UDP-glycosyltransferases Research Articles

Integration of semi-in vivo assays and multi-omics data reveals the effect of galloylated catechins on self-pollen tube inhibition in Camellia oleifera.

Camellia oil extracted from the seeds of Camellia oleifera Abel. is a popular and high-quality edible oil, but its yield is limited by seed setting, which is mainly caused by self-incompatibility (SI). One of the obvious biological features of SI plants is the inhibition of self-pollen tubes; however, the underlying mechanism of this inhibition in C. oleifera is poorly understood. In this study, we constructed a semi-in vivo pollen tube growth test (SIV-PGT) system that can screen for substances that inhibit self-pollen tubes without interference from the genetic background. Combined with multi-omics analysis, the results revealed the important role of galloylated catechins in self-pollen tube inhibition, and a possible molecular regulatory network mediated by UDP-glycosyltransferase (UGT) and serine carboxypeptidase-like (SCPL) was proposed. In summary, galloylation of catechins and high levels of galloylated catechins are specifically involved in pollen tube inhibition under self-pollination rather than cross-pollination, which provides a new understanding of SI in C. oleifera. These results will contribute to sexual reproduction research on C. oleifera and provide theoretical support for improving Camellia oil yield in production.

High-Resolution Genetic Mapping Combined with Transcriptome Profiling Reveals That Both Target-Site Resistance and Increased Detoxification Confer Resistance to the Pyrethroid Bifenthrin in the Spider Mite Tetranychus urticae.

Pyrethroids are widely applied insecticides in agriculture, but their frequent use has provoked many cases of resistance, in which mutations in the voltage-gated sodium channel (VGSC), the pyrethroid target-site, were shown to play a major role. However, for the spider mite Tetranychus urticae, it has also been shown that increased detoxification contributes to resistance against the pyrethroid bifenthrin. Here, we performed QTL-mapping to identify the genomic loci underlying bifenthrin resistance in T. urticae. Two loci on chromosome 1 were identified, with the VGSC gene being located near the second QTL and harboring the well-known L1024V mutation. In addition, the presence of an L925M mutation in the VGSC of a highly bifenthrin-resistant strain and its loss in its derived, susceptible, inbred line indicated the importance of target-site mutations in bifenthrin resistance. Further, RNAseq experiments revealed that genes encoding detoxification enzymes, including carboxyl/choline esterases (CCEs), cytochrome P450 monooxygenases and UDP-glycosyl transferases (UGTs), were overexpressed in resistant strains. Toxicity bioassays with bifenthrin (ester pyrethroid) and etofenprox (non-ester pyrethroid) also indicated a possible role for CCEs in bifenthrin resistance. A selection of CCEs and UGTs were therefore functionally expressed, and CCEinc18 was shown to metabolize bifenthrin, while teturUGT10 could glycosylate bifenthrin-alcohol. To conclude, our findings suggest that both target-site and metabolic mechanisms underlie bifenthrin resistance in T. urticae, and these might synergize high levels of resistance.

Transcriptomic Identification and Expression Profile Analysis of Odorant-Degrading Enzymes from the Asian Corn Borer Moth, Ostrinia furnacalis.

The Asian corn borer moth Ostrinia furnacalis is an important lepidopteran pest of maize in Asia. Odorant-degrading enzymes (ODEs), including carboxylesterases (CCEs), glutathione S-transferases (GSTs), cytochrome P450s (CYPs), UDP-glycosyltransferases (UGTs), and aldehyde oxidases (AOXs), are responsible for rapid inactivation of odorant signals in the insect antennae. In this study, we performed a transcriptome assembly for the antennae of O. furnacalis to identify putative ODE genes. Transcriptome sequencing revealed 35,056 unigenes, and 21,012 (59.94%) of these were annotated by searching against the reference sequences in the NCBI non-redundant (NR) protein database. For functional classification, these unigenes were subjected to Gene Ontology (GO), Eukaryotic Orthologous Groups (KOG), and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations. We identified 79 genes encoding putative ODEs: 19 CCEs, 17 GSTs, 24 CYPs, 13 UGTs, and 6 AOXs. BLASTX best hit results indicated that these genes shared quite high amino acid identities with their respective orthologs from other lepidopteran species. Reverse transcription-quantitative PCR showed that OfurCCE2, OfurCCE5, and OfurCCE18 were enriched in male antennae, while OfurCCE7 and OfurCCE10 were enriched in female antennae. OfurCCE14 and OfurCCE15 were expressed at near-equal amounts in the antennae of both sexes. Our findings establish a solid foundation for future studies aimed at understanding the olfactory functions of these genes in O. furnacalis.

