Flax Tissues Research Articles

Spatiotemporal Transcriptomic Atlas of Developing Embryos and Vegetative Tissues in Flax.

Flax (Linum usitatissimum L.) is an important multipurpose crop widely grown for oil and fiber. Despite recent advances in genomics, detailed gene activities during the important reproductive phase of its development are not well defined. In this study, we employed high-throughput RNA-sequencing methods to generate in-depth transcriptome profiles of flax tissues with emphasis on the reproductive phases of five key stages of embryogenesis (globular embryo, heart embryo, torpedo embryo, cotyledon embryo, and mature embryo), mature seed, and vegetative tissues viz. ovary, anther, and root. These datasets were used to establish the co-expression networks covering 36 gene modules based on the expression patterns for each gene through weighted gene co-expression network analysis (WGCNA). Functional interrogation with Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) of dominantly expressed genetic modules in tissues revealed pathways involved in the development of different tissues. Moreover, the essential genes in embryo development and synthesis of storage reserves were identified based on their dynamic expression patterns. Together, this comprehensive dataset for developing embryos, mature seeds and vegetative tissues provides new insights into molecular mechanisms of seed development with potential for flax crop improvement.

Using FIBexDB for In-Depth Analysis of Flax Lectin Gene Expression in Response to Fusarium oxysporum Infection

Plant proteins with lectin domains play an essential role in plant immunity modulation, but among a plurality of lectins recruited by plants, only a few members have been functionally characterized. For the analysis of flax lectin gene expression, we used FIBexDB, which includes an efficient algorithm for flax gene expression analysis combining gene clustering and coexpression network analysis. We analyzed the lectin gene expression in various flax tissues, including root tips infected with Fusarium oxysporum. Two pools of lectin genes were revealed: downregulated and upregulated during the infection. Lectins with suppressed gene expression are associated with protein biosynthesis (Calreticulin family), cell wall biosynthesis (galactose-binding lectin family) and cytoskeleton functioning (Malectin family). Among the upregulated lectin genes were those encoding lectins from the Hevein, Nictaba, and GNA families. The main participants from each group are discussed. A list of lectin genes, the expression of which can determine the resistance of flax, is proposed, for example, the genes encoding amaranthins. We demonstrate that FIBexDB is an efficient tool both for the visualization of data, and for searching for the general patterns of lectin genes that may play an essential role in normal plant development and defense.

Effect of epibrassynolide on the flavonoids content in plant sprouts under stress caused by N-phosphonomethylglycine

The effect of epibrassinolide (EBL) on the content of flavonoids in seedlings of fiber flax (Linum usitatissimum L.) and spring barley (Hordeum vulgare L.) under chemical stress caused by N-phosphonomethylglycine (glyphosate) was studied. The species specificity of the response of the seedlings to the introduction of EBL in a mixture with an inhibitory dose of glyphosate was noted. This specificity is expressed in the suppression of the inhibitory effect of glyphosate on the flavonoids' content in the tissues of fiber flax and the absence of changes in the level of the content of flavonoids in the roots and aerial part of spring barley seedlings.

Эффективность способов основной обработки серой лесной почвы в звене севооборота при производстве семян яровых рапса и сурепицы

The article offers studies to determine the effectiveness of processing methods for the productivity of spring rapeseed and surepitsa on the dark gray forest soil of the Ryazan region. As a result, it was revealed that the maximum intensity of decomposition of flax tissue was recorded in the steam link of the crop rotation using the dump method of basic tillage for oilseed cabbage crops. The maximum yield of rapeseed was observed on the variant of the steam link of crop rotation + dump processing (31.3 c / ha), in the surepitsa (25.6 c/ha). A high increase in oilseeds in this variant is 4.7 c / ha, where the NSR05 factor with 0.97 c / ha relative to the minimum basic tillage was recorded in 2015. In the experiment, the trends of increasing the yield of oilseeds of spring rapeseed and surepitsa in the fallow link of the crop rotation relative to the row crop are revealed. The maximum oil content of rapeseed was noted in the rowed link of crop rotation during milling tillage (47.6%); in surepitsa – in the rowed link of crop rotation also during milling (45.1%). Keywords: SPRING RAPESEED, SPRING SUREPITSA, DARK GRAY FOREST SOIL, TILLAGE, YIELD, OIL CONTENT

