinensis (L.) O. Kuntze) with various health benefits, and it often occurs in the form of glucosides. The roles of quercetin and its glucosylated forms in plant defense are generally not well-studied, and remain unknown in the defense of tea. Here, we found higher contents of quercetin glucosides and a decline of the aglucone upon Ectropis grisescens (E. grisescens) infestation of tea. Nine UGTs were strongly induced, among which UGT89AC1 exhibited the highest activity toward quercetin in vitro and in vivo. The mass of E. grisescens larvae that fed on plants with repressed UGT89AC1 or varieties with lower levels of UGT89AC1 was significantly lower than that of larvae fed on controls. Artificial diet supplemented with quercetin glucoside also reduced the larval growth rate, whereas artificial diet supplemented with free quercetin had no significant effect on larval growth. UGT89AC1 was located in both the cytoplasm and nucleus, and its expression was modulated by JA, JA-ILE, and MeJA. These findings demonstrate that quercetin glucosylation serves a defensive role in tea against herbivory. Our results also provide novel insights into the ecological relevance of flavonoid glycosides under biotic stress in plants.

2,4-Dihydroxybenzoic Acid, a Novel SA Derivative, Controls Plant Immunity via UGT95B17-Mediated Glucosylation: A Case Study in Camellia Sinensis

The plant hormone salicylic acid (SA) plays critical roles in plant innate immunity. Several SA derivatives and associated modification are identified, whereas the range and modes of action of SA-related metabolites remain elusive. Here, the study discovered 2,4-dihydroxybenzoic acid (2,4-DHBA) and its glycosylated form as native SA derivatives in plants whose accumulation is largely induced by SA application and Ps. camelliae-sinensis (Pcs) infection. CsSH1, a 4/5-hydroxylase, catalyzes the hydroxylation of SA to 2,4-DHBA, and UDP-glucosyltransferase UGT95B17 catalyzes the formation of 2,4-DHBA glucoside. Down-regulation reduced the accumulation of 2,4-DHBA glucosides and enhanced the sensitivity of tea plants to Pcs. Conversely, overexpression of UGT95B17 increased plant disease resistance. The exogenous application of 2,4-DHBA and 2,5-DHBA, as well as the accumulation of DHBA and plant resistance comparison, indicate that 2,4-DHBA functions as a potentially bioactive molecule and is stored mainly as a glucose conjugate in tea plants, differs from the mechanism described in Arabidopsis. When 2,4-DHBA is applied exogenously, UGT95B17-silenced tea plants accumulated more 2,4-DHBA than SA and showed induced resistance to Pcs infection. These results indicate that 2,4-DHBA glucosylation positively regulates disease resistance and highlight the role of 2,4-DHBA as potentially bioactive molecule in the establishment of basal resistance in tea plants.

RpUGT344J7 is involved in the reproduction switch of Rhopalosiphum padi with holocyclic life cycle

Many aphid species exhibit both cyclical parthenogenesis (CP) and the obligate parthenogenesis (OP) life history, which are genetically determined. In CP aphid lineages, the parthenogenetic individuals can switch from asexual to sexual reproduction quickly in response to environmental factors such as changes in photoperiod and temperature. However, the OP aphid lineages do not undergo sexual reproduction under any conditions. So far, mechanisms underlying the reproduction switch in CP aphids have not been fully elucidated. Rhopalosiphum padi, a serious worldwide insect pest of wheat, has both CP and OP lineages. Uridine diphosphate-glycosyltransferases (UGTs) are enzymes that participate in the metabolic detoxification of xenobiotics. Here, we identified 43 RpUGT genes from R. padi genome and transcriptome sequences, and found that: (1) the UGT content of the CP lineage was significantly higher than that in the OP lineage at the key time points when CP lineage mainly produce virginoparae, gynoparae, and males under inducing condition, while there were no significant difference under normal conditions; (2) RpUGT344J7 gene was highly expressed during the time points when CP lineages produce gynopara and males; (3) the critical time points for CP lineages to produce virginoparaee, gynoparae, and males were affected when the CP lineages were injected with dsRpUGT344J7; (4) the knockdown of RpUGT344J7 caused a significant reduction in the total number of virginoparae, gynoparae, and males in the offspring under inducing condition. The findings contribute to our understanding of the molecular mechanisms underlying the quick shift from asexual to sexual reproduction in aphid species.

Recent Advances in Hepatic Metabolic Regulation by the Nuclear Factor Rev-erbɑ

Rev-erbɑ (NR1D1) is a nuclear receptor superfamily member that plays a vital role in mammalian molecular clocks and metabolism. Rev-erbɑ can regulate the metabolism of drugs and the body's glucose metabolism, lipid metabolism, and adipogenesis. It is even one of the important regulatory factors regulating the occurrence of metabolic diseases (e.g., diabetes, fatty liver). Metabolic enzymes mediate most drug metabolic reactions in the body. Rev-erbɑ has been recognized to regulate drug metabolic enzymes (such as Cyp2b10 and Ugt1a9). Therefore, this paper mainly reviewed that Rev-erbɑ regulates I and II metabolic enzymes in the liver to affect drug pharmacokinetics. The expression of these drug metabolic enzymes (up-regulated or down-regulated) is related to drug exposure and effects/ toxicity. In addition, our discussion extends to Rev-erbɑ regulating some transporters (such as P-gp, Mrp2, and Bcrp), as they also play an essential role in drug metabolism. Finally, we briefly describe the role and mechanism of nuclear receptor Rev-erbɑ in lipid and glucose homeostasis, obesity, and metabolic disorders syndrome. In conclusion, this paper aims to understand better the role and mechanism of Rev-erbɑ in regulating drug metabolism, lipid, glucose homeostasis, obesity, and metabolic disorders syndrome, which explores how to target Rev-erbɑ to guide the design and development of new drugs and provide scientific reference for the molecular mechanism of new drug development, rational drug use, and drug interaction.

