Far-red light is stressful to Marchantia polymorpha and reduces the efficiency of photosystem II. In response, Marchantia reorganizes the chloroplast ultrastructure, forming Rubisco condensate regions to physicochemically concentrate CO₂. The light spectral composition is one of the key photomorphogenesis factors. Far-red light (FRL) resulted in marked changes in the morphology of Marchantia polymorpha chloroplasts. However, most aspects of this photomorphogenesis remain unexplored, and this work is devoted to elucidating their nature. We studied in vitro cultured M. polymorpha under FRL or wide spectral range illumination. Transmission electron microscopy and Au-immunolabeling were used for analysis. Gene expression and protein quantification were performed via RT‒PCR and Western blotting. FRL causes the appearance of non-membrane formation in the chloroplast, which has not been previously described for M. polymorpha. This region is enriched in ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and is surrounded by starch grains. FRL negatively regulates the accumulation of Rubisco in M. polymorpha at the transcriptional level. Our study revealed that, under FRL action, M. polymorpha experiences a marked decrease in the key enzyme involved in CO2 assimilation, Rubisco. At the same time, Rubisco condensate structures are formed in chloroplasts, which can be considered a compensatory strategy for the realization of the CO2 concentrating mechanism, which is widely known in phylogenetically close groups.

Late spring frosts and transient cold spells constrain tomato productivity. This study presents a comparative analysis of the chilling response of two Solanum lycopersicum cultivars, MoneyMaker (MM) and Micro-Tom (MT), and the wild relative S. lycopersicoides. The assessment integrated physiological parameters, such as electrolyte leakage and PSII efficiency, expression levels of CBF1–3 genes (via qPCR), and fatty acid composition dynamics of membrane lipids (via gas-liquid chromatography-mass spectrometry). The results revealed distinct response strategies. S. lycopersicoides exhibited comprehensive tolerance and was coordinated across biological levels. Its key mechanisms include superior membrane integrity, sustained PSII photochemical efficiency, stable upregulation of CBF genes (with predominant CBF3 induction), and consistently high α-linolenic acid content. This integration prevented membrane damage and sustained photosynthesis. Conversely, the MM cultivar displayed high sensitivity, characterized by transient CBF1 upregulation, an absence of adaptive lipid remodelling, rapid membrane damage, and severe photoinhibition, explaining its poor recovery. The MT genotype demonstrated an intermediate phenotype, featuring delayed but persistent CBF activation, and the partial lipid profile shifted toward the wild-type pattern, indicating a partial adaptive capacity for membrane adjustment. These findings establish S. lycopersicoides as a vital genetic resource for breeding cold-tolerant tomatoes, while MT provides a model for studying adaptation mechanisms in cultivated varieties.

Cold stress is a critical factor limiting the productivity of agricultural crops, including tomatoes. Despite significant progress in the study of the molecular mechanisms of cold tolerance, the primary sensors involved in the effects of low temperatures on higher plants remain unknown. In this study, a comparative analysis of two species of the genus Solanum, cold-sensitive S. lycopersicum and cold-tolerant wild S. lycopersicoides, has been carried out to identify the relationships among plasma membrane fluidity, cold response gene expression (CBF/COR), and the stability of the photosynthetic apparatus under cold stress.Сold tolerance was assessed by electrolyte leakage and the effective quantum yield of photosystem II (Y(II)). The molecular response was monitored by measuring CBF1-3 and COR413 gene expression via real-time PCR. The plasma membrane fluidity was assayed by electron paramagnetic resonance (EPR) using a lipid soluble spin probe 5-doxil stearate, and the membrane fatty acid composition was determined via gas‒liquid chromatography‒mass spectrometry.Compared with S. lycopersicum, S. lycopersicoides presented lower electrolyte leakage, more stable photosystem II functions, and altered CBF/COR gene expression dynamics. The membranes of the resistant species retained their fluidity longer at lower temperatures, which correlated with a higher content of triene fatty acids in the plasma membrane.These results support the hypothesis that plasma membrane fluidity plays an important role in the initiation of the cold response and highlight the contribution of membrane properties to the physiological and molecular resistance of plants to cold.

