Endophytic fungi in buckwheat seeds: exploring links with flavonoid accumulation

Buckwheat is a famous edible and medicinal coarse cereal which contain abundant of bioactive flavonoids, such as rutin. In this study, the composition and diversity of endophytic fungi in eight different buckwheat seeds were analyzed by high-throughput sequencing of ITS rDNA. Results showed that, the fungal sequences reads were allocated to 272 OTUs, of them, 49 OTUs were shared in eight buckwheat seeds. These endophytic fungi could be classified into 6 phyla, 19 classes, 41 orders, 79 families, 119 genera, and 191 species. At genus level, Alternaria sp. was the domain fungal endophyte. Besides, fungal endophytes belonged to the genera of Epicocum, Cladosporium, Botrytis, Filbobasidium, Stemphylium, and Vishniacozyma were highly abundant in buckwheat seeds. The total flavonoids and rutin contents in tartary buckwheat cultivars (CQ, XQ, CH, K2) were much higher than those in common buckwheat cultivars (HT, T2, T4, T8). For tartary buckwheat cultivars, the total flavonoids and rutin contents were ranging from 2.6% to 3.3% and 0.9% to 1.3%, respectively. Accordingly, the tartary buckwheat samples displayed stronger antioxidant activity than the common buckwheat. Spearman correlation heat map analysis was successfully found that certain fungal species from the genera of Alternaria, Botryosphaeria, Colletorichum and Diymella exhibited significant positive correlation with flavonoids contents. Results of this study preliminary revealed the fungi-plant interaction relationship at secondary metabolite level, and could provide novel strategy for increasing the flavonoids accumulation of buckwheat seeds, as well as improving their quality.

Immunohistochemical Detection of the Wall Components on the Example of Shoot Apical Meristem of Fagopyrum esculentum and Fagopyrum tataricum

Immunohistochemistry is a method that allows the detection of individual components of cell walls in an extremely precise way at the level of a single cell and wall domains. The cell wall antibodies detect specific epitopes of pectins, arabinogalactan proteins (AGP), hemicelluloses, and extensins. The presented method visualization of the selected pectic and AGP epitopes using antibodies directed to wall components is described. The method of the analysis of the chemical composition of the wall is present on the example of the shoot apical meristems of Fagopurum esculentum and Fagopyrum tataricum. Recommended protocols for immunostaining and examination on fluorescence microscopy level are presented.

Immunostaining for Epigenetic Modifications in Fagopyrum Calli

Immunostaining is a well-established technique for identifying specific proteins in tissue samples with specific antibodies to identify a single target protein. It is commonly used in research and provides information about cellular localization and protein expression levels. This chapter describes a detailed protocol for immunostaining fixed Fagopyrum calli embedded in Steedman's wax using nine antibodies raised against histone H3 and H4 methylation and acetylation on several lysines and DNA methylation.

Visualization of Fagopyrum esculentum and Fagopyrum tataricum Chromosomes and Micronuclei

This chapter presents the squash chromosome preparation technique for Fagopyrum esculentum and F. tataricum, using the root tips as the source of the material. Using an optimized version of this method, the chromosomes are free of cytoplasmic debris and are spread evenly on the glass slide. What comes of it is the possibility to make observations of the chromosome number and structure at the metaphase stage. This technique's modified version allows micronuclei analysis in interphase cells of buckwheats.

Immunodetection of Cell Wall Components in Studies on Cell Wall Rebuilding in Fagopyrum esculentum and Fagopyrum tataricum

Immunocytochemical studies of the cell wall are used to visualize specific epitopes of pectins, arabinogalactan proteins, hemicelluloses, extensins, and other wall components using specific primary antibodies. This reaction, combined with calcofluor staining, allows to comprehend how the cell wall is rebuilt during the protoplast culture. In this protocol, the method of immunostaining using antibodies against cell wall components based on Fagopyrum esculentum and Fagopyrum tataricum protoplasts is described.

