UDP-glycosyltransferase Genes Research Articles

Genome-wide characterization of the tomato UDP-glycosyltransferase gene family and functional identification of SlUDPGT52 in drought tolerance

Abiotic stresses are major factors constraining the growth, development and productivity of tomato (Solanum lycopersicum), the most cultivated vegetable crop worldwide. Uridine diphosphate glycosyltransferases (UDPGTs or UGTs) are essential enzymes that utilize 5-uridine diphosphate as a glycosyl donor molecule to facilitate the catalysis of glycosylation reactions across diverse substrates, thereby playing a pivotal role in conferring abiotic stress tolerance. Currently, there is a limited understanding of the structure and functions of the UDPGT gene family in tomato. In this work, 106 members of the SlUDPGT gene family were identified through in silico analysis, besides, their protein sequence properties, phylogenetic relationships, gene structure, chromosomal distribution, cis-acting elements, tissue expression and hormone- and stress-induced expression were comprehensively investigated. The expression of representative SlUDPGTs under abiotic stress and exogenous hormone treatments, including salt, polyethylene glycol, methyl viologen, gibberellic acid, jasmonic acid, abscisic acid and brassinolide, was investigated through qRT‒PCR analysis. Numerous cis-acting elements linked to stress and hormone signaling were present in the promoter regions of SlUDPGTs. According to microarray data, most SlUDPGT genes were responsive to hormones and abiotic stresses, while certain SlUDPGTs were specifically differentially expressed under Botrytis cinerea and tomato spotted wilt virus infection. Additionally, diverse expression profiles of SlUDPGTs were observed in various tissues and developmental stages. Furthermore, CRISPR/Cas9-mediated knockout of SlUDPGT52 led to enhanced drought tolerance due to enhanced reactive oxygen species (ROS) scavenging. These findings lay the foundations for the future functional characterization of specific UDPGT gene family members, assisting the biotechnology-mediated improvement of tomato and other horticultural crops.

Genome-Wide Analysis of Family-1 UDP-Glycosyltransferases in Potato (Solanum tuberosum L.): Identification, Phylogenetic Analysis and Determination of Response to Osmotic Stress.

Family-1 UDP-glycosyltransferases (UGTs) are the most common and functional glycosyltransferases in the plant world. UGT is closely related to plant growth and the response to abiotic stress. However, despite systematic research, our understanding of potato UGT genes is still unclear. In this study, we identified 174 potato UGT proteins based on their conserved plant secondary product glycosyltransferase (PSPG) motifs. Phylogenetic analyses were used to compare these proteins with Arabidopsis UGTs and other plant UGTs, and it was found that they could be clustered into 18 distinct groups. Patterns of intron gain/loss and intron phases within potato UGTs revealed highly conserved intron insertion events. The promoter cis-elements of these 174 UGT genes were systematically investigated. The promoter regions of these UGT genes are known to contain various classes of cis-acting compounds. These include elements that are light-responsive, phytohormone-responsive, and stress-responsive. Transcriptome data analysis established that 25, 10, 6, and 4 of these 174 UGT genes were specifically expressed in leaves, roots, stolons, and young tubers, respectively. The mannitol-treated transcriptomic data showed thirty-eight UGT genes were significantly upregulated. The quantitative real-time PCR results showed that the four genes were all responsive to osmotic stress under a 10% PEG6000 treatment. The results of our study provide a basis for clarifying the molecular mechanism of potato osmotic stress resistance and better understanding its function in the future.

Endophyte-inoculated rhizomes of Paris polyphylla improve polyphyllin biosynthesis and yield: a transcriptomic analysis of the underlying mechanism.

