Search Results (112)

Segregative phase separation technology demonstrates substantial potential for precise molecular fractionation in food and biomaterial applications. The investigation elucidates the causal relationship between viscosity variations and phase separation dynamics, which govern molecular fractionation in GA/HPMC composite systems. By conducting a comparative analysis of two GA subtypes (CGA and SGA) and three HPMC grades with controlled viscosity gradients, we utilized gel permeation chromatography-multi-angle laser light scattering (GPC-MALLS) coupled with rheological characterization to elucidate the critical relationship between continuous phase viscosity and fractionation efficiency. Notably, increasing HPMC viscosity significantly intensified phase separation, resulting in selective enrichment of arabinogalactan-protein complexes: from 6.3% to 8.5% in CGA/HPMC systems and from 27.3% to 36.5% in SGA/HPMC systems. Further mechanistic investigation revealed that elevated HPMC viscosity enhances thermodynamic incompatibility while slowing interfacial mass transfer, synergistically driving component redistribution. These findings establish a quantitative viscosity–fractionation relationship, offering theoretical insights for optimizing GA/HPMC systems in emulsion stabilization, microencapsulation, and functional biopolymer purification via viscosity-mediated phase engineering. Full article

Background: Aluminum (Al) toxicity severely limits Medicago sativa (alfalfa) production on acidic soils, resulting in major yield losses worldwide. The highly conserved miRNA156 (miR156) functions by downregulating at least 11 SQUAMOSA promoter-binding protein-like (SPL) transcription factors in alfalfa, including SPL13, but its role in Al stress remains unclear. This study aimed to investigate the miR156/SPL regulatory network’s function in alfalfa under Al stress. Methods: Gene expression analyses, histochemical staining, nutrient profiling, phenotypic assays, transcriptome profiling, and ChIP-seq were conducted on alfalfa plants with altered miR156 and SPL13 expression to assess their roles in the Al stress response. Results: Al stress induced SPL13 expression while repressing miR156 in the roots. Elevated miR156 intensified Al accumulation, lipid peroxidation, and plasma membrane damage, accompanied by reduced leaf nitrogen, magnesium, sulfur, and phosphorus content. Phenotypically, increased SPL13 enhanced the root length and Al tolerance, whereas SPL13 silencing reduced tolerance. Transcriptome profiling of SPL13-silenced plants identified differentially expressed genes involved in the Al response, including aluminum-activated malate transporters and various transcription factors (GRAS, Myb-related, bHLH041, NAC, WRKY53, bZIP, and MADS-box). ChIP-seq revealed that SPL13 directly regulates genes encoding a protein kinase, cytochrome P450, and fasciclin-like arabinogalactan proteins. Conclusions: The MsmiR156/MsSPL13 network plays a crucial regulatory role in alfalfa’s response to Al toxicity. These findings provide novel genetic targets and foundational knowledge to advance molecular breeding for enhanced Al tolerance in alfalfa. Full article

Wild fruits are distributed worldwide, but are consumed mainly in developing countries, where they are an important part of the diet. Still, in many other countries, they are consumed only locally. Blackthorn (Prunus spinosa L.) is an underutilized species rich in fibres and phenolic compounds, making it suitable as a potential functional food for supporting human health. Cold (Cw) and hot (Hw) water-extracted (poly)phenolic polysaccharide–protein complexes, differing in carbohydrate, phenolic and protein contents, were isolated from blackthorn fruits and characterized. The complexes exhibited molecular weights of 235,200 g/mol (Cw) and 218,400 g/mol (Hw), and were rich in pectic polymers containing galacturonic acid, arabinose, galactose and rhamnose, indicating a dominance of homogalacturonan (HG) [→4)-α-D-GalA(1→4)-α-D-GalA(1→]n and a low content of RGI [→2)-α-L-Rha(1→4)-α-D-GalA(1→2)-α-L-Rha(1→]n sequences associated with arabinan or arabinogalactan. Minor content of glucan, probably starch-derived, was also solubilized. Pectic polysaccharides were highly esterified and partly acetylated. Pharmacological testing was performed in male Dunkin–Hartley guinea pigs, a model with human-like airway reflexes. Both complexes affected airway defense mechanisms. Particularly, Hw significantly suppressed citric acid-induced cough, similar to codeine, and reduced bronchoconstriction comparably to salbutamol in a dose-dependent manner. These findings support further exploration of Hw as a natural antitussive and bronchodilatory agent. Full article

