Rima Norikovna Kirakosyan

Relevance. The study is devoted to developing a scheme for the detection and identification of the bacterium Ralstonia solanacearum the causal agent of potato brown rot, which belongs to the Ralstonia solanacearum species complex ( R. solanacearum , R. pseudosolanacearum , R. syzygii ). This pathogen affects over 200 plant species, including economically important crops (potato, tomato, pepper, eggplant), and is listed as a quarantine organism absent from the territory of the Russian Federation. Objective: to create and test a laboratory diagnostic scheme for R. solanacearum for phytosanitary control of regulated products. Material and ". Methods used in the study: sample preparation method (extraction in phosphate-buffered saline with centrifugation), PCR analysis (real-time PCR using primers RS-IF/RS-II-R/RS-P and a commercial kit; PCR with electrophoretic detection using primers RS-1F/RS-1-R (RS-3-R)). Results. An optimized scheme for the identification and detection of the brown rot pathogen was developed. The scheme was tested on 242 samples of regulated products (potato, roses, peonies, bananas) submitted to the diagnostic laboratory in 2025. The results showed the absence of R. solanacearum complex bacteria in samples from the Russian Federation and revealed 14 cases of potato tuber infection in imported batches. Identification of positive samples using species-specific primers RS-1-F/RS-1-R confirmed the presence of R. solanacearum (sensu stricto). Conclusion. No false-positive or false-negative reactions were recorded during the testing of all used assays within the framework of the developed scheme, indicating their 100% specificity within the study. The outcome of the work is the creation of a reliable laboratory testing algorithm that ensures rapid and accurate diagnosis of the quarantine phytopathogen, thereby guaranteeing phytosanitary safety and compliance of products with importer requirements. plant quarantine, phytopathogenic bacteria, molecular genetic identification methods, detection, identification

Relict yew plants (Taxus L.) are not only ornamental plants with valuable wood but also have the ability to synthesize the unique compound taxol, which is successfully used in the treatment of cancer due to its powerful cytotoxic effect. Due to the presence of taxol, all parts of yew plants are extremely poisonous, but there have been cases where animals have eaten yew cones without fatal consequences. The biosynthesis of taxol is carried out due to the interaction of the isoprenoid and phenolic pathways of the secondary metabolism of plants. Despite the close attention of researchers to the peculiarities of taxol metabolism, there is very little data on the tissue and intracellular localization of both taxols and phenolic compounds in yew plants. Polyphenols are known to be physiologically active mediators involved in respiration, photosynthesis, plant growth and development, as well as in the process of in vitro dedifferentiation. Since Taxus is a relict species and has a limited and hard-to-reach range in nature, technologies that allow yew plants to be restored without removing plant material from the natural environment are of great practical importance: overcoming deep physiological dormancy of seeds, microclonal reproduction and initiation of plant growth. In vitro cultures are possible sources of biologically active and medicinal products. The aims and objectives of this study are to determine the characteristics of the formation and localization of phenolic compounds with high biological activity in various organs of plants of the genus Taxus and to determine the biological activity of ethanolic extracts from this plant. The objects of this study were the generative organs of Taxus canadensis, collected during the entire growing season (April–October) from plants growing in the Moscow region. The localization of various classes of polyphenols was determined by histochemical methods using light microscopy. Histochemical studies have shown the abundant presence of polyphenols in yew megastrobiles, microstrobiles, cones, seeds and aril. Ethanolic plant extracts were used to determine the biological activity. Flavans were dominant in the aril at various stages of vegetation, which was confirmed by our biochemical and histochemical studies. Extractive substances of T. canadensis show high antibacterial activity, especially in its shoot extracts. Ethanolic extracts from plant shoots showed greater biological activity than seed extracts. Aril extracts had the lowest cytotoxicity.