Polyphyllin from Paris polyphylla var. yunnanensis exhibits anti-inflammatory, analgesic, antibacterial, and antiviral properties. However, the current production of polyphyllin can barely meet market demand. To improve the content of polyphyllin produced by P. polyphylla, two endophyte strains, Bacillus cereus LgD2 and Fusarium oxysporum TPB, were isolated from Paris fargesii Franch. and inoculated in the roots of P. polyphylla. Both symbiotic strains significantly promoted the accumulation of saponins in P. polyphylla. The content of polyphyllin in rhizomes of P. polyphylla treated with TPB with LgD2 strain was determined using High Performance Liquid Chromatography and the expressed genes were analyzed by RNA-seq. Gene Ontology and Kyoto Encyclopedia of Genes annotations were performed on the differentially expressed genes, a clustering tree of UDP-glycosyltransferase (UGT) and cytochrome P450 (CYP450) gene families was constructed, and UGT and CYP450 involved in the biosynthesis of polyphyllin were predicted using weighted correlation network analysis (WGCNA). RNA-seq and qRT-PCR analyses showed that endophytic inoculation did not promote polyphyllin accumulation by enhancing the upstream terpene biosynthesis pathway, but probably by up-regulating the downstream CYP450 and UGT genes associated with polyphyllin biosynthesis. Genomes enrichment analyses of differentially expressed genes indicated that inoculation with LgD2 and TPB played a positive role in promoting the defense against pathogenic bacteria, enhancing the biosynthesis of carbohydrates, attenuating the process of nitrogen metabolism, and maintaining the equilibrium of the redox reaction homeostasis, potentially indirectly enhancing the polyphyllin yield of P. polyphylla. By combining differentially expressed genes screening, WGCNA, and phylogenetic tree analyses, 17 CYP450 and 2 UGT candidate genes involved in the biosynthesis of polyphyllin I, polyphyllin II, polyphyllin VII, polyphyllin D, and polyphyllin H were identified. These results suggest that endophytes probably effectively promote the accumulation of polyphyllin by regulating key downstream genes in biosynthetic pathways. This study provides a new approach for investigating the regulatory mechanisms of endophytes that promote the production and accumulation of polyphyllin in P. polyphylla, providing a basis for further elucidating the mechanisms of plant-endophyte interactions.

Identification, evolution and expression analysis of the UDP-glycosyltransferase gene family in cucumber (Cucumis sativus L.)

The UDP-glycosyltransferase (UGT) family is known for having the largest number of glycosyltransferases, and research has highlighted the fundamental role of UGT family members in both plant development and stress response. Cucumber is an important vegetable crop cultivated worldwide, however, the UGT family members was not studied in cucumber. Therefore, identified and characterization of the CsUGT gene family in cucumber was performed in this study. A total of 94 members of the CsUGT family were identified, which were distributed across the seven chromosomes. Cis-acting elements analysis of the CsUGT genes indicated their potential role in development and responses to stresses. Phylogenetic, collinearity, and motif analyses revealed a high degree of conservation among UGT family members in different species. Furthermore, expression analysis of the CsUGT genes was performed using the transcriptome data from previous studies and by quantitative reverse transcription PCR (qRT-PCR) in this study. The results revealed that these genes exhibit specific spatial and temporal expression patterns, and their expression were in response to different stresses. In addition, the CsUGT genes that potentially targeted by miRNA was predicted, and 74 CsUGT genes might be regulated by 41 miRNAs in cucumber. To further investigate the function of CsUGT family members, we conducted analysis of transcriptional regulation and protein-protein interactions (PPI). It showed that 47 CsUGTs have the capability to interact with other members of the CsUGT family, and 1844 transcription factors (TFs) might regulate 64 CsUGT genes. These findings provided a foundation for further investigation into the function of the CsUGT gene family in cucumber.

Identification and Characterization of CtUGT3 as the Key Player of Astragalin Biosynthesis in Carthamus tinctorius L.

Safflower (Carthamus tinctorius L.) is a multipurpose economic crop that is distributed worldwide. Flavonoid glycosides are the main bioactive components in safflower, but only a few UDP-glycosyltransferases (UGT) have been identified. Three differentially expressed UGT genes related with the accumulation of 9 flavonoid O-glycosides were screened from metabolomics and transcriptome analysis. Safflower corolla protoplasts were used to confirm the glycosylation ability of UGT candidates in vivo for the first time. The astragalin content was significantly increased only when CtUGT3 was overexpressed. CtUGT3 also showed flavonoid 3-OH and 7-OH glycosylation activities in vitro. Molecular modeling and site-directed mutagenesis revealed that G15, T136, S276, and E384 were critical catalytic residues for the glycosylation ability of CtUGT3. These results demonstrate that CtUGT3 has a flavonoid 3-OH glycosylation function and is involved in the biosynthesis of astragalin in safflower. This study provides a reference for flavonoid biosynthesis genes research in nonmodel plants.

