Hypophosphatemia Research Articles

UBIQUITIN-CONJUGATING ENZYME34 mediates pyrophosphatase AVP1 turnover and regulates abiotic stress responses in Arabidopsis.

Understanding the molecular mechanisms of abiotic stress responses in plants is instrumental for the development of climate-resilient crops. Key factors in abiotic stress responses, such as the proton- pumping pyrophosphatase (AVP1), have been identified, but their function and regulation remain elusive. Here, we explored the post-translational regulation of AVP1 by the ubiquitin-conjugating enzyme UBC34 and its relevance in the salt stress and phosphate starvation responses of Arabidopsis (Arabidopsis thaliana). Through in vitro and in vivo assays, we established that UBC34 interacts with and ubiquitylates AVP1. Mutant lines in which UBC34 was downregulated showed higher tolerance to salt and low inorganic phosphate (Pi) stresses, while we observed the opposite for plants overexpressing UBC34. Our results showed that UBC34 co-localizes with AVP1, and AVP1 activity is enhanced in the plasma membrane fractions of ubc34 mutants, indicating that UBC34 mediates the turnover of plasma membrane-localized AVP1. We also observed that UBC34 affects the apoplastic pH, but not the vacuolar pH of root cells. Based on our results, we propose a mechanistic model in which UBC34 mediates AVP1 turnover at the plasma membrane of root epidermal cells. Downregulation of UBC34 under salt and phosphate starvation conditions enhances AVP1 activity, leading to a higher proton gradient available for sodium sequestration and phosphate uptake.

Betaine lipids: Biosynthesis, functional diversity and evolutionary perspectives.

Betaine lipids (BL) are relatively understudied non‑phosphorus glycerolipids. They are predominantly found in algae but have also been detected in other unicellular eukaryotes, fungi, bacteria, and some bryophytes and pteridophytes. These extraplastidial lipids are considered as substitute for phospholipids in organisms, particularly under phosphate (Pi) deficiency. This review provides a broader perspective on the roles and functions of BL, revealing their functional diversity across species and environments. It also discuss the biosynthetic pathways of BL. Indeed, the pathway for DGTS (1(3),2-diacylglyceryl-3(1)-O-4'-(N,N,N-trimethyl)-homoserine), the most widespread and studied BL form, is completely known, whereas the pathway for DGTA (1(3),2-diacylglyceryl-3(1)-O-2'-(N,N,N-trimethyl)-β-alanine) is only partially understood. In this review, the role of the BTA1 gene, responsible for the synthesis of DGTS, is discussed. It is revealed to be essential in DGTA synthesis as it enables the production of its intermediate, DGTS. A phylogenetic analysis, conducted on BTA1 gene, does not seem to link the phylogenetic position of BTA1 with the BL species produced but confirms the distribution trends, with a BL diversification in marine environments and the gradual disappearance of DGTS in the evolution of the green lineage. Further research is needed to elucidate the specific roles and biosynthetic pathways of BL across different species.

An intron-split microRNA mediates cleavage of the mRNA encoded by low phosphate root in Solanaceae

Main conclusionA microRNA with a non-canonical precursor structure harbours an intron in between its miRNA-5p and miRNA-3p relevant for its biogenesis, is conserved across Solanaceae, and targets the mRNA of low phosphate root.Hundreds of miRNAs have been identified in plants and great advances have been accomplished in the understanding of plant miRNA biogenesis, mechanisms and functions. Still, many miRNAs, particularly those with less conventional features, remain to be discovered. Likewise, additional layers of regulation from miRNA generation to action and turnover are still being revealed. The current study describes a microRNA not previously identified given its unusual intron-split stem-loop structure, that has been previously observed only within the monocot-specific miRNA444 family. It shows its conservation across a branch of Solanales including agriculturally relevant Solanaceae family, where its transcripts had already been predicted in several species within sequence databases. The miRNA is absent in Arabidopsis thaliana but present in Solanum lycopersicum, Nicotiana benthamiana, Petunia axillaris, and Ipomoea nil. It proves that at least two different pri-miRNA variants are produced from this miRNA gene, one spliced and the other one retaining the intron. It demonstrates the dual function of its intron in the miRNA biogenesis. On the one hand, its presence in the pri-miRNA positively influences mature miRNA accumulation, but on the other hand, it needs to be removed from the pri-miRNA for efficient mature miRNA production. Finally, it sets low phosphate root as one of its targets, a protein known to be involved in root growth regulation under phosphate starvation in other plant species.

