GLN1;5 is one of the five Arabidopsis thaliana glutamine synthetase (GS) cytosolic isoenzymes, almost exclusively expressed in seeds, where it plays a critical role in nitrogen reassimilation during seed maturation and germination. ACT Domain Repeat (ACR) proteins are believed to act as nutrient sensors, although their precise functions in plants remain unclear. The eFP browser expression analysis shown that one ACR isogene, AtACR1, entirely overlaps with AtGLN1;5 expression, suggesting a possible interaction between these proteins. This study aimed to elucidate the functional relationship between the two proteins, using an integrated approach combining phenotypic, biochemical, and molecular analyses. The similarity in phenotypes of the two mutants, acr1 and gln1;5 highlights the crucial role of both proteins in nutrient utilization during germination and supports their potential interaction. Furthermore, in acr1 seeds, GS activity was reduced despite increased protein levels and gene expression, especially of the GLN1;5. Pull-down assays using recombinant proteins and seed extracts from wild-type, acr1, and gln1;5 mutants confirmed a specific interaction between ACR1 and GLN1;5. In addition, recombinant ACR1 protein enhances GS activity in wild-type but not in gln1;5 mutant seed extracts, indicating a regulatory role of ACR1 in GLN1;5 activation. Hormonal treatment of wild-type seed revealed antagonistic regulation of ACR1 and GLN1;5 genes by abscisic and gibberellic acid during germination, further supporting a role for ACR1 in modulating GS activity during this process. By using complementary and alternative approaches, our findings establish ACR1 as a key regulator of glutamine synthetase in seeds, with implications for normal seedling development.

The genus Gymnocalycium represents a distinct lineage within the tribe Cereeae (Cactaceae), recently assigned to the monogeneric subtribe Gymnocalyciinae. Although molecular phylogenetic studies consistently supports the monophyly of the genus, detailed floral morphoanatomical information remains scarce. This study investigates the floral morphoanatomy of four species representing four subgenera (Gymnocalycium saglionis, G. schickendantzii, G. schroederianum, and G. spegazzinii) using light and scanning electron microscopy. Our findings revealed conserved floral morphoanatomical features among the species examined, including nectar chambers with nectarostomata, nectariferous epidermis composed of trichomes or papillae, and rounded-oblate orbicules distributed along the inner anther walls. To our knowledge, this study provides the first report of orbicules in the subfamily Cactoideae. Pollen grains are consistently isopolar, radiosymmetric, and trizonocolpate, with a tectate-punctate exine, whereas interspecific differences occur mainly in exine ornamentation and pollen morphometric variables. Gymnocalycium schroederianum is distinguished by branched stigmatic lobes and nanospinulate pollen ornamentation, while the other species exhibit nanospinulate to microspinulate pollen ornamentation. Branched multicellular trichomes were also observed in the nectar chambers of G. sagionis, G. schickendantzii and G. spegazzinii, a character previously unreported in the family. Overall, the results expand the comparative knowledge of floral morphoanatomy in Gymnocalycium and reveal both conserved and variable characters among the species examined, providing a basis for future studies integrating floral morphology, reproductive biology, palynology, and phylogenetic data.

Autophagy and endocytosis represent two fundamental membrane trafficking pathways that are essential for cellular homeostasis, stress responses, and development in plants. While traditionally studied as independent processes, mounting evidence reveals extensive crosstalk between these pathways at multiple levels, including shared molecular machinery, convergent trafficking routes, and coordinated regulation. This review examines the molecular mechanisms underlying the interplay between autophagy and endocytosis in plants, highlighting recent discoveries of shared protein complexes, membrane contact sites, and regulatory networks. Additionally, this review discusses how these pathways cooperate during stress responses, nutrient recycling, and protein quality control while also exploring their distinct roles in plant immunity and development. Understanding the intricate relationship between autophagy and endocytosis provides crucial insights into plant cell biology and offers potential strategies for improving stress tolerance and crop productivity.