UDP-glycosyltransferase gene SlUGT73C1 from Solanum lycopersicum regulates salt and drought tolerance in Arabidopsis thaliana L.

Among abiotic stresses, plants are the most vulnerable to salt and drought stresses. These stresses affect plant growth and development. Glycosyltransferases are involved in the responses of plants to abiotic stresses. In this study, a UDP-glycosyltransferase gene (SlUGT73C1) from Solanum lycopersicum was isolated and identified, which exhibited induction under salt or drought stress. The full length of SlUGT73C1 was 1485bp, encoding 494 amino acids. Stress-related cis-acting elements were present in the promoter sequence of SlUGT73C1, such as ARE, LTR, and GC motifs. Compared with the wild-type plants, Arabidopsis thaliana overexpressing SlUGT73C1 exhibited increased seed germination rate and SOD and POD activities, decreased MDA content, and increased expression levels of osmotic stress regulators genes, rate-limiting enzymes genes in the proline synthesis pathway, Na+/K+ reverse transporter genes, and rate-limiting genes in the ABA biosynthesis pathway under salt or drought stress. These results indicated that SlUGT73C1 plays an important role in regulating salt and drought tolerance in plants.

Functional analysis of UDP-glycosyltransferase genes conferring indoxacarb resistance in Spodoptera litura

UDP-glycosyltransferase (UGT) is the major detoxification enzymes of phase II involved in xenobiotics metabolism, which potentially mediates the formation of insect resistance. Previous transcriptome sequencing studies have found that several UGT genes were upregulated in indoxacarb resistant strains of Spodoptera litura, but whether these UGT genes were involved in indoxacarb resistance and their functions in resistance were unclear. In this study, the UGTs inhibitor, 5-nitrouracil, enhanced the toxicity of indoxacarb against S. litura, preliminarily suggesting that UGTs were participated in indoxacarb resistance. Two UGT genes, UGT33J17 and UGT41D10 were upregulated in the resistant strains and could be induced by indoxacarb. Alignment of UGT protein sequences revealed two conserved donor-binding regions with several key residues that interact with catalytic sites and sugar donors. Further molecular modeling and docking analysis indicated that two UGT proteins were able to stably bind indoxacarb and N-decarbomethoxylated metabolite (DCJW). Furthermore, knockdown of UGT33J17 and UGT41D10 decreased viability of Spli-221 cells and enhanced susceptibility of larvae to indoxacarb. Transgenic overexpression of these genes reduced the toxicity of indoxacarb in Drosophila melanogaster. This work revealed that upregulation of UGT genes significantly contributes to indoxacarb resistance in S. litura, and is of great significance for the development of integrated and sustainable management strategies for resistant pests in the field.

Metabolite Profiling and Transcriptome Analysis Explain the Difference in Accumulation of Bioactive Constituents in Taxilli Herba from Two Hosts.

Taxilli Herba (TH) is a semi-parasitic herb and the host is a key factor affecting its quality. Flavonoids are the main bioactive constituents in TH. However, studies on the difference in accumulation of flavonoids in TH from different hosts are vacant. In this study, integrated transcriptomic and metabolomic analyses were performed on TH from Morus alba L. (SS) and Liquidambar formosana Hance (FXS) to investigate the relationship between the regulation of gene expression and the accumulation of bioactive constituents. The results showed that a total of 3319 differentially expressed genes (DEGs) were screened in transcriptomic analysis, including 1726 up-regulated genes and 1547 down-regulated genes. In addition, 81 compounds were identified using ultra-fast performance liquid chromatography coupled with triple quadrupole-time of flight ion trap tandem mass spectrometry (UFLC-Triple TOF-MS/MS) analysis, and the relative contents of flavonol aglycones and glycosides were higher in TH from SS group than those from the FXS group. A putative biosynthesis network of flavonoids was created, combined with structural genes, and the expression patterns of genes were mostly consistent with the variation of bioactive constituents. It was noteworthy that the UDP-glycosyltransferase genes might participate in downstream flavonoid glycosides synthesis. The findings of this work will provide a new way to understand the quality formation of TH from the aspects of metabolite changes and molecular mechanism.