INFLUENCE OF SOIL TILLAGE TECHNOLOGIES ON FERTILITY, PRODUCTIVITY AND FEED QUALITY

The article presents the results of long term field research on the influence of various processing systems on the fertility of sod-podzolic soil, productivity and quality of products. Studies have shown that the water-physical properties of the soil differ depending on different technologies of soil treatment, the method of plowing manure and plant residues. Thus, subsurface and combined soil treatment provided the formation of water supply units at the level of 41.4%, soil density-1.35 g/cm3, and total porosity-63.7%. Reserved productive moisture in the first case was 30.6 mm, in the second-28.6 mm. It was found that different technologies for applying organic matter had different effects on the content of earthworms in the soil, the decomposition of flax tissue, the production of carbon dioxide, and, ultimately, on the formation of humus compounds. The largest number of humus substances was formed by plowing technology. Here their growth was 0.16% of the original value or 6.2 t/ha, according to surface treatment of soil-0.15% (5.9 t/ha). The maximum CO2 production was observed at the subsurface cultivator loosening plot of 54.9 mg/h m2, and the minimum value for surface treatment of soil was 52.5 mg/h m2. In other variants, it was within the range of 53.6 mg/h m2. Decomposition of linen fabric for all processing technologies was in the range of 20.6-21.2%. The productivity of agrophytocenoses in processing systems does not differ significantly, except for fine processing. For plowing, subsurface cultivator and combined processing, taking into account byproducts, it varied within 43.2-43.8 C/ha, and surface soil treatment provided only 41.4 C/ha. The pro vision of feed units with digestible protein for plowing, taking into account by-products, was 81.5 g, for the rest at the level of 80.4 g.

ЭКОЛОГИЧЕСКИЙ СПОСОБ ВОЗДЕЛЫВАНИЯ СТОЛОВОЙ СВЕКЛЫ В ГОРНОЙ ЗОНЕ РСО – АЛАНИЯ

In the context of the limited use of technogenic resources to regulate agricultural crops productivity of and soil fertility, the cultivation of varieties and hybrids that are resistant to abiotic and biotic stressors acquires a special role. In this regard, the organization of adaptive vegetable growing is of importance, for it provides for the creating highly productive agrocenoses that most fully realize the bioclimatic resources of the region, as well as for the use of resource-saving technologies. Our research is aimed at optimizing biologized soil-protective crop rotations in the mountainous zone in order to achieve an increase in crop productivity and preserve soil fertility. The studies were carried out in the mountainous zone of North Ossetia – Alania on mountain meadow soils. The influence of the biological product and micronutrient fertilization on the biological parameters of soil fertility in beet crops showed that the maximum loss of flax tissue was observed when seeds were inoculated with a 2% solution of "Extrasol" (29.6%). The enzymatic activity of the soil was higher in the variants with the use of a biological product and microfertilizer: the activity of catalase – by 0.2–0.5 ml of О2 per 100 g of soil, phosphatase – by 0.1–0.3 ml of Р2 О5 per 100 g of soil. The yield increase from the introduction of "Extrasol" and "Kristalon" on the crops of table beet is 0.8–1.6 t/ha. The profitability from the use of the Extrasol biological product and the Kristalon micronutrient fertilizer was 75.1–120.8%. Thus, for the efficiency of farming in mountainous land-poor areas, one should take a differentiated approach to the choice of crops and territories in which they are grown. The implementation of this approach fully meets the conditions for land use in mountainous areas and household plots.