The raphidophycean flagellate Gonyostomum semen (Ehrenberg) Diesing is a stramenopile protist whose ejectosomes - rod-like organelles at the cell periphery - are discharged as mucilaginous threads, which kill some zooplankton grazers. Ejectosomes are formed from fibrils, which are first distinguishable in the Golgi, where they can reach 650 nm in length, have a diameter of 21-27 nm, and possess a narrow electron-transparent lumen. Fusion of Golgi vesicles forms a post-Golgi structure containing many fibrils, which gives rise to an immature ejectosome in which some fibrils crisscross at an angle of approximately 45 degrees to the longitudinal axis of the ejectosome and other fibrils are approximately parallel to the longitudinal axis of the ejectosome. The arrangement of fibrils is not discernible in the mature ejectosome, where they form a densely stained core; between the core and the ejectosome membrane lies a less-stained layer. The anterior end of the core terminates in a domed structure that is in contact with the ejectosome membrane. Mature ejectosomes, which are approximately 1.8 to 3.1 μm long by 0.5-0.6 μm in diameter, migrate to the cell periphery and discharge in response to chemical or physical stimuli. This paper describes the assembly of ejectosomes in G. semen and presents a structure somewhat different from that previously reported.

Cytorrhysis describes the shrinkage of plant cells caused by water loss, during which the protoplast and cell wall contract while remaining connected. Cytorrhysis can occur naturally during drought and freezing and can be experimentally induced by exposure to osmotic substances. Although traditionally studied separately, the cytorrhysis process itself shares the same underlying mechanisms: water efflux along chemical potential gradients and the mechanical response of the cell wall-plasma membrane continuum. Cytorrhysis has been documented across diverse taxa - including algae, bryophytes, ferns and seed plants - indicating that it represents a fundamental response of walled cells to dehydration. Besides osmotic effects, the extent of cytorrhysis is also strongly affected by biomechanical cell structure. Cell size, wall thickness, elasticity and tissue architecture influence the likelihood of cellular collapse. Small, thick-walled cells withstand larger pressure differences and develop negative turgor pressure whereas large, thin-walled cells collapse more readily. During freezing, extracellular ice imposes temperature-dependent dehydration forces, and biomechanical constraints may generate negative turgor pressure. Recent advances, including cryo-microscopy, differential scanning calorimetry and psychrometric water-potential measurements, allow more precise quantification of freeze dehydration and structural responses. Functionally, cytorrhysis can be protective or damaging. Moderate, reversible cytorrhysis helps maintain membrane integrity e.g. in desiccation-tolerant species. In freezing environments, cells undergoing cytorrhysis survive temperatures far below those tolerated by supercooling cells. However, excessive dehydration may cause cell death. Integrating classical observations with modern biophysical approaches provides a renewed perspective on cytorrhysis and highlights structural traits that could be exploited to enhance plant resilience to drought and freezing stress in a changing climate.

This study was conducted to comparatively investigate the accumulation of carbohydrates and transcript levels of genes encoding relevant enzymes in two rice (Oryza sativa L.) cultivars 'Hashemi' (cold-sensitive) and 'Kouhsar' (cold-tolerant) at 1, 3 and 6 days after cold stress (DAS) (4℃). The sinusoidal pattern of H2O2 and MDA in Hashemi under cold, compared with the steadily decreasing levels in Kouhsar indicates differing oxidative damage, reflected in 2.28- and 2.39-fold higher contents, respectively, at 6 DAS. Kouhsar had higher sucrose than Hashemi on all stress days, with a peak increase of 24% at 6 DAS. Glucose and fructose values increased more in Hashemi but changes ratio in fructose were more prominent and was accompanied by higher expression of sucrose transporters and invertase genes. In both cultivars, raffinose and trehalose values reached their highest levels at 6 DAS with no significant difference between them. During stress, higher expression of galactinol synthase, trehalose-6-phosphate phosphatase and phosphoenol pyruvate carboxylase genes was observed in Kouhsar, with the most increases of 23%, 35% and 30%, respectively, at 6 DAS. Despite chlorophyll deceasing and carotenoids increasing under cold, Kouhsar exceeded Hashemi by 69% in chlorophyll and 31% in carotenoids at 6 DAS. The results suggest that cold tolerance is more effectively conferred by the maintenance of sucrose level at the beginning of stress and its continued increase along with Raf and Treh accumulation throughout the stress period. Enhancing these features may pave the way for breeding programs to increase production sustainability in cold regions.