Molecular Identification and Characterization of UDP-glycosyltransferase (UGT) Multigene Family in Pomegranate

Pomegranate (Punica granatum L.) is regarded as one of the functional fruits because of its large amounts of secondary metabolites. The glycosylation processes mediated by UDP-glycosyltransferases (UGTs) play a decisive role in regulating secondary metabolite availability. In this study, a genome-wide search identified 145 UGT genes in pomegranate, and further phylogenetic analysis defined 17 distinct groups: A to P and R. PgUGTs were dispersed unevenly across all eight chromosomes. Duplication events analysis revealed that both segmental and tandem duplications were the main mechanisms leading to gene family expansions. The comparison of exon–intron patterns identified 53 intron-less genes. A total of 24 types of cis-acting elements related to hormone, stress, and developmental responses were predicted in the promoter regions. Expression analysis of PgUGT genes using RNA-seq data and quantitative real-time PCR (qRT-PCR) verification suggested that PgUGT genes were expressed at specific stages of fruit development, and different PgUGT members likely played different roles in specific fruit developmental stages. In an attempt to identify the UGTs involved in the glycosylation of flavonoids, 44 PgUGTs were putatively determined, and 5 well-defined orthologous groups (OGs) were characterized by the regioselectivity of these enzymes. These results provide significant insight into the UGT multi-gene family in pomegranate, and will be helpful to further elucidate their roles involved in secondary and specialized metabolism in pomegranate.

Genome-wide analysis of UDP-glycosyltransferases family and identification of UGT genes involved in abiotic stress and flavonol biosynthesis in Nicotiana tabacum

BackgroundUridine disphosphate (UDP) glycosyltransferases (UGTs) act upon a huge variety of highly diverse and complex substrates, such as phytohormones and specialized metabolites, to regulate plant growth, development, disease resistance, and environmental interactions. However, a comprehensive investigation of UGT genes in tobacco has not been conducted.ResultsIn this study, we carried out a genome-wide analysis of family-1 UDP glycosyltransferases in Nicotiana tabacum. We predicted 276 NtUGT genes, which were classified into 18 major phylogenetic subgroups. The NtUGT genes were invariably distributed among all the 24 chromosomes with structural diversity in exon/intron structure, conserved motifs, and cis-acting elements of promoters. Three groups of proteins which involved in flavonoid biosynthesis, plant growth and development, transportation and modification were identified that interact with NtUGT proteins using the PPI analysis. Expression analysis of NtUGT genes in cold stress, drought stress and different flower color using both online RNA-Seq data and the realtime PCR analysis, suggested the distinct role of NtUGT genes in resistance of cold, drought and in flavonoid biosynthesis. The enzymatic activities of seven NtUGT proteins that potentially involved in flavonoid glycosylation were analyzed, and found that all seven exhibited activity on myricetin; six (NtUGT108, NtUGT123, NtUGT141, NtUGT155, NtUGT179, and NtUGT195) showed activity on cyanidin; and three (NtUGT108, NtUGT195, and NtUGT217) were active on the flavonol aglycones kaempferol and quercetin, which catalyzing the substrates (myricetin, cyanidin or flavonol) to form new products. We further investigated the enzymatic products and enzymatic properties of NtUGT108, NtUGT195, and NtUGT217, suggested their diverse enzymatic activity toward flavonol, and NtUGT217 showed the highest catalyzed efficient toward quercetin. Overexpression of NtUGT217 significantly increase the content levels of the quercetin-3-O-glucoside, quercetin-3-O-rutinoside and kaempferol-3-O-rutinoside in transgenic tobacco leaves.ConclusionWe identified 276 UGT genes in Nicotiana tabacum. Our study uncovered valuable information about the phylogenetic structure, distribution, genomic characters, expression patterns and enzymatic activity of NtUGT genes in tobacco. We further identified three NtUGT genes involved in flavonoid biosynthesis, and overexpressed NtUGT217 to validate its function in catalyze quercetin. The results provide key candidate NtUGT genes for future breeding of cold and drought resistance and for potential metabolic engineering of flavonoid compounds.