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 .

26. Identification of novel genomic structural variations in Angiosarcoma by Optical Genome Mapping

Angiosarcomas are malignant vascular tumors with a number of known molecular aberrations identified by standard technologies, such as FISH and next generation sequencing. However, potentially clinically significant large genomic aberrations, such as gene fusion, large amplification and deletions, may not be detectable by these technologies. To gain further insights into the genomic landscape of angiosarcoma, we performed optical genome mapping (OGM) of 3 primary human angiosarcoma cell lines. OGM analysis of these cells revealed multiple unique structural aberrations, including large insertions/deletions, inversions, duplications, inter-chromosomal and intra-chromosomal translocations. Further analysis showed a 354-Kb deletion in Plexin D1 gene locus that regulates the migration of endothelial cells and is required for normal development of the heart and vasculature; reciprocal t(4;9) translocation in UGT8 (UDP Glycosyltransferase 8) gene locus that is involved in biosynthesis of galactocerebrosidase; reciprocal t(6;22) translocation involving HIRA (Histone Cell Cycle Regulator) and EYS (Eyes Shut Homolog) gene loci; and 14 Mb inversion interrupting RYR2 (Ryanodine Receptor 2) and TAF1A (TATA-Box Binding Protein Associated Factor) gene loci. These findings demonstrate the utility of optical genome mapping as a new tool to uncover large genomic structural variations to better understand the molecular pathogenesis of malignant vascular tumors. Future studies are aimed to determine the biological significance of these structural variations in angiosarcoma.

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.

Rice glycosyltransferase gene UGT2 functions in salt stress tolerance under the regulation of bZIP23 transcription factor.

Rice glycosyltransferase gene UGT2 was identified to play a crucial role in salt tolerance. The transcription factor OsbZIP23 was demonstrated to regulate the UGT2 expression under stress conditions. UDP-glycosyltransferases (UGTs) play key roles in modulating plant responses to environmental challenges. In this study, we characterized a novel glycosyltransferase, UGT2, which plays an important role in salt stress responses in rice (Oryza sativa L). We found that seedlings overexpressing UGT2 exhibited better growth than wild type in shoot and root under hydroponic culture with salt stress treatments, while ugt2ko mutant lines suffered much more growth inhibition. When the soil-grown UGT2 transgenic plants were subjected to salt stress, we also found that ugt2ko mutant lines were severely withered and most of them died, while the overexpression lines grew well and had higher survival rate. Compared with wild-type plants, UGT2 overexpression greatly increased the expression levels of the reactive oxygen species scavenging genes and stress-responsive genes. Furthermore, the upstream regulatory mechanism of the UGT2 gene was identified and we found that a bZIP transcription factor, OsbZIP23, can bind to the UGT2 promoter and enhance the UGT2 transcription levels. This work reveals that OsbZIP23-UGT2 module may play a major role in regulating the salt stress tolerance in rice.

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.

Glycosyltransferase engineering and multi-glycosylation routes development facilitating synthesis of high-intensity sweetener mogrosides

SummaryMogrosides are widely served as natural zero-calorie sweeteners. To date, the biosynthesis of high-intensity sweetness mogrosides V from mogrol has not been achieved because of inefficient and uncontrollable multi-glycosylation process. To address this challenge, we reported three UDP-glycosyltransferases (UGTs) catalyzing the primary and branched glycosylation of mogrosides and increased the catalytic efficiency by 74–400-folds toward branched glycosylation using an activity-based sequence conservative analysis engineering strategy. The computational studies provided insights into the origin of improved catalytic activity. By virtue of UGT mutants, we provided regio- and bond-controllable multi-glycosylation routes, successfully facilitating sequential glycosylation of mogrol to three kinds of mogroside V in excellent yield of 91–99%. Meanwhile, the feasibility of the routes was confirmed in engineered yeasts. It suggested that the multi-glycosylation routes would be combined with mogrol synthetic pathway to de novo produce mogrosides from glucose by aid of metabolic engineering and synthetic biology strategies in the future.

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.

Genome-Wide Analysis of UGT Genes in Petunia and Identification of PhUGT51 Involved in the Regulation of Salt Resistance.