Arabinogalactan proteins (AGPs) constitute a diverse class of hydroxyproline-rich glycoproteins implicated in various aspects of plant growth and development. However, their functional characterization in cotton (Gossypium spp.) remains limited. As a globally significant economic crop, cotton serves as the primary source of natural fiber, making it essential to understand the genetic mechanisms underlying its growth and development. This study aims to perform a comprehensive genome-wide identification and characterization of the AGP gene family in Gossypium spp., with a particular focus on elucidating their structural features, evolutionary relationships, and functional roles. A genome-wide analysis was conducted to identify AGP genes in Gossypium spp., followed by classification into distinct subfamilies based on sequence characteristics. Protein motif composition, gene structure, and phylogenetic relationships were examined to infer potential functional diversification. Subcellular localization of a key candidate gene, GhAGP50, was determined using fluorescent protein tagging, while gene expression patterns were assessed through β-glucuronidase (GUS) reporter assays. Additionally, hormonal regulation of GhAGP50 was investigated via treatments with methyl jasmonate (MeJA), abscisic acid (ABA), indole-3-acetic acid (IAA), and gibberellin (GA). A total of 220 AGP genes were identified in Gossypium spp., comprising 19 classical AGPs, 28 lysine-rich AGPs, 55 AG peptides, and 118 fasciclin-like AGPs (FLAs). Structural and functional analyses revealed significant variation in gene organization and conserved motifs across subfamilies. Functional characterization of GhAGP50, an ortholog of AGP18 in Arabidopsis thaliana, demonstrated its role in promoting epidermal hair formation in leaves and stalks. Subcellular localization studies indicated that GhAGP50 is targeted to the nucleus and plasma membrane. GUS staining assays revealed broad expression across multiple tissues, including leaves, inflorescences, roots, and stems. Furthermore, hormonal treatment experiments showed that GhAGP50 expression is modulated by MeJA, ABA, IAA, and GA, suggesting its involvement in hormone-mediated developmental processes. This study presents a comprehensive genome-wide analysis of the AGP gene family in cotton, providing new insights into their structural diversity and functional significance. The identification and characterization of GhAGP50 highlight its potential role in epidermal hair formation and hormonal regulation, contributing to a deeper understanding of AGP functions in cotton development. These findings offer a valuable genetic resource for future research aimed at improving cotton growth and fiber quality through targeted genetic manipulation. Full article

Bryophytes, or non-vascular plants, provide valuable models for studying plant adaptation to land, as their physiology differs significantly from that of vascular plants. This study examines the cell wall structure of bryophytes, focusing on the tissue-specific distribution of cell wall epitopes in Sphagnum compactum (a peat moss) and Marchantia polymorpha (the model liverwort) using specific stains and immunolabeling techniques. In S. compactum, chlorocysts and hyalocysts exhibit distinct polysaccharide compositions, with methylesterified and demethylesterified homogalacturonans, arabinans, and hemicelluloses contributing to water retention, structural integrity, and photosynthetic efficiency. In contrast, M. polymorpha demonstrates a simpler yet polarized distribution of homogalacturonans, arabinans, mannans, and xyloglucans, with arabinogalactan proteins uniquely localized in rhizoids, improving their flexibility and anchorage to the substrate. Cellulose was uniformly distributed throughout all tissues in both bryophytes, while crystalline cellulose was only faintly observed. These findings highlight how cell wall adaptations contribute to ecological specialization, providing insights into the evolutionary innovations that enable bryophytes to thrive in terrestrial environments. Full article