Cloning and functional analysis of the promoter of a UDP-glycosyltransferase gene from Panax quinquefolium L.

Pq3-O-UGT2 is a key UDP-glycosyltransferase gene in the ginsenoside biosynthesis pathway of Panax quinquefolium L. Functional analysis of promoter sequences plays an important role in understanding the regulation of functional gene expression. In this study, chromosome walking technology was used to isolate the 1399 bp sequence upstream of the ATG initiation codon of Pq3-O-UGT2. Bioinformatics analysis shows that the promoter sequence contains a large number of putative cis-acting elements responsive to exogenous and endogenous factors. The full-length promoter and six 5′ terminal truncations were fused with the GUS reporter gene to test their activities. The results of histochemical staining showed that a strong GUS activity were observed in flowers, siliques, leaves, stems and roots of transgenic Arabidopsis containing the full length Pq3-O-UGT2 promoter. Fluorometric assays showed that the highest enzyme activity is the full-length promoter with 4370 pmol 4-MU/min/mg protein, and the shortest promoter containing P-198::GUS with 45 pmol 4-MU/min/mg protein was sufficient to activate GUS expression. In addition, extended light, low temperatures, MeJA, ABA, NAA and GA3 were selected to investigate the Pq3-O-UGT2 promoter in response to abiotic stress and hormone treatment. The GUS activity of Pq3-O-UGT2 full-length promoter (P-1399) was 2.12 times that of the control plant after MeJA treatment, suggesting that P-1399 is a MeJA-inducible promoter. Furthermore, the assay results showed that ABA could extensively induce GUS expression in five 5′ truncated promoter transgenic plants, except P-198. These experimental results will help us to better explore the regulatory mechanisms in the promoter region of the Pq3-O-UGT2 gene and contribute to further studies of the molecular mechanisms of glycosylation in ginseng plants. The Pq3-O-UGT2 promoter was successfully cloned. Seven 5′ truncations could drive the expression of GUS gene in transgenic Arabidopsis plants and the full-length promoter is a MeJA-inducible promoter.

Characterization and Expression Analysis of the UDP Glycosyltransferase Family in Pomegranate (Punica granatum L.)

UDP glycosyltransferases (UGTs) play an indispensable role in regulating signaling pathways and intracellular homeostasis in plants by catalyzing the glycosylation of metabolites. To date, the molecular characteristics and potential biological functions of the UGT gene family in pomegranate (Punica granatum L.) remain elusive. In this study, a total of 120 PgUGT genes were identified in the pomegranate genome. Phylogenetic analysis revealed that these PgUGTs were clustered into 15 groups: 13 conserved groups (A–J and L–N) and two newly discovered groups (P and R). Structural analysis showed that most members in the same evolutionary branch shared similar motifs and gene structures. Gene duplication analysis demonstrated that tandem duplication and fragment duplication were the primary driving force for the expansion of the PgUGT family. Expression analysis based on RNA-seq data indicated that PgUGTs exhibited various expression profiles in different pomegranate tissues. We further analyzed the expression patterns of the PgUGTs of groups E and L in the seed coat of the hard-seeded cultivar ‘Dabenzi’ and the soft-seeded cultivar ‘Tunisia’ at different developmental stages. There were eight PgUGTs with high expression levels in the seed coat of both cultivars: PgUGTE10 was highly expressed in inner and outer seed coats; PgUGTE20, PgUGTE21, PgUGTL6, PgUGTL11, and PgUGTL12 were mainly expressed in the inner seed coat; and PgUGTE12 and PgUGTL13 were mainly expressed in the outer seed coat. Interestingly, the relative expression levels of PgUGTE10 and PgUGTL11 in ‘Tunisia’ were higher than in ‘Dabenzi’. In the seedlings, quantitative real-time PCR analysis showed that the expression level of PgUGTE10 was induced by brassinolide treatment, while the expression of PgUGTL11 was up-regulated both by indole-3-acetic acid and the brassinolide treatment. In addition, the expressions of PgUGTE10 and PgUGTL11 were highly correlated with the expression of genes involved in hormone signaling and lignin biosynthesis pathways. These results suggested that PgUGTE10 and PgUGTL11 are potential candidate genes involved in seed hardness development by catalyzing the glycosylation of specific substrates.