UDP-glycosyltransferase (UGT) plays an essential role in regulating the synthesis of hormones and secondary metabolites in plants. In this study, 129 members of the Petunia UGT family were identified and classified into 16 groups (A–P) based on phylogenetic analysis. The same subgroups have conserved motif compositions and intron/exon arrangement. In the promoters of the Petunia UGT genes, several cis-elements associated with plant hormones, growth and development, and abiotic stress have been discovered. Their expression profiles in five tissues were revealed by tissue expression based on RNA-seq data. Subcellular localization analysis showed that PhUGT51 was located in the nucleus and cell membrane. Salt stress caused an increase in the expression level of PhUGT51, but the expression level remained stable with the growth over time. In addition, the overexpression of PhUGT51 caused a significant increase in salt resistance. Our study systematically analyses the UGT gene family in Petunia for the first time and provides some valuable clues for the further functional studies of UGT genes.

Genome Wide Analysis of Family-1 UDP Glycosyltransferases in Populus trichocarpa Specifies Abiotic Stress Responsive Glycosylation Mechanisms.

Populus trichocarpa (Black cottonwood) is a dominant timber-yielding tree that has become a notable model plant for genome-level insights in forest trees. The efficient transport and solubility of various glycoside-associated compounds is linked to Family-1 UDP-glycosyltransferase (EC 2.4.1.x; UGTs) enzymes. These glycosyltransferase enzymes play a vital role in diverse plant functions, such as regulation of hormonal homeostasis, growth and development (seed, flower, fiber, root, etc.), xenobiotic detoxification, stress response (salt, drought, and oxidative), and biosynthesis of secondary metabolites. Here, we report a genome-wide analysis of the P. trichocarpa genome that identified 191 putative UGTs distributed across all chromosomes (with the exception of chromosome 20) based on 44 conserved plant secondary product glycosyltransferase (PSPG) motif amino acid sequences. Phylogenetic analysis of the 191 Populus UGTs together with 22 referenced UGTs from Arabidopsis and maize clustered the putative UGTs into 16 major groups (A–P). Whole-genome duplication events were the dominant pattern of duplication among UGTs in Populus. A well-conserved intron insertion was detected in most intron-containing UGTs across eight examined eudicots, including Populus. Most of the UGT genes were found preferentially expressed in leaf and root tissues in general. The regulation of putative UGT expression in response to drought, salt and heat stress was observed based on microarray and available RNA sequencing datasets. Up- and down-regulated UGT expression models were designed, based on transcripts per kilobase million values, confirmed their maximally varied expression under drought, salt and heat stresses. Co-expression networking of putative UGTs indicated their maximum co-expression with cytochrome P450 genes involved in triterpenoid biosynthesis. Our results provide an important resource for the identification of functional UGT genes to manipulate abiotic stress responsive glycosylation in Populus.

Detoxification Gene Families at the Genome-Wide Level of Rhus Gall Aphid Schlechtendalia chinensis.

The Rhus gall aphid Schlechtendalia chinensis uses the species Rhus chinensis as its primary host plant, on which galls are produced. The galls have medicinal properties and can be used in various situations due to their high tannin content. Detoxification enzymes play significant roles in the insect lifecycle. In this study, we focused on five detoxification gene families, i.e., glutathione-S-transferase (GST), ABC transporter (ABC), Carboxylesterase (CCE), cyto-chrome P450 (CYP), and UDP-glycosyltransferase (UDP), and manually annotated 144 detoxification genes of S. chinensis using genome-wide techniques. The detoxification genes appeared mostly on chromosome 1, where a total of two pair genes were identified to show tandem duplications. There were 38 gene pairs between genomes of S. chinensis and Acyrthosiphon pisum in the detoxification gene families by collinear comparison. Ka/Ks ratios showed that detoxification genes of S. chinensis were mainly affected by purification selection during evolution. The gene expression numbers of P450s and ABCs by transcriptome sequencing data were greater, while gene expression of CCEs was the highest, suggesting they might be important in the detoxification process. Our study has firstly identified the genes of the different detoxification gene families in the S. chinensis genome, and then analyzed their general features and expression, demonstrating the importance of the detoxification genes in the aphid and providing new information for further research.

Identification and Characterization of the Tomato UGT Gene Family and Effects of GAME 17 Overexpression on Plants and Growth and Development under High-CO2 Conditions

