Anthriscus sylvestris Deoxypodophyllotoxin Synthase Involved in the Podophyllotoxin Biosynthesis.

Tetrahydrofuran ring formation from dibenzylbutyrolactone lignans is a key step in the biosynthesis of aryltetralin lignans including deoxypodophyllotoxin and podophyllotoxin. Previously, Fe(II)- and 2-oxoglutarate-dependent dioxygenase (2-ODD) from Podophyllum hexandrum (Himalayan mayapple, Berberidaceae) was found to catalyze the cyclization of a dibenzylbutyrolactone lignan, yatein, to give deoxypodophyllotoxin and designated as deoxypodophyllotoxin synthase (DPS). Recently, we reported that the biosynthesis of deoxypodophyllotoxin and podophyllotoxin evolved in a lineage-specific manner in phylogenetically unrelated plant species such as P. hexandrum and Anthriscus sylvestris (cow parsley, Apiaceae). Therefore, a comprehensive understanding of the characteristics of DPSs that catalyze the cyclization of yatein to deoxypodophyllotoxin in various plant species is important. However, for plant species other than P. hexandrum, the isolation of the DPS enzyme gene and the type of the enzyme, e.g. whether it is 2-ODD or another type of enzyme such as cytochrome P-450, have not been reported. In this study, we report the identification and characterization of A. sylvestris DPS (AsDPS). Phylogenetic analysis showed that AsDPS belonged to the 2-ODD superfamily and shared moderate amino acid sequence identity (40.8%) with P. hexandrum deoxypodophyllotoxin synthase (PhDPS). Recombinant protein assay indicated that AsDPS and PhDPS differ in terms of the selectivity of substrate enantiomers. Protein modeling using AlphaFold2 and site-directed mutagenesis indicated that the Tyr305 residue of AsDPS probably contributes to substrate recognition. This study advances our understanding of the podophyllotoxin biosynthetic pathway in A. sylvestris and provides new insight into 2-ODD involved in plant secondary (specialized) metabolism.

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.

Exploring the Evolvability of Plant Specialized Metabolism: Uniqueness Out Of Uniformity and Uniqueness Behind Uniformity.

The huge structural diversity exhibited by plant specialized metabolites has primarily been considered to result from the catalytic specificity of their biosynthetic enzymes. Accordingly, enzyme gene multiplication and functional differentiation through spontaneous mutations have been established as the molecular mechanisms that drive metabolic evolution. Nevertheless, how plants have assembled and maintained such metabolic enzyme genes and the typical clusters that are observed in plant genomes, as well as why identical specialized metabolites often exist in phylogenetically remote lineages, is currently only poorly explained by a concept known as convergent evolution. Here, we compile recent knowledge on the co-presence of metabolic modules that are common in the plant kingdom but have evolved under specific historical and contextual constraints defined by the physicochemical properties of each plant specialized metabolite and the genetic presets of the biosynthetic genes. Furthermore, we discuss a common manner to generate uncommon metabolites (uniqueness out of uniformity) and an uncommon manner to generate common metabolites (uniqueness behind uniformity). This review describes the emerging aspects of the evolvability of plant specialized metabolism that underlie the vast structural diversity of plant specialized metabolites in nature.

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 ß-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 ß-D-glucopyranoside arabinosylation to produce HexVic in planta.

Two O-Methyltransferases from Phylogenetically Unrelated Cow Parsley (Anthriscus sylvestris) and Hinoki-Asunaro (Thujopsis dolabrata var. hondae) as a Signature of Lineage-Specific Evolution in Lignan Biosynthesis.

O-Methyltransferases (OMTs) play important roles in antitumor lignan biosynthesis. To date, six OMTs catalyzing the methylation of dibenzylbutyrolactone lignans as biosynthetic precursors of antitumor lignans have been identified. However, there is still no systematic understanding of the diversity and regularity of the biosynthetic mechanisms among various plant lineages. Herein, we report the characterization of two OMTs from Anthriscus sylvestris and Thujopsis dolabrata var. hondae [designated as AsSecoNorYatein (SNY) OMT and TdSNYOMT] together with the six known OMTs to evaluate their diversity and regularity. Although A. sylvestris 5-O-methylthujaplicatin (SecoNorYatein) and 4-O-demethylyatein (NorYatein) OMT (AsSNYOMT) and TdSNYOMT accept 5-O-methylthujaplicatin and 4-O-demethylyatein as substrates, phylogenetic analysis indicated that these two OMTs shared low amino acid sequence identity, 33.8%, indicating a signature of parallel evolution. The OMTs and the six previously identified OMTs were found to be diverse in terms of their substrate specificity, regioselectivity and amino acid sequence identity, indicating independent evolution in each plant species. Meanwhile, two-entropy analysis detected four amino acid residues as being specifically acquired by dibenzylbutyrolactone lignan OMTs. Site-directed mutation of AsSNYOMT indicated that two of them contributed specifically to 5-O-methylthujaplicatin methylation. The results provide a new example of parallel evolution and the diversity and regularity of OMTs in plant secondary (specialized) metabolism.