Influence of water chemistry and contaminant occurrence on the oxidative stress ecology of Cottus gobio in a high-mountain lake (Carnic Alps)

Understanding oxidative stress in high-mountain lake fish offers crucial insights into their health, resilience, and adaptation to extreme environmental changes. This study investigates the oxidative stress response of Cottus gobio in a high-mountain lake (Dimon Lake) located in the northeast Italy during the ice-free season, focusing on the relationship between oxidative stress biomarkers and physicochemical water parameters, as well as persistent and emerging contaminants. Significant seasonal variations were observed in water parameters, with lower oxygen, pH, conductivity, and phosphate levels in summer compared to autumn, while temperature, ammonium, and nitrate were higher in summer. Metal concentrations in C. gobio muscle were higher in autumn, with Zn showing the most significant increase. PAHs, NDL-PCBs, and pesticides were all below the limit of quantification in the fish muscle samples. No microplastics items were found in the gastrointestinal tracts of fish. Oxidative stress biomarkers revealed organ-specific and seasonal variations. The liver exhibited the highest activities of catalase (CAT), glutathione peroxidase (GPx), glutathione S-tranferase (GST), and glutathione reductase (GR), highlighting its central role in detoxification and metabolic processes. Superoxide dismutase (SOD) activity was notably higher in muscle tissue during summer, suggesting increased metabolic activity. A strong correlation was found between pH and the activities of SOD, CAT, GPx, GR, and metallothioneins (MTs), emphasizing the importance of water chemistry in influencing oxidative stress responses. This approach not only aids in understanding the local adaptations of these fish but also highlights the impacts of environmental stressors on high-mountain ecosystems. Continuous monitoring of water chemistry, particularly pH, is crucial for understanding and managing oxidative stress in aquatic organisms, especially in the context of global environmental changes.

Characterization of endophytic bacteria in Vietnamese rice seeds

Rice is a staple food and is commonly used in daily life not only in Vietnam but worldwide. However, pests, diseases, and nutrient deficiencies are threatening Vietnam's rice production by causing significant damage. The endophytic bacteria (EB) which are isolated from plants, may help improve certain quality traits of rice seeds assist plants in coping with abiotic and biotic stresses from the environment. Therefore, this study aims to investigate some promising characteristics of EBs in rice seeds, including gelatinase production, starch hydrolysis, phosphate solubilizing, cellulase, and IAA synthesis. Rice seeds from various rice varieties were used to isolate the endophytic bacteria. The bacteria were grown in Petri dishes or glass test tubes in some selective media in a controlled environment to screen for investigated traits. A total of five EBs were isolated, and MALDI-TOF mass spectrometry with a log score of MALDI Biotypes greater than 2.0 was employed for bacterial identification. Interestingly, the results revealed that the bacteria in rice grains have a high ability to synthesize cellulase, hydrolyze starch and gelatin, and produce auxin. The highest cellulase activity was associated with Staphylococcus caprae while Micrococcus luteus exhibited maximum IAA hormon and gelatinase enzyme production. Starch hydrolysis was highest in Bacillus. However, these bacteria showed low phosphate solubilization ability. The promising bacteria identified in this study include Bacillus cereus, M. luteus, and Bacillus atrophaeus. The promising results from our study can be utilized for further in vivo studies in rice plants to develop biocontrol reagents and biofertilizers for agricultural applications.

Endocrine impact of transfusion therapy: parathyroid status in pediatric thalassemia major