Systematic analysis of the UDP-glucosyltransferase family: discovery of a member involved in rutin biosynthesis in Solanum melongena

Eggplant (Solanum melongena) is an economically important crop and rich in various nutrients, among which rutin that has positive effects on human health is found in eggplant. Glycosylation mediated by UDP-glycosyltransferases (UGTs) is a key step in rutin biosynthesis. However, the UGT gene has not been reported in eggplant to date. Herein, 195 putative UGT genes were identified in eggplant by genome-wide analysis, and they were divided into 17 subgroups (Group A-P and Group R) according to the phylogenetic evolutionary tree. The members of Groups A, B, D, E and L were related to flavonol biosynthesis, and rutin was the typical flavonol. The expression profile showed that the transcriptional levels of SmUGT genes in Clusters 7-10 were closely related to those of rutin biosynthetic pathway genes. Notably, SmUGT89B2 was classified into Cluster 7 and Group B; its expression was consistent with rutin accumulation in different tissues and different leaf stages of eggplant. SmUGT89B2 was located in the nucleus and cell membrane. Virus-induced gene silencing (VIGS) and transient overexpression assays showed that SmUGT89B2 can promote rutin accumulation in eggplant. These findings provide new insights into the UGT genes in eggplant, indicating that SmUGT89B2 is likely to encode the final enzyme in rutin biosynthesis.

Quantitative analysis of the UDP-glucuronosyltransferase transcriptome in human tissues

UDP-glucuronosyltransferases (UGTs) are phase II drug metabolizing enzymes that play important roles in the detoxification of endogenous and exogenous substrates. The 22 human UGTs belong to four families (UGT1, UGT2, UGT3, and UGT8) and differ in their expression, substrate specificity, UDP-sugar preference, and physiological functions. Differential expression/activity of the UGTs contributes to interperson variability in drug responses and toxicity, hormone homeostasis, and disease/cancer risks. However, in normal tissues, the tissue-specific expression profiles and transcriptional regulation of the UGTs are still not fully understood. In this study, we comprehensively analyzed the transcriptome of 22 UGTs in 54 human tissues/regions using RNAseq data from GTEx. We then validated the findings in the liver and small intestine samples using real-time PCR. Our results showed large interindividual variability across tissues in the expression of each UGT and the overall composition of UGT pools, consisting of different UGTs and their splice isoforms. Our results also revealed coexpression of the UGTs, Cytochrome P450s, and many transcription factors in the liver, suggesting potential coregulation or functional coordination. Our results provide the groundwork for future studies to detail further the regulation of the expression and activity of the UGTs.

Nuclear factor OsNF-YC5 modulates rice seed germination by regulating synergistic hormone signaling

Regulation of seed dormancy/germination is of great importance for seedling establishment and crop production. Nuclear factor-Y (NF-Y) transcription factors regulate plant growth and development, as well as stress responses; however, their roles in seed germination remain largely unknown. In this study, we reported that NF-Y gene OsNF-YC5 knockout increased, while its overexpression reduced, the seed germination in rice (Oryza sativa L.). ABA-induced seed germination inhibition assays showed that the osnf-yc5 mutant was less sensitive but OsNF-YC5-overexpressing lines were more sensitive to exogenous ABA than the wild type. Meanwhile, MeJA treatment substantially enhanced the ABA sensitivity of OsNF-YC5-overexpressing lines during seed germination. Mechanistic investigations revealed that the interaction of OSMOTIC STRESS/ABA-ACTIVATED PROTEIN KINASE 9 (SAPK9) with OsNF-YC5 enhanced the stability of OsNF-YC5 by protein phosphorylation, while the interaction between JASMONATE ZIM-domain protein 9 (OsJAZ9) and OsNF-YC5 repressed OsNF-YC5 transcriptional activity and promoted its degradation. Furthermore, OsNF-YC5 transcriptionally activated ABA catabolic gene OsABA8ox3, reducing ABA levels in germinating seeds. However, the transcriptional regulation of OsABA8ox3 by OsNF-YC5 was repressed by addition of OsJAZ9. Notably, OsNF-YC5 improved seed germination under salinity conditions. Further investigation showed that OsNF-YC5 activated the high-affinity K+ transporter gene (OsHAK21) expression, and addition of SAPK9 could increase the transcriptional regulation of OsHAK21 by OsNF-YC5, thus substantially reducing the ROS levels to enhance seed germination under salt stress. Our findings establish that OsNF-YC5 integrates ABA and JA signaling during rice seed germination, shedding light on the molecular networks of ABA-JA synergistic interaction.

A Muti-Substrate Flavonol O-glucosyltransferases from Safflower

To explore the complete biosynthesis process of flavonoid glycosides in safflower, specifically the key glycosyltransferase that might be involved, as well as to develop an efficient biocatalyst to synthesize flavonoid glycosides, a glycosyltransferase CtUGT4, with flavonoid-O-glycosyltransferase activity, was identified in safflower. The fusion protein of CtUGT4 was heterologously expressed in Escherichia coli, and the target protein was purified. The recombinant protein can catalyze quercetin to form quercetin-7-O-glucoside, and kaempferol to form kaempferol-3-O in vitro, and a series of flavones, flavonols, dihydroflavones, chalcones, and chalcone glycosides were used as substrates to generate new products. CtUGT4 was expressed in the tobacco transient expression system, and the enzyme activity results showed that it could catalyze kaempferol to kaempferol-3-O-glucoside, and quercetin to quercetin-3-O-glucoside. After overexpressing CtUGT4 in safflower, the content of quercetin-3-O-rutinoside in the safflower florets increased significantly, and the content of quercetin-3-O-glucoside also tended to increase, which preliminarily confirmed the function of CtUGT4 flavonoid-O-glycosyltransferase. This work demonstrated the flavonoid-O-glycosyltransferase function of safflower CtUGT4 and showed differences in the affinity for different flavonoid substrates and the regioselectivity of catalytic sites in safflower, both in vivo and in vitro, providing clues for further research regarding the function of UGT genes, as well as new ideas for the cultivation engineering of the directional improvement of effective metabolites in safflower.