The mechanisms of plant resistance and adaptation to low temperature and frost stress remain a very important topic for research, as they can directly and indirectly affect the productivity of the agricultural sector. Evolved plant defence systems are currently one of the main methods recommended for use in biotechnology. One of them is to increase the proportion of unsaturated fatty acids in membrane phospholipids. Desaturases are enzymes that promote the formation of double bonds in fatty acids and thereby convert them from saturated to unsaturated. However, the insertion and expression of transferred genes can have both positive and negative effects, so we used the cold-inducible promoter of CBF1 to regulate the expression of the Δ12-acyl-lipid desaturase gene from the cyanobacterium Synechocystis sp. PCC 6803 in the model plant Nicotiana tabacum. We found an altered spectrum of unsaturated fatty acids in transgenic plants and better adaptive parameters under conditions of in vitro plant cultivation based on the results of the study of superoxide dismutase activity, the level of malondialdehyde accumulation and electrolyte loss compared to control plants.

Selenium (Se) is a bioactive trace element that influences plant growth, development, and metabolic processes. However, the molecular and metabolic responses of medicinal plants to exogenous sodium selenite remain poorly understood. In this study, Stemona tuberosa Lour. roots were treated with 20 mg/L sodium selenite (Na2SeO3) for 40 days, and integrated transcriptomic and metabolomic analyses were performed to characterize Se-responsive changes. The results revealed substantial transcriptional and metabolic changes in response to Na2SeO3 treatment. Metabolomic analysis identified 669 differentially accumulated metabolites (DAMs), predominantly involving amino acids and derivatives, organic acids, carbohydrates, lipids, and secondary metabolism-related compounds. KEGG enrichment analysis showed that DAMs were mainly associated with metabolic pathways, amino acid biosynthesis, nucleotide metabolism, inositol phosphate metabolism, and secondary metabolite biosynthesis. Transcriptomic analysis identified 16,577 differentially expressed genes (DEGs), including 9,134 upregulated and 7,443 downregulated genes. These DEGs were mainly enriched in metabolic processes, stimulus responses, plant hormone signal transduction, phenylpropanoid biosynthesis, flavonoid biosynthesis, and starch and sucrose metabolism. Transcription factor analysis indicated that AP2/ERF, MYB, WRKY, bHLH, and NAC families were prominently represented among Se-responsive transcription factors. Integrated analyses identified coordinated associations among genes, transcription factors, and metabolites, suggesting that these coordinated molecular patterns may be associated with the response of S. tuberosa roots to Na2SeO3. Overall, this study provides insights into the molecular and metabolic changes associated with Na2SeO3 exposure in medicinal plants.

Coscinium fenestratum (Gaertn.) Colebr., commonly known as tree turmeric, is a critically endangered medicinal plant extensively used in Ayurveda and Siddha systems for treating metabolic disorders and various infectious diseases. Due to overexploitation and habitat loss, Coscinium fenestratum faces severe conservation threats, resulting in a scarcity of authentic raw material and frequent adulteration with morphologically similar species such as Anamirta cocculus. The present study reports the development and validation of an internal transcribed spacer (ITS) based loop-mediated isothermal amplification (LAMP) assay for rapid authentication of C. fenestratum and sensitive detection of A. cocculus adulteration. Species specific LAMP primers were designed targeting the variable regions of ITS sequence, and assay optimization identified 7 mM MgSO4 and 1 M betaine as the optimal reagent concentrations. Colorimetric detection using hydroxy naphthol blue (HNB) dye enabled closed-tube visual detection with a violet to sky blue color transition upon amplification. The assay demonstrated 100 per cent specificity with no cross-reactivity between species and achieved a limit of detection of 0.05 per cent adulterant DNA. Analysis of ten market samples including bark and powdered bark specimens revealed 30 per cent adulteration in the tested samples. The developed LAMP assay requires minimal equipment, uses crude DNA extracts, and delivers results within 60 min, making it suitable for resource-limited laboratory settings. This rapid, sensitive, and user-friendly molecular tool enables reliable authentication and quality control of Ayurvedic medicinal raw materials.

Male sterility is a valuable trait in plant breeding that enables efficient hybrid seed production by eliminating the need for manual emasculation. In Lycium barbarum, the male sterile line Ningqi-5 exhibits complete pollen abortion, but the underlying cytological mechanisms remain unclear. In this study, we systematically compared anther development between the fertile line Ningqi-1 and the male sterile line Ningqi-5 using light microscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and TUNEL assays to elucidate the cellular basis of male sterility. Our results revealed that microspore abortion in Ningqi-5 occurs at the tetrad stage, characterized by delayed callose wall degradation, failure of microspore release, and progressive degeneration of tetrads. TEM and SEM analyses showed abnormal tapetal ultrastructure in Ningqi-5, including thickened cell walls, absence of Ubisch bodies, aggregated and adherent secretions, and disrupted sporopollenin transport. Furthermore, TUNEL assays demonstrated premature initiation of programmed cell death (PCD) in the tapetum of Ningqi-5 during the tetrad stage. These defects collectively disrupt nutrient supply, exine formation, and microspore maturation. We conclude that male sterility in L. barbarum Ningqi-5 results from a synergistic interplay of three key factors, include failure to degrade the callose wall, impaired tapetal secretion function, and precocious tapetal PCD. This study provides a comprehensive cytological framework for understanding pollen abortion in L. barbarum.