The phytochrome-regulated responses of a etiolated M. polymorpha culture to red light (RL), far-red light (FRL) and their combinations (RL/FRL 1/1, 1/2, 2/1) were studied. The explants were exposed to continuous irradiation for 240 h. At this time, the growth, chlorophyll a fluorescence, photosynthetic pigment content, chloroplast ultrastructure and light-dependent gene expression of the explants were assessed. The phytochrome of M. polymorpha (MpPHY) serves as the only receptor for RL and FRL, combining the functions of both PhyB and PhyA. It regulates the transcription of key genes involved in the functioning of the photosynthetic apparatus, including the small subunit of Rubisco (RbcS) and PSII antenna complex proteins; however, the mechanism underlying this regulation under different spectral compositions remains unclear. When grown on FRL, M. polymorpha retained the granal structure of chloroplasts, but its photosynthetic activity, pigment biosynthesis, and biomass were significantly reduced. When the plants were grown under light at a 2/1 ratio, the greatest increase in biomass was observed. These effects correlated with the activation of genes involved in auxin and cytokinin biosynthesis, as well as the cellulose synthase gene. Both the PSII activity and the pigment content significantly decreased under FRL. It is suggested that under RL dominance, MpPHY functions similarly to PhyB, promoting photosynthesis and growth, whereas under FRL dominance, its activity resembles that of PhyA, restricting photomorphogenesis. Compared with fully etiolated explants, M. polymorpha grown under white light adapts likely more effectively to FRL than fully etiolated explants, highlighting the importance of light conditions during precultivation.

Humans have been using lipids for many centuries; these are oils found in plants, particularly in seeds. However, relatively recently, it has become clear that lipids are the primary metabolites of any living organism. Fatty acids (FAs) are a structural component of lipids, and their role in building the framework of the lipid bilayer cannot be overstated. They participate in maintaining homeostasis by controlling membrane permeability. Changes in the FA composition of lipid bilayers can modulate the transition of the membrane from a liquid crystalline to a gel-like state. Thus, knowledge of a plant’s FA profile can aid in understanding the physiological mechanisms underlying their interaction with the environment and the ways in which they adapt to various stress factors. Throughout the colonization of terrestrial habitats, plants evolved, and new phylogenetic groups appeared; at present, some features of the FA composition of their individual representatives are known. However, the overall change in the composition of lipid FAs during the evolution of higher plants is still not understood. Our analysis of the literature showed that the FA diversity tends to decrease from mosses to angiosperms, mainly due to a reduction in polyunsaturated very-long-chain FAs, while the average acyl chain length remains unchanged. It is important to recognize the trends in this process in order to understand the adaptive capabilities of higher plants. This knowledge can be useful not only from a fundamental point of view, but also in practical human activities.

We investigated the total lipid fatty acid (FA) composition of the fern Asplenium scolopendrium gametophyte, representing 25 individual FA species, for the first time. Conjugated octadecadienoates-18:2(10,12), rarely found in plant tissues-were identified. The possibility of modulating the lipid FAs composition under the action of light of different wavelengths on in vitro cultured gametophytes was demonstrated. Thus, exposure to blue (450 nm) and red (660 nm) light resulted in only insignificant changes in the minor FAs. This stability can be attributed to the fact that these wavelengths of light are necessary for photosynthesis and therefore optimal for the fern gametophyte. Green (GL, 525 nm) and far-red (FRL, 730 nm) light caused dramatic changes in the FA profile-the triene FAs decreased and the very-long-chain (VLC) FAs increased, mainly at the expense of saturated even-VLCFAs. This resulted in a dramatic decrease in the unsaturation index, indicating a decrease in membrane fluidity under GL and FRL illumination conditions. These changes indicate a significant rearrangement of the lipid metabolism of the A. scolopendrium gametophyte at light wavelengths not directly involved in photosynthetic processes (GL and FRL), in particular by triggering β-oxidation and blocking the plastidial pathway of FA synthesis.