Integrated evolutionary pattern analyses reveal multiple origins of steroidal saponins in plants

Steroidal saponins are a class of specialized metabolites essential for plant's response to biotic and abiotic stresses. They are also important raw materials for the industrial production of steroid drugs. Steroidal saponins are present in some monocots, such as Dioscorea and Paris, but their distribution, origin, and evolution in plants remain poorly understood. By reconstructing the evolutionary history of the steroidal saponin-associated module (SSAM) in plants, we reveal that the steroidal saponin pathway has its origin in Asparagus and Dioscorea. Through evaluating the distribution and evolutionary pattern of steroidal saponins in angiosperms, we further show that steroidal saponins originated multiple times in angiosperms, and exist in early diverged lineages of certain monocot lineages including Asparagales, Dioscoreales, and Liliales. In these lineages, steroidal saponins are synthesized through the high copy and/or high expression mechanisms of key genes in SSAM. Together with shifts in gene evolutionary rates and amino acid usage, these molecular mechanisms shape the current distribution and diversity of steroidal saponins in plants. Consequently, our results provide new insights into the distribution, diversity and evolutionary history of steroidal saponins in plants, and enhance our understanding of plants' resistance to abiotic and biotic stresses. Additionally, fundamental understanding of the steroidal saponin biosynthesis will facilitate their industrial production and pharmacological applications.

The apiosyltransferase celery UGT94AX1 catalyzes the biosynthesis of the flavone glycoside apiin

Apiose is a unique branched-chain pentose found in plant glycosides and a key component of the cell wall polysaccharide pectin and other specialized metabolites. More than 1,200 plant-specialized metabolites contain apiose residues, represented by apiin, a distinctive flavone glycoside found in celery (Apium graveolens) and parsley (Petroselinum crispum) in the family Apiaceae. The physiological functions of apiin remain obscure, partly due to our lack of knowledge on apiosyltransferase during apiin biosynthesis. Here, we identified UGT94AX1 as an A. graveolens apiosyltransferase (AgApiT) responsible for catalyzing the last sugar modification step in apiin biosynthesis. AgApiT showed strict substrate specificity for the sugar donor, UDP-apiose, and moderate specificity for acceptor substrates, thereby producing various apiose-containing flavone glycosides in celery. Homology modeling of AgApiT with UDP-apiose, followed by site-directed mutagenesis experiments, identified unique Ile139, Phe140, and Leu356 residues in AgApiT, which are seemingly crucial for the recognition of UDP-apiose in the sugar donor pocket. Sequence comparison and molecular phylogenetic analysis of celery glycosyltransferases suggested that AgApiT is the sole apiosyltransferase-encoding gene in the celery genome. Identification of this plant apiosyltransferase gene will enhance our understanding of the physioecological functions of apiose and apiose-containing compounds.

Case report: Crigler-Najjar syndrome type 1 in Croatia-more than a one in a million: a case series

Crigler-Najjar syndrome (CNS) is an exceedingly rare autosomal recessive disease with an estimated incidence of 1 in a million live births. CNS type 1 (CNS1) is the most severe form, characterized by severe unconjugated hyperbilirubinemia since birth due to the absence of hepatic uridine 5'-diphosphate glucuronyltransferase (UGT1A1) activity. Daily phototherapy (PT) and liver transplant (LT) are the mainstays of therapy. Here, we present a higher-than-expected incidence of CNS1 in Croatia (6,1 in a million). In the last 31 years, we treated eight CNS1 patients from five families with no reported consanguinity. Four patients are descendants of an isolated enclave in Kosovo with a small gene pool and a high potential for inbreeding. Severe unconjugated hyperbilirubinemia was verified in a neonatal period and PT was initiated. Four patients underwent LT from living-related donors. One of them had unsuccessful hepatocyte transplantation earlier. LT was successful in three patients, and one patient died due to primary graft dysfunction. Four patients are currently treated with 9-12 h daily PT with inconsistent disease control, and gradually increasing bilirubin. One patient developed kernicterus before LT, while others have normal psychomotor development and no neurologic impairment. Genetic testing of the UGT1A1 gene in six patients from three families revealed three different homozygous mutations (c.722_723 delAG, c.717_718 delAG, and c.1021 C >T), all previously described in other populations. There is a possibility of the founder effect as an explanation for the higher incidence of CNS1 in at least a subgroup of Croatians.

UDP-glucuronosyltransferase is involved in susceptibility of Chironomus kiiensis Tokunaga, 1936 (Diptera: Chironomidae) to insecticides

UDP-glucuronosyltransferases (UGTs) could transform various exogenous and endogenous compounds, which help detoxification of pesticides in insects. To investigate the role of UGTs in the detoxification metabolism of insecticides in Chironomus kiiensis, CkUGT302M1, CkUGT302N1, CkUGT308N1 and CkUGT36J1 genes were identified with 1449-1599 bp encoding 482-532 amino acids. Four UGT genes shared 40.86∼53.36% identity with other homologous insect species, and expressed in all developmental stages, notably in the larval and adult stages. Expression of CkUGTs was higher in the gastric caecum, midgut and head. Moreover, CkUGTs expression and activity were significantly increased in C. kiiensis larvae in exposure to sublethal concentrations of carbaryl, deltamethrin and phoxim, respectively. To further explore the functions of UGT genes, the CkUGT308N1 was effectively silenced in 4th instar C. kiiensis larvae by RNA interference, which resulted in the mortality of dsCkUGT308N1 treated larvae increased by 71.43%, 111.11% and 62.50% under sublethal doses of carbaryl, deltamethrin and phoxim at the 24-h time point, respectively. The study revealed that the CkUGT308N1 gene in C. kiiensis could contribute to the metabolism of pesticides and provide a scientific basis for evaluating the water pollution of pesticides.

UGT2B13 and UGT2C1 are involved in lambda-cyhalothrin resistance in Rhopalosiphum padi

Uridine diphosphate-glucuronosyltransferases (UGTs) are major multifunctional detoxification phase II enzymes involved in the metabolic detoxification of xenobiotics. However, their roles in insecticides resistance are still unclear. In this study, we identified two UGTs genes (UGT2B13 and UGT2C1) in Rhopalosiphum padi, a serious insect pest of wheat worldwide. Bioassays results showed that the resistance ratio of R. padi resistance strain (LC-R) to lambda-cyhalothrin (LC) was 2963.8 fold. The roles of UGT2B13 and UGT2C1 in lambda-cyhalothrin resistance were evaluated. Results indicated that the UGTs contents were significantly increased in the LC resistant strain of R. padi. UGT2B13 and UGT2C1 were significantly overexpressed in the LC-R strain. Transcription levels of UGT2B13 and UGT2C1 were relatively higher in the gut of LC-R strain. RNA interference (RNAi) of UGT2B13 or UGT2C1 significantly decreased the UGTs contents of the LC-R aphids and increased mortality of R. padi exposure to the LC50 concentration of LC. This study provides a new view that UGTs are involved in LC resistance of R. padi. The findings will promote further work to detailed the functions of UGTs in the metabolism resistance of insects to insecticides.

