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Flax seeds are the richest plant source of lignans, which prevent the development of many diseases. In the seeds of cultivated species Linum usitatissimum, the lignan secoisolariciresinol diglucoside (SDG) predominates. In the present study, transcriptome sequencing of flax seeds was performed at five developmental stages for eight varieties differing in lignan content and grown under three variants of conditions, and expression of the PLR1 and UGT74S1 genes, which play a key role in the SDG synthesis, was assessed. Co-expression of the PLR1 and UGT74S1 genes, as well as tenfold and hundredfold changes in the expression level of these genes during seed development were revealed, which testified to their role in the synthesis of SDG in flax seeds. Reduced temperature (16°C) and excessive watering led to a shift in the maximum expression level of both genes to a later date (14th day after flowering), compared to the conditions of insufficient watering and elevated temperature (24°C), as well as optimum conditions (20°C) (7th day after flowering). Moreover, at elevated temperatures and insufficient watering, the PLR1 and UGT74S1 expression levels were lower than under optimum conditions. No association between the lignan content in seeds of the studied flax varieties and the PLR1 and UGT74S1 expression levels was found. These findings provide insight into the contribution of genotype and environment to the expression of key genes for SDG synthesis, which, among other things, is necessary for the development of optimum approaches for obtaining the lignan-rich flax seeds. [ABSTRACT FROM AUTHOR]

The goal of this investigation was the interpretation of genetic polymorphism in flax using the random amplified polymorphic DNA (RAPDPCR) technique in relation to genealogical information and eco geographic origin of the accessions. Protein markers have been successfully applied for identification of ecotypes of cultivated plants and for cultivar identification and registration. However, for intraspecific differentiation in flax effective protein markers have not been found. The DNA markers developed during the recent decades proved to be more efficient in detecting polymorphism in flax. The plant material were 287 accessions from the flax collection at the All-Russian Flax Research Institute (VNIIL) belonging to different botanical and eco-geographical groups based on the classification of the species Linumu sitatissimum L. On the basis of a molecular estimation the gene pool offlax it can be assumed that the fiber flax from northern continental Russia is not exclusively of Indoafghan origin as suggested by Sinskaja (1959), but also has genetic roots in flax from Kolchidian. Essential genetic similarity between cultivar of fiber flax from Russia and other the European countries is established. Results of a generality of an origin of fiber flax cultivar from Russia are confirmed also with the analysis of their genealogy. Essential genetic polymorphism of linseed flax is shown. The distinctness of linseed and fiber flax in their genetic constitution as revealed by the RAPD analysis is of strategic importance in preservation of the genetic diversity and for efficient use of the flax gene pool in breeding. [ABSTRACT FROM AUTHOR]

To assess the genomic diversity of Fusarium oxysporum f. sp. lini strains and compile a comprehensive gene repertoire, we constructed a pangenome using 13 isolates from four different clonal lineages, each exhibiting distinct levels of virulence. Syntenic analyses of two selected genomes revealed significant chromosomal rearrangements unique to each genome. A comprehensive examination of both core and accessory pangenome content and diversity points at an open genome state. Additionally, Gene Ontology (GO) enrichment analysis indicated that non-core pangenome genes are associated with pathogen recognition and immune signaling. Furthermore, the Folini pansecterome, encompassing secreted proteins critical for fungal pathogenicity, primarily consists of three functional classes: effector proteins, CAZYmes, and proteases. These three classes account for approximately 3.5% of the pangenome. Each functional class within the pansecterome was meticulously annotated and characterized with respect to pangenome category distribution, PFAM domain frequency, and strain virulence assessment. This analysis revealed that highly virulent isolates have specific types of PFAM domains that are exclusive to them. Upon examining the repertoire of SIX genes known for virulence in other formae speciales, it was found that all isolates had a similar gene content except for two, which lacked SIX genes entirely., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Logachev, Kanapin, Rozhmina, Stanin, Bankin, Samsonova, Orlova and Samsonova.)

In this paper, we explore potential genetic factors in control of flax phenotypes associated with fiber by mining a collection of 306 flax accessions from the Federal Research Centre of the Bast Fiber Crops, Torzhok, Russia. In total, 11 traits were assessed in the course of 3 successive years. A genome-wide association study was performed for each phenotype independently using six different single-locus models implemented in the GAPIT3 R package. Moreover, we applied a multivariate linear mixed model implemented in the GEMMA package to account for trait correlations and potential pleiotropic effects of polymorphisms. The analyses revealed a number of genomic variants associated with different fiber traits, implying the complex and polygenic control. All stable variants demonstrate a statistically significant allelic effect across all 3 years of the experiment. We tested the validity of the predicted variants using gene expression data available for the flax fiber studies. The results shed new light on the processes and pathways associated with the complex fiber traits, while the pinpointed candidate genes may be further used for marker-assisted selection.

A collection of flax accessions maintained by the Russian Federal Research Center for Bast Fiber Crops was characterized to evaluate its resistance to Fusarium wilt. 297 samples representing different morphotypes and selection status were infected with highly virulent MI39 strain of Fusarium oxysporum f. sp. lini . Evaluation of disease symptoms was performed at the full emergence stage in a greenhouse. The experiment lasted for 3 successive years. The disease severity index (DSI) record was obtained for every genotype in each year of the experiment. The data set was produced in a framework of a project focused on both a) deciphering the mechanisms of plant immunity, and b) development of flax cultivars resistant to Fusarium wilt. The data is available via Figshare repository., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships which have or could be perceived to have influenced the work reported in this article., (© 2022 The Author(s). Published by Elsevier Inc.)