Comparative and population genomics of buckwheat species reveal key determinants of flavor and fertility

Common buckwheat (Fagopyrum esculentum) is an ancient crop with a world-wide distribution. Due to its excellent nutritional quality and high economic and ecological value, common buckwheat is becoming increasingly important throughout the world. The availability of a high-quality reference genome sequence and population genomic data will accelerate the breeding of common buckwheat, but the high heterozygosity due to the outcrossing nature has greatly hindered the genome assembly. Here we report the assembly of a chromosome-scale high-quality reference genome of F. esculentum var. homotropicum, a homozygous self-pollinating variant of common buckwheat. Comparative genomics revealed that two cultivated buckwheat species, common buckwheat (F. esculentum) and Tartary buckwheat (F. tataricum), underwent metabolomic divergence and ecotype differentiation. The expansion of several gene families in common buckwheat, including FhFAR genes, is associated with its wider distribution than Tartary buckwheat. Copy number variation of genes involved in the metabolism of flavonoids is associated with the difference of rutin content between common and Tartary buckwheat. Furthermore, we present a comprehensive atlas of genomic variation based on whole-genome resequencing of 572 accessions of common buckwheat. Population and evolutionary genomics reveal genetic variation associated with environmental adaptability and floral development between Chinese and non-Chinese cultivated groups. Genome-wide association analyses of multi-year agronomic traits with the content of flavonoids revealed that Fh05G014970 is a potential major regulator of flowering period, a key agronomic trait controlling the yield of outcrossing crops, and that Fh06G015130 is a crucial gene underlying flavor-associated flavonoids. Intriguingly, we found that the gene translocation and sequence variation of FhS-ELF3 contribute to the homomorphic self-compatibility of common buckwheat. Collectively, our results elucidate the genetic basis of speciation, ecological adaptation, fertility, and unique flavor of common buckwheat, and provide new resources for future genomics-assisted breeding of this economically important crop.

The pan-plastome of tartary buckwheat (fagopyrum tataricum): key insights into genetic diversity and the history of lineage divergence

BACKGROUND

Tartary buckwheat (Fagopyrum tataricum) is an important food and medicine crop plant, which has been cultivated for 4000 years. A nuclear genome has been generated for this species, while an intraspecific pan-plastome has yet to be produced. As such a detailed understanding of the maternal genealogy of Tartary buckwheat has not been thoroughly investigated.

RESULTS

In this study, we de novo assembled 513 complete plastomes of Fagopyrum and compared with 8 complete plastomes of Fagopyrum downloaded from the NCBI database to construct a pan-plastome for F. tartaricum and resolve genomic variation. The complete plastomes of the 513 newly assembled Fagopyrum plastome sizes ranged from 159,253 bp to 159,576 bp with total GC contents ranged from 37.76 to 37.97%. These plastomes all maintained the typical quadripartite structure, consisting of a pair of inverted repeat regions (IRA and IRB) separated by a large single copy region (LSC) and a small single copy region (SSC). Although the structure and gene content of the Fagopyrum plastomes are conserved, numerous nucleotide variations were detected from which population structure could be resolved. The nucleotide variants were most abundant in the non-coding regions of the genome and of those the intergenic regions had the most. Mutational hotspots were primarily found in the LSC regions. The complete 521 Fagopyrum plastomes were divided into five genetic clusters, among which 509 Tartary buckwheat plastomes were divided into three genetic clusters (Ft-I/Ft-II/Ft-III). The genetic diversity in the Tartary buckwheat genetic clusters was the greatest in Ft-III, and the genetic distance between Ft-I and Ft-II was the largest. Based on the results of population structure and genetic diversity analysis, Ft-III was further subdivided into three subgroups Ft-IIIa, Ft-IIIb, and Ft-IIIc. Divergence time estimation indicated that the genera Fagopyrum and Rheum (rhubarb) shared a common ancestor about 48 million years ago (mya) and that intraspecies divergence in Tartary buckwheat began around 0.42 mya.

CONCLUSIONS

The resolution of pan-plastome diversity in Tartary buckwheat provides an important resource for future projects such as marker-assisted breeding and germplasm preservation.

Reproductive development of common buckwheat (Fagopyrum esculentum Moench) and its wild relatives provides insights into their evolutionary biology

INTRODUCTION

Understanding the complex inflorescence architecture and developmental morphology of common buckwheat (Fagopyrum esculentum) is crucial for crop yield. However, most published descriptions of early flower and inflorescence development in Polygonaceae are based on light microscopy and often documented by line drawings. In Fagopyrum and many other Polygonaceae, an important inflorescence module is the thyrse, in which the primary axis never terminates in a flower and lateral cymes (monochasia) produce successively developing flowers of several orders. Each flower of a cyme is enclosed together with the next-order flower by a bilobed sheathing bract-like structure of controversial morphological nature.

