Physiological Analysis Research Articles

Rehmannia glutinosa RgMATE35 Participates in the Root Secretion of Phenolic Acids and Modulates the Development of Plant Replant Disease

Phenolic allelochemicals from root exudates dominate rhizosphere formation, lead to autotoxicity in plants subjected to continuous monoculture (CM) stress and induce the emergence of replant disease. However, the regulatory mechanisms governing the transport of phenolics from plant roots to the rhizosphere remain poorly understood. A potential phenolic efflux transporter from Rehmannia glutinosa, designated RgMATE35, has been preliminarily characterized. The objective of this study was to elucidate the molecular function of RgMATE35 in the secretion of phenolics and to investigate its role in the development of plant replant disease using quantitative real-time PCR (qRT-PCR), genetic transformation, HPLC-Q-TOF-MS and other analytical techniques. A tissue expression pattern analysis of RgMATE35 revealed that it is highly expressed in plant roots. Transient expression analysis confirmed the localization of the protein in plasma membranes. An assessment of the transport activity of RgMATE35 in Xenopus oocytes indicated that it plays a role in facilitating the efflux of labeled ferulic acid ([2H3]-FA) and trans-p-coumaric acid [2H6]-pCA. The results of functional studies in R. glutinosa demonstrated that RgMATE35 positively mediates the secretion of FA and pCA from plant roots into the rhizosphere. A molecular and physiological analysis of RgMATE35 transgenic plants subjected to CM stress revealed that the overexpression or repression of RgMATE35 resulted in notable changes in the degree of autotoxic injury in plants. These findings demonstrate that RgMATE35 plays a positive role in the development of replant disease through the secretion of phenolic acids from plant roots. They also provide a fundamental framework for elucidating the molecular regulatory mechanism through which MATEs regulate replant disease through the root secretion of allelochemicals.

Photosynthetic characteristics and genetic mapping of a yellow-green leaf mutant jym165 in soybean

BackgroundLeaves are important sites for photosynthesis and can convert inorganic substances into organic matter. Photosynthetic performance is an important factor affecting crop yield. Leaf colour is closely related to photosynthesis, and leaf colour mutants are considered an ideal material for studying photosynthesis.ResultsWe obtained a yellow-green leaf mutant jym165, using ethyl methane sulfonate (EMS) mutagenesis. Physiological and biochemical analyses indicated that the contents of chlorophyll a, chlorophyll b, carotenoids, and total chlorophyll in the jym165 mutant decreased significantly compared with those in Jiyu47 (JY47). The abnormal chloroplast development of jym165 led to a decrease in net photosynthetic rate and starch content compared with that of JY47. However, quality traits analysis showed that the sum of oil and protein contents in jym165 was higher than that in JY47. In addition, the regional yield (seed spacing: 5 cm) of jym165 increased by 2.42% compared with that of JY47 under high planting density. Comparative transcriptome analysis showed that the yellow-green leaf phenotype was closely related to photosynthesis and starch and sugar metabolism pathways. Genetic analysis suggests that the yellow-green leaf phenotype is controlled by a single recessive nuclear gene. Using Mutmap sequencing, the candidate regions related of leaf colour was narrowed to 3.44 Mb on Chr 10.ConclusionsAbnormal chloroplast development in yellow-green mutants leads to a decrease in the photosynthetic pigment content and net photosynthetic rate, which affects the soybean photosynthesis pathway and starch and sugar metabolism pathways. Moreover, it has the potentiality to increase soybean yield under dense planting conditions. This study provides a useful reference for studying the molecular mechanisms underlying photosynthesis in soybean.