Establishment of the 'imbibed seed piercing' method for Agrobacterium-mediated transformation of jute and flax bast fibre crops via phloem-specific expression of the β-glucuronidase Gene

Jute (Corchorus capsularis) and flax (Linum usitatissimum) have been established as important sources of bast fibres (phloem fibres) worldwide. These long and lustrous natural fibres are used for various commercial and industrial purposes and hold immense future prospects. To meet the worldwide demand for bast fibres, improvement in the production and quality of jute and flax is essential. Molecular breeding is an expeditious approach for varietal improvement and requires an efficient gene transformation system. The available methods for jute and flax transformation are highly specific to species and variety, requiring a long time and rigorous preparation of media, explants, and screening procedures. In this study, we used a fast and stable method for Agrobacterium tumefaciens-mediated transformation of jute (variety JRC321) and flax (variety FT-897), known as the ‘imbibed seed piercing’ method (ISPM), where seeds were used as explants. A phloem-specific Arabidopsis sucrose-proton H+ symporter 2 (AtSUC2) promoter-driven gus gene (β-glucuronidase) was used for the assessment of genetic transformation of jute and flax plants. Transformed seedlings were selected following three consecutive selection pressure tests conducted at two-week intervals using kanamycin-supplemented culture media. Transgene integration was verified using Southern blotting and PCR-based molecular characterization of jute and flax plants. The gus gene expression levels in the transgenic jute and flax tissue samples were analysed by semi-quantitative and quantitative RT-PCR. The GUS protein expression in transgenic plant tissues was confirmed by the development of blue colour in the histochemical GUS assay. Blue colouration was observed only in phloem cells of the tested plant tissues. Transgenic progeny plants of subsequent generations followed the 3:1 transgene segregation pattern and exhibited phloem-specific GUS expression. This fast, easy, and stable ISPM could also be applied to other fibre producing industrial crops and could form a part of a modern CRISPR/Cas9-based genome editing tool by efficiently delivering CRISPR vectors in jute and flax plants.

Genes with bast fiber-specific expression in flax plants - Molecular keys for targeted fiber crop improvement

Plant fibers, owing to their unique properties, have been used by mankind for the production of textiles and composite materials for thousands of years. Currently, the use of plant fibers in various innovative fields has become very popular as they are an environmentally friendly, biodegradable, and renewable resource. Each of the numerous fiber-consuming industrial fields has special demands on the properties of fiber. The quality of plant fibers is a multicomponent parameter that depends on morphological and anatomical characteristics, as well as on the structure and proportions of fiber bundle chemical constituents. These features are formed during plant ontogenesis and can be subjected to management by manipulating the key stages of fiber development: fiber elongation by intrusive growth and cell wall thickening. To determine the molecular keys for manipulating certain fiber features related to crop quality, we summarized the RNA-Seq data obtained for different flax tissues and revealed the genes specifically upregulated in bast fibers. These genes were additionally subdivided into three groups considering the differential expression of the genes at the stage of fiber intrusive elongation versus the stage of cell wall thickening. The first group included genes specifically expressed in fibers without differential expression at the two stages. The second included those upregulated at the intrusive elongation stage compared to the further stage of development, and the third included those upregulated at tertiary cell wall deposition. The qPCR analysis of the expression level of the selected genes in fibers isolated from the developing plants of several varieties of fiber and linseed, Linum usitatissimum, as well as of two wild flax species revealed that the samples cluster into different groups in accordance with bast fiber yield and quality. The genes with tissue- and stage-specific characters of expression provide new insights into the mechanisms of fiber development and may serve as a target for molecular-genetic modulation of crop quality, as there is a high possibility of exclusively affecting bast fiber parameters, without influencing other tissues.

Биологизированные севообороты – основной фактор повышения плодородия дерново-подзолистых почв и продуктивности пашни в Верхневолжье