METHODS

We explored patterns of flower structure and arrangement in buckwheat and its wild relatives, using comparative morphology, scanning electron microscopy and X-ray microtomography.

RESULTS

Our data support interpretation of the sheathing bract as two congenitally fused phyllomes (prophylls), one of which subtends a next-order flower. In tepal-like bract, a homeotic mutant of F. esculentum, the bilobed sheathing bract-like organ acquires tepal-like features and is sometimes replaced by two distinct phyllomes. Wild representatives of F. esculentum (ssp. ancestrale) and most cultivars of common buckwheat possess an indeterminate growth type with lateral thyrses produced successively on the primary inflorescence axis until cessation of growth. In contrast, determinate cultivars of F. esculentum develop a terminal thyrse after producing lateral thyrses. In contrast to F. esculentum, the occurrence of a terminal thyrse does not guarantee a determinate growth pattern in F. tataricum. The number of lateral thyrses produced before the terminal thyrse on the main axis of F. tataricum varies from zero to c. 19.

DISCUSSION

The nine stages of early flower development formally recognized here and our outline of basic terminology will facilitate more standardized and readily comparable descriptions in subsequent research on buckwheat biology. Non-trivial relative arrangements of tepals and bracteoles in Fagopyrum and some other Polygonaceae require investigation using refined approaches to mathematical modelling of flower development. Our data on inflorescence morphology and development suggest contrasting evolutionary patterns in the two main cultivated species of buckwheat, F. esculentum and F. tataricum. The genus Fagopyrum offers an excellent opportunity for evo-devo studies related to inflorescence architecture.

Plastome comparison and phylogenomics of Fagopyrum (Polygonaceae): insights into sequence differences between Fagopyrum and its related taxa

BACKGROUND

Fagopyrum (Polygonaceae) is a small plant lineage comprised of more than fifteen economically and medicinally important species. However, the phylogenetic relationships of the genus are not well explored, and the characteristics of Fagopyrum chloroplast genomes (plastomes) remain poorly understood so far. It restricts the comprehension of species diversity in Fagopyrum. Therefore, a comparative plastome analysis and comprehensive phylogenomic analyses are required to reveal the taxonomic relationship among species of Fagopyrum.

RESULTS

In the current study, 12 plastomes were sequenced and assembled from eight species and two varieties of Fagopyrum. In the comparative analysis and phylogenetic analysis, eight previously published plastomes of Fagopyrum were also included. A total of 49 plastomes of other genera in Polygonaceae were retrieved from GenBank and used for comparative analysis with Fagopyrum. The variation of the Fagopyrum plastomes is mainly reflected in the size and boundaries of inverted repeat/single copy (IR/SC) regions. Fagopyrum is a relatively basal taxon in the phylogenomic framework of Polygonaceae comprising a relatively smaller plastome size (158,768-159,985 bp) than another genus of Polygonaceae (158,851-170,232 bp). A few genera of Polygonaceae have nested distribution of the IR/SC boundary variations. Although most species of Fagopyrum show the same IRb/SC boundary with species of Polygonaceae, only a few species show different IRa/SC boundaries. The phylogenomic analyses of Fagopyrum supported the cymosum and urophyllum groups and resolved the systematic position of subclades within the urophyllum group. Moreover, the repeat sequence types and numbers were found different between groups of Fagopyrum. The plastome sequence identity showed significant differences between intra-group and inter-group.

CONCLUSIONS

The deletions of intergenic regions cause a short length of Fagopyrum plastomes, which may be the main reason for plastome size diversity in Polygonaceae species. The phylogenomic reconstruction combined with the characteristics comparison of plastomes supports grouping within Fagopyrum. The outcome of these genome resources may facilitate the taxonomy, germplasm resources identification as well as plant breeding of Fagopyrum.

