Plant Plasma Membrane Research Articles

Boosting the resilience to drought of crop plants using wood distillate: A pilot study with lettuce (Lactuca sativa L.)

Increasingly severe drought driven by climate change is harming crop quality and productivity, making it crucial to find nature-based solutions like wood distillate (WD) to aid crops withstand these stressful conditions. This study investigated the effects of WD application on the growth and stress responses of lettuce (Lactuca sativa L.) under drought conditions. The experiment included periodic measurements of plant growth-related parameters and stress indices to evaluate the effectiveness of WD in mitigating drought-induced damage. The results showed a significant increase (13–26 %) in fresh biomass of the aboveground portion of lettuce treated with WD, indicating the potential of WD as a biostimulant to promote plant growth. In addition, treatment with WD led to a significant increase in total soluble protein content (14–28 %), showing a possible positive effect on protein synthesis. The enhancement of anti-radical activity (measured in terms of DPPH) following the application of WD up to 42 % reflected the ability of the plant to scavenge harmful reactive oxygen species and alleviate oxidative stress. The observed reduction (up to 19 % in comparison with control) in MDA content also confirmed the effectiveness of WD in protecting the integrity of plant cell membranes from oxidative damage. Despite the beneficial effects on anti-radical activity, the total content of the antioxidant compounds (phenols and flavonoids) decreased with the use of WD (5–14 %), most likely suggesting complex interactions between WD and the biosynthesis of these secondary metabolites. The study showed the positive effect of WD application on the growth and stress tolerance of lettuce plants under drought conditions. These results can provide new insights into sustainable agricultural practices and the potential application of WD as a nature-based and effective means to improve crop productivity, especially in water scarce areas.

Diverse INOSITOL PHOSPHORYLCERAMIDE SYNTHASE mutant alleles of Physcomitrium patens offer new insight into complex sphingolipid metabolism.

Sphingolipids are widespread, abundant, and essential lipids in plants and in other eukaryotes. Glycosyl inositol phosphorylceramides (GIPCs) are the most abundant class of plant sphingolipids, and are enriched in the plasma membrane of plant cells. They have been difficult to study due to lethal or pleiotropic mutant phenotypes. To overcome this, we developed a CRISPR/Cas9-based method for generating multiple and varied knockdown and knockout populations of mutants in a given gene of interest in the model moss Physcomitrium patens. This system is uniquely convenient due to the predominantly haploid state of the Physcomitrium life cycle, and totipotency of Physcomitrium protoplasts used for transformation. We used this approach to target the INOSITOL PHOSPHORYLCERAMIDE SYNTHASE (IPCS) gene family, which catalyzes the first, committed step in the synthesis of GIPCs. We isolated knockout single mutants and knockdown higher-order mutants showing a spectrum of deficiencies in GIPC content. Remarkably, we also identified two mutant alleles accumulating inositol phosphorylceramides, the direct products of IPCS activity, and provide our best explanation for this unexpected phenotype. Our approach is broadly applicable for studying essential genes and gene families, and for obtaining unusual lesions within a gene of interest.

The mechanism behind tenuazonic acid-mediated inhibition of plant plasma membrane H+-ATPase and plant growth

The Increasing prevalence of herbicide-resistant weeds has led to a search for new herbicides that target plant growth processes differing from those targeted by current herbicides. In recent years, some studies have explored the use of natural compounds from microorganisms as potential new herbicides. We previously demonstrated that tenuazonic acid (TeA) from the phytopathogenic fungus Stemphylium loti inhibits the plant plasma membrane (PM) H+-ATPase, representing a new target for herbicides. In this study, we further investigated the mechanism by which TeA inhibits PM H+-ATPase and the effect of the toxin on plant growth using Arabidopsis thaliana. We also studied the biochemical effects of TeA on the PM H+-ATPases from spinach (Spinacia oleracea) and A. thaliana (AHA2) by examining PM H+-ATPase activity under different conditions and in different mutants. Treatment with 200 μM TeA induced cell necrosis in larger plants, and treatment with 10 μM TeA almost completely inhibited cell elongation and root growth in seedlings. We show that the isoleucine backbone of TeA is essential for inhibiting the ATPase activity of the PM H+-ATPase. Additionally, this inhibition depends on the C-terminal domain of AHA2, and TeA binding to PM H+-ATPase requires the Regulatory Region I of the C-terminal domain in AHA2. TeA likely has a higher binding affinity towards PM H+-ATPase than the phytotoxin fusicoccin. Finally, our findings show that TeA retains the H+-ATPase in an inhibited state, suggesting that it could act as a lead compound for creating new herbicides targeting the PM H+-ATPase.