Functional diversity and plasticity in the sugar preferences of Saccharomyces MALT transporters in domesticated yeasts.

Maltose and maltotriose, together with glucose, are the major carbohydrates found in malts. Thus, brewing yeasts grown in malt-based brewing processes with serial re-pitching have likely increased their ability to uptake these sugars during domestication by modulating the expression and copy number of maltose transporter genes (MALT, also known as Malx1). However, the molecular basis for and structural insights into the sugar preferences of MALT proteins remain to be elucidated. Here we report the functional evaluation of two novel Saccharomyces cerevisiae MALT proteins, ScMalt#2p and ScMalt#5p, from industrial brewing yeasts, focusing on their maltose and maltotriose preferences. Structural models of the MALT proteins generated by AlphaFold2 and functional analyses of substitution mutants revealed that a very small number of amino acid residues in two spatially adjacent transmembrane helixes, TMH7 and TMH11, appear to be crucial for sugar preference. Thus, subtle conformational alterations conferred by a small number of amino acid polymorphisms within MALTs would contribute to the adaptation of domesticated brewing yeasts to the constrained carbohydrate environment of industrial wort during beer brewing.

Transgenic Forsythia plants expressing sesame cytochrome P450 produce beneficial lignans.

Lignans are widely distributed plant secondary metabolites that have received attention for their benefits to human health. Sesamin is a furofran lignan that is conventionally extracted from Sesamum seeds and shows anti-oxidant and anti-inflammatory activities in the human liver. Sesamin is biosynthesized by the Sesamum-specific enzyme CYP81Q1, and the natural sources of sesamin are annual plants that are at risk from climate change. In contrast, Forsythia species are widely distributed perennial woody plants that highly accumulate the precursor lignan pinoresinol. To sustainably supply sesamin, we developed a transformation method for Forsythia leaf explants and generated transgenic Forsythia plants that heterologously expressed the CYP81Q1 gene. High-performance liquid chromatography (HPLC) and LC-mass spectrometry analyses detected sesamin and its intermediate piperitol in the leaves of two independent transgenic lines of F. intermedia and F. koreana. We also detected the accumulation of sesamin and piperitol in their vegetatively propagated descendants, demonstrating the stable and efficient production of these lignans. These results indicate that CYP81Q1-transgenic Forsythia plants are promising prototypes to produce diverse lignans and provide an important strategy for the cost-effective and scalable production of lignans.

Seed-coat protective neolignans are produced by the dirigent protein AtDP1 and the laccase AtLAC5 in Arabidopsis.

Lignans/neolignans are generally synthesized from coniferyl alcohol (CA) in the cinnamate/monolignol pathway by oxidation to generate the corresponding radicals with subsequent stereoselective dimerization aided by dirigent proteins (DIRs). Genes encoding oxidases and DIRs for neolignan biosynthesis have not been identified previously. In Arabidopsis thaliana, the DIR AtDP1/AtDIR12 plays an essential role in the 8-O-4' coupling in neolignan biosynthesis by unequivocal structural determination of the compound missing in the atdp1 mutant as a sinapoylcholine (SC)-conjugated neolignan, erythro-3-{4-[2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-1-hydroxymethylethoxy]-3,5-dimethoxyphenyl}acryloylcholine. Phylogenetic analyses showed that AtDP1/AtDIR12 belongs to the DIR-a subfamily composed of DIRs for 8-8' coupling of monolignol radicals. AtDP1/AtDIR12 is specifically expressed in outer integument 1 cells in developing seeds. As a putative oxidase for neolignan biosynthesis, we focused on AtLAC5, a laccase gene coexpressed with AtDP1/AtDIR12. In lac5 mutants, the abundance of feruloylcholine (FC)-conjugated neolignans decreased to a level comparable to those in the atdp1 mutant. In addition, SC/FC-conjugated neolignans were missing in the seeds of mutants defective in SCT/SCPL19, an enzyme that synthesizes SC. These results strongly suggest that AtDP1/AtDIR12 and AtLAC5 are involved in neolignan biosynthesis via SC/FC. A tetrazolium penetration assay showed that seed coat permeability increased in atdp1 mutants, suggesting a protective role of neolignans in A. thaliana seeds.