Разнообразные молекулы патогенного происхождения, такие как бактериальный флагеллин (flg22), распознаются растениями через рецепторы плазматической мембраны и индуцируют как местные, так и системные иммунные реакции. При этом везикулярный транспорт является ключевым в обеспечении быстрого и точного реагирования. При взаимодействии с патогенами, локализованными на поверхности клеток, иммунные рецепторы подвергаются эндоцитозу по общему эндосомальному пути. Какой из везикулярных путей патогены используют для проникновения в ткани и какое значение имеет в этом процессе flot1 остается не до конца изученным. Данное исследование посвящено влиянию биотических факторов стресса на иммунную реакцию растений Arabidopsis thaliana дикого типа и его нокаут-мутанта Atflot1ko. Изучены процессы эндоцитоза под действием разных агентов: 1-нафталинлуксусной кислоты и метил-ß-циклодекстрина. С помощью трансмиссионной электронной микроскопии выявлены различия в ответных реакциях клеток на стресс, индуцированный flg22. Показано, что биотический стресс у нокаут-мутантов активирует секреторный путь (экзоцитоз), необходимый для защиты клеток от действиях патогена на поверхности клетки, тогда как у растений дикого типа активируется эндоцитоз, направленный на перемещение патогена в вакуоль. Полученные данные показали, что обработка мутантов Atflot1ko бактериальным пептидом сохраняет активность работы комплекса Гольджи и способность этой структуры формировать ранние эндосомы, принимающие непосредственное участие в транспорте защитных белков к месту проникновения патогена.

A variety of molecules of pathogenic origin, such as bacterial flagellin (flg22), are recognized by plants through plasma membrane receptors and induce both local and systemic immune responses. In this case, vesicular transport is key to ensuring a rapid and accurate response. When interacting with pathogens localized on the cell surface, immune receptors undergo endocytosis along the common endosomal pathway. Which vesicular pathway pathogens are used to penetrate tissues and the importance of flot1 in this process remains incompletely understood. This study is devoted to the influence of biotic stress factors on the immune response of wild type Arabidopsis thaliana plants and its knockout mutant Atflot1ko. The processes of endocytosis under the influence of various agents have been studied: 1-naphthaleneacetic acid and methyl-ß-cyclodextrin. Transmission electron microscopy revealed differences in cell responses to stress induced by flg22. It has been shown that biotic stress in knockout mutants activates the secretory pathway (exocytosis), which is necessary to protect cells from the actions of the pathogen on the cell surface, while endocytosis aimed at moving the pathogen into the vacuole is activated in wild-type plants. The obtained data showed that treatment of Atflot1ko mutants with bacterial peptide preserves the activity of the Golgi complex and the ability of this structure to form early endosomes, which are directly involved in the transport of protective proteins to the site of pathogen penetration.

The effects of silver nanoparticles (AgNPs), both alone and in combination with mineral nutrients, on the growth and photosynthesis of Solanum lycopersicum plants during ontogeny were studied. The experiment involved weekly applications of 10 μmol of AgNPs for 15 weeks in a greenhouse over a summer period. A comprehensive characterization of the AgNPs was performed via TEM, ESI/EELS, and zeta potential measurements before and throughout the experiment. The activity of PSII, stomatal conductivity, photosynthesis, transpiration and respiration rates were measured, and the photosynthetic pigments, chloroplast ultrastructure, and dry and fresh masses of leaves, roots, and fruits were assessed. The results indicated that combining AgNPs with mineral nutrients increased PSII activity and the photosynthesis rate and altered the chloroplast ultrastructure. However, the use of mineral nutrients or AgNPs alone did not induce these changes. Atomic absorption spectrometry detected AgNPs in all the plant organs except the fruits. The highest fruit yield was associated with Veni Prisma®, a commercial product containing colloidal silver, which also caused desynchronized fruit maturation. This study hypothesizes that the synergistic effect of AgNPs and mineral nutrients enhances silver accumulation in chloroplasts, improving light utilization and photosynthetic efficiency, particularly under low light, thus increasing fruit quantity and dry mass. Conversely, long-term use of AgNPs alone was accompanied by silver accumulation outside the chloroplasts and did not lead to increased photosynthesis or an increase in fresh fruit mass.