Combined effect of silicon dioxide nanoparticles and plant-derived smoke solution on physiological and biochemical parameters of pea plant (Pisum sativum L.)

Nanomaterials exhibit distinctive advantages due to their characteristic size range falling within 1-100 nanometers, which can easily penetrate through plant cell membranes. The application of plant-derived smoke (PDS) solutions is also recognized for its beneficial impact on seed germination and growth of diverse plant species. In this context, in the present study, we investigated the effects of silicon dioxide nanoparticles (SiO2 NPs), PDS, and their combined application on pea seeds, and thereafter evaluated a spectrum of morphological and biochemical growth parameters. The results demonstrated that SiO2 NPs significantly enhanced pea seed germination, seedling length/weight, secondary root formation, as well as key biochemical indicators including photosynthetic pigments, total soluble sugars, and protein content. Notably, the PDS solution also exerted a significant positive influence on all growth parameters in comparison to that of SiO2 NPs. However, the combined application of SiO2 NPs and PDS exhibited superior effects on the morphological and biochemical growth characteristics as compared to their individual applications. From these findings, it can be concluded that both SiO2 NPs and PDS solutions, whether used independently or in combination, impart beneficial effects on the morphological and biochemical growth parameters of pea plants. This research highlights the potential of SiO2 NPs and PDS solutions as promising tools for enhancing plant growth and seedling development. Future studies could further explore the underlying mechanisms and optimize application methods for maximizing the beneficial effects of these materials, thus contributing to sustainable agricultural practices and improved crop yields.

The Ralstonia solanacearum effector RipV1 acts as a novel E3 ubiquitin ligase to suppress plant PAMP‐triggered immunity responses and promote susceptibility in potato

AbstractBacterial wilt caused by Ralstonia solanacearum is a destructive plant disease, particularly in potato (Solanum tuberosum). R. solanacearum deploys a diverse and potent arsenal of type III effectors to inhibit the plant immune system. However, the understanding of individual effectors promoting susceptibility in host plants and interfering with plant immunity responses is still limited. Here, we demonstrated that the type III effector RipV1 functioned as a novel E3 ubiquitin ligase (NEL) effector and exhibited E3 ubiquitin ligase activity in vitro. Transient expression of RipV1 suppressed plant pathogen‐associated molecular pattern (PAMP)‐triggered immunity (PTI) responses in Nicotiana benthamiana, such as the expression of PTI‐related genes and the reactive oxygen species (ROS) burst. Prolonged expression of RipV1 induced cell death in N. benthamiana leaves. Notably, mutating the conserved cysteine residue of RipV1 abolished its E3 ligase activity and its ability to suppress plant PTI responses. This study also revealed the indispensability of RipV1 for R. solanacearum's full virulence in potato. Transgenic potato plants overexpressing ripV1 but not the catalytic mutant ripV1‐C444A displayed enhanced susceptibility to R. solanacearum. RipV1 was observed to localize specifically to the plant plasma membrane, with its N‐terminus being pivotal in determining this localization. These findings showcase that RipV1 acts as a NEL effector and contributes to R. solanacearum virulence by suppressing plant PTI responses through its E3 activity.