(+)-Sesamin-oxidising CYP92B14 shapes specialised lignan metabolism in sesame.

Sesamum spp. (sesame) are known to accumulate a variety of lignans in a lineage-specific manner. In cultivated sesame (Sesamum indicum), (+)-sesamin, (+)-sesamolin and (+)-sesaminol triglucoside are the three major lignans found richly in the seeds. A recent study demonstrated that SiCYP92B14 is a pivotal enzyme that allocates the substrate (+)-sesamin to two products, (+)-sesamolin and (+)-sesaminol, through multiple reaction schemes including oxidative rearrangement of α-oxy-substituted aryl groups (ORA). In contrast, it remains unclear whether (+)-sesamin in wild sesame undergoes oxidation reactions as in S. indicum and how, if at all, the ratio of the co-products is tailored at the molecular level. Here, we functionally characterised SrCYP92B14 as a SiCYP92B14 orthologue from a wild sesame, Sesamum radiatum, in which we revealed accumulation of the (+)-sesaminol derivatives (+)-sesangolin and its novel structural isomer (+)-7´-episesantalin. Intriguingly, SrCYP92B14 predominantly produced (+)-sesaminol either through ORA or direct oxidation on the aromatic ring, while a relatively low but detectable level of (+)-sesamolin was produced. Amino acid substitution analysis suggested that residues in the putative distal helix and the neighbouring heme propionate of CYP92B14 affect the ratios of its co-products. These data collectively show that the bimodal oxidation mechanism of (+)-sesamin might be widespread across Sesamum spp., and that CYP92B14 is likely to be a key enzyme in shaping the ratio of (+)-sesaminol- and (+)-sesamolin-derived lignans from the biochemical and evolutionary perspectives.

Author Correction: Identification of a binding protein for sesamin and characterization of its roles in plant growth.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Author Correction: Identification of a binding protein for sesamin and characterization of its roles in plant growth.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Glycoside-specific glycosyltransferases catalyze regio-selective sequential glucosylations for a sesame lignan, sesaminol triglucoside.

Sesame (Sesamum indicum) seeds contain a large number of lignans, phenylpropanoid-related plant specialized metabolites. (+)-Sesamin and (+)-sesamolin are major hydrophobic lignans, whereas (+)-sesaminol primarily accumulates as a water-soluble sesaminol triglucoside (STG) with a sugar chain branched via ß1→2 and ß1→6-O-glucosidic linkages [i.e. (+)-sesaminol 2-O-ß-d-glucosyl-(1→2)-O-ß-d-glucoside-(1→6)-O-ß-d-glucoside]. We previously reported that the 2-O-glucosylation of (+)-sesaminol aglycon and ß1→6-O-glucosylation of (+)-sesaminol 2-O-ß-d-glucoside (SMG) are mediated by UDP-sugar-dependent glucosyltransferases (UGT), UGT71A9 and UGT94D1, respectively. Here we identified a distinct UGT, UGT94AG1, that specifically catalyzes the ß1→2-O-glucosylation of SMG and (+)-sesaminol 2-O-ß-d-glucosyl-(1→6)-O-ß-d-glucoside [termed SDG(ß1→6)]. UGT94AG1 was phylogenetically related to glycoside-specific glycosyltransferases (GGTs) and co-ordinately expressed with UGT71A9 and UGT94D1 in the seeds. The role of UGT94AG1 in STG biosynthesis was further confirmed by identification of a STG-deficient sesame mutant that predominantly accumulates SDG(ß1→6) due to a destructive insertion in the coding sequence of UGT94AG1. We also identified UGT94AA2 as an alternative UGT potentially involved in sugar-sugar ß1→6-O-glucosylation, in addition to UGT94D1, during STG biosynthesis. Yeast two-hybrid assays showed that UGT71A9, UGT94AG1, and UGT94AA2 were found to interact with a membrane-associated P450 enzyme, CYP81Q1 (piperitol/sesamin synthase), suggesting that these UGTs are components of a membrane-bound metabolon for STG biosynthesis. A comparison of kinetic parameters of these UGTs further suggested that the main ß-O-glucosylation sequence of STG biosynthesis is ß1→2-O-glucosylation of SMG by UGT94AG1 followed by UGT94AA2-mediated ß1→6-O-glucosylation. These findings together establish the complete biosynthetic pathway of STG and shed light on the evolvability of regio-selectivity of sequential glucosylations catalyzed by GGTs.