Glycosylation of Quercetin by Selected Entomopathogenic Filamentous Fungi and Prediction of Its Products' Bioactivity

Quercetin is the most abundant flavonoid in food products, including berries, apples, cauliflower, tea, cabbage, nuts, onions, red wine and fruit juices. It exhibits various biological activities and is used for medical applications, such as treating allergic, inflammatory and metabolic disorders, ophthalmic and cardiovascular diseases, and arthritis. However, its low water solubility may limit quercetin's therapeutic potential. One method of increasing the solubility of active compounds is their coupling to polar molecules, such as sugars. The attachment of a glucose unit impacts the stability and solubility of flavonoids and often determines their bioavailability and bioactivity. Entomopathogenic fungi are biocatalysts well known for their ability to attach glucose and its 4-O-methyl derivative to bioactive compounds, including flavonoids. We investigated the ability of cultures of entomopathogenic fungi belonging to Beauveria, Isaria, Metapochonia, Lecanicillium and Metarhizium genera to biotransform quercetin. Three major glycosylation products were detected: (1), 7-O-β-D-(4″-O-methylglucopyranosyl)-quercetin, (2) 3-O-β-D-(4″-O-methylglucopyranosyl)-quercetin and (3) 3-O-β-D-(glucopyranosyl)-quercetin. The results show evident variability of the biotransformation process, both between strains of the tested biocatalysts from different species and between strains of the same species. Pharmacokinetic and pharmacodynamic properties of the obtained compounds were predicted with the use of cheminformatics tools. The study showed that the obtained compounds may have applications as effective modulators of intestinal flora and may be stronger hepato-, cardio- and vasoprotectants and free radical scavengers than quercetin.

Qualitative metabolomics-based characterization of a phenolic UDP-xylosyltransferase with a broad substrate spectrum from Lentinus brumalis

Wood-decaying fungi are the major decomposers of plant litter. Heavy sequencing efforts on genomes of wood-decaying fungi have recently been made due to the interest in their lignocellulolytic enzymes; however, most parts of their proteomes remain uncharted. We hypothesized that wood-decaying fungi would possess promiscuous enzymes for detoxifying antifungal phytochemicals remaining in the dead plant bodies, which can be useful biocatalysts. We designed a computational mass spectrometry-based untargeted metabolomics pipeline for the phenotyping of biotransformation and applied it to 264 fungal cultures supplemented with antifungal plant phenolics. The analysis identified the occurrence of diverse reactivities by the tested fungal species. Among those, we focused on O-xylosylation of multiple phenolics by one of the species tested, Lentinus brumalis. By integrating the metabolic phenotyping results with publicly available genome sequences and transcriptome analysis, a UDP-glycosyltransferase designated UGT66A1 was identified and validated as an enzyme catalyzing O-xylosylation with broad substrate specificity. We anticipate that our analytical workflow will accelerate the further characterization of fungal enzymes as promising biocatalysts.

Identification of two key UDP-glycosyltransferases responsible for the ocotillol-type ginsenoside majonside-R2 biosynthesis in Panax vietnamensis var. fuscidiscus

MAIN CONCLUSION

Two UDP-glycosyltransferases from Panax vienamensis var. fuscidiscus involved in ocotillol-type ginsenoside MR2 (majonside-R2) biosynthesis were identified. PvfUGT1 and PvfUGT2 sequentially catalyzes 20S,24S-Protopanxatriol Oxide II and 20S,24R-Protopanxatriol Oxide I to pseudoginsenoside RT4/RT5 and RT4/RT5 to 20S, 24S-MR2/20S, 24S-MR2. Ocotilol type saponin MR2 (majonside-R2) is the main active component of Panax vietnamensis var. fuscidiscus (commonly known as 'jinping ginseng') and is well known for its diverse pharmacological activities. The use of MR2 in the pharmaceutical industry currently depends on its extraction from Panax species. Metabolic engineering provides an opportunity to produce high-value MR2 by expressing it in heterologous hosts. However, the metabolic pathways of MR2 remain enigmatic, and the two-step glycosylation involved in MR2 biosynthesis has not been reported. In this study, we used quantitative real-time PCR to investigate the regulation of the entire ginsenoside pathway by MeJA (methyl jasmonate), which facilitated our pathway elucidation. We found six candidate glycosyltransferases by comparing transcriptome analysis and network co-expression analysis. In addition, we identified two UGTs (PvfUGT1 and PvfUGT2) through in vitro enzymatic reactions involved in the biosynthesis of MR2 which were not reported in previous studies. Our results show that PvfUGT1 can transfer UDP-glucose to the C6-OH of 20S, 24S-protopanaxatriol oxide II and 20S, 24R-protopanaxatriol oxide I to form pseudoginsenoside RT4 and pseudoginsenoside RT5, respectively. PvfUGT2 can transfer UDP-xylose to pseudoginsenoside RT4 and pseudoginsenoside RT5 to form 20S, 24S-MR2 and 20S, 24S-MR2. Our study paves the way for elucidating the biosynthesis of MR2 and producing MR2 by synthetic biological methods.

UDP-glucosyltransferase OsUGT75A promotes submergence tolerance during rice seed germination

Submergence stress represents a major obstacle limiting the application of direct seeding in rice cultivation. Under flooding conditions, coleoptile elongation can function as an escape strategy that contributes to submergence tolerance during seed germination in rice; however, the underlying molecular bases have yet to be fully determined. Herein, we report that natural variation of rice coleoptile length subjected to submergence is determined by the glucosyltransferase encoding gene OsUGT75A. OsUGT75A regulates coleoptile length via decreasing free abscisic acid (ABA) and jasmonic acid (JA) levels by promoting glycosylation of these two phytohormones under submergence. Moreover, we find that OsUGT75A accelerates coleoptile length through mediating the interactions between JASMONATE ZIMDOMAIN (OsJAZ) and ABSCISIC ACID-INSENSITIVE (OsABI) proteins. Last, we reveal the origin of the haplotype that contributes to coleoptile length in response to submergence and transferring this haplotype to indica rice can enhance coleoptile length in submergence conditions. Thus, we propose that OsUGT75A is a useful target in breeding of rice varieties suitable for direct seeding cultivation.