Impact of Sublethal Insecticides Exposure on Vespa magnifica: Insights from Physiological and Transcriptomic Analyses

Insecticides are widely used to boost crop yields, but their effects on non-target insects like Vespa magnifica are still poorly understood. Despite its ecological and economic significance, Vespa magnifica has been largely neglected in risk assessments. This study employed physiological, biochemical, and transcriptomic analyses to investigate the impact of sublethal concentrations of thiamethoxam, avermectin, chlorfenapyr, and β-cypermethrin on Vespa magnifica. Although larval survival rates remained unchanged, both pupation and fledge rates were significantly reduced. Enzymatic assays indicated an upregulation of superoxide dismutase and catalase activity alongside a suppression of peroxidase under insecticide stress. Transcriptomic analysis revealed increased adenosine triphosphate-related processes and mitochondrial electron transport activity, suggesting elevated energy expenditure to counter insecticide exposure, potentially impairing essential functions like flight, hunting, and immune response. The enrichment of pathways such as glycolysis, hypoxia-inducible factor signaling, and cholinergic synaptic metabolism under insecticide stress highlights the complexity of the molecular response with notable effects on learning, memory, and detoxification processes. These findings underscore the broader ecological risks of insecticide exposure to non-target insects and highlight the need for further research into the long-term effects of newer insecticides along with the development of strategies to safeguard beneficial insect populations.

Mechanism of Exogenous Jasmonic Acid-Induced Resistance to Thrips palmi in Hemerocallis citrina Baroni Revealed by Combined Physiological, Biochemical and Transcriptomic Analyses

Jasmonic acid (JA) is a regulator of plant resistance to phytophagous insects, and exogenous JA treatment induces plant insect resistance. This study investigated the mechanism of exogenous JA-induced resistance of Hemerocallis citrina Baroni (daylily) to Thrips palmi at the biochemical and molecular levels. Daylily leaves sprayed with JA showed significantly higher levels of secondary metabolites—tannins, flavonoids, and total phenols, and activity of defense enzymes—peroxidase, phenylalanine ammonia lyase, polyphenol oxidase, and protease inhibitor (PI) than control leaves; the most significant effects were observed with 1 mmol L−1 JA. Owing to an improved defense system, significantly fewer T. palmi were present on the JA-treated plants than control plants. The JA-treated leaves had a smoother wax layer and fewer stomata, which was unfavorable for insect egg attachment. The differentially expressed genes (DEGs) were significantly enriched in insect resistance pathways such as lignin and wax biosynthesis, cell wall thickening, antioxidant enzyme synthesis, PI synthesis, secondary metabolite synthesis, and defense hormone signaling. A total of 466 DEGs were predicted to be transcription factors, mainly bHLH and WRKY family members. Weighted gene co-expression network analysis identified 13 key genes; TRINITY_DN16412_c0_g1 and TRINITY_DN6953_c0_g1 are associated with stomatal regulation and lipid barrier polymer synthesis, TRINITY_DN7582_c0_g1 and TRINITY_DN11770_c0_g1 regulate alkaloid synthesis, and TRINITY_DN7597_c1_g3 and TRINITY_DN1899_c0_g1 regulate salicylic acid and ethylene biosynthesis. These results indicate that JA treatment of daylily improved its resistance to T. palmi. These findings provide a scientific basis for the utilization of JA as an antagonist to control T. palmi in daylily.

Biomarker and adverse outcome pathway responses of Tubifex tubifex(sludge worm) exposed to environmentally-relevant levels of acenaphthene: insights from behavioral, physiological, and chemical structure-activity analyses.