The Complete Chloroplast Genome Sequences of Eight Fagopyrum Species: Insights Into Genome Evolution and Phylogenetic Relationships

Buckwheat (Fagopyrum genus, Polygonaceae), is an annual or perennial, herbaceous or semi-shrub dicotyledonous plant. There are mainly three cultivated buckwheat species, common buckwheat (Fagopyrum esculentum) is widely cultivated in Asia, Europe, and America, while Tartary buckwheat (F. tataricum) and F. cymosum (also known as F. dibotrys) are mainly cultivated in China. The genus Fagopyrum is taxonomically confusing due to the complex phenotypes of different Fagopyrum species. In this study, the chloroplast (cp) genomes of three Fagopyrum species, F. longistylum, F. leptopodum, F. urophyllum, were sequenced, and five published cp genomes of Fagopyrum were retrieved for comparative analyses. We determined the sequence differentiation, repeated sequences of the cp genomes, and the phylogeny of Fagopyrum species. The eight cp genomes ranged, gene number, gene order, and GC content were presented. Most of variations of Fagopyrum species cp genomes existed in the LSC and SSC regions. Among eight Fagopyrum chloroplast genomes, six variable regions (ndhF-rpl32, trnS-trnG, trnC, trnE-trnT, psbD, and trnV) were detected as promising DNA barcodes. In addition, a total of 66 different SSR (simple sequence repeats) types were found in the eight Fagopyrum species, ranging from 8 to 16 bp. Interestingly, many SSRs showed significant differences especially in some photosystem genes, which provided valuable information for understanding the differences in light adaptation among different Fagopyrum species. Genus Fagopyrum has shown a typical branch that is distinguished from the Rumex, Rheum, and Reynoutria, which supports the unique taxonomic status in Fagopyrum among the Polygonaceae. In addition, phylogenetic analysis based on the cp genomes strongly supported the division of eight Fagopyrum species into two independent evolutionary directions, suggesting that the separation of cymosum group and urophyllum group may be earlier than the flower type differentiation in Fagopyrum plants. The results of the chloroplast-based phylogenetic tree were further supported by the matK and Internal Transcribed Spacer (ITS) sequences of 17 Fagopyrum species, which may help to further anchor the taxonomic status of other members in the urophyllum group in Fagopyrum. This study provides valuable information and high-quality cp genomes for identifying species and evolutionary analysis for future Fagopyrum research.

The first complete chloroplast genome of Fagopyrum leptopodum (Diels) Hedberg (Caryophyllales: Polygonaceae) with phylogenetic implications

In the present study, we sequenced and assembled the complete chloroplast genome of Fagopyrum leptopodum (Diels) Hedberg. The chloroplast genome of F. leptopodum was composed of 85 protein-coding genes, 8 ribosomal RNA genes, and 37 transfer RNA genes. The F. leptopodum chloroplast genome is 159,375 bp in length, with a GC content of 37.81%. Phylogenetic analysis based on the combined chloroplast gene dataset indicated that the F. leptopodum exhibited a close relationship with Fagopyrum luojishanense.

Breeding Buckwheat for Nutritional Quality in the Czech Republic

Buckwheat is a nutritionally valuable crop, an alternative to common cereals also usable in gluten-free diets. The selection of buckwheat genotypes suitable for further breeding requires the characterization and evaluation of genetic resources. The main objective of this work was to evaluate selected phenotypic and morphological traits using international buckwheat descriptors, including total phenolic content and antioxidant activity, on a unique set of 136 common buckwheat accessions grown in 2019-2020 under Czech Republic conditions. In addition, UHPLC-ESI- MS/MS was used to analyze a wide spectrum of 20 phenolic compounds in buckwheat seeds, including four flavanols, three phenolic acids, seven flavonols, four flavones, and two flavanones. Significant differences among years and genotypes were observed for morphological traits (plant height and 1000-seed weight) and antioxidant activity, as well as levels of observed chemical compounds. Antioxidant activity, crude protein content, plant height and rutin content were characterized by higher mean values in 2020 than in 2019 and vice versa for total polyphenol content and 1000-seed weight. Crude protein content was the most stable across years, while total polyphenol content and rutin content varied greatly from year to year. The most abundant phenolic compounds were rutin, hyperoside, epicatechin, catechin, vitexin, isovitexin, orientin and isoorientin. Protein content was negatively correlated with plant height, catechin and epicatechin content. On the other hand, AA and TPC were positively correlated with rutin, hyperoside and chlorogenic acid. Five accessions showed high stability of the evaluated traits under changing conditions within both years of observation. These materials can be used in breeding programmes aimed at improving buckwheat genotypes with emphasis on quality traits.