Effects of azadirachtin on detoxification-related gene expression in the fat bodies of the fall armyworm, Spodoptera frugiperda

The fall armyworm, Spodoptera frugiperda, has become a worldwide pest and threatens world food production. A previous study indicated that azadirachtin, the most effective botanical insecticide for S. frugiperda, inhibits larval growth of the insect. The effect of azadirachtin on the tissues of the larvae, however, remains to be determined. In this study, the effects of azadirachtin on the structure of fat bodies were analyzed. Comparative transcriptomic analysis was conducted between controls and samples treated with 0.1 μg/g azadirachtin for 7 days to explore potential relevant mechanisms. The expression of 5356 genes was significantly affected after azadirachtin treatment, with 3020 up-regulated and 2336 down-regulated. Among them, 137 encode detoxification enzymes, including 53 P450s, 20 GSTs, 27 CarEs, 16 UGTs, and 12 ABC transporters. Our results indicated that azadirachtin could destroy fat body structure and change the mRNA levels of detoxification-related genes. The up-regulated genes encoding detoxification enzymes might be related to detoxifying azadirachtin. Our results elucidate a preliminary mechanism of azadirachtin detoxification in the fat bodies of S. frugiperda larvae.

UDP-Glycosyltransferases in Edible Fungi: Function, Structure, and Catalytic Mechanism

UDP-glycosyltransferases (UGTs) are the most studied glycosyltransferases, and belong to large GT1 family performing the key roles in antibiotic synthesis, the development of bacterial glycosyltransferase inhibitors, and in animal inflammation. They transfer the glycosyl groups from nucleotide UDP-sugars (UDP-glucose, UDP-galactose, UDP-xylose, and UDP-rhamnose) to the acceptors including saccharides, proteins, lipids, and secondary metabolites. The present review summarized the recent of UDP-glycosyltransferases, including their structures, functions, and catalytic mechanism, especially in edible fungi. The future perspectives and new challenges were also summarized to understand of their structure–function relationships in the future. The outputs in this field could provide a reference to recognize function, structure, and catalytic mechanism of UDP-glycosyltransferases for understanding the biosynthesis pathways of secondary metabolites, such as hydrocarbons, monoterpenes, sesquiterpene, and polysaccharides in edible fungi.

Identification of a tomato UDP-arabinosyltransferase for airborne volatile reception

Volatiles from herbivore-infested plants function as a chemical warning of future herbivory for neighboring plants. (Z)-3-Hexenol emitted from tomato plants infested by common cutworms is taken up by uninfested plants and converted to (Z)-3-hexenyl β-vicianoside (HexVic). Here we show that a wild tomato species (Solanum pennellii) shows limited HexVic accumulation compared to a domesticated tomato species (Solanum lycopersicum) after (Z)-3-hexenol exposure. Common cutworms grow better on an introgression line containing an S. pennellii chromosome 11 segment that impairs HexVic accumulation, suggesting that (Z)-3-hexenol diglycosylation is involved in the defense of tomato against herbivory. We finally reveal that HexVic accumulation is genetically associated with a uridine diphosphate-glycosyltransferase (UGT) gene cluster that harbors UGT91R1 on chromosome 11. Biochemical and transgenic analyses of UGT91R1 show that it preferentially catalyzes (Z)-3-hexenyl β-D-glucopyranoside arabinosylation to produce HexVic in planta.

Recruitment of distinct UDP-glycosyltransferase families demonstrates dynamic evolution of chemical defense within Eucalyptus L'Hér

The economic and ecologically important genus Eucalyptus is rich in structurally diverse specialized metabolites. While some specialized metabolite classes are highly prevalent across the genus, the cyanogenic glucoside prunasin is only produced by c. 3% of species. To investigate the evolutionary mechanisms behind prunasin biosynthesis in Eucalyptus, we compared de novo assembled transcriptomes, together with online resources between cyanogenic and acyanogenic species. Identified genes were characterized in vivo and in vitro. Pathway characterization of cyanogenic Eucalyptus camphora and Eucalyptus yarraensis showed for the first time that the final glucosylation step from mandelonitrile to prunasin is catalyzed by a novel UDP-glucosyltransferase UGT87. This step is typically catalyzed by a member of the UGT85 family, including in Eucalyptus cladocalyx. The upstream conversion of phenylalanine to mandelonitrile is catalyzed by three cytochrome P450 (CYP) enzymes from the CYP79, CYP706, and CYP71 families, as previously shown. Analysis of acyanogenic Eucalyptus species revealed the loss of different ortholog prunasin biosynthetic genes. The recruitment of UGTs from different families for prunasin biosynthesis in Eucalyptus demonstrates important pathway heterogeneities and unprecedented dynamic pathway evolution of chemical defense within a single genus. Overall, this study provides relevant insights into the tremendous adaptability of these long-lived trees.

Illuminating the biosynthesis pathway genes involved in bioactive specific monoterpene glycosides in Paeonia veitchii Lynch by a combination of sequencing platforms

BACKGROUND

Paeonia veitchii Lynch, a well-known herb from the Qinghai-Tibet Plateau south of the Himalayas, can synthesize specific monoterpene glycosides (PMGs) with multiple pharmacological activities, and its rhizome has become an indispensable ingredient in many clinical drugs. However, little is known about the molecular background of P. veitchii, especially the genes involved in the biosynthetic pathway of PMGs.

RESULTS

A corrective full-length transcriptome with 30,827 unigenes was generated by combining next-generation sequencing (NGS) and single-molecule real-time sequencing (SMRT) of six tissues (leaf, stem, petal, ovary, phloem and xylem). The enzymes terpene synthase (TPS), cytochrome P450 (CYP), UDP-glycosyltransferase (UGT), and BAHD acyltransferase, which participate in the biosynthesis of PMGs, were systematically characterized, and their functions related to PMG biosynthesis were analysed. With further insight into TPSs, CYPs, UGTs and BAHDs involved in PMG biosynthesis, the weighted gene coexpression network analysis (WGCNA) method was used to identify the relationships between these genes and PMGs. Finally, 8 TPSs, 22 CYPs, 7 UGTs, and 2 BAHD genes were obtained, and these putative genes were very likely to be involved in the biosynthesis of PMGs. In addition, the expression patterns of the putative genes and the accumulation of PMGs in tissues suggested that all tissues are capable of biosynthesizing PMGs and that aerial plant parts could also be used to extract PMGs.