Contribution of UDP-glycosyltransferases to chlorpyrifos resistance in Nilaparvata lugens

As a multigene superfamily of Phase II detoxification enzymes, uridine diphosphate (UDP)-glycosyltransferases (UGTs) play important roles in the metabolism of xenobiotics including insecticides. In this study, 5-nitrouracil, an inhibitor of UGT enzyme activity, effectively increased the toxicity of chlorpyrifos to the chlorpyrifos-resistant strain of Nilaparvata lugens, one of the most resistant rice pests. The enzyme content of UGT in the resistant strain was significantly higher than that in the susceptible strain. Among 20 identified UGT genes, UGT386H2, UGT386J2, UGT386N2 and UGT386P1 were found significantly overexpressed in the resistant strain and can be effectively induced by chlorpyrifos. These four UGT genes were most highly expressed in the midgut and/or fat body, two main insect detoxification tissues. Amino acid sequence alignments revealed that these four UGTs contained a variable N-terminal substrate-binding domain and a conserved C-terminal sugar donor-binding domain. Furthermore, homology modeling and molecular docking analyses showed that these UGTs could stably bind to chlorpyrifos and chlorpyrifos oxon, with the binding free energies from −19.4 to −110.62 kcal mol−1. Knockdown of UGT386H2 or UGT386P1 by RNA interference dramatically increased the susceptibility of the resistant strain to chlorpyrifos. These findings suggest that overexpression of these two UGT genes contributes to chlorpyrifos resistance in N. lugens.

Characterization of anthocyanin accumulation, nutritional properties, and postharvest attributes of transgenic purple tomato

Anthocyanins are natural pigments with diverse physiological roles and protective effects, but most tomatoes produce little. In this study, the anthocyanin characteristics, nutritional properties, and postharvest attributes of purple tomato (SlMYB75-OE) obtained by overexpression of SlMYB75 gene were first analyzed. Compared to wild-type (WT), eight monomeric anthocyanins were newly produced by overexpression of SlMYB75, and further study demonstrated the expression of dihydroflavonol-4-reductase (SlDFR) and two UDP-glycosyltransferase (SlUGTs) genes was activated by SlMYB75. The contents of sugars (sucrose, glucose, and fructose) and citric acid content in SlMYB75-OE were higher and lower, respectively, than in WT. In addition, FRAP and DPPH assays indicated SlMYB75-OE had higher antioxidant capacity, when compared to WT. Moreover, SlMYB75-OE exhibited a longer shelf life and stronger resistance to Botrytis cinerea than WT, and this characteristic was positively correlated with anthocyanin content. These results help to clarify the function of SlMYB75 and provide a reference for tomato breeding.

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.

Comprehensive analysis of the UDP‑glycosyltransferase gene family in flax [Linum usitatissimum L.] and functional verification of the role of LuUGT175 in the regulation of lignin biosynthesis