Steroidal glycoalkaloids (SGAs), the nitrogen-containing compounds produced primarily by Liliaceae and Solanaceae species, are toxic to animals and humans and have putative roles in defense against pests. UDP-glycosyltransferases (UGTs) catalyze the final glycosylation steps of SGA biosynthesis. Although previously published studies focused on the effect of UGT proteins on SGA biosynthesis, research to understand the effects of constitutive overexpression of UGTs on plant phenotype and fruit development is limited. The constitutive overexpression of a UGT encoding gene, GAME 17, may provide an alternative method to study the role of UGTs on the fruit development. In this study, we have identified 162 SlUGT proteins in tomato that are classified into t 23 groups. Gene structure and motif analyses have demonstrated that all SlUGTs have similar intron/exon distribution and motif compositions. RNA-seq data analysis has shown that SlUGTs exhibit differential expression patterns in different organs or different stages of fruit development. When the constitutive promoter 35S is used to control the expression of GAME 17, we have observed significant differences in growth parameters (i.e., plant height, leaf length, leaf width, internode length, and stem diameter) between WT and transgenic plants under high-CO2 conditions, and slight differences in growth parameters between WT and transgenic plants have beendetected. In addition, the contents of glucose, fructose, and soluble sugar of transgenic plants are significantly higher than those of WT plants. The increases in glucose, fructose, and soluble sugar in transgenic tomato fruits at three developmental stages under high-CO2 conditions are significantly higher than under natural conditions. This study provides additional evidence that the GAME 17 gene plays an important role in controlling plant phenotype and sugar homeostasis, especially in environments with high concentration of CO2.

Identification and characterization of salt-responsive proteins in mango (Mangifera indica L.)

Increasing salinity is a cause of concern for meeting UN sustainable development goals and needs urgent mitigation strategies. The widespread use of salinity tolerant rootstocks in salt-sensitive fruits provides long-term solutions to the harsh effects of soil salinization. Polyembryonic mango cultivar 13-1, a salinity-tolerant variety from Israel, was used to unravel initial salt adaptive mechanism by imposing a salinity screen at 200mM NaCl. Differentially accumulated proteins were separated through 2-D electrophoresis (pH gradient 4.0-7.0), and identified through properties of pI and molecular weight by annotation against Citrus isoelectric focusing database. Protein spots (309) were detected on Coomassie-stained gels and about 22 spots were found differentially expressed in control and stress. Overproduction of stress-related proteins like polygalacturonase (97 kDa/4.9PI) and alcohol dehydrogenase (38kDa/5.6PI) is linked to enhanced cell wall integrity, transpiration rate regulation and ionic maintenance in adaptability mechanism. The upregulated phenylpropanoid pathway proteins p-coumaroyl ester, Flavanone3-hydroxylase-2 and UDP-glycosyl transferase are also involved in stress alleviation through flavonoid accumulation. Glutathione S-transferase was also identified with 2.21-fold accumulation in plants exposed to salinity stress, thereby elucidating its role in oxidative stress mitigation. Cell wall and cytoskeleton metabolism-related proteins were also found to be associated with salinity adaptation in mango cv 13-1. Differential accumulation of proteins implicated in signal transduction pathway, transcription regulation and hormone signaling were also identified. Thus, role of differentially expressed proteins under initial salinity stress conditions provide new insights molecular adjustment mechanisms orchestrated by mango rootstock variety by hormone signaling, osmotic arrangements, cytoskeleton modifications, phenol accumulation and transcription regulation.

Integrative SMRT sequencing and ginsenoside profiling analysis provide insights into the biosynthesis of ginsenoside in Panax quinquefolium.

Panax quinquefolium is one of the most common medicinal plants worldwide. Ginsenosides are the major pharmaceutical components in P. quinquefolium. The biosynthesis of ginsenosides in different tissues of P. quinquefolium remained largely unknown. In the current study, an integrative method of transcriptome and metabolome analysis was used to elucidate the ginsenosides biosynthesis pathways in different tissues of P. quinquefolium. Herein, 22 ginsenosides in roots, leaves, and flower buds showed uneven distribution patterns. A comprehensive P. quinquefolium transcriptome was generated through single molecular real-time (SMRT) and second-generation sequencing (NGS) technologies, which revealed the ginsenoside pathway genes and UDP-glycosyltransferases (UGT) family genes explicitly expressed in roots, leaves, and flower buds. The weighted gene co-expression network analysis (WGCNA) of ginsenoside biosynthesis genes, UGT genes and ginsenoside contents indicated that three UGT genes were positively correlated to pseudoginsenoside F11, notoginsenoside R1, notoginsenoside R2 and pseudoginsenoside RT5. These results provide insights into ginsenoside biosynthesis in different tissues ofP. quinquefolium.

Genome-wide analysis of UGT gene family identified key gene for the biosynthesis of bioactive flavonol glycosides in Epimedium pubescens Maxim.