Abstract. The purpose of the study was to study the influence of biologized crop rotation with six fields by 50 %, saturated with legumes, on soil fertility and crop productivity on typical sod-podzolic light loamy soils of the Upper Volga. As a result of field experiments and laboratory studies, new data and knowledge about the effect of crop bipolarization on its productivity and the properties of sod-podzolic soil were obtained. For the first time in the region, it has been studied and established that use of legumes in the crop rotation instead of organic fertilizers partially contributes to the replenishment of the soil with organic matter and nitrogen in the form of organic residues and nodule bacteria, which leads to a decrease in the degradation of soil fertility or even to some improvement. By the end of rotation of the crop rotation when applying (NPK) 90 kg/ha compared with the control version (without NPK), in the biologized crop rotation, the humus content increased by 0.14 %, the acidity of the soil solution slightly decreased by 0.25 units, the content of nitrate nitrogen increased by 59 %, mobile phosphorus – by 72.8 % and exchange potassium – by 70.4 %. The density of soil compaction as a whole in a layer of 0–20 cm in occupied steam, under spring wheat and oats amounted to 1.22–1.24 g/cm3, in other crops (where treatment was not carried out for 2 years) – 1.35–1.39 g/cm3. Mineralization of flax tissue more actively occurred under clover 1st and 2nd years of use – 35.6–42.7 % and 31.0 and 37.3 % and in the employed (vetch-oat) – 26.5–34.4 %, less intensively under winter wheat – 20.9–27.5 and oats – 20.1–25.2 % and very weakly under spring wheat – 13.0–16.5 % at the control and the level of mineral nutrition, respectively. There were fewer weeds in winter wheat sowings – 84 pcs/m2, since it is more competitive with them, oats – 112 pcs, clover – 131 pcs, in a couple – 124 pcs and spring wheat – 138 pcs/m2. Productivity of crops to a greater extent was determined by the applied fertilizers. In fertilized plots, compared with the control, the productivity of the oatmeal mixture was 36.2 % higher, spring wheat – 24.4 %, clover 1st year of use – by 36.2 %, 2nd year of use – by 45.7 %, winter wheat – by 25.7 % and oats – by 30 %.

Flax rhamnogalacturonan lyases: phylogeny, differential expression and modeling of protein structure.

Rhamnogalacturonan lyases (RGLs; EC 4.2.2.23) degrade the rhamnogalacturonan I (RG-I) backbone of pectins present in the plant cell wall. These enzymes belong to polysaccharide lyase family 4, members of which are mainly from plants and plant pathogens. RGLs are investigated, as a rule, as pathogen 'weapons' for plant cell wall degradation and subsequent infection. Despite the presence of genes annotated as RGLs in plant genomes and the presence of substrates for enzyme activity in plant cells, evidence supporting the involvement of this enzyme in certain processes is limited. The differential expression of some RGL genes in flax (Linum usitatissimum L.) tissues, revealed in our previous work, prompted us to carry out a total revision (phylogenetic analysis, analysis of expression and protein structure modeling) of all the sequences of flax predicted as coding for RGLs. Comparison of the expressions of LusRGL in various tissues of flax stem revealed that LusRGLs belong to distinct phylogenetic clades, which correspond to two co-expression groups. One of these groups comprised LusRGL6-A and LusRGL6-B genes and was specifically upregulated in flax fibers during deposition of the tertiary cell wall, which has complex RG-I as a key noncellulosic component. The results of homology modeling and docking demonstrated that the topology of the LusRGL6-A catalytic site allowed binding to the RG-I ligand. These findings lead us to suggest the presence of RGL activity in planta and the involvement of special isoforms of RGLs in the modification of RG-I of the tertiary cell wall in plant fibers.

MicroRNA (miRNA) in food resources and medicinal plant

MicroRNAs (miRNAs) are a class of 19 - 24 nucleotide long non-coding RNAs derived from hairpin precursors, regulating various biological, metabolic and developmental processes at the post-transcriptional level. Many of the known miRNAs are evolutionary conserved across diverse plant species and function in the regulatory control of fundamentally important biological processes. It is known that exogenous plant miRNAs specifically target approximately 30% of protein-coding genes in mammals. The research was focused to analyze the occurrence of selected families of miRNAs (miR156, miR168 and miR171) in less used species but nutritionally important plant food resources (flax and medlar) and medicinal plant (milk thistle). The analyses were done by two individual approaches, by (a) miRNA-based molecular markers - as a novel type of functional markers and (b) qualitative Real-Time PCR. The expression pattern of selected miRNAs was analyzed depending on various plant tissues and developmental stages. Results have confirmed the significance and reliability of novel type of markers based on miRNA molecules as well as the species-specific and tissues-specific expression patterns of plants miRNAs. Significant polymorphism profile of miR156b was detected in various flax tissues of genotypes varying in the content of alpha-linolenic acid. Conclusions indicate that the variable behavior of the miRNA molecules, depending on various factors, may reflect the variability of the gene expression regulation of the human genome. The exploitation of the background of miRNA functioning within different species and plant tissues will help us to understand the molecular machinery as well as the regulatory mechanisms involved in the expression of miRNAs in plants and consequently in human genome.