Polycyclic aromatic hydrocarbons (PAHs), including acenaphthene, pose a significant threat to aquatic ecosystems by harming vital organisms such as benthic invertebrates. This study evaluated the impact of environmentally relevant concentrations of acenaphthene on Tubifex tubifex, focusing on sublethal acute toxicity and subchronic biomarker responses. Key biomarkers assessed included histopathological changes and the modulation of antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), and malondialdehyde (MDA). Additionally, the study examined structure-activity relationships and species sensitivity distribution (SSD). Concentrations exceeding the solubility threshold of acenaphthene (3.9 mg/L) triggered distinct, concentration-dependent behavioral responses in Tubifex tubifex, such as clumping, mucus secretion, and body wrinkling. Prolonged exposure exacerbated these behavioral dysfunctions, while subchronic exposure resulted in significant histopathological alterations, including epithelial hyperplasia, inflammation, edema, fibrosis, and degenerative changes. The edematic appearance of the body wall suggested a potential immune response to exposure. Furthermore, increased activities of CAT, SOD, and GST indicated oxidative stress in the worms. The study found a 1.5-fold increase in CAT and GST activity, a fivefold increase in SOD, and a striking 100-fold increase in MDA levels compared to controls, signifying an overwhelmed antioxidant defense system and potential cellular disruption. The SSD curve revealed hazard concentrations (HC50 and HC90), indicating that Tubifex tubifex exhibited lower sensitivity to acenaphthene compared to other taxa. In silico analysis and read-across models confirmed the potential of acenaphthene to induce significant oxidative stress upon exposure. The correlation between biomarker responses and structure-activity relationship analysis highlighted the aromatic nature of acenaphthene as a key factor in generating reactive metabolites, inhibiting antioxidant enzymes, and promoting redox cycling, ultimately contributing to adverse outcomes. These findings, coupled with behavioral responses and SSD curve inferences, underscore the importance of the solubility threshold of acenaphthene as a critical benchmark for evaluating its ecological impact in aquatic environments.

Physiological and transcriptomic analysis reveals the coating of microcapsules embedded with bacteria can enhance wheat salt tolerance

Salt stress is one of the most important abiotic stress factors limiting crop production. Therefore, improving the stress resistance of seeds is very important for crop growth. Our previous studies have shown that using microcapsules encapsulating bacteria (Pontibacter actiniarum DSM 19842) as seed coating for wheat can alleviate salt stress. In this study, the genes and pathways involved in the response of wheat to salt stress were researched further. The results showed that compared with the control, the coating can improve osmotic stress and decrease oxidative damage by increasing the content of proline (29.1%), the activity of superoxide dismutase (SOD) (94.2%), peroxidase (POD) (45.7%) and catalase (CAT) (3.3%), reducing the content of hydrogen peroxide (H2O2) (39.8%) and malondialdehyde (MDA) (45.9%). In addition, ribonucleic acid (RNA) sequencing data showed that 7628 differentially expressed genes (DEGs) were identified, and 4426 DEGs up-regulated, 3202 down-regulated in the coated treatment. Many DEGs related to antioxidant enzymes were up-regulated, indicating that coating can promote the expression of antioxidant enzyme-related genes and alleviate oxidative damage under salt stress. The differential gene expression analysis demonstrated up-regulation of 27 genes and down-regulation of 20 genes. Transcription factor families, mostly belonging to bHLH, MYB, B3, NAC, and WRKY. Overall, this seed coating can promote the development of sustainable agriculture in saline soil.

Identification of Key Enzymes and Genes Modulating L-Ascorbic Acid Metabolism During Fruit Development of Lycium chinense by Integrating Metabolome, Transcriptome, and Physiological Analysis

Lycium chinense is acknowledged for its substantial nutritional benefits, particularly attributed to the high levels of ascorbic acid (AsA) found in its fruits. The “Mengqi No.1” variety of L. chinense, which is cultivated in Qinghai, is known for its high yield and exceptional quality. We utilized the “Mengqi No.1” variety as experimental materials and combined metabolomic, transcriptomic, and physiological analyses to investigate the metabolites, genes, and enzymes related to AsA metabolism in L. chinense fruits. The results revealed nine differential metabolites associated with AsA metabolism in L. chinense fruits across three stages, including 1D-Myo-Inositol-1,4-Bisphosphate, D-Fructose, L-(+)-Arabinose, I-Inositol, L-Arabinitol, D-Galactose-1-P, lactose, α-D-Glucose, and D-Glucose-6-P. Notably, the contents of D-Glucose-6-P, D-Galactose-1-P, and D-Fructose were increased as the fruit developed. Additionally, fresh weight, longitudinal length, and radial width were increased, while the contents of AsA and DHA were decreased. GalDH and DHAR are critical enzymes for the accumulation of AsA and DHA, exhibiting positive correlation coefficient. Furthermore, PMM1, PMM5, GME2, and GME3 were identified as key regulatory genes in the L-Galactose pathway of AsA synthesis, influencing D-Galactose-1-P, D-Glucose-6-P, α-D-Glucose, and D-Fructose. DHAR1 and DHAR2 are considered key positive regulator genes of AsA and DHA in the AsA-GSH cycle. However, the majority of genes (nine) act as negative regulators of AsA and DHA. These findings provide a foundation for the understanding of the regulatory mechanism of AsA metabolism in L. chinense fruits and offer insights into the utilization of AsA from L. chinense.

