Jan Szopa

Tocopherols are essential lipid-soluble antioxidants that play important roles in plant protection against oxidative stress and are closely connected with isoprenoid metabolism. To the best of our knowledge, this is the first report of stable constitutive expression of Arabidopsis thaliana VTE2 (AtVTE2) in flax (Linum usitatissimum L.) and its effects on plant metabolism and development. As a dual-purpose oil and fibre crop, flax combines PUFA-rich seeds with industrially important fibre-rich stems, providing a useful system for assessing the broader consequences of antioxidant-pathway engineering. Three independent transgenic lines were characterized by RT-qPCR analysis of genes associated with tocopherol, MEP, MVA, and carotenoid biosynthesis, targeted metabolite profiling, antioxidant-capacity assays, field phenotyping, and biochemical and spectroscopic analyses of mature straw. Three independent transgenic lines were characterized using gene-expression analyses, metabolic profiling, antioxidant assays, phenotypic evaluation, and biochemical analyses of mature stems. Constitutive AtVTE2 expression was associated with α-tocopherol accumulation and was accompanied by coordinated transcriptional changes in genes associated with the plastidial methylerythritol phosphate and cytosolic mevalonate pathways. These changes were associated with modifications in isoprenoid and phenylpropanoid metabolism, enhanced antioxidant capacity in selected transgenic lines, and altered plant architecture under field conditions. In mature straw, transgenic plants exhibited changes in phytosterol composition, lignin accumulation, and pectin distribution, whereas cellulose content remained unchanged. FT-IR spectra retained the same principal bands but showed differences in the relative intensities of selected cell-wall-associated bands. Collectively, these findings demonstrate that constitutive AtVTE2 expression is associated with tissue-dependent metabolic responses extending beyond vitamin E accumulation and affecting interconnected pathways involved in secondary metabolism, antioxidant capacity, and cell-wall organization.

The purpose of this study was to present a chemical analysis of the metabolome of cell aggregates of the tree fern Cyathea smithii (J.D. Hooker) cell suspension culture. The LC/MS and GC/MS techniques were used for identification of metabolites. The kinetics of fresh weight, dry weight, and ash content showed 3.5-fold increases during 15-day-long culture. The analysis demonstrated high metabolic activity of cultured cells. In total, 160 metabolites from primary and secondary metabolism and almost 2000 compounds of unknown identity were identified. Three flavonoids—the chalcone isookanin [(2S)-2-(3,4-dihydroxyphenyl)-7,8-dihydroxy-2,3-dihydrochromen-4-one], a methoxy derivative of the flavone gardenin B (5-Hydroxy-2-(4-methoxyphenyl)-6,7,8-trimethoxy-4H-1-benzopyran-4-one), and the isoflavone tectoridin (4′,5-Dihydro-6-methoxy-7-(O-glucoside)isoflavone)—had not been previously detected in the cell culture of C. smithii. Principal component analysis revealed five distinct groups of samples; groups 4 and 5 showed the greatest similarity and corresponded to cultures on days 12 and 15, respectively. The number of differentiating compounds was 75, indicated by a heatmap showing positive and negative correlations between the days of culture. The studies described in this paper are crucial for further identification of metabolites and establishing the relationship between the metabolic composition of tree fern cells in culture and their biological activity, assessed by physiological parameters. By determining the relationship between the chemical composition of cells and their growth from culture initiation to senescence, we will provide a more complete picture of the potential for environmental factors to regulate this relationship. Based on previous studies, environmental stimuli such as electromagnetic fields or light of different wavelengths can result in altered growth physiology and cell mass, as well as metabolite diversification and accumulation. The research results presented in this paper provide a foundation for further studies aimed at predicting and regulating the productivity of C. smithii cells in suspension culture and elucidating the significance of tree fern-derived metabolic products in human cell biology, particularly in thyroid cells.