Intra-platform comparison of 25-mer and 60-mer oligonucleotide Nimblegen DNA microarrays

BackgroundWe performed a Nimblegen intra-platform microarray comparison by assessing two categories of flax target probes (short 25-mers oligonucleotides and long 60-mers oligonucleotides) in identical conditions of target production, design, labelling, hybridization, image analyses, and data filtering. We compared technical parameters of array hybridizations, precision and accuracy as well as specific gene expression profiles.ResultsComparison of the hybridization quality, precision and accuracy of expression measurements, as well as an interpretation of differential gene expression in flax tissues were performed. Both array types yielded reproducible, accurate and comparable data that are coherent for expression measurements and identification of differentially expressed genes. 60-mers arrays gave higher hybridization efficiencies and therefore were more sensitive allowing the detection of a higher number of unigenes involved in the same biological process and/or belonging to the same multigene family.ConclusionThe two flax arrays provide a good resolution of expressed functions; however the 60-mers arrays are more sensitive and provide a more in-depth coverage of candidate genes potentially involved in different biological processes.

Identification and characterization of miRNAs and their potential targets in flax

MicroRNAs (miRNAs) are small non-protein coding regulatory RNAs released after the cleavage of a primary transcript. A computational homology search of expressed sequence tags (ESTs) available in public databases allowed the identification of 20 conserved miRNAs belonging to 13 different families in flax (Linum usitatissimum). Most of the miRNAs were 21 nucleotides-long and carried a uracil at the 5′ end. They originated from precursor transcripts that vary greatly in length. A single precursor containing 2 different stem-loop structures, each one carrying a member of the miR398 family, was identified for the first time in plants. qRT-PCR analyses of 4 selected miRNAs indicated that all were differentially expressed in flax tissues. The 20 miRNAs could potentially regulate 112 different targets including genes involved in cell wall metabolism. Analyses of pri-miRNA and potential gene expression profiles in a publically available microarray data set allowed the identification of a number of highly opposite pri-miRNA/target gene profiles potentially involved in regulating plantacyanin levels, F-box mediated signalling processes, protein metabolism and ion homeostasis, as well as 6 unknown processes.

Influence of salicylic acid pre-treatment on cadmium tolerance and its relationship with non-protein thiol production in flax root

Dose-dependent changes in cadmium (Cd) tolerance, non-protein thiol (NP-SH) production and their relationship were investigated in sixteen-day-old flax ( Linum usitatissimum L.) seedlings derived from seeds pre-soaked with various salicylic acid (SA) doses and grown hydroponically under increased Cd concentrations (0, 50 and 100 μM CdCl 2 ). The results show that single Cd subjection decreased root elongation as expressed by tolerance index (TI). Moreover, an overproduction of NP-SH was detected in both roots and shoots. These Cd toxicity effects were directly related to the high levels of Cd amounts in flax tissues as expressed by root and shoot Cd bioaccumulation factors (BAF). In addition, Cd-tolerance of roots TI was negatively correlated with changes in root BAF but positively correlated with shoot BAF. However, positive correlation was illustrated between root TI and NP-SH contents. SA considerably reversed the Cd-induced decrease in root growth parameters and TI. Moreover, in Cd-treated plants, SA pre-soaking prevented Cd accumulation in the shoot as consequence of significant decreases in BAF of roots, Cd transport estimated by the translocation factor (TF) and shoot BAF, respectively. Interestingly, SA pre-treatment reduced BAF of roots and shoots, enhanced NP-SH production in roots and decreased it in leaves. These results suggest that SA might play a preventive role in Cd uptake, sequestration and translocation processes based primarily in roots where SA-enhanced NP-SH contribute to the improvement of flax tolerance to Cd stress. Key words: Cadmium, salicylic acid, bioaccumulation, growth, non-protein thiols, Linum usitatissimum .