New data were obtained on specific bionanostructures, cutinsomes, which are involved in the formation of cuticles on the surface of leaf blades and pericarp of Malus domestica Borkh (Malus Mill., Rosaceae)introduced to the mountains at the altitudes of 1200 and 1700m above sea level. Cutinsomes, which are electron-dense structures of spherical shape, have been identified by transmission electron microscopy. It was demonstrated that plastids can be involved in the synthesis of their constituent nanocomponents. The greatest number of nanoparticles was observed in the granal thylakoid lumen of the chloroplasts in palisade mesophyll cells and pericarp hypodermal cells. The transmembrane transport of cutinsomes into the cell wall cuticle proper by exocytosis has been visualized for the first time. The plasma membrane is directly involved in the excretion of nanostructures from the cell. Nanoparticles of cutinsomes in the form of necklace-like formations line up in a chain near cell walls, merge into larger conglomerates and are loaded into plasmalemma invaginations, and then, in membrane packing, they move into the cuticle, which covers both outer and inner cell walls of external tissues. The original materials obtained by us supplement the ideas about the non-enzymatic synthesis of cuticle components available in the literature and expand the cell compartment geography involved in this process.

This pilot study aimed at comparing zinc (Zn) and nickel (Ni) effects on the fatty acid (FA) profiles, oxidative stress and desaturase activity in the Zn hyperaccumulator Arabidopsis halleri and the excluder Arabidopsis lyrata to allow a better picture of the physiological mechanisms which may contribute to metal tolerance or acclimation. The most significant changes in the FA composition were observed in the shoots of the hyperaccumulator and in the roots of the excluder, and were not only metal-dependent, but also species-specific, since the most significant changes in the shoots of A. halleri were observed under Ni treatment, though Ni, in contrast to Zn, was accumulated mainly in its roots. Several FAs appeared in the roots and shoots of A. lyrata only upon metal exposure, whereas they were already found in control A. halleri. In both species, there was an increase in oleic acid under Ni treatment in both organs, whereas in Zn-treated plants the increase was shown only for the shoots. A rare conjugated α-parinaric acid was identified only in the shoots of metal-treated A. halleri. In the shoots of the hyperaccumulator, there was an increase in the content of saturated FAs and a decrease in the content of unsaturated FAs, while in the roots of the excluder, the opposite pattern was observed. These metal-induced changes in FA composition in the shoots of A. halleri can lead to a decrease in the fluidity of membranes, which could diminish the penetration of ROS into the membrane and thus maintain its stability.

Pollen germination in vivo on wet stigmas is assisted by the receptive fluid-stigma exudate. Its exact composition is still unknown because only some components have been studied. For the first time, hormonal screening was carried out, and the fatty acid (FA) composition of lipid-rich (Nicotiana tabacum) and sugar-rich (Lilium longiflorum) exudates was studied. Screening of exudate for the presence of plant hormones using HPLC-MS revealed abscisic acid (ABA) in tobacco stigma exudate at the two stages of development, at pre-maturity and in mature stigmas awaiting pollination, increasing at the fertile stage. To assess physiological significance of ABA on stigma, we tested the effect of this hormone in vitro. ABA concentration found in the exudate strongly stimulated the germination of tobacco pollen, a lower concentration had a weaker effect, increasing the concentration did not increase the effect. GC-MS analysis showed that both types of exudate are characterized by a predominance of saturated FAs. The lipids of tobacco stigma exudate contain significantly more myristic, oleic, and linoleic acids, resulting in a higher unsaturation index relative to lily stigma exudate lipids. The latter, in turn, contain more 14-hexadecenoic and arachidic acids. Both exudates were found to contain significant amounts of squalene. The possible involvement of saturated FAs, ABA, and squalene in various exudate functions, as well as their potential relationship on the stigma, is discussed.

Marchantia polymorpha is a convenient model for studying light of different spectral compositions on various physiological and biochemical processes because its photoreceptor system is vastly simplified. The influence of red light (RL, 660 nm), far-red light (FRL, 730 nm), blue light (BL, 450 nm), and green light (GL, 525 nm) compared to white light (high-pressure sodium light (HPSL), white LEDs (WL 450 + 580 nm) and white fluorescent light (WFL) on photosynthetic and transpiration rates, photosystem II (PSII) activity, photomorphogenesis, and the expression of light and hormonal signaling genes was studied. The ultrastructure of the chloroplasts in different tissues of the gametophyte M. polymorpha was examined. FRL led to the formation of agranal chloroplasts (in the epidermis and the chlorenchyma) with a high starch content (in the parenchyma), which led to a reduced intensity of photosynthesis. BL increased the transcription of genes for the biosynthesis of secondary metabolites - chalcone synthase (CHS), cellulose synthase (CELL), and L-ascorbate peroxidase (APOX3), which is consistent with the increased activity of low-molecular weight antioxidants. FRL increased the expression of phytochrome apoprotein (PHY) and cytokinin oxidase (CYTox) genes, but the expression of the phytochrome interacting factor (PIF) gene decreased, which was accompanied by a significant change in gametophyte morphology. Analysis of crosstalk gene expression, and changes in morphology and photosynthetic activity was carried out.