Beta-ketothiolases are involved in the beta-oxidation of fatty acids and the metabolism of hormones, benzenoids, and hydroxybutyrate. The expression of bacterial beta-ketothiolase in flax (Linum usitatissimum L.) results in an increase in endogenous beta-ketothiolase mRNA levels and beta-hydroxybutyrate content. In the present work, the effect of overexpression of beta-ketothiolase on retting and stem and fibre composition of flax plants is presented. The content of the components was evaluated by high-performance liquid chromatography, gas chromatography–mass spectrometry, Fourier-transform infrared spectroscopy, and biochemical methods. Changes in the stem cell walls, especially in the lower lignin and pectin content, resulted in more efficient retting. The overexpression of beta-ketothiolase reduced the fatty acid and carotenoid contents in flax and affected the distribution of phenolic compounds between free and cell wall-bound components. The obtained fibres were characterized by a slightly lower content of phenolic compounds and changes in the composition of the cell wall. Based on the IR analysis, we concluded that the production of hydroxybutyrate reduced the cellulose crystallinity and led to the formation of shorter but more flexible cellulose chains, while not changing the content of the cell wall components. We speculate that the changes in chemical composition of the stems and fibres are the result of the regulatory properties of hydroxybutyrate. This provides us with a novel way to influence metabolic composition in agriculturally important crops.

This review was designed to summarize the present state of research around the genetic and epigenetic modification of selected plant species and the potential for their application in industry. This review summarizes the activity of research groups from the University of Wrocław completed over the last 3 decades which tends to focus on potatoes and flax likely as a result of their centuries-old tradition of cultivation, processing, and use in Poland. The aims of these studies were various and included the creation of pathogen-resistant plants, increased antioxidant production, improved flax fiber quality, and improved oil properties. New plant breeds initially produced using genetic engineering technology provide an excellent basis for improving our understanding of the genes involved in potato and flax productivity and the quality of their products. These results have been published in many papers and have given rise to new methods for plant breeding and product prototypes which have been patented. However, none of the prototypes have been commercialized because of their GMO origins. In addition, later development of a novel, epigenetic method has led to the creation of more diverse products based on the newly obtained variety of flax called Silesia. These developments have facilitated the production of a range of new raw materials from these epigenetically modified plants. These include a modified oil for improved nutrition and regeneration of skin cells, seed- cake extracts that act as anti-infection agents, improved fiber production for use as bandages for chronic wounds, improved fibers for application as bio composite materials for the development of biodegradable packaging materials and scaffolds for tissue engineering, and micronized fiber for drug delivery. These modifications mean that flax has become a more useful and valuable source of a wide range of raw materials applicable in industry, allowing for the application of these materials in zero waste applications.

Fusarium culmorum is a ubiquitous soil pathogen with a wide host range. In flax (Linum ussitatissimum), it causes foot and root rot and accumulation of mycotoxins in flax products. Fungal infections lead to huge losses in the flax industry. Moreover, due to mycotoxin accumulation, flax products constitute a potential threat to the consumers. We discovered that the defense against this pathogen in flax is based on early oxidative burst among others. In flax plants infected with F. culmorum, the most affected genes are connected with ROS production and processing, callose synthesis and ABA production. We hypothesize that ABA triggers defense mechanism in flax and is a significant player in a successful response to infection.

The aim of the work was to compare the new variety of oil flax (Silesia) with already cultivated varieties in terms of plant productivity, oil content, fatty acid composition and significant secondary metabolites. The analyzed linseed varieties are characterized by low (Linola), medium (Silesia) and high (Szafir) content of omega-3 fatty acids. Special attention was paid to the quality of the oil and the characteristics that determine its stability (reduction of susceptibility to oxidation). A number of antioxidant compounds of secondary metabolism (simple phenols, phenolic acids, flavonoids, tannins) were identified in the linseed oils. All of these compounds can affect lipid oxidation by a mechanism that attenuates initiating radicals such as hydroxyl or forms an oxidizing primary product such as peroxides. Chelation of metal ions may also be involved in lipid oxidation. We propose a mechanism that encompasses all these processes and facilitates understanding of the complex relationships between them. The general thesis is that the ratio of polyunsaturated fatty acids is associated with a better metabolic state of flaxseed, and thus with a higher nutritional value. In addition, we find a number of specialized secondary metabolites characteristic of the flax studied, which could be useful for chemotaxonomy.