Honey has been used for centuries for its antibacterial and healing properties. The aim of this study was to investigate the antibacterial properties, arabinogalactan proteins (AGPs), antioxidant activities, and polyphenolic content of eight different types of New Zealand honey (clover, mānuka, beech honeydew, pōhutukawa, kānuka, rewarewa, kāmahi and thyme honey). The results showed varying antibacterial activities across the honey types, with mānuka, pōhutukawa, and kāmahi honey exhibiting significant inhibitory effects. Interestingly, all honey samples demonstrated inhibitory effects on bacterial growth at 25% concentration. Furthermore, AGPs were found in all eight honey samples, with higher amounts in kānuka, kāmahi, pōhutukawa, mānuka, and rewarewa honey. Thyme had the highest antioxidant values in terms of CUPRAC, FRAP and DPPH, while kāmahi honey had the lowest antioxidant value. Beech honeydew honey had the highest Total Flavonoid Content (TFC) values, while thyme and clover honey had the lowest TFC values. Similarly, thyme honey exhibited the highest Total Phenolic Content (TPC) value, with kāmahi and clover honey having the lowest TPC values. Furthermore, only thyme and beech honeydew New Zealand honeys contained vitamin C. The different honeys contained varying concentrations of polyphenols, with mānuka, kānuka, and pōhutukawa honeys having high amounts of quercetin, luteolin, and gallic acid, respectively. In contrast, clover honey had notable levels of chrysin, pinocembrin, caffeic acid, and pinobanksin. Overall, this study provides valuable insights into the antibacterial properties and bioactivities of native New Zealand honeys, contributing to our understanding of the potential health benefits associated with these honeys and their potential use as natural alternatives to improve human health. Full article

Arabinogalactan proteins (AGPs) are complex proteoglycans present in plant cell walls across the kingdom. They play crucial roles in biological functions throughout the plant life cycle. In this study, we identified 43 gene members of the AG peptide (an AGP subfamily) within the rice genome, detailing their structure, protein-conserved domains, and motif compositions for the first time. We also examined the expression patterns of these genes across 18 tissues and organs, especially the different parts of the flower (anthers, pollen, pistil, sperm cells, and egg cells). Interestingly, the expression of some AG peptides is mainly present in the pollen grain. Transcription data and GUS staining confirmed that OsAGP6P—a member of the AG peptide gene family—is expressed in the stamen during pollen development stages 11–14, which are critical for maturation as microspores form after meiosis of pollen mother cells. It became noticeable from stage 11, when exine formation occurred—specifically at stage 12, when the intine began to develop. The overexpression of this gene in rice decreased the seed-setting rate (from 91.5% to 30.5%) and plant height (by 21.9%) but increased the tillering number (by 34.1%). These results indicate that AGP6P contributes to the development and fertility of pollen, making it a valuable gene target for future genetic manipulation of plant sterility through gene overexpression or editing. Full article

Drought stress is one of the main factors limiting the high yield and quality of potatoes. Arabinogalactan proteins (AGPs) are an important class of glycoproteins widely present in the cell walls, plasma membranes, and extracellular matrices of higher plants. Among them, fasciclin-like arabinogalactan proteins (FLAs) are involved in plant development, stress responses, and hormone signal regulation. However, little is known about the FLAs gene in potatoes. Based on transcriptome sequencing data, this study screened a drought stress-related candidate FLA gene (StFLA4) through bioinformatics and expression analysis in potatoes. qRT-PCR analysis showed that StFLA4 was induced by drought stress, and its expression decreased with the extension of stress time. Moreover, the relative expression level of StFLA4 in the drought-resistant variety “Kexin 1” was lower than in the drought-sensitive variety “Atlantic”. The StFLA4 protein was located in the cell membrane and interacted with nineteen proteins, mainly related to response to environmental stimulus, cellular response to abiotic stimulus, and cell maturation. After heterologous overexpression of StFLA4 in tobacco, the transgenic plants showed more withered leaves than the wild-type tobacco under drought stress. During the drought stress period, the expression level of StFLA4 in the transgenic plants significantly decreased, and the activity of SOD and POD was significantly lower than that of WT. However, the MDA content was higher than that of WT. These results indicated that StFLA4 negatively regulates the response to drought stress. In addition, in the germination test of potato “Variety V7” tubers, it was found that the variation tendency of StFLA4 expression was along with the concentration of arabinogalactan proteins, and it may participate in the regulation of potato tuber germination. This study lays the foundation for elucidating the function and expression pattern of StFLA4 response to drought stress and tuber germination in potatoes. Full article