Herbage accumulation, nutritive value, and fatty acid profile of bermudagrass cultivars grown in different latitudes

AbstractThe geographical distribution of bermudagrass cultivars is limited by freezing events (<0°C), commonly associated with higher latitudes in the northern hemisphere. The lipid composition in the plant cell membranes is critical to promote persistence under freezing conditions. This study evaluated herbage accumulation (HA), nutritive value, and lipid biosynthesis of different bermudagrass cultivars in Ona, FL (27°26' N 82°55' W) and Marianna, FL (30o52' N 85o11' W), in 2 years. Treatments were five bermudagrass cultivars (Coastal, Tifton 44, Tifton 85, Jiggs, and Mislevy) distributed in a randomized complete block design with four replicates. HA was greater in Marianna than in Ona for all cultivars (p < 0.05). Mislevy and Jiggs had greater HA in Marianna than the others (p < 0.05), while all cultivars were similar in Ona (p > 0.05). There was no difference between locations or among the cultivars for crude protein and neutral detergent fibre, but bermudagrass cultivars had greater in vitro digestibility of organic matter (IVDOM) in Marianna than in Ona (p < 0.05). The concentration of unsaturated fatty acids increased in the northern latitude (Marianna; p < 0.05). Coastal had greater unsaturated fatty acid concentration than other cultivars (p < 0.05). Geographical location affects HA, IVDOM, and unsaturated fatty acid concentration of bermudagrass cultivars. The unsaturated fatty acid concentration plays a key role in acclimating bermudagrass to different thermal environments. Coastal showed great potential to tolerate chilling stress in Florida. Further studies may be developed to identify promising molecular markers for cold tolerance in bermudagrass.

Targeted and Long-Term Fluorescence Imaging of Plant Cytomembranes Using Main-Chain Charged Polyelectrolytes with Aggregation-Induced Emission.

Fluorescent polyelectrolytes have attracted tremendous attention due to their unique properties and wide applications. However, current research objects of fluorescent polyelectrolytes mainly focus on side-chain charged polyelectrolytes, and the applications of polyelectrolytes in plant cytomembrane imaging with long time and high specificity still remain challenging. Herein, long-time and targeted fluorescence imaging of plant cytomembranes was achieved for the first time using main-chain charged polyelectrolytes (MCCPs) with aggregation-induced emission (AIE). A series of MCCPs were designed and synthesized, among which the red-emissive and AIE-active MCCP with a triphenylamine linker and a cyano group around the cationic ring-fused heterocyclic core showed the best fluorescence imaging performance of plant cells. Unlike other MCCPs and its neutral form of polymer, this cyano-substituted conjugated polyelectrolyte can specifically target the cytomembrane of plant cells within a short staining time with many advantages, including wash-free staining, high photostability and imaging integrity, excellent durability (at least 12 h), and low biotoxicity. In addition to onion epidermal cells, this AIE fluorescence probe also shows good imaging capabilities for other kinds of plant cells such as Glycine max and Vigna radiata. Such an AIE-active MCCP-based imaging system provides an effective design strategy to develop fluorescence probes with high specificity and long-term imaging ability toward plant plasma membranes.

Identification of the toxin components of Rhizoctonia solani AG1-IA and its destructive effect on plant cell membrane structure.

Rice sheath blight is a fungal disease caused mainly by Rhizoctonia solani AG1-IA. Toxins are a major pathogenic factor of R. solani, and some studies have reported their toxin components; however, there is no unified conclusion. In this study, we reported the toxin components and their targets that play a role in R. solani AG1-IA. First, toxins produced by R. solani AG1-IA were examined. Several important phytotoxins, including benzoic acid (BZA), 5-hydroxymethyl-2-furanic aid (HFA), and catechol (CAT), were identified by comparative analysis of secondary metabolites from AG1-IA, AG1-IB, and healthy rice. Follow-up studies have shown that the toxin components of this fungus can rapidly disintegrate the biofilm structure while maintaining the content of host plant membrane components, thereby affecting the organelles, which may also explain the lack of varieties highly resistant to sheath blight.

Assessment of the oxidative stress intensity and the integrity of cell membranes under the manganese nanoparticles toxicity in wheat seedlings

A response to manganese nanoparticles was studied in seedlings of two wheat cultivars and a model system of plant cell membranes. Nanoparticles at concentrations of 125 and 250 mg/ml were applied foliar. The application of NPs enhanced the content of Mn in plant cells, indicating its penetration through the leaf surface. The stressful effect in the plant cells was estimated based on changes in the activity of antioxidant enzymes, content of chlorophylls and starch. MnNPs evoked no significant changes in the leaf morphology, however, an increase in enzyme activity, starch accumulation, and a decrease in chlorophyll synthesis indicated the stress occurrence. Moreover, a rise in the electrokinetic potential of the chloroplast membrane surface and the reconstruction of their hydrophobic parts toward an increase in fatty acid saturation was found.