Cannabinoid-like anti-inflammatory compounds from flax fiber.

Flax is a valuable source of fibers, linseed and oil. The compounds of the latter two products have already been widely examined and have been proven to possess many health-beneficial properties. In the course of analysis of fibers extract from previously generated transgenic plants overproducing phenylpropanoids a new terpenoid compound was discovered.The UV spectra and the retention time in UPLC analysis of this new compound reveal similarity to a cannabinoid-like compound, probably cannabidiol (CBD). This was confirmed by finding two ions at m/z 174.1 and 231.2 in mass spectra analysis. Further confirmation of the nature of the compound was based on a biological activity assay. It was found that the compound affects the expression of genes involved in inflammatory processes in mouse and human fibroblasts and likely the CBD from Cannabis sativa activates the specific peripheral cannabinoid receptor 2 (CB2) gene expression. Besides fibers, the compound was also found in all other flax tissues. It should be pointed out that the industrial process of fabric production does not affect CBD activity.The presented data suggest for the first time that flax products can be a source of biologically active cannabinoid-like compounds that are able to influence the cell immunological response. These findings might open up many new applications for medical flax products, especially for the fabric as a material for wound dressing with anti-inflammatory properties.

Development and validation of a flax (Linum usitatissimum L.) gene expression oligo microarray.

BackgroundFlax (Linum usitatissimum L.) has been cultivated for around 9,000 years and is therefore one of the oldest cultivated species. Today, flax is still grown for its oil (oil-flax or linseed cultivars) and its cellulose-rich fibres (fibre-flax cultivars) used for high-value linen garments and composite materials. Despite the wide industrial use of flax-derived products, and our actual understanding of the regulation of both wood fibre production and oil biosynthesis more information must be acquired in both domains. Recent advances in genomics are now providing opportunities to improve our fundamental knowledge of these complex processes. In this paper we report the development and validation of a high-density oligo microarray platform dedicated to gene expression analyses in flax.ResultsNine different RNA samples obtained from flax inner- and outer-stems, seeds, leaves and roots were used to generate a collection of 1,066,481 ESTs by massive parallel pyrosequencing. Sequences were assembled into 59,626 unigenes and 48,021 sequences were selected for oligo design and high-density microarray (Nimblegen 385K) fabrication with eight, non-overlapping 25-mers oligos per unigene. 18 independent experiments were used to evaluate the hybridization quality, precision, specificity and accuracy and all results confirmed the high technical quality of our microarray platform. Cross-validation of microarray data was carried out using quantitative qRT-PCR. Nine target genes were selected on the basis of microarray results and reflected the whole range of fold change (both up-regulated and down-regulated genes in different samples). A statistically significant positive correlation was obtained comparing expression levels for each target gene across all biological replicates both in qRT-PCR and microarray results. Further experiments illustrated the capacity of our arrays to detect differential gene expression in a variety of flax tissues as well as between two contrasted flax varieties.ConclusionAll results suggest that our high-density flax oligo-microarray platform can be used as a very sensitive tool for analyzing gene expression in a large variety of tissues as well as in different cultivars. Moreover, this highly reliable platform can also be used for the quantification of mRNA transcriptional profiling in different flax tissues.

Preceding crop and phosphorus fertilization affect cadmium and zinc concentration of flaxseed under conventional and reduced tillage

Field studies were conducted over 4 years at two locations in Manitoba, Canada to evaluate effects of preceding crop, tillage and phosphorus (P) fertilization on Cd and Zn concentration in oilseed flax (linseed—Linum usitatissimum L.). Canola (Brassica napus L.) and spring wheat (Triticum aestivum L.) were grown under conventional and reduced tillage with three rates of monoammonium phosphate. Flax was seeded the year following the spring wheat or canola, with or without P fertilizer, and Cd and Zn concentration and accumulation were determined in the flax tissue at 5 weeks and in the mature seed. Flax following canola had lower Zn concentration and accumulation and higher Cd concentration and Cd:Zn ratio in the tissue and seed relative to flax following wheat. Phosphorus fertilization tended to increase Cd concentration and Cd:Zn ratio and decrease Zn concentration in the tissue and seed. Effects of tillage and interactions among tillage, preceding crop, and P fertilization were inconsistent. Changes in flax Cd and Zn concentration may be due to changes in mycorrhizal colonization or by the high concentration of Cd in the decomposing canola residue. Crop sequence and P management can be used to improve flaxseed food quality, by increasing Zn and decreasing Cd concentration.