Flax ( Linum usitatissimum L.) is an important fiber crop worldwide, but the lignin in L. usitatissimum fiber leads to hard and brittle fiber, reducing its quality and resulting in poor spinnability. UDP glycosyltransferases (UGTs) play an important role in plant secondary metabolism . Therefore, the identification and characterization of L. usitatissimum UGTs and the screening and validation of UGTs related to lignin biosynthesis are research priorities. In this study, the conserved PSPG motif was used to identify 190 L. usitatissimum UGT genes ( LuUGTs ) with uneven distribution on chromosomes and scaffolds. The genes were divided into 16 phylogenetic groups. L. usitatissimum UGT family members in the same groups had similar protein motifs and gene structures, but there were some differences between the groups. Whole genome duplication and segmental duplication were the main replication events that led to the expansion of the L. usitatissimum UGT family. The expression patterns of LuUGTs in different tissues and at different developmental stages of L. usitatissimum can be divided into three types: low expression, constitutive expression, and tissue-specific expression. It was found that lack of function of LuUGT175 in L. usitatissimum led to slow plant growth, serious lignification in stems and ectopic lignification in fibers. LuNAC61 was identified as an upstream negative regulator of LuUGT175 . In vivo and in vitro validation confirmed a direct interaction between the two. Our research provides key theoretical and material support for an in-depth and comprehensive understanding of the mechanism of L. usitatissimum lignin synthesis and the use of biotechnology to reduce the lignin content of L. usitatissimum fiber. It also provides an important breakthrough and a research opportunity for analyzing the contribution of glycosylation to lignin metabolism and cell wall lignification. • LuUGTs were divided into 16 phylogenetic groups. • Whole genome duplication and segmental duplication were main replication events. • Lack function of LuUGT175 led to slow plant growth, serious lignification in flax. • LuNAC61 was identified as an upstream negative regulator of LuUGT175 .

Identification and characterization of UDP-glycosyltransferase genes and the potential role in response to insecticides exposure in Bactrocera dorsalis.

The oriental fruit fly, Bactrocera dorsalis (Hendel) is a worldwide pest damaging a wide range of hosts. Due to the long-term indiscriminate use of insecticides, B. dorsalis has developed serious resistance to several insecticides. UDP-glycosyltransferases (UGTs) are secondary metabolic enzymes involved in biotransformation and play an important role in the metabolism of plant secondary metabolites and synthetic insecticides in insects. Thus, we suspect that UGTs in B. dorsalis play an important role in insecticide tolerance. In this study, 31 UGT genes were identified in the genome of B. dorsalis, belonging to 13 subfamilies. Real-time quantitative polymerase chain reaction (RT-qPCR) results revealed that 12 UGT genes were highly expressed in the antennae, midgut, Malpighian tubule and fat body. The mRNA expressions of 17 UGT genes were up-regulated upon exposure to λ-cyhalothrin, imidacloprid, abamectin and chlorpyrifos. Knockdown of the selected five UGT genes (BdUGT301D2, BdUGT35F2, BdUGT36K2, BdUGT49D2, BdUGT50B5) by RNA interference increased the mortality of B. dorsalis from 9.29% to 27.22% upon exposure to four insecticides. The abundance of UGTs in B. dorsalis is similar to other insect species, and 12 out of 31 UGTs were specifically expressed in metabolic tissues, suggesting a key role in detoxification. Down-regulation of five selected UGT genes increased the susceptibility of B. dorsalis to various insecticides, indicating that UGTs may play an important role in tolerance of B. dorsalis to multiple insecticides. © 2022 Society of Chemical Industry.

Genome-wide characterization of the UDP-glycosyltransferase gene family reveals their potential roles in leaf senescence in cotton

Uridine diphosphate (UDP) glycosyltransferases (UGTs) involved in many metabolic processes and are essential for plant growth and development. Although UGTs proteins have been studied in many plants, the biological functions of UGT genes in cotton leaf senescence are still unknown. In the present study, we performed a genome-wide survey and identified 157 GrUGT, 152 GaUGT and 261 GHUGT genes in Gossypium raimondii, G. arboreum, and G. hirsutum, respectively, that were classified into 15 groups. Analysis of protein motif and gene structure demonstrated that structural and functional conservation occurred within same groups but diverged among the different groups. Gene duplication analysis indicated the different duplication ways happened between tetraploid G. hirsutum and the two diploid species. Whole genome or segmental duplications played a main role in the expansion of the GHUGT family in cotton, and experienced purifying selection during the long evolutionary process in cotton. Cis-acting regulatory elements analysis indicated that they were associated with complex hormone regulatory networks and the stress response. Additionally, to identify GHUGT candidate genes responsive to leaf senescence, we analyzed the expression patterns of GHUGT genes using our transcriptome data from two cultivars of upland cotton with contrasting tolerance to leaf senescence. Subsequently, gene expression profiling based on real-time quantitative PCR showed that selected GHUGT candidate genes might be involved in ABA and JA regulation. Through further functional verification, silencing GHUGT116 gene via VIGS (Virus-induced gene silencing) delayed dark-induced leaf senescence. Overall, the results provide useful and valuable information for understanding the evolution of cotton UGTs genes and the function in leaf senescence.