Phosphoregulation of the yeast Pma1 H+-ATPase autoinhibitory domain involves the Ptk1/2 kinases and the Glc7 PP1 phosphatase and is under TORC1 control.

Plasma membrane (PM) H+-ATPases of the P-type family are highly conserved in yeast, other fungi, and plants. Their main role is to establish an H+ gradient driving active transport of small ions and metabolites across the PM and providing the main component of the PM potential. Furthermore, in both yeast and plant cells, conditions have been described under which active H+-ATPases promote activation of TORC1, the rapamycin-sensitive kinase complex controlling cell growth. Fungal and plant PM H+-ATPases are self-inhibited by their respective cytosolic carboxyterminal tails unless this domain is phosphorylated at specific residues. In the yeast H+-ATPase Pma1, neutralization of this autoinhibitory domain depends mostly on phosphorylation of the adjacent Ser911 and Thr912 residues, but the kinase(s) and phosphatase(s) controlling this tandem phosphorylation remain unknown. In this study, we show that S911-T912 phosphorylation in Pma1 is mediated by the largely redundant Ptk1 and Ptk2 kinase paralogs. Dephosphorylation of S911-T912, as occurs under glucose starvation, is dependent on the Glc7 PP1 phosphatase. Furthermore, proper S911-T912 phosphorylation in Pma1 is required for optimal TORC1 activation upon H+ influx coupled amino-acid uptake. We finally show that TORC1 controls S911-T912 phosphorylation in a manner suggesting that activated TORC1 promotes feedback inhibition of Pma1. Our results shed important new light on phosphoregulation of the yeast Pma1 H+-ATPase and on its interconnections with TORC1.

Intact cell lipidomics using the Bruker MBT lipid Xtract assay allows the rapid detection of glycosyl-inositol-phospho-ceramides from Aspergillus fumigatus.

Glycosyl-inositol-phospho-ceramides (GIPCs) or glycosylphosphatidylinositol-anchored fungal polysaccharides are major lipids in plant and fungal plasma membranes and play an important role in stress adaption. However, their analysis remains challenging due to the multiple steps involved in their extraction and purification prior to mass spectrometry analysis. To address this challenge, we report here a novel simplified method to identify GIPCs from Aspergillus fumigatus using the new Bruker MBT lipid Xtract assay. A. fumigatus reference strains and clinical isolates were cultured, harvested, heat-inactivated and suspended in double-distilled water. A fraction of this fungal preparation was then dried in a microtube, mixed with an MBT lipid Xtract matrix (Bruker Daltonik, Germany) and loaded onto a MALDI target plate. Analysis was performed using a Bruker MALDI Biotyper Sirius system in the linear negative ion mode. Mass spectra were scanned from m/z 700 to m/z 2 000. MALDI-TOF MS analysis of cultured fungi showed a clear signature of GIPCs in Aspergillus fumigatus reference strains and clinical isolates. Here, we have demonstrated that routine MALDI-TOF in the linear negative ion mode combined with the MBT lipid Xtract is able to detect Aspergillus fumigatus GIPCs.

Identification of Aly1 and Aly2 as Modulators of Cytoplasmic pH in Saccharomyces cerevisiae.

The regulation of intracellular pH in yeast (Saccharomyces cerevisiae) cells is critical for cell function and viability. In yeast, protons (H+) can be excreted from the cell by plasma membrane ATPase PMA1 and pumped into vacuoles by vacuolar H+-ATPase. Because PMA1 is critical to the survival of yeast cells, it is unknown whether other compensatory components are involved in pH homeostasis in the absence of PMA1. To elucidate how intracellular pH is regulated independently of PMA1, we employed a screening approach by exposing the yeast haploid deletion mutant library (ver 4.0) to the selective plant plasma membrane H+-ATPase inhibitor PS-1, which we previously reported. After repeated screenings and verification, we identified two proteins, Aly1 and Aly2, that play a role in the regulation of intracellular pH when PMA1 is deficient. Our research uncovers a new perspective on the regulation of intracellular pH related to PMA1 and also preliminarily reveals a role for Aly1 and Aly2 in the regulation of intracellular pH.