CONCLUSION

We generated a large-scale transcriptome database across the major tissues in P. veitchii, providing valuable support for further research investigating P. veitchii and understanding the genetic information of plants from the Qinghai-Tibet Plateau. TPSs, CYPs, UGTs and BAHDs further contribute to a better understanding of the biology and complexity of PMGs in P. veitchii. Our study will help reveal the mechanisms underlying the biosynthesis pathway of these specific monoterpene glycosides and aid in the comprehensive utilization of this multifunctional plant.

Chemotherapy-related hyperbilirubinemia in pediatric acute lymphoblastic leukemia: a genome-wide association study from the AIEOP-BFM ALL study group

BACKGROUND

Characterization of clinical phenotypes in context with tumor and host genomic information can aid in the development of more effective and less toxic risk-adapted and targeted treatment strategies. To analyze the impact of therapy-related hyperbilirubinemia on treatment outcome and to identify contributing genetic risk factors of this well-recognized adverse effect we evaluated serum bilirubin levels in 1547 pediatric patients with acute lymphoblastic leukemia (ALL) and conducted a genome-wide association study (GWAS).

PATIENTS AND METHODS

Patients were treated in multicenter trial AIEOP-BFM ALL 2000 for pediatric ALL. Bilirubin toxicity was graded 0 to 4 according to the Common Toxicity Criteria (CTC) of the National Cancer Institute. In the GWAS discovery cohort, including 650 of the 1547 individuals, genotype frequencies of 745,895 single nucleotide variants were compared between 435 patients with hyperbilirubinemia (CTC grades 1-4) during induction/consolidation treatment and 215 patients without it (grade 0). Replication analyses included 224 patients from the same trial.

RESULTS

Compared to patients with no (grade 0) or moderate hyperbilirubinemia (grades 1-2) during induction/consolidation, patients with grades 3-4 had a poorer 5-year event free survival (76.6 ± 3% versus 87.7 ± 1% for grades 1-2, P = 0.003; 85.2 ± 2% for grade 0, P < 0.001) and a higher cumulative incidence of relapse (15.6 ± 3% versus 9.0 ± 1% for grades 1-2, P = 0.08; 11.1 ± 1% for grade 0, P = 0.007). GWAS identified a strong association of the rs6744284 variant T allele in the UGT1A gene cluster with risk of hyperbilirubinemia (allelic odds ratio (OR) = 2.1, P = 7 × 10^- 8). TT-homozygotes had a 6.5-fold increased risk of hyperbilirubinemia (grades 1-4; 95% confidence interval (CI) = 2.9-14.6, P = 7 × 10^- 6) and a 16.4-fold higher risk of grade 3-4 hyperbilirubinemia (95% CI 6.1-43.8, P = 2 × 10^- 8). Replication analyses confirmed these associations with joint analysis yielding genome-wide significance (allelic OR = 2.1, P = 6 × 10^- 11; 95% CI 1.7-2.7). Moreover, rs6744284 genotypes were strongly linked to the Gilbert's syndrome-associated UGT1A1*28/*37 allele (r² = 0.70), providing functional support for study findings. Of clinical importance, the rs6744284 TT genotype counterbalanced the adverse prognostic impact of high hyperbilirubinemia on therapy outcome.

CONCLUSIONS

Chemotherapy-related hyperbilirubinemia is a prognostic factor for treatment outcome in pediatric ALL and genetic variation in UGT1A aids in predicting the clinical impact of hyperbilirubinemia.

TRIAL REGISTRATION

http://www.

CLINICALTRIALS

gov ; #NCT00430118.

Molecular Cloning, Expression, and Functional Analysis of Glycosyltransferase (TbUGGT) Gene from Trapa bispinosa Roxb

Trapa bispinosa Roxb. is an economical crop for medicine and food. Its roots, stems, leaves, and pulp have medicinal applications, and its shell is rich in active ingredients and is considered to have a high medicinal value. One of the main functional components of the Trapa bispinosa Roxb. shell is 1-galloyl-beta-D-glucose (βG), which can be used in medical treatment and is also an essential substrate for synthesizing the anticancer drug beta-penta-o-Galloyl-glucosen (PGG). Furthermore, gallate 1-beta-glucosyltransferase (EC 2.4.1.136) has been found to catalyze gallic acid (GA) and uridine diphosphate glucose (UDPG) to synthesize βG. In our previous study, significant differences in βG content were observed in different tissues of Trapa bispinosa Roxb. In this study, Trapa bispinosa Roxb. was used to clone 1500 bp of the UGGT gene, which was named TbUGGT, to encode 499 amino acids. According to the specificity of the endogenous expression of foreign genes in Escherichia coli, the adaptation codon of the cloned original genes was optimized for improved expression. Bioinformatic and phylogenetic tree analyses revealed the high homology of TbUGGT with squalene synthases from other plants. The TbUGGT gene was constructed into a PET-28a expression vector and then transferred into Escherichia coli Transsetta (DE3) for expression. The recombinant protein had a molecular weight of 55 kDa and was detected using SDS-PAGE. The proteins were purified using multiple fermentation cultures to simulate the intracellular environment, and a substrate was added for in vitro reaction. After the enzymatic reaction, the levels of βG in the product were analyzed using HPLC and LC-MS, indicating the catalytic activity of TbUGGT. The cloning and functional analysis of TbUGGT may lay the foundation for further study on the complete synthesis of βG in E. coli.