Методом газово-жидкостной хроматографии с масс-спектрометрией в эксудате рылец лилии (Lilium longiflorum L., сорт Белое небо) и табака (Nicotiana tabacum L., сорт. Маленькая Гаванна SR1) был обнаружен сквален (2,6,10,15,19,23-гексаметилтетракоза-2,6,10,14,18,22-гексаен). Данное вещество идентифицировано в эксудате цветковых впервые. Концентрацию сквалена в эксудате можно выразить на среднюю массу рыльца (у табака она составляет в среднем 2,7 мг, для лилии около 60 мг), которую определяли гравиметрическим методом в ходе эксперимента. Таким образом. на 1 мг массы рыльца табака приходится 0,18 нг сквалена, а для лилии 0,29 нг.

The vegetative organs of common basil (Ocimum basilicum L.) grown in water culture at different levels of illumination (50, 100, and 150 μmol PAR quanta/(m2 s)) for 21 days were studied. In the work, the Purple Velvet basil variety, which is popular in agriculture and has intensely colored leaves was used. The biomass, water content, and composition of fatty acids (FA) of total lipids in the leaves and roots of plants and the content of malondialdehyde and chlorophylls (a, b) in the aerial parts of plants were determined. The sensitivity of the FA composition and morphophysiological parameters (biomass and chlorophyll content in leaves) of O. basilicum plants to the intensity of illumination was shown. The greatest effect was caused by the illumination intensity mode of 150 µmol/(m2 s). Species composition of O. basilicum FA under all lighting conditions was wider in root lipids; however, more pronounced changes in the qualitative composition of FAs were observed in leaves. Photodependent regulation of FA component composition of O. basilicum manifested itself in an increase in the proportion of unsaturated FAs, especially polyene ones, which led to an increase in the unsaturation index (UI) of esterified lipid FAs. The highest UI values were obtained with illumination of 150 µmol/(m2 s). At the same time, with an increase in the illumination intensity, a significant increase in the activity of ω-3 and ω-9-desaturases occurred, which indicates in favor of their light-dependent activation. Thus, increasing the intensity of lighting to certain values directly proportionally affects the physiological parameters of O. basilicum. The maximum indicators of productive growth and the implementation of adaptive mechanisms of green and underground parts of basil plants correspond to illumination of 150 µmol/(m2 s).

Scutellaria baicalensis Georgi. is a valuable medicinal plant. The hairy roots strain of S. baicalensis (Sc. baic.-1) from IPP RAS collection was used as a model system for the study. Effects of 1 and 10 mM of hydrogen peroxide (H 2 O 2 ) were first reported on the growth characteristics of hairy roots, fatty acid (FAs) composition of total lipids, and major root-specific flavones during the cultivation cycle. H 2 O 2 at a concentration of 1 mM exhibited the properties of a signaling molecule: the total FAs content of total lipids increased mainly due to polyunsaturated FAs, including very-long-chain FAs (VLCFAs); the total flavones content was about 1.5-fold higher than in the control. Besides, at 1 mM H 2 O 2 the content of aglycones, especially wogonin, was higher than in the other variants. At 10 mM H 2 O 2 , the properties of H 2 O 2 as reactive oxygen species were manifested: inhibition in the growth of hairy root culture was observed against the background of an increase in the content of malondialdehyde; the proportion of saturated FAs and the total proportion of VLCFAs increased; the amount of the aglycone baicalein was also significantly reduced. Based on the data obtained, we can speak about a possible role of VLCFAs in the protection of S. baicalensis roots against oxidative stress.