The Role of Chloride Channels in Plant Responses to NaCl.

Chloride (Cl-) is considered a crucial nutrient for plant growth, but it can be a challenge under saline conditions. Excessive accumulation of Cl- in leaves can cause toxicity. Chloride channels (CLCs) are expressed in the inner membranes of plant cells and function as essential Cl- exchangers or channels. In response to salt stress in plants, CLCs play a crucial role, and CLC proteins assist in maintaining the intracellular Cl- homeostasis by sequestering Cl- into vacuoles. Sodium chloride (NaCl) is the primary substance responsible for causing salt-induced phytotoxicity. However, research on plant responses to Cl- stress is comparatively rare, in contrast to that emphasizing Na+. This review provides a comprehensive overview of the plant response and tolerance to Cl- stress, specifically focusing on comparative analysis of CLC protein structures in different species. Additionally, to further gain insights into the underlying mechanisms, the study summarizes the identified CLC genes that respond to salt stress. This review provides a comprehensive overview of the response of CLCs in terrestrial plants to salt stress and their biological functions, aiming to gain further insights into the mechanisms underlying the response of CLCs in plants to salt stress.

γ irradiation mediated the inhibitory effect of Ca2+ signals on softening of blueberry fruit during cold storage

Postharvest blueberries tend to soften and rot, resulting in serious fruit waste. Gamma (γ) irradiation can delay the softening of blueberries and improve fruit quality. Calcium is a structural component of plant cell wall and membrane, and plays a role as a second messenger in the physiological process of fruit. To explore the mechanism of inhibiting the softening of cold storage blueberry fruit by γ irradiation, ‘Bluecrop’ blueberry fruit were treated by γ irradiation at a dose of 2.5 kGy, and then combined with calcium ion (Ca2+) inhibitors and intracellular calmodulin antagonists. The Ca2+ fluorescence signals, fruit firmness, protopectin and different soluble pectin contents, cellulose and hemicellulose contents, and hydrolase activities were detected. Results showed that irradiation induced Ca2+ release from intracellular calcium store to generate fluorescence signals. Irradiation mediated the Ca2+ signals to exert a positive effect on fruit firmness of blueberries during cold storage, for the degradation of protopectin and chelator-soluble pectin to water-soluble pectin was reduced by inhibiting activities of polygalacturonase and pectin methylesterase. Therefore, γ irradiation-induced Ca2+ signals played an important role in regulation of pectin-involved fruit softening in blueberries during cold storage. This study provides a theoretical basis for the mechanism of Ca2+ signaling in blueberry storage.

Light-gated channelrhodopsin sparks proton-induced calcium release in guard cells.

Although there has been long-standing recognition that stimuli-induced cytosolic pH alterations coincide with changes in calcium ion (Ca2+) levels, the interdependence between protons (H+) and Ca2+ remains poorly understood. We addressed this topic using the light-gated channelrhodopsin HcKCR2 from the pseudofungus Hyphochytrium catenoides, which operates as a H+ conductive, Ca2+ impermeable ion channel on the plasma membrane of plant cells. Light activation of HcKCR2 in Arabidopsis guard cells evokes a transient cytoplasmic acidification that sparks Ca2+ release from the endoplasmic reticulum. A H+-induced cytosolic Ca2+ signal results in membrane depolarization through the activation of Ca2+-dependent SLAC1/SLAH3 anion channels, which enabled us to remotely control stomatal movement. Our study suggests a H+-induced Ca2+ release mechanism in plant cells and establishes HcKCR2 as a tool to dissect the molecular basis of plant intracellular pH and Ca2+ signaling.