A Physiological Analysis of Desiccation Stress in the Green Tide Species Ulva stenophylloides and Ulva uncialis in the South Pacific

Global green tide blooms of the Ulva genus have been increasing due to human activities, with mass accumulation in Algarrobo Bay, Chile, causing ecological and social issues. In this area, five Ulva species were previously identified, with Ulva stenophylloides dominating across seasons and intertidal zones; Ulva uncialis was the second most abundant, mainly in winter. In this study, we tested the hypothesis that U. stenophylloides is more tolerant to desiccation than U. uncialis, explaining its dominance in the upper intertidal zone. Based on in vitro cultures, we assessed the impact of desiccation stress on weight, blade length, cellular activity, and lipoperoxide levels. In U. uncialis, desiccation treatment caused a decrease in weight; conversely, in U. stenophylloides, both control and desiccation treatments caused a slight decrease in weight. No significant differences (p > 0.05) in blade length or lipoperoxide levels as a function of culture time were detected in the control and desiccation treatment groups for both species. Furthermore, desiccation had no negative effects on the cellular activity of either species. Although the observed weight changes suggest that U. uncialis is more desiccation-tolerant than U. stenophylloides under the experimental conditions, the cellular activity and lipoperoxidation indicate high desiccation tolerance in both species, which partly explains their intertidal dominance.

Integration of transcriptomics, gut microbiota, and physiology reveals the toxic response of bensulfuron-methyl in Procambarus clarkii

Bensulfuron-methyl (BSM) enters the environment through agricultural practices, posing a threat to the health of aquatic organisms. Currently, the toxic mechanisms of BSM on crayfish (Procambarus clarkii) have not been thoroughly investigated. In this study, crayfish were exposed to BSM solutions at concentrations of 0, 5, and 10 mg/L for 48 h. The study integrated physiological, gut microbiota, and transcriptomic analyses to investigate the mechanisms of action. BSM exposure induced oxidative stress responses in crayfish, resulting in changes in superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GSH) activity, and malondialdehyde (MDA) levels. Exposure to BSM caused damage to the intestinal tissues, reduced gut microbiota diversity, increased the abundance of harmful bacteria, and led to intestinal dysfunction. Analysis of the hepatopancreas revealed significant tissue damage. Transcriptomic data indicated that BSM affects the growth of crayfish through genes related to immune response (SLC17A5, CTSD, CTSB, NFKBIA, Mincle). The lysosomal pathway and NF-κB pathway were notably affected. This study analyzed the negative impacts of BSM on crayfish from various levels and provided detailed data to enhance our understanding of the toxic mechanisms of BSM in aquatic organisms.

A Comprehensive Assessment of Nutritional Value, Antioxidant Potential, and Genetic Diversity in Metapenaeus ensis from Three Different Populations.

Due to its high tolerance to salinity and temperature, as well as its strong adaptability, Metapenaeus ensis holds an important position in the Chinese aquaculture industry. However, studies on the evaluation of its germplasm resources remain insufficient. This research conducted an in-depth comparative evaluation of M. ensis from three representative farming regions in China: Sanya, Zhuhai, and Raoping. The nutritional analysis of muscle tissue showed no statistically significant differences in crude ash, moisture, and crude protein content among the populations (p > 0.05). However, significant differences were observed in crude fat and total sugar content (p < 0.05). The MeSY and MeRP populations had higher crude fat content than the MeZH population (p < 0.05), while the MeZH population exhibited the highest total sugar content. In terms of amino acid composition, the MeSY population had relatively higher total essential amino acid content and proportion, as well as higher total amino acid content, both of which were statistically significant (p < 0.05). A fatty acid composition analysis further highlighted the advantages of the MeRP population in several key fatty acids (p < 0.05). Physiological and biochemical analyses showed no significant differences among the three populations in total antioxidant capacity, superoxide dismutase activity, or catalase activity (p > 0.05). A genetic diversity analysis indicated that M. ensis has relatively low diversity, with the MeSY population showing higher SNP density and nucleotide diversity. A genetic differentiation analysis revealed significant genetic differentiation between the MeSY and MeZH populations, while differentiation between the MeZH and MeRP populations was relatively smaller. This comprehensive assessment of nutritional components, amino acids, fatty acids, antioxidant capacity, and genetic diversity highlights the advantages of germplasm resources from different regions. These findings provide valuable insights for future research on the genetic characteristics and breeding potential of M. ensis.