Sequoia sempervirens (D. Don) Endl. is the tallest relict plants capable of accumulating unique secondary metabolites that can be used in pharmacognosy. Given the documented reproductive vulnerability of the coast redwood, biotechnological methods for establishing in vitro genetic banks and bioresource collections are increasingly relevant for the preservation of its gene pool. This study utilized nodal segments of S. sempervirens harvested from a donor tree maintained in the stock greenhouse of the N.V. Tsitsin Main Botanical Garden of the Russian Academy of Sciences (Moscow). The research investigates the effects of mineral and hormonal nutrient media compositions, as well as the explant’s original position on the shoot, on in vitro propagation efficiency. Stepwise sterilization using a 0.1 % (w/v) mercuric chloride solution for 18 min resulted in a successful sterile culture rate exceeding 80 %. Findings indicate that explants should initially be cultured on a hormone-free Murashige and Skoog (MS) basal medium, followed by a proliferation medium supplemented with either 2 mg/L 2,4-D + 0.5 mg/L BAP + 0.5 mg/L NAA or 2 mg/L 2,4-D + 2 mg/L 2iP for effective multiplication. For rooting, it is advisable to transfer regenerants to a medium containing 2 mg/L 2,4-D + 0.5 mg/L BAP + 0.5 mg/L NAA. Following the development of the root system, the resulting clones are prepared for ex vitro transfer. Acclimatization is conducted in a soil substrate under a polyethylene cover with a 16-hour photoperiod to support the transition to ex vitro conditions.

Pothos (Epipremnum aureum G.S. Bunting), which belongs to the Arum family (Araceae Juss.), can be used for medicinal, ornamental, and pollutant-purifying purposes. Due to the usefulness of pothos, the market demand for this species is increasing. Our study attempts to fill in the shortcomings of previous studies on the effect of activated carbon and plant growth regulators on the ability of shoots to take root in vitro, as well as the effect of inexpensive and readily available materials on the transition of seedlings from in vitro to the greenhouse stage. To evaluate the shooting results, Murashige and Skoog medium (MS) was used, which included 6-benzylaminopurine (BA), kinetin (Kn), α-naphthaleneacetic acid (α-NAA), coconut water, activated carbon, and indole-3-butyric acid (IBA) in various concentrations and combinations. Our results showed that the MS medium with the addition of 2.5 mg/L BA and 1.0 mg/L Kn was optimal for propagation by shoots. In this variant, 2.86 shoots per explant, 1.87 cm of shoot length, and 1.59 leaves per shoot were obtained. Despite the fact that this treatment provided the highest total cytokinin concentration, it was significantly more effective than only BA (2.5 mg/L) and all combinations of BA+α-NAA or Kn+α-NAA. For rooting, the micro shoots obtained on the above medium were transferred to MS + 0.25 mg/L α-NAA + 0.5 g/L AC, which allowed for rooting by 93.33%, 1.93 roots per explant, and root lengths by 2.37 cm. This is higher than with the IBA-based treatment, which led to a shortening of the roots and a reduction in their branching. Acclimatization in a 1:1 mixture (by volume) of loamy garden soil (pH 6.2, 2.1% organic matter) and coconut coir (particle size 0.5–2 mm) gave 75% survival after 40 days. These results have opened up the prospect of developing an effective method for reproducing pothos species in vitro by organogenesis at the lowest cost.

The transfer of plants from in vitro conditions to ex vitro conditions is a key stage in the process of clonal micropropagation. Based on our experiments and data from other researchers, it was found that when transferring microclones to non-sterile conditions, plants experience stress due to significant changes in their growing conditions. To minimize this stress, it is important to create conditions as close as possible to those in the artificial in vitro environment. One promising approach in this direction is aeroponic technologies, which were not previously used for these purposes. The conducted studies have shown that at the final stage of clonal micropropagation, the application of aeroponic technologies enables simultaneous rooting and adaptation of microclones of garden crops. It has been established that the use of aeroponic setups contributes to reducing mortality rates of raspberry and blackberry plants, as well as stimulating the growth of above-ground biomass and the development of root systems of microclones under ex vitro conditions. This ensures the production of high-quality planting material with minimal time and resource expenditure.