In-silico identification and characterization of sucrose transporter genes and their differential expression pattern under salinity stress in Glycine max

Plant sucrose transporters, involved in sugar transport, are key in facilitating sugar flux across the plant cell membranes. However, external stress stimuli significantly impact these sucrose transporters (SWEET/MST/SUT) and, ultimately, the distribution of photosynthates. This has importance as sucrose is a prime energy source, a signaling molecule, and an osmolyte playing a key role in growth and development processes. This study aims to identify and comprehensive in silico characterization and involvement of soybean sucrose transporters GlymaSWEET, GlymaMST, and GlymaSUT in plant development and salt stress responses in an important oilseed crop soybean (Glycine max L.). A genome-wide screening of soybean revealed 13 GlymaSWEET, 6 GlymaMST, and 5 GlymaSUT orthologues as confirmed from the eggNOG database. Probable sites of these proteins were found to be the membranes of cells and organelles, as suggested by their sub-cellular localization. The cis-regulatory elements of these transporters’ promoters indicated their involvement in environmental stress responses. MicroRNA interactions with these transporters were also studied, besides 3-D protein structure prediction using in silico approaches. To gain an insight into the functional divergence of GlymaSWEET, GlymaMST, and GlymaSUT transporters, qRT-PCR-based gene expression analysis was done both in control and salt-treated root and leaf tissues of two contrasting Indian soybean varieties MAUS-47 (salt-tolerant) and Gujosoya-2 (salt-sensitive). Differential gene expression was observed with varying degrees amongst the varieties and the treatments. Overall, we can conclude that the identified GlymaSWEET, GlymaMST, and GlymaSUT have the potential to be explored as candidate genes for engineering salinity stress tolerance in soybean and other plants.

Effects of D128N Mutation on OsSERK2 in Xa21-Mediated Immune Complex: An In Silico Study

Receptor-like kinases (RLKs) are plant proteins that form signaling circuits to transduce information through the plant cell membrane to the nucleus and activate processes that direct growth, development, stress response, and disease resistance. Upon sensing various environmental stress stimuli, RLKs interact with specific targets and recruit several other proteins to initiate the defense mechanism. Among many RLK subfamilies, leucine-rich repeat RLKs (LRR-RLKs) are the largest. Xa21, a member of LRR-RLK, is a vital receptor protein in rice plants that binds with bacterial RaxX21-sY, whereas OsSERK2 is a somatic embryogenic receptor kinase (SERK) that acts as a coreceptor in this process. This study focuses on the effect of a substitution mutation of aspartate128 with asparagine128 (D128N) in OsSERK2 on the interdependent binding pattern of the Xa21, RaxX21-sY, and OsSERK2 D128N proteins. The in silico results showed that the D128N mutation in OsSERK2 can significantly change the interaction pattern of the critical residues of the OsSERK2 and affects its receptor-ligand (Xa21-RaxX21-sY) interaction in the complex. These findings are expected to significantly contribute to the study of the structural basis of Xa21-mediated immunity and the first layer of plant defense mechanisms, thereby aiding further research on these structures and their phenotypic implications.

Integrated proteomic analysis reveals interactions between phosphorylation and ubiquitination in rose response to Botrytis infection.

As two of the most abundant post-translational modifications, phosphorylation and ubiquitination play a significant role in modulating plant-pathogen interactions and increasing evidence indicates their crosstalk in plant immunity. Rose (Rosa sp.) is one of the most important ornamental plants and can be seriously infected by Botrytis cinerea. Here, integrated proteomics analysis was performed to detect global proteome, phosphorylation, and ubiquitination changes in rose upon B. cinerea infection and investigate the possible phosphorylation and ubiquitination crosstalk. A total of 6165 proteins, 11 774 phosphorylation and 10 582 ubiquitination sites, and 77 phosphorylation and 13 ubiquitination motifs were identified. Botrytis cinerea infection resulted in 169 up-regulated and 122 down-regulated proteins, 291 up-regulated and 404 down-regulated phosphorylation sites, and 250 up-regulated and 634 down-regulated ubiquitination sites. There were 12 up-regulated PR10 proteins and half of them also showed reduced ubiquitination. A lot of kinases probably involved in plant pattern-triggered immunity signaling were up-regulated phosphoproteins. Noticeably, numerous kinases and ubiquitination-related proteins also showed a significant change in ubiquitination and phosphorylation, respectively. A cross-comparison of phosphoproteome and ubiquitylome indicated that both of two post-translational modifications of 104 proteins were dynamically regulated, and many putative pattern-triggered immunity signaling components in the plant plasma membrane were co-regulated. Moreover, five selected proteins, including four PR10 proteins and a plasma membrane aquaporin, were proven to be involved in rose resistance to B. cinerea. Our study provides insights into the molecular mechanisms underlying rose resistance to B. cinerea and also increases the database of phosphorylation and ubiquitination sites in plants.