The Somatic Mutation Landscape of UDP-Glycosyltransferase (UGT) Genes in Human Cancers

The human UDP-glycosyltransferase (UGTs) superfamily has a critical role in the metabolism of anticancer drugs and numerous pro/anti-cancer molecules (e.g., steroids, lipids, fatty acids, bile acids and carcinogens). Recent studies have shown wide and abundant expression of UGT genes in human cancers. However, the extent to which UGT genes acquire somatic mutations within tumors remains to be systematically investigated. In the present study, our comprehensive analysis of the somatic mutation profiles of 10,069 tumors from 33 different TCGA cancer types identified 3427 somatic mutations in UGT genes. Overall, nearly 18% (1802/10,069) of the assessed tumors had mutations in UGT genes with huge variations in mutation frequency across different cancer types, ranging from over 25% in five cancers (COAD, LUAD, LUSC, SKCM and UCSC) to less than 5% in eight cancers (LAML, MESO, PCPG, PAAD, PRAD, TGCT, THYM and UVM). All 22 UGT genes showed somatic mutations in tumors, with UGT2B4, UGT3A1 and UGT3A2 showing the largest number of mutations (289, 307 and 255 mutations, respectively). Nearly 65% (2260/3427) of the mutations were missense, frame-shift and nonsense mutations that have been predicted to code for variant UGT proteins. Furthermore, about 10% (362/3427) of the mutations occurred in non-coding regions (5' UTR, 3' UTR and splice sites) that may be able to alter the efficiency of translation initiation, miRNA regulation or the splicing of UGT transcripts. In conclusion, our data show widespread somatic mutations of UGT genes in human cancers that may affect the capacity of cancer cells to metabolize anticancer drugs and endobiotics that control pro/anti-cancer signaling pathways. This highlights their potential utility as biomarkers for predicting therapeutic efficacy and clinical outcomes.

Duplication, Loss, and Evolutionary Features of Specific UDP-Glucuronosyltransferase Genes in Carnivora (Mammalia, Laurasiatheria)

UDP-glucuronosyltransferases (UGTs) are one of the most important enzymes for xenobiotic metabolism or detoxification. Through duplication and loss of genes, mammals evolved the species-specific variety of UGT isoforms. Among mammals, Carnivora is one of the orders that includes various carnivorous species, yet there is huge variation of food habitat. Recently, lower activity of UGT1A and 2B were shown in Felidae and pinnipeds, suggesting evolutional loss of these isoforms. However, comprehensive analysis for genetic or evolutional features are still missing. This study was conducted to reveal evolutional history of UGTs in Carnivoran species. We found specific gene expansion of UGT1As in Canidae, brown bear and black bear. We also found similar genetic duplication in UGT2Bs in Canidae, and some Mustelidae and Ursidae. In addition, we discovered contraction or complete loss of UGT1A7–12 in phocids, some otariids, felids, and some Mustelids. These studies indicate that even closely related species have completely different evolution of UGTs and further imply the difficulty of extrapolation of the pharmacokinetics and toxicokinetic result of experimental animals into wildlife carnivorans.

Influence of UGT1A1 Genetic Variants on Free Bilirubin Levels in Japanese Newborns: A Preliminary Study

BACKGROUND

Free bilirubin (Bf) is a better marker than total serum bilirubin (TSB) for predicting bilirubin encephalopathy (BE). To date, two UGT1A1 genetic variants (rs4148323 and rs3064744) have been associated with neonatal hyperbilirubinemia; however, the direct association between UGT1A1 variants and Bf levels in newborns has not been elucidated.

METHODS

We retrospectively analyzed the clinical data of 484 infants, including the genotype data of two UGT1A1 genetic variants. We divided the infants into a high Bf group (Bf ≥ 1.0 µg/dL, n = 77) and a non-high Bf group (Bf < 1.0 µg/dL, n = 407), based on the peak Bf values. Logistic regression analysis was performed to calculate the odds ratios (ORs) for each variant allele compared to wild-type alleles.

RESULTS

The frequencies of the A allele in rs4148323 and (TA)₇ allele in rs3064744 in the high Bf group (29% and 4%, respectively) were significantly different from those in the non-high Bf group (16% and 12%, respectively). In logistic regression analysis, for rs4148323, the A allele was significantly associated with an increased risk of hyper-free bilirubinemia over the G allele (adjusted OR: 1.80, 95% confidence interval [CI]: 1.19-2.72, p < 0.01). However, for rs3064744, the (TA)₇ allele was significantly associated with a decreased risk of hyper-free bilirubinemia over the (TA)₆ allele (adjusted OR: 0.42, 95% CI: 0.18-0.95, p = 0.04).

CONCLUSIONS

This study is the first to show that the A allele in rs4148323 is a risk factor and that the (TA)₇ allele in rs3064744 is a protective factor for developing hyper-free bilirubinemia in Japanese newborns.

Genome-wide identification, evolution and function analysis of UGTs superfamily in cotton

Glycosyltransferases mainly catalyse the glycosylation reaction in living organisms and widely exists in plants. UGTs have been identified from G. raimondii, G. arboreum and G. hirsutum. However, Genome-wide systematic analysis of UGTs superfamily have not been studied in G. barbadense. 752 UGTs were identified from four cotton species and grouped into 18 clades, of which R was newly discovered clades. Most UGTs were clustered at both ends of the chromosome and showed a heterogeneous distribution. UGT proteins were widely distributed in cells, with the highest distribution in chloroplasts. UGTs of the same clade shared similar intron/exon structural features. During evolution, the gene family has undergone strong selection for purification. UGTs were significantly enriched in “transcriptional activity (GO:0016758)” and “metabolic processes (GO:0008152)”. Genes from the same clade differed in function under various abiotic stresses. The analysis of cis-acting element and qRT–PCR may indicate that GHUGTs play important roles in plant growth, development and abiotic stress. We further found that GHUGT74-2 plays an important role under submergence. The study broadens the understanding of UGTs in terms of gene characteristics, evolutionary processes, and gene function in cotton and provides a new way to systematically and globally understand the structure–function relationship of multigene families in the evolutionary process.

Deciphering the Molecular Mechanisms of Insecticide Resistance From the Transcriptome Data of Field Evolved Spinosad Resistant and Susceptible Populations of Plutella xylostella (Lepidoptera: Plutellidae)

Diamondback moth, Plutella xylostella is a serious pest of cruciferous vegetables and causes substantial economic loss all over the world. This study was undertaken to decipher the molecular mechanisms involved in the field evolved insecticide resistance in P. xylostella upon exposure to spinosad. To do so, spinosad-resistant and susceptible larval populations were subjected to transcriptome analysis using Illumina paired-end sequencing. De novo assembly was generated from raw reads of both the samples which resulted in the identification of 41,205 unigenes. Functional annotation and digital gene expression analysis were carried out to determine the differentially expressed genes. 1,348 unigenes were found to have a significant differential expression in the resistant population. Several genes involved in insecticide resistance like CYP P450, GSTs, small heat shock protein, and UDP glycosyltransferase were found to be up-regulated while genes related to mitochondrial energy metabolism and cuticular processes were down-regulated. Further, gene mining and phylogenetic analysis of two important gene families namely, CYP and GSTs were performed and the results revealed that these genes could play a major role in the development of field evolved spinosad resistance in P. xylostella by gene duplication and differential gene expression.