Crape myrtle (Lagerstroemia indica and its relatives) is an important summer-flowering plant in numerous countries worldwide. However, there are few reports on salt-tolerant (ST) crape myrtle germplasm resources and their morphological and molecular biological foundations for adaptation to salinized soil, one of the main abiotic stresses in plants. This study identified the salt tolerance characteristics of 19 crape myrtle varieties and created four salt-tolerant germplasms through hybridization. Morphological anatomy and transcriptome analyses clarified that the xylem of the ST variety possessed a high number of vessels with a small lumen. Transcriptome research has indicated that under salt stress conditions, Ca²⁺, abscisic acid (ABA), and reactive oxygen species (ROS) pathways are involved in salt stress responses. One of the candidate genes LiTIP1;1 (encoding a tonoplast intrinsic protein) was overexpressed in Arabidopsis and the resultant overexpression (OE) lines performed better under CK and 100 mmol∙L⁻¹ NaCl salt stress, but not under 200 mmol∙L⁻¹ NaCl salt stress. Corresponding to physiological traits, genes encoding tubulin and fasciclin-like arabinogalactan proteins (FLAs), which are related to the plasma membrane localization of the cellulose synthase complex, are maintained at higher levels and are induced more by salt. In summary, this research has revealed the morphological, physiological, and molecular bases of ST crape myrtle to a certain extent and has provided a theoretical basis for further screening and breeding of salt-tolerant crape myrtle varieties. Full article

Alhagi camelorum, a desert shrub known for its impressive drought tolerance, exhibits notable resilience under arid conditions. However, the underlying mechanisms driving its drought resistance remain largely unexplored. This study aims to investigate these mechanisms by exposing A. camelorum to osmotic stress using varying polyethylene glycol (PEG) concentrations (1%, 5%, 10%) in a controlled laboratory setting. Growth analysis revealed significant inhibition and phenotypic changes with increasing PEG levels. Transcriptomic analysis, including differentially expressed gene identification, GO enrichment analysis, and hierarchical cluster analysis of genes in roots and shoots, identified key pathways associated with drought adaptation, such as ABA-activated signaling, cell wall biogenesis, photosynthesis, and secondary metabolite biosynthesis. Notably, some genes involved in these pathways exhibited tissue-specific expression patterns and showed PEG concentration-dependent regulation. Key findings include the dose-dependent (R² > 0.8) upregulation of a proline-rich protein (Asp01G030840) and a BURP domain-containing protein (Asp02G039780), as well as critical genes involved in cell wall biogenesis (encoding Pectinesterase inhibitor domain-containing and Fasciclin-like arabinogalactan protein), and secondary metabolite biosynthesis (encoding enzymes for terpenoid and flavonoid biosynthesis). The regulation of these genes is likely influenced by phytohormones such as ABA and other stress-related hormones, along with significant transcription factors like ABI4, TALE, MYB61, GRAS, and ERF. These insights lay the groundwork for further research into the functional roles of these genes, their regulatory networks, and their potential applications in enhancing drought resistance in desert plants and agricultural crops. Full article

Tannins, one of the most common anti-nutritional factors in feed, can be effectively degraded by various enzymes secreted by Aspergillus tubingensis (A. tubingensis). The cultivation method of fungi significantly impacts gene expression, which influences the production of enzymes and metabolites. In this study, we analyzed the tannin biodegredation efficiency and the transcriptomic responses of A. tubingensis in liquid and solid cultures with tannin added. The observed morphology of A. tubingensis resembled typical fungal hyphae of mycelium submerged and grown in liquid cultures, while mainly spore clusters were observed in solid cultures. Furthermore, the tannin biodegredation efficiency and protein secretion of A. tubingensis in liquid cultures were significantly higher than in solid cultures. Additionally, 54.6% of the 11,248 differentially expressed genes were upregulated in liquid cultures, including AtWU_03490 (encoding ABC multidrug transporter), AtWU_03807 (ribonuclease III), AtWU_10270 (peptidyl-tRNA hydrolase), and AtWU_00075 (arabinogalactan endo-1,4-beta-galactosidase). Functional and gene ontology enrichment analyses indicated upregulation in processes including oxidation reduction, drug metabolism, and monocarboxylic acid metabolism. Overall, this study provides insight into the transcriptomic response to tannin biodegradation by A. tubingensis in different cultures and reveals that liquid cultures induce greater transcriptomic variability compared to solid cultures. Full article