Anticancer activity and other biomedical properties of β-sitosterol: Bridging phytochemistry and current pharmacological evidence for future translational approaches.

Sterols, including β-sitosterol, are essential components of cellular membranes in both plant and animal cells. Despite being a major phytosterol in various plant materials, comprehensive scientific knowledge regarding the properties of β-sitosterol and its potential applications is essential for scholarly pursuits and utilization purposes. β-sitosterol shares similar chemical characteristics with cholesterol and exhibits several pharmacological activities without major toxicity. This study aims to bridge the gap between phytochemistry and current pharmacological evidence of β-sitosterol, focusing on its anticancer activity and other biomedical properties. The goal is to provide a comprehensive understanding of β-sitosterol's potential for future translational approaches. A thorough examination of the literature was conducted to gather relevant information on the biological properties of β-sitosterol, particularly its anticancer therapeutic potential. Various databases were searched, including PubMed/MedLine, Scopus, Google Scholar, and Web of Science using appropriate keywords. Studies investigating the effects of β-sitosterol on different types of cancer were analyzed, focusing on mechanisms of action, pharmacological screening, and chemosensitizing properties. Modern pharmacological screening studies have revealed the potential anticancer therapeutic properties of β-sitosterol against various types of cancer, including leukemia, lung, stomach, breast, colon, ovarian, and prostate cancer. β-sitosterol has demonstrated chemosensitizing effects on cancer cells, interfering with multiple cell signaling pathways involved in proliferation, cell cycle arrest, apoptosis, survival, metastasis invasion, angiogenesis, and inflammation. Structural derivatives of β-sitosterol have also shown anti-cancer effects. However, research in the field of drug delivery and the detailed mode of action of β-sitosterol-mediated anticancer activities remains limited. β-sitosterol, as a non-toxic compound with significant pharmacological potential, exhibits promising anticancer effects against various cancer types. Despite being relatively less potent than conventional cancer chemotherapeutics, β-sitosterol holds potential as a safe and effective nutraceutical against cancer. Further comprehensive studies are recommended to explore the biological properties of β-sitosterol, including its mode of action, and develop novel formulations for its potential use in cancer treatment. This review provides a foundation for future investigations and highlights the need for further research on β-sitosterol as a potent superfood in combating cancer.

Persistent free radicals generated from a range of biochars and their physiological effects on wheat seedlings

Biochar is a promising soil conditioner and environmental remediation material. However, the amount, type, and environmental effect and risk of persistent free radicals (PFRs) associated with biochar need to be better understood. Thus, this study characterized PFRs in a range of biochar types and their effects on the growth and oxidative stress of wheat seedlings. Among the biochars prepared by pyrolysis of different types of biomass at 500 °C, the concentrations of PFRs in cow dung and egg shell biochar were the highest and the lowest, respectively. They both increased with artificial weathering treatment but decreased with aging. The dominant types of biochar PFRs were transformed from carbon-centered to oxygen and carbon/oxygen-centered free radicals with weathering. The amount and type of biochar PFRs in mixtures of biochar and soil varied with soil type and biochar dose. After 30 d incubation in different soil-biochar mixtures, measures of wheat plant germination and growth and antioxidant enzyme activity showed increases at lower biochar doses but decreases at higher doses. Catalase activity was 38.1 % greater at 20 g·kg−1 biochar dosage and 25.2 % less at 80 g·kg−1 dosage, on average. In contrast, leaf malondialdehyde content and staining by Evans Blue, both indicators of plant cell membrane damage, generally increased with increasing biochar dosages. Finally, soil hydrolase enzyme activity also displayed an inverted U-shaped dose response. The toxicity indicators showed an increasing trend with higher PFR concentrations in the soil-biochar combinations. While these findings provide evidence for significant potential agricultural and ecological risks associated with the application of biochar due to PFRs damage, it also points to ways that these risks could be mediated such as through biochar dosage restrictions and pre-aging. This study provides new insights into the potential toxicological mechanism and ecological risks associated with the application of biochar in agricultural and environmental settings.