Introduction. Taxus сanadensis Marshall are the shortest shade–tolerant and frost-resistant representatives of relict gymnosperms belonging to the genus Taxus. Valuable yew wood is able to accumulate unique secondary metabolites that have no synthetic analogues and are successfully used in the treatment of oncological diseases. It is known that secondary metabolites of plants play a direct regulatory role in the physiological and biochemical processes of the plant organism. Therefore, at the first stage of our research, it is necessary to determine the features of formation and localization of secondary compounds of phenolic and terpenoid nature with high biological activity in the arils of seeds of plants of the genus Taxus. The purpose of the study to investigate the features of formation and localization of secondary compounds of phenolic and terpenoid nature with high biological activity in the arils of seeds of plants of the genus Taxus and to determine their cytotoxic effect. Material and methods. The object of the study was the seed-cones of Canadian yew (Taxus canadensis), collected during the growing season (June-October) from plants introduced in the Moscow region. The localization of phenolic compounds was studied in the appendage (aril) of yew seeds collected at different stages of formation and maturation. To do this, histochemical methods were used: to identify the amount of phenolic compounds, the material was stained with 0.08% Fast Blue reagent raster, and a reaction with vanillin reagent in hydrochloric acid vapor was used to study the localization of flavans (catechins and proanthocyanidins). The localization of terpenoids was determined using NADI reagent. The content of the sum of soluble phenolic compounds, flavans and flavonols in the extracts was determined by the spectrophotometric method. The cytotoxic properties of the extracts were studied using an MTT test. Results. Plants of the genus Taxus are characterized by the formation of an overgrown fleshy appendage – aril rich in metabolites of primary and secondary origin. It was shown that, during the entire growing season, and at various stages of aril development, the studied parts of the plant have a high ability to biosynthesize secondary compounds of phenolic and terpenoid nature, which were localized in the epidermal cells of the apex and the underlying layer of parenchyma cells, the cells of the basal part of the aril, and also in some idioblasts located in the parenchyma. Flavones are the dominant components of the phenolic complex of aril. localized Conclusion. Extracts from the vegetative organs of yew plants have pronounced cytotoxic activity, and extractive substances from aril have shown no cytotoxic effect, which indirectly indicates its low toxicity.

In order to scientifically search for new sources of secondary metabolites with valuable qualities for phytopharmacognosy, tasks requiring a step-by-step solution were set. The primary task is the development of technologies for obtaining in vitro highly productive biomass of cells of relict gymnosperms of the genus Sequoia, capable of accumulating various classes of secondary metabolites. The study of the accumulation and localization of secondary metabolites allowed us to evaluate the biological activity and cytotoxicity of in vitro Sequoia cultures. In our study, histochemical methods were used to determine the localization of secondary compounds (phenolic and terpenoid in nature) in plant tissues. Secondary metabolites—polyphenols, catechins, and terpenoids—are mainly localized in the epidermal, parenchymal, and conductive tissues of Sequoia leaves and stems. In callus and suspension cultures of Sequoia, secondary metabolites were localized in cell walls and vacuoles. The mineral composition of the nutrient medium (MS and WPM), the light source (photoperiod), and the endogenous content of polyphenols in the primary explant influenced the initiation and growth characteristics of the in vitro culture of Sequoia plants. Inhibition of growth in suspension cultures on the WPM nutrient medium was noted. The cultivation of Sequoia cell lines at a 16 h photoperiod stimulated the formation of polyphenols but had a negative effect on the growth of callus cultures. Extractive substances obtained from intact and callus tissues of evergreen Sequoia demonstrate high biological (fungicidal) activity and cytotoxicity. The inhibitory effect on Fusarium oxisporum was noted when 200 mg/L of Sequoia extract was added to the nutrient medium. Extracts of redwood callus cultures were low in toxicity to normal FetMSC cells but inhibited the growth of lines of “immortal” cervical HeLa cancer cells and human glioblastoma A172. Intact tissues of Sequoia plants and cell cultures initiated from them in vitro are producers of secondary metabolites with high biological activity.