Though seed shattering continues to be a significant barrier affecting yield stability and harvesting efficiency in millets and other grasses, millets are increasingly acknowledged as climate-resilient, nutrient-rich 2007cereal crops with the potential to strengthen global nutritional and food security under the combined pressures of climate change, population growth, and limited natural resources. Since strong artificial selection favoured non-shattering phenotypes during domestication, seed shattering, an adaptive trait in wild species that promotes seed dispersal through the formation and activation of specialised abscission layers, became a distinguishing feature of cultivated cereals. With a focus on the morphological, physiological, hormonal, and genetic modulation of the abscission zone, this article summarizes the state of the art regarding seed shattering in millets. Abscission layer morphology, location, and lignification vary greatly among grasses, from well-defined lignified zones in rice and sorghum to non-lignified and anatomically subtle zones in Setaria and Panicum species. Cell wall-modifying enzymes like polygalacturonases, cellulases, expansins, and pectin methylesterases that mediate middle lamella degradation are modulated by coordinated hormonal signalling involving auxin, ethylene, and abscisic acid, which controls the timing and progression of cell separation at the physiological level. Domestication-related genes, including SH1, qSH1, SH4, and LES1, demonstrate convergent evolutionary mechanisms controlling abscission layer development in a variety of grass lineages at the molecular level. Understanding these regulatory networks has been greatly enhanced by recent developments in transcriptomics, functional genomics, and genome sequencing in both model species and underused millets. The role of millets as climate-smart cereals for sustainable future agriculture is reinforced by the integration of anatomical, physiological, and genetic insights, which offer a solid basis for targeted breeding and genome-editing strategies intended to improve seed retention, enhance yield stability, and increase harvest efficiency.

Floral nectaries are specialized structures that secrete nectar, a key floral reward mediating plant-pollinator interactions. Although floral morphology and nectar traits have been moderately studied in Salvia, the detailed structure and anatomy of nectaries remain less explored, limiting our understanding of their diversity and functional variation. This study compares the nectary accessibility, morphology, anatomy, and nectar production of two Salvia taxa with different floral traits and floral visitor assemblages: S. uliginosa and the the sterile hybrid cultivar S. 'Amistad'. Both possess annular, four-lobed nectaries positioned below the ovary, with the anterior lobe being the most developed. However, S. 'Amistad' exhibits significantly larger nectaries and produces higher nectar volumes (16.85 ± 1.13 µL) than S. uliginosa (0.36 ± 0.03 µL), with nectary size, particularly anterior lobe length, associated with nectar production differences. Anatomically, both taxa show a single-layered epidermis with open nectarostomata and a nectariferous parenchyma well supplied by vascular bundles containing phloem and xylem. Epidermal micromorphology differs between species: the cuticle is smooth in S. uliginosa but striate in S. 'Amistad'. Although bees dominated floral visitation in both taxa, hummingbirds accounted for a substantial proportion of visits (35.1%) to S. 'Amistad' and were the only visitors contacting its reproductive structures, whereas only bees contacted the reproductive structures of S. uliginosa. Because S. 'Amistad' is a sterile cultivar, floral visitor observations are interpreted in the context of differences in nectar accessibility, nectar production, and floral visitor assemblages rather than as evidence of pollinator-mediated selection. These comparative data reveal conserved nectary anatomy with subtle structural variation associated with nectar production differences between two Salvia taxa with contrasting visitor assemblages.