Epimedium pubescens Maxim. is a well-known traditional Chinese medicinal herb with flavonol glycosides as the major pharmaceutically active compounds. UDP-glycosyltransferases (UGTs) are a group of enzymes responsible for the glycosylation of flavonoid glycosides. In this study, a genome-wide analysis was performed to identify UGT family genes in E. pubescens. As a result, a total of 339 putative UGT genes were identified, which represents the largest UGT gene family known thus far, implying a significant expansion of the UGT gene family in E. pubescens. All EpUGTs were unevenly distributed across six chromosomes, and they were classified into 17 major groups. The expression profiles showed that UGT genes were differentially expressed in roots, leaves, flowers, shoots and fruits. In particular, several EpUGTs were highly induced by high light intensity, which was consistent with the accumulation level of bioactive flavonoids in E. pubescens. Six UGT79 genes that were preferentially expressed in roots or leaves were successfully expressed in E. coli, and only the recombinant EpGT60 protein was found to be active toward 8-prenylkaempferol and icaritin to produce the key bioactive compounds baohuoside II and baohuoside I. The optimal temperature, pH, km and Vmax were determined for the recombinant EpGT60 protein. In addition, expression of recombinant EpGT60 in E. coli cell culture led to successful production of baohuoside II when fed 8-prenylkaempferol. Our study provides a foundation for further functional characterization of UGT genes in E. pubescens and provides key candidate genes for bioengineering bioactive flavonoids in E. pubescens.

Transcriptomic Analysis Reveals Potential Gene Regulatory Networks Under Cold Stress of Loquat (Eriobotrya japonica Lindl.).

Loquat (Eriobotrya japonica Lindl. ) is one of the most economically important evergreen fruit crops in China, while it often suffered the injury of cold stress in winter and earlier spring, and the annual yield loss of loquat fruits caused by cold or freezing stress was immeasurable. However, knowledge about the physiological response and molecular mechanism under cold stress is still limited. To investigate the potential regulation mechanism pre- and post-cold stress in loquat and the changes in physiological indicators, a comparative transcriptome analysis was performed against a cold-resistant cv. “Huoju” and a cold-sensitive cv. “Ninghaibai”. The results of physiological indicators related to cold resistance indicated that rachis was most sensitive to cold stress and was considered as the representative organ to directly evaluate cold resistance of loquat based on subordinate function analysis. Here, we compared the transcriptome profiles of rachis pre- and under cold stress in “Huoju” and “Ninghaibai”. A total of 4,347 and 3,513 differentially expressed genes (DEGs) were detected in “Ninghaibai” and “Huoju”, among which 223 and 166 were newly identified genes, respectively, most of them were functionally enriched in plant hormone signal transduction (Huoju: 142; Ninghaibai: 200), and there were higher plant hormone content and related DEG expression levels in “Huoju” than that of “Ninghaibai”. Moreover, a total of 3,309 differentially expressed transcription factors (DETFs) were identified, and some DEGs and DETFs were screened to be subjected to co-expression network analysis based on the gene expression profile data. Some candidate DEGs, including UDP-glycosyltransferase (UGT), glycosyltransferase (GT), sugar phosphate/phosphate translocator (SPT), sugar transport protein (STP), proline-rich receptor-like protein kinase (PERK), and peroxidise (POD), were significantly affected by cold stress, and the expression level of these genes obtained from real-time quantitative RT-PCR was consistent with the pattern of transcriptome profile, which suggested that these genes might play the vital roles in cold resistance of loquat. Our results provide an invaluable resource for the identification of specific genes and TFs and help to clarify gene transcription during the cold stress response of loquat.

Glutathione Promotes Degradation and Metabolism of Residual Fungicides by Inducing UDP-Glycosyltransferase Genes in Tomato.

Reduced glutathione (GSH) is a key antioxidant, which plays a crucial role in the detoxification of xenobiotics in plants. In the present study, glutathione could reduce chlorothalonil (CHT) residues in tomatoes by inducing the expression of the UDP-glycosyltransferase (UGT) gene. In plants, UGT is an important glycosylation catalyst, which can respond to stresses in time by activating plant hormones and defense compounds. Given the importance of plant growth and development, the genome-wipe analyses of Arabidopsis and soybean samples have been carried out, though not on the tomato, which is a vital vegetable crop. In this study, we identified 143 UGT genes in the tomato that were unevenly distributed on 12 chromosomes and divided into 16 subgroups and found that a variety of plant hormones and stress response cis-elements were discovered in the promoter region of the SlUGT genes, indicating that the UGT genes were involved in several aspects of the tomato stress response. Transcriptome analysis and results of qRT-PCR showed that most SlUGT genes could be induced by CHT, and the expression of these genes was regulated by glutathione. In addition, we found that SlUGT genes could participate in plant detoxification through interaction with transcription factors. These findings further clarify the potential function of the UGT gene family in the detoxification of exogenous substances in tomatoes and provide valuable information for the future study of functional genomics of tomatoes.