Identification of a binding protein for sesamin and characterization of its roles in plant growth.

Sesamin is a furofuran-type lignan that is found abundantly in seeds of Sesamum indicum (sesame) and has been widely accepted as a dietary supplement with positive effects on human health. The biological activity of sesamin in human cells and organs has been analysed extensively, although comparatively few studies show biological functions for sesamin in planta. Herein we screened sesamin-binding proteins (SBP) from sesame seedling extracts using sesamin-immobilized nano-beads. In subsequent peptide mass fingerprinting analyses, we identified a SBP, Steroleosin B, which is one of the membrane proteins found in oil bodies. In addition, pull-down assays and saturation transfer difference-nuclear magnetic resonance (STD-NMR) experiments demonstrated that sesamin binds directly to recombinant Steroleosin B in vitro. Finally, ectopic accumulations of sesamin and Steroleosin B in transgenic Arabidopsis thaliana plants induced severe growth defects including suppression of leaf expansion and root elongation. Collectively, these results indicate that sesamin influences tissue development in the presence of Steroleosin B.

Functional specialization of UDP-glycosyltransferase 73P12 in licorice to produce a sweet triterpenoid saponin, glycyrrhizin.

Glycyrrhizin, a sweet triterpenoid saponin found in the roots and stolons of Glycyrrhiza species (licorice), is an important active ingredient in traditional herbal medicine. We previously identified two cytochrome P450 monooxygenases, CYP88D6 and CYP72A154, that produce an aglycone of glycyrrhizin, glycyrrhetinic acid, in Glycyrrhiza uralensis. The sugar moiety of glycyrrhizin, which is composed of two glucuronic acids, makes it sweet and reduces its side-effects. Here, we report that UDP-glycosyltransferase (UGT) 73P12 catalyzes the second glucuronosylation as the final step of glycyrrhizin biosynthesis in G. uralensis; the UGT73P12 produced glycyrrhizin by transferring a glucuronosyl moiety of UDP-glucuronic acid to glycyrrhetinic acid 3-O-monoglucuronide. We also obtained a natural variant of UGT73P12 from a glycyrrhizin-deficient (83-555) strain of G. uralensis. The natural variant showed loss of specificity for UDP-glucuronic acid and resulted in the production of an alternative saponin, glucoglycyrrhizin. These results are consistent with the chemical phenotype of the 83-555 strain, and suggest the contribution of UGT73P12 to glycyrrhizin biosynthesis in planta. Furthermore, we identified Arg32 as the essential residue of UGT73P12 that provides high specificity for UDP-glucuronic acid. These results strongly suggest the existence of an electrostatic interaction between the positively charged Arg32 and the negatively charged carboxy group of UDP-glucuronic acid. The functional arginine residue and resultant specificity for UDP-glucuronic acid are unique to UGT73P12 in the UGT73P subfamily. Our findings demonstrate the functional specialization of UGT73P12 for glycyrrhizin biosynthesis during divergent evolution, and provide mechanistic insights into UDP-sugar selectivity for the rational engineering of sweet triterpenoid saponins.

Formation of a Methylenedioxy Bridge in (+)-Epipinoresinol by CYP81Q3 Corroborates with Diastereomeric Specialization in Sesame Lignans.