Drought tolerance and recovery capacity of two ornamental shrubs: Combining physiological and biochemical analyses with online leaf water status monitoring for the application in urban settings

When plants are transferred from nursery to urban environments, they often face drought stress due to inadequate maintenance, such as insufficient irrigation. Using drought tolerant species may help mitigate the adverse impact of drought stress in urban settings. Additionally, utilizing novel technologies for water status monitoring may help optimize irrigation schedules to prevent transplanting failures. This study investigated the physiological and biochemical responses of two ornamental shrubs, Photinia x fraseri and Viburnum tinus, subjected to water stress of increasing severity and rewatering. Water relations, gas exchanges, chlorophyll fluorescence and biochemical analyses were conducted alongside real-time monitoring of water status using leaf-water-meter sensors (LWM).The progression of water stress had a notable negative impact on leaf gas exchanges and water relations in both species. Notably, P. fraseri avoided photoinhibition by reducing chlorophyll content and actual efficiency of PSII. Adjustments in leaf phenolic compounds played a significant role in enhancing drought tolerance of both species due to their antioxidant and photoprotective properties.Upon rewatering, both species exhibited complete recovery in their physiological functions, underscoring their remarkable tolerance and resilience to drought stress. Additionally, LWM sensors efficiently tracked the dehydration levels, exhibiting a rising trend during the water stress progression and a subsequent decline after rewatering for both species. These findings confirm the reliability of LWM sensors in monitoring physiological status of plants in outdoor contexts, making them a suitable tool for use in urban settings.

Ferroptosis-Mediated Inflammation Promotes Pulmonary Hypertension.

Mitochondrial dysfunction, characterized by impaired lipid metabolism and heightened reactive oxygen species generation, results in lipid peroxidation and ferroptosis. Ferroptosis is an inflammatory mode of cell death that promotes complement activation and macrophage recruitment. In pulmonary arterial hypertension (PAH), pulmonary arterial endothelial cells exhibit cellular phenotypes that promote ferroptosis. Moreover, there is ectopic complement deposition and inflammatory macrophage accumulation in the pulmonary vasculature. However, the effects of ferroptosis inhibition on these pathogenic mechanisms and the cellular landscape of the pulmonary vasculature are incompletely defined. Multiomics and physiological analyses evaluated how ferroptosis inhibition-modulated preclinical PAH. The impact of adeno-associated virus 1-mediated expression of the proferroptotic protein ACSL (acyl-CoA synthetase long-chain family member) 4 on PAH was determined, and a genetic association study in humans further probed the relationship between ferroptosis and pulmonary hypertension. Ferrostatin-1, a small-molecule ferroptosis inhibitor, mitigated PAH severity in monocrotaline rats. RNA-sequencing and proteomics analyses demonstrated ferroptosis was associated with PAH severity. RNA-sequencing, proteomics, and confocal microscopy revealed complement activation and proinflammatory cytokines/chemokines were suppressed by ferrostatin-1. In addition, ferrostatin-1 combatted changes in endothelial, smooth muscle, and interstitial macrophage abundance and gene activation patterns as revealed by deconvolution RNA-sequencing. Ferroptotic pulmonary arterial endothelial cell damage-associated molecular patterns restructured the transcriptomic signature and mitochondrial morphology, promoted the proliferation of pulmonary artery smooth muscle cells, and created a proinflammatory phenotype in monocytes in vitro. Adeno-associated virus 1-Acsl4 induced an inflammatory PAH phenotype in rats. Finally, single-nucleotide polymorphisms in 6 ferroptosis genes identified a potential link between ferroptosis and pulmonary hypertension severity in the Vanderbilt BioVU repository. Ferroptosis promotes PAH through metabolic and inflammatory mechanisms in the pulmonary vasculature.