Genome-wide identification, characterization, and expression analysis of UDP-glycosyltransferase genes associated with secondary metabolism in alfalfa (Medicago sativa L.).

Uridine diphosphate glycosyltransferases (UGTs) are enzymes that catalyze glycosylation modifications and play an essential role in regulating plant metabolism. Alfalfa (Medicago sativa L.) is the most important legume in the world due to its high yields and protein content; however, the UGT genes in alfalfa have not yet been studied. Identifying UGT genes with metabolic roles in alfalfa is essential for identifying and modifying genetic traits that are relevant to yield and quality. In this study, 90 of the 239 UGT genes identified from the alfalfa “Zhongmu No. 1” genome database were found to be related to secondary metabolism, and a series of gene family characterization analyses were conducted on each. The results demonstrated that all 90 UGT genes were unevenly distributed on eight chromosomes with few introns and that tandem duplications were the crucial driving force expanding the UGT family in alfalfa. Notably, the 90 UGT genes can be clustered into ten evolutionary groups which contain specific PSPG motifs, and genes in these ten groups have specific tissue expressions. This suggests that the UGT genes in each group could have similar glycosylation roles corresponding to analogous secondary metabolites in alfalfa. Additionally, multiple cis-acting elements found in MsUGT promoter regions, such as phytohormone and flavonoids, indicate that 90 UGT members could be induced by these features, which are also related to secondary metabolism. Therefore, our study identified 90 UGT members inten evolutionary groups that are likely related to glycosylation modifications with secondary metabolites in alfalfa. These findings help uncover pivotal regulatory mechanisms associated with secondary metabolism in plant yield and quality and contribute to genetic modification and breeding in alfalfa and other plant species.

Genome-wide analysis of UDP-glycosyltransferase gene family and identification of members involved in flavonoid glucosylation in Chinese bayberry (Morella rubra).

Glycosylation was catalyzed by UDP-glycosyltransferase (UGT) and was important for enriching diversity of flavonoids. Chinese bayberry (Morella rubra) has significant nutritional and medical values because of diverse natural flavonoid glycosides. However, information of UGT gene family was quite limited in M. rubra. In the present study, a total of 152 MrUGT genes clustered into 13 groups were identified in M. rubra genome. Among them, 139 MrUGT genes were marked on eight chromosomes and 13 members located on unmapped scaffolds. Gene duplication analysis indicated that expansion of MrUGT gene family was mainly forced by tandem and proximal duplication events. Gene expression patterns in different tissues and under UV-B treatment were analyzed by transcriptome. Cyanidin 3-O-glucoside (C3Glc) and quercetin 3-O-glucoside (Q3Glc) were two main flavonoid glucosides accumulated in M. rubra. UV-B treatment significantly induced C3Glc and Q3Glc accumulation in fruit. Based on comprehensively analysis of transcriptomic data and phylogenetic homology together with flavonoid accumulation patterns, MrUFGT (MrUGT78A26) and MrUGT72B67 were identified as UDP-glucosyltransferases. MrUFGT was mainly involved in C3Glc and Q3Glc accumulation in fruit, while MrUGT72B67 was mainly involved in Q3Glc accumulation in leaves and flowers. Gln375 and Gln391 were identified as important amino acids for glucosyl transfer activity of MrUFGT and MrUGT72B67 by site-directed mutagenesis, respectively. Transient expression in Nicotiana benthamiana tested the function of MrUFGT and MrUGT72B67 as glucosyltransferases. The present study provided valuable source for identification of functional UGTs involved in secondary metabolites biosynthesis in M. rubra.