Esculetin, a coumarin derivative, exhibits diverse biological activities; however, its impact on pancreatic β-cell stress responses and survival remains poorly defined. In this study, we investigated the effects of esculetin on cellular stress signaling, apoptosis, and functional gene expression in INS-1 pancreatic β-cells. Following treatment with 3000 µM esculetin for 6 h, cell viability, proliferation, apoptosis, oxidative stress, endoplasmic reticulum (ER) stress markers, MAPK signaling components, cell cycle distribution, and β-cell-specific gene expression were assessed. In silico molecular docking was performed to explore putative interactions between esculetin and proteins involved in ER stress, MAPK signaling, and apoptosis. Treatment with 3000 µM esculetin for 6 h increased apoptotic cell death by approximately 32-fold and elevated total oxidation status and oxidative stress index. Intracellular insulin, Ca[2+], and CA19-9 levels were increased, accompanied by cell cycle arrest characterized by G0/G1 phase accumulation and a reduction in the G2/M population. Expression of ER stress sensors ATF6, IRE1α, and CHOP was upregulated, whereas PERK expression was reduced. In parallel, MAPK/JNK pathway activation was evidenced by increased levels of p-ATF2, p-c-Jun, and HSP90, along with decreased p-Elk1. Gene expression analysis revealed marked downregulation of β-cell functional and identity-associated genes, including Ins1, Ins2, IR, Akt, MafA, Nkx6.1, Pdx1, NeuroD1, and Pax6, while FoxO1 expression was upregulated. Collectively, these findings suggest the involvement of ER stress-associated MAPK/JNK signaling in esculetin-induced apoptosis and functional impairment in INS-1 pancreatic β-cells, providing mechanistic insight into stress-associated β-cell dysfunction.

Intestinal inflammation and barrier disruption induced by high-altitude exposure are recognized contributors to colitis. Although artificial-enzyme-engineered Bifidobacterium longum (AE-BL) has demonstrated therapeutic potential against inflammatory bowel disease, the precise mechanisms remain elusive. The present study aimed to assess the efficacy of AE-BL against high-altitude colitis and to elucidate its underlying mechanisms. AE-BL was generated through the assembly of single-atom enzymes (SAzymes) with Bifidobacterium longum (BL). In vivo investigations involved housing mice in a hypobaric hypoxic chamber to replicate high-altitude conditions, followed by AE-BL administration. After seven days, colon specimens were collected for histopathological evaluation, inflammatory and ferroptosis-related parameter analyses, and the expression of glycerol-3-phosphate dehydrogenase 2 (GPD2), tight junction proteins, and ferroptosis markers. An in vitro colitis model was also established using Caco-2 cells subjected to lipopolysaccharide (LPS) and hypoxia, followed by AE-BL treatment. Administration of AE-BL markedly ameliorated high-altitude-induced colitis in mice, as reflected by attenuated weight loss, increased colon length, reduced disease activity index (DAI), and diminished histopathological injury. Pro-inflammatory cytokine production was suppressed, and intestinal barrier integrity was preserved. Mechanistic investigations indicated that the protective actions of AE-BL were potentially mediated through suppression of GPD2-driven ferroptosis. Under hypoxic conditions, AE-BL significantly reduced ferroptosis in colon tissue and colonic epithelial cells both in vivo and in vitro, thereby alleviating inflammation and restoring intestinal barrier function.

Plant secondary metabolites are mainly synthesized and stored in secretory tissues. Secretory canal development has been mainly characterized in Apiaceae. The secretory canals of Peucedanum praeruptorum contain pharmacologically active coumarins, but their organ-specific distribution and developmental dynamics remain poorly understood. This study integrated light microscopy (LM), transmission electron microscopy (TEM), X-ray microcomputed tomography (µ-CT), and high-performance liquid chromatography (HPLC) to investigate canal development, distribution, ultrastructure, 3D architecture, and coumarin accumulation in P. praeruptorum roots. Histological analysis showed that canals adjacent to the periderm originate from pericycle cells, whereas those in secondary phloem arise from parenchyma differentiation; both develop schizogenously. Canal quantity and dimensions varied temporally. Canals located in phloem showed density increasing toward the cambial zone, where cross-sectional areas were smaller. The canal density index increased from September to November, peaking on November 15, then declined. HPLC revealed dynamic accumulation of five major coumarins: content increased from September, peaked on November 15, then gradually decreased. TEM showed that epithelial cells surrounding the canal lumen were rich in Golgi, ER, mitochondria, plastids, starch grains, and osmiophilic droplets. µ-CT volumetric analysis and segmentation generated detailed 3D models, revealing spatial organization and enabling size-based grouping of canals (1000-3000 μm). These dimensional characteristics aligned with developmental progression. This study characterizes the ontogeny, distribution, ultrastructure, and 3D architecture of secretory canals, providing a structural foundation for investigating correlations between secretory tissues and compound synthesis.