ZmLSD1 Enhances Salt Tolerance by Regulating the Expression of ZmWRKY29 in Maize.

Salt stress significantly impairs plant growth, presenting a challenge to agricultural productivity. Exploring the regulatory mechanisms underlying salt stress responses is critically important. Here, we identified a significant role for the maize LESION-SIMULATING DISEASE transcription factor, ZmLSD1, in enhancing salt stress response. Subcellular localization analysis indicated that ZmLSD1-GFP was localized in the nucleus in the maize protoplast. Overexpressing ZmLSD1 in maize obviously enhanced the tolerance of plants to salt stress. Physiological analysis indicated that overexpressed ZmLSD1 in maize could mitigate the accumulation of H2O2 and MDA content exposed to salt stress. RNA-seq and qPCR-PCR analyses showed that ZmLSD1 positively regulated ZmWRKY29 expression. ChIP-qPCR and EMSA experiments demonstrated that ZmLSD1 could directly bind to the promoter of ZmWRKY29 through the GTAC motif both in vitro and in vivo. Overall, our findings suggest that ZmLSD1 plays a positive role in enhancing the tolerance of maize to salt by affecting ZmWRKY29 expression.

Physiological, biochemical, and transcriptomic alterations in Castor (Ricinus communis L.) under polyethylene glycol-induced oxidative stress

BackgroundCastor is an important industrial raw material. Drought-induced oxidative stress leads to slow growth and decreased yields in castor. However, the mechanisms of drought-induced oxidative stress in castor remain unclear. Therefore, in this study, physiological, biochemical, and RNA-seq analyses were conducted on the roots of castor plants under PEG-6000 stress for 3 d and 7 d followed by 4 d of hydration.ResultsThe photosynthetic rate of castor leaves was inhibited under PEG-6000 stress for 3 and 7 d. Biochemical analysis of castor roots stressed for 3 d and 7 d, and rehydrated for 4 d revealed that the activities of APX and CAT were highest after only 3 d of stress, whereas the activities of POD, GR, and SOD peaked after 7 d of stress. RNA-seq analysis revealed 2926, 1507, and 111 differentially expressed genes (DEGs) in the roots of castor plants under PEG-6000 stress for 3 d and 7 d and after 4 d of rehydration, respectively. GO analysis of the DEGs indicated significant enrichment in antioxidant activity. Furthermore, KEGG enrichment analysis of the DEGs revealed significantly enriched metabolic pathways, including glutathione metabolism, fatty acid metabolism, and plant hormone signal transduction. WGCNA identified the core genes PP2C39 and GA2ox4 in the navajowhite1 module, which was upregulated under PEG-6000 stress. On the basis of these results, we propose a model for the response to drought-induced oxidative stress in castor.ConclusionsThis study provides valuable antioxidant gene resources, deepening our understanding of antioxidant regulation and paving the way for further molecular breeding of castor plants.

Integration of physiology, genomics and microbiomics analyses reveal the biodegradation mechanism of petroleum hydrocarbons by Medicago sativa L. and growth-promoting bacterium Rhodococcus erythropolis KB1.