Species in the genus Utricularia are carnivorous plants that prey on invertebrates using traps of leaf origin. The traps are equipped with numerous different glandular trichomes. Trichomes (quadrifids) produce digestive enzymes and absorb the products of prey digestion. The main aim of this study was to determine whether arabinogalactan proteins (AGPs) occur in the cell wall ingrowths in the quadrifid cells. Antibodies (JIM8, JIM13, JIM14, MAC207, and JIM4) that act against various groups of AGPs were used. AGP localization was determined using immunohistochemistry techniques and immunogold labeling. AGPs localized with the JIM13, JIM8, and JIM14 epitopes occurred in wall ingrowths of the pedestal cell, which may be related to the fact that AGPs regulate the formation of wall ingrowths but also, due to the patterning of the cell wall structure, affect symplastic transport. The presence of AGPs in the cell wall of terminal cells may be related to the presence of wall ingrowths, but processes also involve vesicle trafficking and membrane recycling, in which these proteins participate. Full article

The genus Utricularia (bladderworts) species are carnivorous plants that prey on invertebrates using traps with a high-speed suction mechanism. The outer trap surface is lined by dome-shaped glands responsible for secreting water in active traps. In terminal cells of these glands, the outer wall is differentiated into several layers, and even cell wall ingrowths are covered by new cell wall layers. Due to changes in the cell wall, these glands are excellent models for studying the specialization of cell walls (microdomains). The main aim of this study was to check if different cell wall layers have a different composition. Antibodies against arabinogalactan proteins (AGPs) were used, including JIM8, JIM13, JIM14, MAC207, and JIM4. The localization of the examined compounds was determined using immunohistochemistry techniques and immunogold labeling. Differences in composition were found between the primary cell wall and the cell secondary wall in terminal gland cells. The outermost layer of the cell wall of the terminal cell, which was cuticularized, was devoid of AGPs (JIM8, JIM14). In contrast, the secondary cell wall in terminal cells was rich in AGPs. AGPs localized with the JIM13, JIM8, and JIM14 epitopes occurred in wall ingrowths of pedestal cells. Our research supports the hypothesis of water secretion by the external glands. Full article

Although several therapeutic effects have been attributed to wild blackthorn fruits, their use is still negligible. Purification of the antioxidant-active fraction, obtained from wild blackthorn fruits by hot ammonium oxalate extraction (Ao), yielded seven fractions after successive elution with water, sodium chloride and sodium hydroxide solutions. The purified fractions differ in carbohydrates, proteins, and phenolics. About 60% of the applied Ao material was recovered from the column, with the highest yields eluted with 0.25 M NaCl solution, accounting for up to 70 wt% of all eluted material. Analyses have shown that two dominant fractions (3Fa and 3Fb) contain 72.8–81.1 wt% of galacturonic acids, indicating the prevalence of homogalacturonans (HG) with a low acetyl content and a high degree of esterification. The low content of rhamnose, arabinose and galactose residues in both fractions indicates the presence of RG-I associated with arabinogalactan. In terms of yield, the alkali-eluted fraction was also significant, as a dark brown-coloured material with a yield of ~15 wt% with the highest content of phenolic compounds of all fractions. However, it differs from other fractions in its powdery nature, which indicates a high content of salts that could not be removed by dialysis. Full article

Carnivorous plants can survive in poor habitats because they have the ability to attract, capture, and digest prey and absorb animal nutrients using modified organs that are equipped with glands. These glands have terminal cells with permeable cuticles. Cuticular discontinuities allow both secretion and endocytosis. In Drosophyllum lusitanicum, these emergences have glandular cells with cuticular discontinuities in the form of cuticular gaps. In this study, we determined whether these specific cuticular discontinuities were permeable enough to antibodies to show the occurrence of the cell wall polymers in the glands. Scanning transmission electron microscopy was used to show the structure of the cuticle. Fluorescence microscopy revealed the localization of the carbohydrate epitopes that are associated with the major cell wall polysaccharides and glycoproteins. We showed that Drosophyllum leaf epidermal cells have a continuous and well-developed cuticle, which helps the plant inhibit water loss and live in a dry environment. The cuticular gaps only partially allow us to study the composition of cell walls in the glands of Drosophyllum. We recoded arabinogalactan proteins, some homogalacturonans, and hemicelluloses. However, antibody penetration was only limited to the cell wall surface. The localization of the wall components in the cell wall ingrowths was missing. The use of enzymatic digestion improves the labeling of hemicelluloses in Drosophyllum glands. Full article