Implications of Fagopyrin Formation In Vitro by UV Spectroscopic Analysis

The present work aims at studying the possible biosynthesis of fagopyrin in buckwheat plants with an attempt to address the existing gaps. The developed method of differential spectrophotometry can be used for identification of naphthodianthrones fagopyrins. It was found that in the vegetative mass of buckwheat plants, fagopyrin precursor-2-(piperidine-2-yl)-emodindianthron could be present. As fagopyrin can be produced by light effect, the temperature factor may influence the formation of protofagopyrin in vitro. An optimum temperature range was estimated for protofagopyrin formation. A possible fagopyrin biosynthesis under in vitro conditions was suggested.

psbE-psbL and ndhA Intron, the Promising Plastid DNA Barcode of Fagopyrum

Buckwheat is an important functional food material with high nutritional value. However, it is still a difficult task for the taxonomy studies of wild buckwheat that are only based on morphology. In order to demonstrate the most efficient DNA barcode in the phylogenetic research of buckwheat, promote the investigation of wild buckwheat, and also reveal the phylogenetic relationship between Fagopyrum species, psbE-psbL and ndhA intron were validated here, which previously have been proved to be promising DNA barcode candidates for phylogenetic studies in genera Fagopyrum. Meanwhile, ndhA intron + psbE-psbL and matK + psbE-psbL could distinguish the relationship between species clearly. Combining the results of morphology and molecular markers, we suggested the buckwheat species should be divided into two subgroups, one subgroup consisted of F. tataricum, F. esculentum, F. cymosum and its related wild species, and the other subgroup included other wild buckwheat species. Our results could fulfill molecular markers of taxonomy research in genera Fagopyrum, promote wild buckwheat species identification, and assist in the use of wild buckwheat resources in the future. Additionally, the phylogenetic relationship revealed here could provide valuable information for molecular breeding of buckwheat and provide reference for inter-species hybridization.

Buckwheat: a crop from outside the major Chinese domestication centres? A review of the archaeobotanical, palynological and genetic evidence

The two cultivated species of buckwheat, Fagopyrum esculentum (common buckwheat) and F. tataricum (Tartary buckwheat) are Chinese domesticates whose origins are usually thought to lie in upland southwestern China, outside the major centres of agricultural origins associated with rice and millet. Synthesis of the macro- and microfossil evidence for buckwheat cultivation in China found just 26 records across all time periods, of which the majority were pollen finds. There are few or no identifying criteria distinguishing F. esculentum and F. tataricum for any sample type. The earliest plausibly agricultural Fagopyrum occurs in northern China from the mid 6th millennium cal bp. The archaeobotanical record requires reconciliation with biogeographic and genetic inferences of a southwestern Chinese origin for buckwheat. Scrutiny of the genetic data indicates limitations related to sampling, molecular markers and analytical approaches. Common buckwheat may have been domesticated at the range margins of its wild progenitor before its cultivation expanded in the north, mediated by changing ranges of wild species during the Holocene and/or by cultural exchange or movement of early agriculturalists between southwest China, the Chengdu Plain and the southern Loess Plateau. Buckwheat probably became a pan-Eurasian crop by the 3rd millennium cal bp, with the pattern of finds suggesting a route of westward expansion via the southern Himalaya to the Caucasus and Europe.

Transitions from distyly to homostyly are associated with floral evolution in the buckwheat genus (Fagopyrum)

PREMISE OF THE STUDY

Documenting trait transitions among species with dimorphic flowers can help to test whether similar patterns of selection are responsible for divergence in floral traits among different species. Heterostyly is thought to promote outcrossing. Theory suggests that the evolutionary transition from heterostylous to homostylous flowers should be accompanied by a reduction in floral size in which pollen size and style length are expected to covary. Patterns of such correlated floral trait evolution have not, however, been widely examined.

METHODS

The evolutionary history of heterostyly and homostyly was reconstructed from a molecular phylogeny of 13 species of Fagopyrum and two outgroups, based on one nuclear gene (nrITS) and three chloroplast regions (matK, atpB-rbcL, and psbA-trnH spacer). Floral traits of nine Fagopyrum species including pollen number and size, as well as stigma depth (length of the capitate stigma), were measured and ancestral characters of the herkogamic condition were reconstructed.