Despite the effectiveness of microbial-phytoremediation for remediating total petroleum hydrocarbons (TPH)-contaminated soil, the underlying mechanisms remain elusive. This study investigated the whole-genome and biological activity of Rhodococcus erythropolis KB1, revealing its plant growth promotion (PGP), TPH degradation, and stress resistance capabilities. Phytoremediation (using alfalfa) and plant-microbial remediation (using alfalfa and KB1) were employed to degrade TPH. The highest TPH degradation rate, reaching 95%, was observed with plant-microbial remediation. This is attributed to KB1's ability to promote alfalfa growth, induce the release of signaling molecules to activate plant antioxidant enzymes, actively recruit TPH-degrading bacteria (e.g., Sphingomonas, Pseudomonas, C1-B045), and increase soil nitrogen and phosphorus levels, thereby accelerating TPH degradation by both plants and microorganisms. This study demonstrates that R. erythropolis KB1 holds great potential for enhancing the remediation of TPH-contaminated soil through its multifaceted mechanisms, particularly in plant-microbial remediation strategies, providing valuable theoretical support for the application of this technology.

Isolation of Sphingopyxis kveilinensis sp. nov., a Potential Antibiotic-Degrading Bacterium, from a Karst Wetland.

A Gram-stain-negative, aerobic, mesophilic, motile, rod-shaped bacterium, designated strain TUF1T, was isolated from a karst wetland in south-west China. It was demonstrated to be capable of growing on plates containing oxytetracycline, streptomycin, or ofloxacin as the sole carbon source. Phylogenetic analysis of the 16S rRNA gene sequence revealed that this organism belongs to the genus Sphingopyxis and is closely related to S. chilensis S37T (99.17%) and S. alaskensis RB2256T (99.12%). The orthologous average nucleotide identity values (OrthoANIu, 84.42% and 87.53%) and digital DNA-DNA hybridization values (dDDH, 41.7% and 48.9%) between strain TUF1T and its close relatives were all below the standard recommended threshold values for species discrimination. The genomic DNA G + C content was determined to be 64.7%. The predominant cellular fatty acids were identified as summed feature 8 (C18:1ω7c and/or C18:1ω6c) and summed feature 3 (C16:1ω7c and/or C16:1ω6c). The major polar lipids found to be diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, and sphingoglycolipid. The sole respiratory quinone present was ubiquinone Q10. Based on the phylogenetic, biochemical, physiological, and chemotaxonomic analyses, strain TUF1T represents a novel species of the genus Sphingopyxis. The designation "Sphingopyxis kveilinensis sp. nov." is proposed as the name for this novel species, and the strain TUF1T (= CGMCC1.62043T = JCM36394T) is designated as the type strain.

Biochar addition enhances remediation efficiency and rapeseed yield in copper-contaminated soil.

Soil contamination with copper (Cu) threatens ecological security and human health. Rapeseed demonstrates potential in remediating copper-contaminated soil, and biochar-assisted phytoremediation is increasingly being employed to improve remediation efficiency. However, the combined application of them has not been thoroughly studied in terms of the synergistic effects and the mechanisms of their interaction. In this regard, this study conducted a pot experiment to evaluate biochar-assisted remediation under Cu-contaminated soil with varying biochar application rates; Furthermore, the plant physiological mechanism and soil physicochemical properties involved in the biocharrapeseed system was explored. Our results showed that the exchangeable pool of copper in soil decreased by 10.0% and 12.3% with adding 5% biochar (BC1) and 10% biochar (BC2) relative to control (BC0), respectively, prior to rapeseed cultivation. The rapeseed cultivation for one season further reclaimed 4.9%, 9.0%, and 13.6% of the available copper in this soil by root extraction under the BC0, BC1, and BC2 treatments, respectively. The overall copper concentration in plants decreased by 23.7% under BC2 and 13.3% under BC1 compared to BC0. However, the plant's dry biomass at BC1 and BC2 treatments increased by 1.7-fold and 2.7-fold relative to BC0, which offset the negative impact of the decreased copper concentration on phytoremediation. Physiological analysis showed adding 10% biochar decreased the MDA content by 36% in the leaf and 49% in the root, compared to BC0. The transmission electron microscopy for cell wall ultrastructure in root tips showed that biochar addition in Cu-contaminated soil increased the mechanical strength of the celL wall, explicitly increasing the thickness of the secondary cell wall. Further cell wall components analysis revealed a remarkable increment of the pectin content in BC2 relative to BC0, increased by 56% in the leaf and 99% in the root, respectively. Additionally, 10% biochar application led to a roughly 2-fold increase in seed yield via ameliorating the soil physicochemical properties and increasing the rapeseed growth. These findings offer insights into synergistic rapeseed-biochar use for Cu-contaminated soil remediation.