Genetic diversity in a breeding program is essential to overcome modern-day environmental challenges faced by humanity and produce robust, resilient crop cultivars with improved agronomic characteristics, as well as to trace crop domestication history. Flax ( Linum usitatissimum ), one of the first crops domesticated by mankind, has been traditionally cultivated for fiber as well as for medicinal purposes and as a nutritional product. The origins of fiber flax are hidden in the mists of time and can be hypothetically traced back to either the Indo-Afghan region or Fertile Crescent. To shed new light on fiber flax genetic diversity and breeding history, in this study, we presented a comprehensive analysis of the core collection of flax (306 accessions) of different morphotypes and geographic origins maintained by the Russian Federal Research Center for Bast Fiber Crops. We observed significant population differentiation between oilseed and fiber morphotypes, as well as mapped genomic regions affected by recent breeding efforts. We also sought to unravel the origins of kryazhs, Russian heritage landraces, and their genetic relatedness to modern fiber flax cultivars. For the first time, our results provide strong genetic evidence in favor of the hypothesis on kryazh's mixed origin from both the Indo-Afghan diversity center and Fertile Crescent. Finally, we showed predominant contribution from Russian landraces and kryazhs into the ancestry of modern fiber flax varieties. Taken together, these findings may have practical implications on the development of new improved flax varieties with desirable traits that give farmers greater choice in crop management and meet the aspirations of breeders., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Duk, Kanapin, Rozhmina, Bankin, Surkova, Samsonova and Samsonova.)

Modern flax cultivars are susceptible to many diseases; arguably, the most economically damaging of these is the Fusarium wilt fungal disease. Over the past decades international flax breeding initiatives resulted in the development of resistant cultivars. However, much remains to be learned about the mechanisms of resistance to Fusarium infection in flax. As a first step to uncover the genetic factors associated with resistance to Fusarium wilt disease, we performed a genome-wide association study (GWAS) using 297 accessions from the collection of the Federal Research Centre of the Bast Fiber Crops, Torzhok, Russia. These genotypes were infected with a highly pathogenic Fusarium oxysporum f.sp. lini MI39 strain; the wilt symptoms were documented in the course of three successive years. Six different single-locus models implemented in GAPIT3 R package were applied to a selected subset of 72,526 SNPs. A total of 15 QTNs (Quantitative Trait Nucleotides) were detected during at least two years of observation, while eight QTNs were found during all three years of the experiment. Of these, ten QTNs occupied a region of 640 Kb at the start of chromosome 1, while the remaining QTNs mapped to chromosomes 8, 11 and 13. All stable QTNs demonstrate a statistically significant allelic effect across 3 years of the experiment. Importantly, several QTNs spanned regions that harbored genes involved in the pathogen recognition and plant immunity response, including the KIP1-like protein ( Lus10025717 ) and NBS-LRR protein ( Lus10025852 ). Our results provide novel insights into the genetic architecture of flax resistance to Fusarium wilt and pinpoint potential candidate genes for further in-depth studies.

A collection of flax accessions from Russian Federal Research Center for Bast Fiber Crops was characterised to evaluate its phenotypic diversity. 406 samples representing different morphotypes were selected for thorough quantitative assessment of various agronomic traits. We measured height, length of technical part of the stem, technical part weight, inflorescence length, number of bolls and seeds per plant, 1000 seed weight, the diameter of the stem, the number of internodes and finally, distance between internodes. The fiber quality was estimated by calculating stem slenderness, stem taperingness and elementary fiber length. The dataset was produced in a framework of a project focused on characterization of diversity of flax genotypes and phenotypes, as well as on identification of genomic regions associated with various traits, it is hosted on Figshare., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships which have or could be perceived to have influenced the work reported in this article., (© 2021 The Authors. Published by Elsevier Inc.)

Fusarium wilt of flax is an aggressive disease caused by the soil-borne fungal pathogen Fusarium oxysporum f. sp. lini . It is a challenging pathogen presenting a constant threat to flax production industry worldwide. Previously, we reported chromosome-level assemblies of 5 highly pathogenic F. oxysporum f. sp. lini strains. We sought to characterize the genomic architecture of the fungus and outline evolutionary mechanisms shaping the pathogen genome. Here, we reveal the complex multi-compartmentalized genome organization and uncover its diverse evolutionary dynamics, which boosts genetic diversity and facilitates host adaptation. In addition, our results suggest that host of functions implicated in the life cycle of mobile genetic elements are main contributors to dissimilarity between proteomes of different Fusaria . Finally, our experiments demonstrate that mobile genetics elements are expressed in planta upon infection, alluding to their role in pathogenicity. On the whole, these results pave the way for further in-depth studies of evolutionary forces shaping the host-pathogen interaction.

Fusarium wilt is the most destructive fungal disease in flax, limiting flax cultivation in all the main flax and linseed growing countries. The causative agent is seedborne and soilborne fungus F. oxysporum f. sp. lini. Here, we report, for the first time, genome assemblies of five highly pathogenic isolates of Fusarium oxysporum f. sp. lini , namely monoisolate 39 and strains F329, F324, F282, F287. In addition, syntenic analysis provided a powerful approach to distinguish between core and lineage-specific parts of the genome. These results lay a solid foundation for comparative genomics studies of plant fungal pathogens, evolution of pathogenicity, and virulence factors underlying the dynamics of host-pathogen interactions, thus eventually offering solutions to Fusarium disease control.