KEY RESULTS

Three transitions from distyly to homostyly were observed. In two transitions, flower size (corolla diameter, pedicel length), herkogamy (stigma-anther distance) and pollen production decreased, but stigma depth and pollen size did not. Changes of anther height and style length were inconsistent. The predicted positive relationship between style length and pollen size in the two transitions to homostyly was not observed.

CONCLUSIONS

Floral evolution accompanying transitions to homostyly in Fagopyrum were found to be consistent with predictions of mating system evolution theory, and the correlation of traits in distylous vs. homostylous species revealed that pollen size generally correlates with stigma depth rather than style length.

Phytochemical and Pharmacological Profiles of Three Fagopyrum Buckwheats

The genus Fagopyrum (Polygonaceae), currently comprising 15 species of plants, includes three important buckwheat species: Fagopyrum esculentum (F. esculentum) Moench. (common buckwheat), Fagopyrum tataricum (F. tataricum) (L.) Gaertn. (tartary buckwheat) and Fagopyrum dibotrys (F. dibotrys) (D. Don) Hara. (perennial buckwheat), which have been well explored due to their long tradition of both edible and medicinal use. This review aimed to present an up-to-date and comprehensive analysis of the phytochemistry and pharmacology of the three Fagopyrum buckwheats. In addition, the scope for future research was also discussed. All available references included in this paper were compiled from major databases, such as MEDLINE, Pubmed, Scholar, Elsevier, Springer, Wiley and CNKI. A total of 106 compounds isolated from three Fagopyrum buckwheats can be mainly divided into six classes: flavonoids, phenolics, fagopyritols, triterpenoids, steroids and fatty acids. Flavonoids and phenolic compounds were considered to be the major active components. Considerable pharmacological experiments both in vitro and in vivo have validated that Fagopyrum buckwheats possess antitumor, anti-oxidant, anti-inflammatory, hepatoprotective, anti-diabetic activities, etc. All reported data lead us to conclude that Fagopyrum buckwheats have convincing medicinal potential. However, further research is needed to explore its bioactive constituents, the relationship to their structural activities and the molecular mechanisms of action.

Buckwheat as a Functional Food and Its Effects on Health

Buckwheat (BW) is a gluten-free pseudocereal that belongs to the Polygonaceae family. BW grain is a highly nutritional food component that has been shown to provide a wide range of beneficial effects. Health benefits attributed to BW include plasma cholesterol level reduction, neuroprotection, anticancer, anti-inflammatory, antidiabetic effects, and improvement of hypertension conditions. In addition, BW has been reported to possess prebiotic and antioxidant activities. In vitro and animal studies suggest that BW's bioactive compounds, such as D-chiro-inositol (DCI), BW proteins (BWP), and BW flavonoids (mainly rutin and quercetin) may be partially responsible for the observed effects. The purpose of this paper is to review the recent research regarding the health benefits of BW, in vitro and in vivo, focusing on the specific role of its bioactive compounds and on the mechanisms by which these effects are exerted.

Physiological characterization of aluminum tolerance and accumulation in tartary and wild buckwheat

Ionic aluminum (Al) is toxic for plant growth, but some plant species are able to accumulate Al at high concentrations without showing toxicity symptoms. In order to determine whether other species in the genus Fagopyrum are able to accumulate Al like common buckwheat (Fagopyrum esculentum), we investigated the external and internal detoxification mechanisms of Al in two self-compatible species: tartary (Fagopyrum tataricum) and wild buckwheat (Fagopyrum homotropicum). Both tartary and wild buckwheat showed high Al tolerance comparable to common buckwheat. Furthermore, these two species also secreted oxalate rapidly from the roots in response to Al in a time-dependent manner. Both tartary and wild buckwheat accumulated > 1 mg g(-1) Al in the leaves after short-term exposure to Al. Analysis with (27) Al-nuclear magnetic resonance (NMR) revealed that Al was present in the form of Al-oxalate (1 : 3 ratio) in the roots and leaves, but in the form of Al-citrate (1 : 1 ratio) in the xylem sap in both species. These results indicate that similar to common buckwheat, both tartary and wild buckwheat detoxify Al externally and internally, respectively, by secreting oxalate from the roots and by forming the Al-oxalate complex, which is a nonphytotoxic form. These features of Al response and accumulation may be conserved in genus Fagopyrum.