Plant specialized metabolites are often found as lineage-specific diastereomeric isomers. For example, Sesamum alatum accumulates the specialized metabolite (+)-2-episesalatin, a furofuran-type lignan with a characteristic diastereomeric configuration rarely found in other Sesamum spp. However, little is known regarding how diastereomeric specificity in lignan biosynthesis is implemented in planta. Here, we show that S. alatum CYP81Q3, a P450 orthologous to S. indicum CYP81Q1, specifically catalyzes methylenedioxy bridge (MDB) formation in (+)-epipinoresinol to produce (+)-pluviatilol. Both (+)-epipinoresinol and (+)-pluviatilol are putative intermediates of (+)-2-episesalatin based on their diastereomeric configurations. On the other hand, CYP81Q3 accepts neither (+)- nor (-)-pinoresinol as a substrate. This diastereomeric selectivity of CYP81Q3 is in clear contrast to that of CYP81Q1, which specifically converts (+)-pinoresinol to (+)-sesamin via (+)-piperitol by the sequential formation of two MDBs but does not accept (+)-epipinoresinol as a substrate. Moreover, (+)-pinoresinol does not interfere with the conversion of (+)-epipinoresinol to (+)-pluviatilol by CYP81Q3. Amino acid substitution and CO difference spectral analyses show that polymorphic residues between CYP81Q1 and CYP81Q3 proximal to their putative substrate pockets are crucial for the functional diversity and stability of these two enzymes. Our data provide clues to understanding how the lineage-specific functional differentiation of respective biosynthetic enzymes substantiates the stereoisomeric diversity of lignan structures.

MAL73, a novel regulator of maltose fermentation, is functionally impaired by single nucleotide polymorphism in sake brewing yeast.

For maltose fermentation, budding yeast Saccharomyces cerevisiae operates a mechanism that involves transporters (MALT), maltases (MALS) and regulators (MALR) collectively known as MAL genes. However, functional relevance of MAL genes during sake brewing process remains largely elusive, since sake yeast is cultured under glucose-rich condition achieved by the co-culture partner Aspergillus spp.. Here we isolated an ethyl methane sulfonate (EMS)-mutagenized sake yeast strain exhibiting enhanced maltose fermentation compared to the parental strain. The mutant carried a single nucleotide insertion that leads to the extension of the C-terminal region of a previously uncharacterized MALR gene YPR196W-2, which was renamed as MAL73. Introduction of the mutant allele MAL73L with extended C-terminal region into the parental or other sake yeast strains enhanced the growth rate when fed with maltose as the sole carbon source. In contrast, disruption of endogenous MAL73 in the sake yeasts decreased the maltose fermentation ability of sake yeast, confirming that the original MAL73 functions as a MALR. Importantly, the MAL73L-expressing strain fermented more maltose in practical condition compared to the parental strain during sake brewing process. Our data show that MAL73(L) is a novel MALR gene that regulates maltose fermentation, and has been functionally attenuated in sake yeast by single nucleotide deletion during breeding history. Since the MAL73L-expressing strain showed enhanced ability of maltose fermentation, MAL73L might also be a valuable tool for enhancing maltose fermentation in yeast in general.

Author Correction: Oxidative rearrangement of (+)-sesamin by CYP92B14 co-generates twin dietary lignans in sesame.

The original version of of the Supplementary Information associated with this Article inadvertently omitted oligonucleotide primer sequences from Supplementary Table 3 and Supplementary Methods describing the molecular cloning of CYP92B14, CPR1 and CYP81Q cDNA fragments. The HTML has been updated to include a corrected version of the Supplementary Information.

Oxidative rearrangement of (+)-sesamin by CYP92B14 co-generates twin dietary lignans in sesame.

(+)-Sesamin, (+)-sesamolin, and (+)-sesaminol glucosides are phenylpropanoid-derived specialized metabolites called lignans, and are rich in sesame (Sesamum indicum) seed. Despite their renowned anti-oxidative and health-promoting properties, the biosynthesis of (+)-sesamolin and (+)-sesaminol remained largely elusive. Here we show that (+)-sesamolin deficiency in sesame is genetically associated with the deletion of four C-terminal amino acids (Del4C) in a P450 enzyme CYP92B14 that constitutes a novel clade separate from sesamin synthase CYP81Q1. Recombinant CYP92B14 converts (+)-sesamin to (+)-sesamolin and, unexpectedly, (+)-sesaminol through an oxygenation scheme designated as oxidative rearrangement of α-oxy-substituted aryl groups (ORA). Intriguingly, CYP92B14 also generates (+)-sesaminol through direct oxygenation of the aromatic ring. The activity of CYP92B14 is enhanced when co-expressed with CYP81Q1, implying functional coordination of CYP81Q1 with CYP92B14. The discovery of CYP92B14 not only uncovers the last steps in sesame lignan biosynthesis but highlights the remarkable catalytic plasticity of P450s that contributes to metabolic diversity in nature.