Physiological and Microstructure Analysis Reveals the Mechanism by Which Formic Acid Delays Postharvest Physiological Deterioration of Cassava.

Formic acid is reported to act as a food preservative and feed additive, but its effects on controlling postharvest physiological deterioration (PPD) development in cassava are unclear. In this study, we assessed the effectiveness of different concentrations of formic acid in attenuating PPD occurrence in fresh-cut cassava. The results showed that the concentration of 0.1% (v/v) formic acid could significantly delay the occurrence of PPD, and that the higher the concentration of formic acid supplied, the later the occurrence of PPD symptoms. The physiological and biochemical analysis of 0.5%-formic-acid-treated cassava slices revealed that formic acid decreased the degradation of starch, inhibited the accumulation of hydrogen peroxide (H2O2), malondialdehyde (MDA), and water-soluble pectin in cassava slices with PPD development, and increased the activities of the antioxidant enzymes ascorbate peroxidase (APX) and glutathione reductase (GR). A microscopic observation showed that the formic acid treatment inhibited the enlargement of the intercellular space during the cassava PPD process, which suggests that the formation of an intercellular layer of the cell wall was inhibited by formic acid. This study thus revealed the mechanism used by formic acid to extend the cassava shelf life; however, a detailed evaluation of the possible side effects on, for example, the cyanide content will be needed to categorically ensure the safety of this method.

Physiological and transcriptomic analyses of the mechanism of metformin-mediated relief in toxicity caused by saline-alkali to Akebia trifoliata

Physiological and transcriptomic analyses of the mechanism of metformin-mediated relief in toxicity caused by saline-alkali to Akebia trifoliata

Physiological and Transcriptomic Analyses Reveal the Role of the Antioxidant System and Jasmonic Acid (JA) Signal Transduction in Mulberry (Morus alba L.) Response to Flooding Stress

In recent decades, the frequency of flooding has increased as a result of global climate change. Flooding has become one of the major abiotic stresses that seriously affect the growth and development of plants. Mulberry (Morus alba L.) is an important economic tree in China. Flooding stress is among the most severe abiotic stresses that affect the production of mulberry. However, the physiological and molecular biological mechanisms of mulberry responses to flooding stress are still unclear. In the present study, reactive oxygen species (ROS) metabolism, antioxidant mechanism, and plant hormones in mulberry associated with the response to flooding stress were investigated using physiological and transcriptomic analysis methods. The results showed significant increases in the production rate of superoxide anion (O2•−) and the content of hydrogen peroxide (H2O2) in leaves on the 5th day of flooding stress. This led to membrane lipid peroxidation and elevated malondialdehyde (MDA) levels. Antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) exhibited enhanced activities initially, followed by fluctuations. The ascorbic acid–glutathione (AsA-GSH) cycle played a crucial role in scavenging ROS, promoting the reduction of oxidized glutathione (GSSG) to reduced glutathione (GSH). Transcriptomic analysis revealed the up-regulation of the gene-encoding antioxidant enzymes (APX, MDHAR, GPX, GR, GST) involved in ROS scavenging and stress tolerance mechanisms. Jasmonic acid (JA) levels and the expression of JA synthesis-related genes increased significantly in mulberry leaves under flooding stress. This activation of the JA signaling pathway contributed to the plant’s adaptability to flooding conditions. Proline (Pro) and soluble sugar (SS) contents increased notably in response to flooding stress. Proline helped maintain cell turgor and protected enzymes and membranes from damage, while soluble sugars supported anaerobic respiration and energy supply. However, soluble protein (SP) content decreased, suggesting inhibition of protein synthesis. The study provides insights into mulberry’s flooding tolerance mechanisms, guiding future molecular breeding efforts. This summary captures the key findings and implications of the study on mulberry’s response to flooding stress, focusing on physiological and molecular mechanisms identified in the research.