Expression of Critical Lignin Metabolism Genes in Flax (<I>Linum usitatissimum</I>)

Flax (Linum usitatissimum) is an important bast fiber crop. High lignin content in the flax fiber greatly affects the per- formance and quality in the flax textile industry. CCoAOMT1, 4CL1, 4CL2, COMT, F5H1, F5H2, and F5H3 are putative genes coding the key enzymes involved in lignin accumulation. The expression patterns of these genes were analyzed by semi-quantitative RT-PCR in different flax tissues and in xylem and phloem (bark) at different development stages of the variety Baihua. The results revealed that all genes were detected to express in seedlings, roots, florescent xylem, florescent phloem, leaves, flowers, and young fruits excluding F5H1 in roots. Expression of CCoAOMT1 was consistently high in all the tissues detected. There existed complementary expression between two 4CL genes and among the three F5H genes in various tissues. In the phloem, all genes lowly expressed except for 4CL2 at florescence and highly expressed after flowering. The expression of 4CL1 was high, and that of F5H3 was low in the phloem at all stages compared with that of other genes. In the xylem, expression of 4CL1 gene was low at all the developing stages, that of F5H1 reached a peak before flowering and that of the other genes in the xylem reached the highest at 30 d after emergence of seedlings and gradually declined at late growing stages, with a sharp de- crease to very lower level after flowering. The expression of 4CL1compared with other genes was significantly higher in phloem

Free galactose and galactosidase activity in the course of flax fiber development

Composition and content of free monosaccharides and β-galactosidase activity were determined in the course of development of the flax (Linum usitatissimum L.) tissues containing bast fibers. In the stem regions where the fibers were at the stage of formation of the secondary cell wall of gelatinous type, the content of free galactose was high (14 mM) and 13–20 times greater than in the upper part of the stem where the fibers were at the stage of intrusive growth. Pulse-chase experiments demonstrated the differences in the metabolism of individual low-molecular sugars. In respect to glucose and sucrose, all the examined characteristics (content, absolute and specific radioactivity, and the temporal changes of these indices) were identical in the stem regions wherein the fibers were at different stages of development. Labeled galactose was detected only in the stem regions where the fibers were at the stage of secondary cell wall formation. The specific radioactivity of glucose and sucrose reached the maximum immediately after photosynthesis in the presence of 14CO2 and changed in the same way as in the primary products of photosynthesis. The time-course of label incorporation into galactose indicated that this monosaccharide arose as a result of hydrolytic processes. At the stage of secondary cell wall formation, high activity of β-galactosidase was observed, with tissue- and stage-specific fiber β-1,4-galactan as its substrate.

The Temporal and Spatial Expression of PR‐5 Linusitin‐Like Gene in Healthy and Ethylene‐Treated Flax Plants

Linusitin‐like protein (LIN1) is a new osmotin‐like protein isolated from flax radicles. The LIN1 gene is developmentally regulated and accumulated in an organ‐specific manner in healthy flax plants. In an attempt to find the role and function of the LIN1 gene, we followed its temporal and spatial expression in different flax tissues during development and its induction after diverse osmotic stresses. The LIN1 mRNA was differentially expressed among the various organs during flax blooming. It was not detected in flowers, stems, or leaves, but a positive signal was found in roots. The major sites of LIN1 expression in roots were in the lateral roots. The LIN1 gene was activated in leaf by treatment with ethylene but not by methyl jasmonate or methyl salicylate. To understand its stress‐response expression better, we isolated the promoter region of LIN1. Analysis of the promoter region revealed that it contains several ATATT “root motif” elements and one AGCCGCC sequence that is conserved in most basic pathogenesis‐related (PR) protein genes and is responsible for ethylene induction.