Evolved transcriptional responses and their trade-offs after long-term adaptation of Bemisia tabaci to a marginally-suitable host

Although generalist insect herbivores can migrate and rapidly adapt to a broad range of host plants, they can face significant difficulties when accidentally migrating to novel and marginally-suitable hosts. What happens, both in performance and gene expression regulation, if these marginally-suitable hosts must be used for multiple generations before migration to a suitable host can take place, largely remains unknown. In this study, we established multigenerational colonies of the whitefly Bemisia tabaci, a generalist phloem-feeding species, adapted to a marginally-suitable host (habanero pepper) or an optimal host (cotton). We used reciprocal host tests to estimate the differences in performance of the populations on both hosts under optimal (30 oC) and mild-stressful (24 oC) temperature conditions, and documented the associated transcriptomic changes. The habanero pepper-adapted population greatly improved its performance on habanero pepper but did not reach its performance level on cotton, the original host. It also showed reduced performance on cotton, relative to the non-adapted population, and an antagonistic effect of the lower-temperature stressor. The transcriptomic data revealed that most of the expression changes, associated with long-term adaptation to habanero pepper, can be categorized as "evolved" with no initial plastic response. Three molecular functions dominated: enhanced formation of cuticle structural constituents, enhanced activity of oxidation-reduction processes involved in neutralization of phytotoxins and reduced production of proteins from the cathepsin B family. Taken together, these findings indicate that generalist insects can adapt to novel host plants by modifying the expression of a relatively small set of specific molecular functions.

Complete Reaction Phenotyping of Propranolol and 4-Hydroxypropranolol with the 19 Enzymes of the Human UGT1 and UGT2 Families

Propranolol is a competitive non-selective beta-receptor antagonist that is available on the market as a racemic mixture. In the present study, glucuronidation of propranolol and its equipotent phase I metabolite 4-hydroxypropranolol by all 19 members of the human UGT1 and UGT2 families was monitored. UGT1A7, UGT1A9, UGT1A10 and UGT2A1 were found to glucuronidate propranolol, with UGT1A7, UGT1A9 and UGT2A1 mainly acting on (S)-propranolol, while UGT1A10 displays the opposite stereoselectivity. UGT1A7, UGT1A9 and UGT2A1 were also found to glucuronidate 4-hydroxypropranolol. In contrast to propranolol, 4-hydroxypropranolol was found to be glucuronidated by UGT1A8 but not by UGT1A10. Additional biotransformations with 4-methoxypropanolol demonstrated different regioselectivities of these UGTs with respect to the aliphatic and aromatic hydroxy groups of the substrate. Modeling and molecular docking studies were performed to explain the stereoselective glucuronidation of the substrates under study.

Naftopidil enantiomers suppress androgen accumulation and induce cell apoptosis via the UDP-glucuronosyltransferase 2B15 in benign prostate hyperplasia

Accumulation of androgens mediate alterations in prostate growth and has emerged as an essential factor in benign prostate hyperplasia (BPH). Dihydrotestosterone (DHT), the most potent natural androgen, binds to androgen receptors (AR) and regulates the prostate growth. Many inhibitors of DHT synthesis have been developed to reduce DHT levels and used in the treatment of prostate diseases. However, therapies targeting the elimination of the DHT remain limited. The DHT in prostate is metabolized by UDP-glucuronosyltransferase 2B (UGT2B) and transforms into inactive products. In this study, we analyzed and demonstrated that two enantiomers of naftopidil (NAF), an α1D/1A-adrenoceptor blocker, induced expression and activity of UGT2B in BPH rat prostate models as well as UGT2B15 in human prostate cells, BPH-1. The NAF enantiomers reduced intraprostatic and intracellular DHT levels, thus promoting cell apoptosis. Besides, assays with siRNA UGT2B15 transfection showed that UGT2B15 played an essential role in mediating the effects of the NAF enantiomers. The UGT2B15 mediated the inhibition of AR and PSA expression by NAF enantiomers. The data showed that the mechanism of upregulating UGT2B15 by the NAF enantiomers might differ from that of AR antagonists and 5α-reductase inhibitors. Together, our results demonstrated that NAF enantiomers could be potential and novel UGT2B15 regulators, which accelerated the DHT elimination and promoted apoptosis of BPH-1 cells. This study could help expand the clinical application of NAF and support the development of new therapeutic strategies targeting the elimination of androgens for the treatment of BPH and other androgen-sensitive diseases.

Genome-Wide Analysis and Profile of UDP-Glycosyltransferases Family in Alfalfa (Medicago sativa L.) under Drought Stress

Drought stress is one of the major constraints that decreases global crop productivity. Alfalfa, planted mainly in arid and semi-arid areas, is of crucial importance in sustaining the agricultural system. The family 1 UDP-glycosyltransferases (UGT) is indispensable because it takes part in the regulation of plant growth and stress resistance. However, a comprehensive insight into the participation of the UGT family in adaptation of alfalfa to drought environments is lacking. In the present study, a genome-wide analysis and profiling of the UGT in alfalfa were carried out. A total of 409 UGT genes in alfalfa (MsUGT) were identified and they are clustered into 13 groups. The expression pattern of MsUGT genes were analyzed by RNA-seq data in six tissues and under different stresses. The quantitative real-time PCR verification genes suggested the distinct role of the MsUGT genes under different drought stresses and abscisic acid (ABA) treatment. Furthermore, the function of MsUGT003 and MsUGT024, which were upregulated under drought stress and ABA treatment, were characterized by heterologous expression in yeast. Taken together, this study comprehensively analyzed the UGT gene family in alfalfa for the first time and provided useful information for improving drought tolerance and in molecular breeding of alfalfa.