New data on the micromorphology, histochemistry, and fluorescence of colleters on leaf structures at different stages of development (leaf blade, stipules, and petiole) of Mespilus germanica L. are presented. Colleters are found on the tips of the teeth of both young and mature leaf blades and stipules, less often on the petioles. The leaf veins approach the leaf tooth, but no vascularization was found in the colleter. On leaf structures inside the bud, young colleters were observed in the form of finger-shaped or rounded outgrowths consisting of isodiametric cells. Mature colleters are multicellular secretory structures that have a head on a short stalk. The central part of the head consists of densely packed parenchymal cells, which are surrounded by radially elongated palisade-like secretory cells covered with a cuticle. The main secretion process of the colleter falls on the period of active growth of leaf structures. The secreted substances accumulated in the intercellular spaces of the palisade-like cells of the head and then were released outside in the form of translucent vesicles. The secretion products were released when the cuticle was ruptured and spread over the surface of the head and tooth of the leaf blade and stipules. After the end of secretion, the sizes of the head of the colleter decreased, and an abscission zone appeared in the cells of the colleter stalk, along the border of which a fracture occurred when the head fell off. Histochemical analysis of the contents of the colleter showed the presence of polysaccharides, especially at a young age, substances of a phenolic nature and lipids at a more mature age. In the fluorescence spectrum of young leaf colleter secretion, a peak at 671-672 nm was observed upon excitation at 405 and 473 nm. The obtained data on Mespilus germanica L. colleter can be used in the taxonomy of Pyrinae and Rosaceae.

A pollen grain is a unique haploid organism characterized by a special composition and structure. The pollen of angiosperms and gymnosperms germinate in fundamentally similar ways, but the latter also have important features, including slow growth rates and lower dependence on female tissues. These features are, to some extent, due to the properties of pollen lipids, which perform a number of functions during germination. Here, we compared the absolute content and the fatty acid (FA) composition of pollen lipids of two species of flowering plants and spruce using GC-MS. The FA composition of spruce pollen differed significantly, including the predominance of saturated and monoene FAs, and a high proportion of very-long-chain FAs (VLCFAs). Significant differences between FAs from integumentary lipids (pollen coat (PC)) and lipids of gametophyte cells were found for lily and tobacco, including a very low unsaturation index of the PC. The proportion of VLCFAs in the integument was several times higher than in gametophyte cells. We found that the absolute content of lipids in lily pollen is almost three times higher than in tobacco and spruce pollen. For the first time, changes in the FA composition were analyzed during pollen germination in gymnosperms and angiosperms. The stimulating effect of H2O2 on spruce germination also led to noticeable changes in the FA content and composition of growing pollen. For tobacco in control and test samples, the FA composition was stable.

Plants are subjected to various stress factors within their lifespan. In this respect, the plasma membrane is a principal cell compartment responsible for plant adaptations to stresses. It is capable of remodeling its protein composition by means of endocytosis. In the plants, the main mode of this process is a clathrin-mediated endocytosis. Several clathrin-independent pathways are also known; these alternative mechanisms involve Flot1 protein. In the present research, the role of Flot1 in the endocytosis process was examined in seedling roots of a wild type and an Atflot1ko knockout mutant of Arabidopsis thaliana (L.) Heynh. Light microscopy with an FM4-64 lipophilic probe and transmission electron microscopy were used. It was found that endocytosis was arrested in the root cells of the wild type after a simultaneous treatment of the roots with an inhibitor of clathrin-mediated endocytosis (1-naphthylacetic acid) and the agent depleting the plasma membrane of sterols (methyl-β-cyclodextrin). In this case, such morphological change as reduction in cytoplasm vesiculation (including the early endosomes, the small vesicles originated from the agranular ER, the microvacuoles from its fragments, and the clathrin vesicles) was observed. The vesiculation was diminished in both the control and the stressed plants (exposed to 100 mM NaCl). In the Atflot1ko mutant, the cisterns of the Golgi complex closed up to a ring, and the process of formation of the early endosomes was completely abolished under these conditions. It is suggested that, in the roots of A. thaliana exposed to the inhibitors, the microdomain-associated Flot1 protein of the plasma membrane conserves the structure of the Golgi complex and its capacity to build early endosomes on the trans -side. In addition, the protein appears to participate in formation of the early endosomes from the trans -Golgi network.