Catecholamines are biogenic aromatic amines common among both animals and plants. In animals, they are synthesized via tyrosine hydroxylation, while both hydroxylation or decarboxylation of tyrosine are possible in plants, depending on the species, though no tyrosine hydroxylase—a counterpart of the animal enzyme—has been identified yet. It is known that in potato plants, it is the decarboxylation of tyrosine that leads to catecholamine production. In this paper, we present the effects of the induction of an alternative route of catecholamine production by introducing the tyrosine hydroxylase gene from rat. We demonstrate that an animal system can be used by the plant. However, it does not function to synthesize catecholamines. Instead, it leads to elevated reactive oxygen species content and a constant stress condition in the plant, which responds with elevated antioxidant levels and improved resistance to infection.

Cyanogenic glucosides (CG), the monoglycosides linamarin and lotaustralin, as well as the diglucosides linustatin and neolinustatin, have been identified in flax. The roles of CG and hydrogen cyanide (HCN), specifically the product of their breakdown, differ and are understood only to a certain extent. HCN is toxic to aerobic organisms as a respiratory inhibitor and to enzymes containing heavy metals. On the other hand, CG and HCN are important factors in the plant defense system against herbivores, insects and pathogens. In this study, fluctuations in CG levels during flax growth and development (using UPLC) and the expression of genes encoding key enzymes for their metabolism (valine N-monooxygenase, linamarase, cyanoalanine nitrilase and cyanoalanine synthase) using RT-PCR were analyzed. Linola cultivar and transgenic plants characterized by increased levels of sulfur amino acids were analyzed. This enabled the demonstration of a significant relationship between the cyanide detoxification process and general metabolism. Cyanogenic glucosides are used as nitrogen-containing precursors for the synthesis of amino acids, proteins and amines. Therefore, they not only perform protective functions against herbivores but are general plant growth regulators, especially since changes in their level have been shown to be strongly correlated with significant stages of plant development.

Catecholamines are biogenic aromatic amines common among both animals and plants. In animals they are synthesized via tyrosine hydroxylation, while in plants, both hydroxylation or decarboxylation of tyrosine are possible, depending on the species, though no tyrosine hydroxylase – a counterpart of animal enzyme has been identified yet. It is known that in potato plants it is the decarboxylation of tyrosine that leads to catecholamine production. In this paper we present the effects of induction of an alternative route of catecholamine production by introducing tyrosine hydroxylase gene from rat. We demonstrate that an animal system can be used by the plant, however, it does not function to synthesize catecholamines. Instead it leads to elevated reactive oxygen species content and constant stress condition to the plant which responds with elevated antioxidant level and further with improved resistance to infection. One sentence summary: Introduction of rat tyrosine hydroxylase gene to potato disturbs catecholamine synthesis, causes oxidative stress and activates antioxidant response.

In mammalian cells, 3-hydroxybutyrate (3-HB) is not only an intermediate metabolite during the oxidation of fatty acids, but also an important signaling molecule. On the other hand, the information about the metabolism or function of this compound in plants is scarce. In our study, we show for the first time that this compound naturally occurs in flax. The expression of bacterial β-ketothiolase in flax affects expression of endogenous genes of the 3-HB biosynthesis pathway and the compound content. The increase in 3-HB content in transgenic plants or after control plants treatment with 3-HB resulted in upregulation of genes involved in chromatin remodeling. The observation that 3-HB is an endogenous activator of methyltransferase 3 (CMT3), decreased DNA methylation I (DDM1), DEMETER DNA glycosylase (DME), and an inhibitor of sirtuin 1 (SRT1) provides an example of integration of different genes in chromatin remodeling. The changes in chromatin remodeling gene expression concomitant with those involved in phenolics and the lignin biosynthesis pathway suggest potential integration of secondary metabolic status with epigenetic changes.