De Novo Transcriptomes of Forsythia koreana Using a Novel Assembly Method: Insight into Tissue- and Species-Specific Expression of Lignan Biosynthesis-Related Gene.

Forsythia spp. are perennial woody plants which are one of the most extensively used medicinal sources of Chinese medicines and functional diets owing to their lignan contents. Lignans have received widespread attention as leading compounds in the development of antitumor drugs and healthy diets for reducing the risks of lifestyle-related diseases. However, the molecular basis of Forsythia has yet to be established. In this study, we have verified de novo deep transcriptome of Forsythia koreana leaf and callus using the Illumina HiSeq 1500 platform. A total of 89 million reads were assembled into 116,824 contigs using Trinity, and 1,576 of the contigs displayed the sequence similarity to the enzymes responsible for plant specialized metabolism including lignan biosynthesis. Notably, gene ontology (GO) analysis indicated the remarkable enrichment of lignan-biosynthetic enzyme genes in the callus transcriptome. Nevertheless, precise annotation and molecular phylogenetic analyses were hindered by partial sequences of open reading frames (ORFs) of the Trinity-based contigs. To obtain more numerous contigs harboring a full-length ORF, we developed a novel overlapping layout consensus-based procedure, virtual primer-based sequence reassembly (VP-seq). VP-seq elucidated 709 full-length ORFs, whereas only 146 full-length ORFs were assembled by Trinity. The comparison of expression profiles of leaf and callus using VP-seq-based full-length ORFs revealed 50-fold upregulation of secoisolariciresinol dehydrogenase (SIRD) in callus. Expression and phylogenetic cluster analyses predicted candidates for matairesinol-glucosylating enzymes. We also performed VP-seq analysis of lignan-biosynthetic enzyme genes in the transcriptome data of other lignan-rich plants, Linum flavum, Linum usitatissimum and Podophyllum hexandrum. The comparative analysis indicated both common gene clusters involved in biosynthesis upstream of matairesinol such as SIRD and plant lineage-specific gene clusters, in particular, genes responsible for biosynthetic pathways for production of podophyllotoxin; CYP71BE54, a key enzyme gene for podophyllotoxin biosynthesis in P. hexandrum, was not found in L. flavum, although both P. hexandrum. and L. flavum yield podophyllotoxin. Altogether, these data have established the fruitful molecular basis of Forsythia and provided insight into the molecular evolution and diversity of lignan biosynthetic pathways.

The "putative" role of transcription factors from HlWRKY family in the regulation of the final steps of prenylflavonid and bitter acids biosynthesis in hop (Humulus lupulus L.).

Lupulin glands localized in female hop (Humulus lupulus L.) cones are valuable source of bitter acids, essential oils and polyphenols. These compounds are used in brewing industry and are important for biomedical applications. In this study we describe the potential effect of transcription factors from WRKY family in the activation of the final steps of lupulin biosynthesis. In particular, lupulin gland-specific transcription factor HlWRKY1 that shows significant similarity to AtWRKY75, has ability to activate the set of promoters driving key genes of xanthohumol and bitter acids biosynthesis such as chalcone synthase H1, valerophenone synthase, prenyltransferase 1, 1L and 2 and O-methyltransferase-1. When combined with co-factor HlWDR1 and silencing suppressor p19, HlWRKY1 is able to enhance transient expression of gus gene driven by Omt1 and Chs_H1 promoters to significant level as compared to 35S promoter of CaMV in Nicotiana. benthamiana. Transformation of hop with dual Agrobacterium vector bearing HlWRKY1/HlWDR1 led to ectopic overexpression of these transgenes and further activation of lupulin-specific genes expression in hop leaves. It was further showed that (1) HlWRKY1 is endowed with promoter autoactivation; (2) It is regulated by post-transcriptional gene silencing (PTGS) mechanism; (3) It is stimulated by kinase co-expression. Since HlWRKY1 promotes expression of lupulin-specific HlMyb3 gene therefore it can constitute a significant component in hop lupulin regulation network. Putative involvement of HlWRKY1 in the regulation of lupulin biosynthesis may suggest the original physiological function of lupulin components in hop as flower and seed protective compounds.