The paper deals with the results of clonal micropropagation of promising potato varieties for cultivation in the conditions of the Komi Republic. The study material is three potato varieties (Zyryanets, Pechorsky, Vychegodsky), characterized by the high resistance to late blight and abiotic stress factors in the conditions of the Komi Republic. The primary explants were weakly germinated eyeholes, as well as cuttings and shoot tips isolated from 14- and 30-day-old potato plants which underwent surface sterilization and then were cultivated in the Murashige–Skoog nutrient medium containing various hormones. The Pechorsky variety was identified to have the high growth index and specific growth rate of shoots in vitro. This variety can be included in studies on cell and genetic engineering aimed at creating potato forms with the complex resistance.

Chlorella is a green eukaryotic microalga (Chlorella vulgaris). The microscopic cell is spherical, 2–10 μm in diameter. This microalga is one of the most important and promising for biomass production. Chlorella is cultivated in ponds or bioreactors with specified parameters that create favorable conditions for the growth of chlorella biomass. Each set of conditions creates the opportunities for changing the growth rate and output of individual products. Two strains of chlorella were the object of the study: 1 – chlorella with a thin cell wall (Chlorella vulgaris VKPM Al-24); 2 – chlorella with a thick cell wall (Chlorella vulgaris Beijer). The culture of chlorella was cultivated on modified Tamiya nutrient medium, at 24°C and 24-hour illumination. It was cultivated for 5 days in 1000 ml flasks, in opaque grow boxes with different lighting regimes. The control variant was grown in a light room with white fluorescent lamps with an intensity of 150 μmol/m2 s, and the culture was also grown in the dark. Laboratory experiments studying the effect of spectral composition of light on growth of two strains of chlorella culture allowed identifying some regularities: 1 – the largest increase in biomass is observed when using white fluorescent lamps (T = 2700K); 2 – in the case of using FR>R or FR=R, their inhibitory effect on the growth of the studied strains of chlorella was observed. In addition, similar results were obtained when determining the optical density of the cultures, suggesting that the chlorella strains studied are similarly responsive to the action of different spectral compositions of light. Analyzing the absorption spectrum, it should be noted that it has a continuous character. It has been experimentally established that the first maximum is located in the red region (660 to 690 nm) and the second in the blue region (430 to 450 nm). The minimum absorption is observed in the green light region (500 to 610 nm).

The antioxidant defense system can be stimulated by growth regulators in plants when they are under stress, such as exposure to pathogens. There are a lot of natural growth regulators on the market, but no research has been carried out yet to determine how effective they are. This field and laboratory study examines the impact of two commonly used Russian growth regulators, Crezacin and Zircon, along with artificial infection with Fusarium culmorum on the antioxidant system of naked oat. The results show that, compared to the control, Crezacin-treated plants had higher contents of low molecular weight fructose and nonenzymatic antioxidants like proline, phenolic compounds, and flavonoids. Zircon-treated plants had a lower content of proline, carbohydrates, and lower total antioxidant activity than the control plants. The obtained data show that Crezacin treatment mainly affected nonenzymatic systems of the antioxidant defense. This treatment was more successful than the Zircon application, which did not show any appreciable effectiveness and was typically associated with an improvement in oat productivity. The treatment with growth regulators and a fungal suspension performed at the flowering phase provided the best effect on the biochemical parameters and productivity of naked oats. Moreover, oat treatment with the pathogen promoted the reproductive capabilities of the plants, while growth regulators helped in avoiding infectious stress.