Background: Thalassemia major, a severe form of inherited anemia, requires lifelong blood transfusions to manage the condition and sustain hemoglobin levels. However, these repeated transfusions often lead to iron overload, which can deposit in various organs, including endocrine glands and disrupt normal hormone production. One such affected gland is the parathyroid, responsible for regulating calcium and phosphate balance through parathyroid hormone (PTH) secretion. This study aimed to assess the parathyroid status in children with thalassemia major. Methods: This case-control analytical study design was considered to assess the parathyroid status in children with thalassemia major. The study was carried out at the Department of Pediatric Hematology and Oncology, Dhaka Medical College Hospital, Dhaka, from July 2012 to June 2013. A total of 40 children with thalassemia major (termed as case) and another 32 normal children (termed as control) were included in the study. Data were analyzed using SPSS (Statistical Package for Social Sciences) version 16. Results: The study found that children with thalassemia major had significantly lower parathyroid hormone (PTH) levels and higher phosphate levels compared to healthy controls, though calcium levels were similar between groups. Thalassemia patients, primarily receiving blood from professional donors, underwent transfusions for an average of six years, with limited use of chelation therapy (15%). Hypoparathyroidism was significantly more common in thalassemia patients (10%) compared to controls, with 25% also showing hyperphosphatemia. No significant differences were observed in age or sex distribution between the groups. Conclusions: It can be concluded children with thalassemia possess significantly low serum PTH and high phosphate levels. The serum calcium level does not alter significantly compared to healthy children of similar age and sex. The findings call attention to the critical need for early intervention, regular endocrine screening and diligent chelation therapy in managing thalassemia major.

Clinical and molecular genetic characteristics of patients with hereditary hypophosphatemia.

Hereditary hypophosphatemia (HH), is a rare condition related to decreased renal tubular phosphate reabsorption. Although X-linked hypophosphatemia or PHEX gene variant is the most frequent cause of HH, recent advances in next-generation sequencing (NGS) techniques enable the identification of genetic etiologies as a whole. To identify genetic causes of HH using various genetic testing methods and to compare clinical features between FGF23-dependent and FGF23-independent HH groups. Fifty patients (24 males) from 39 unrelated families were included. Based on initial evaluation, PHEX gene sequencing was performed in patients with clinical and biochemical findings suggestive of FGF23-dependent HH. If sequencing showed no alterations, multiplex ligation-dependent probe amplification (MLPA) analysis for PHEX was conducted. Initially, a specific gene panel was performed for FGF23-independent HH or those in whom PHEX gene showed no genetic alteration. Genetic etiology was revealed in 43 patients from 33 families. PHEX gene variants were identified (four novel) in 24 patients from 19 unrelated families (50%). SLC34A3 was the second most common (16.6%) and the rest were rarer causes of hypophosphatemia (DMP1 n=3, SLC34A1 n=2, CLCN5 n=2, OCRL n=2, FAM2°C n=1, SLC2A2 n=1). When the genetically proven FGF23-dependent (n=28) and FGF23-independent (n=15) HH groups were compared for clinical and biochemical features; lower phosphate and TmP/GFR SDSs and higher ALP SDS with more severe clinical rickets were detected in FGF23-dependent group, whereas, higher serum and urine calcium and lower PTH levels were detected in FGF23-independent group. The application of MLPA provided an additional explanatory value of 10% to the molecular etiology. However, 10% of the cases of HH still remain unexplained even after a comprehensive genetic work-up. Biochemical findings suggest distinct biochemical profiles between FGF23-dependent and FGF23-independent HH groups.

Research of batch and fixed-bed column adsorption for phosphorus removal from wastewater using sewage sludge biochar

Wastewater treatment and the efficient use of sewage sludge biochar are critical in addressing the needs of ever-increasing population in the world. Recently, phosphorus (P) removal from wastewater has become highly relevant and important, primarily to reduce eutrophication in surface waters. Using sewage sludge biochar as an adsorbent for phosphate removal from wastewater offers an opportunity to reuse sewage sludge (SS) and return phosphorus to the biogeochemical cycle. In this study, the efficiency of two phosphate removal methods - batch adsorption and fixed-bed column process – was investigated using pyrolyzed sewage sludge biochar (PSSB) produced at different temperatures (300 °C, 400 °C, 500 °C, 600 °C). In the batch adsorption experiment, direct mixing of 600 °C pyrolyzed sewage sludge biochar with wastewater resulted in a relatively low phosphate removal efficiency (only about 18 %) at an initial phosphate concentration of 100 mg/l. In contrast, the fixed-bed column process, using PSSB as a filter for phosphate adsorption, showed significantly better results. The highest phosphate removal efficiency (up to 90%) was achieved after 30 min of filtration, using an initial phosphate concentration of 30 mg/l initial and biochar pyrolyzed at 600 °C.

The Effect of Dietary Phosphate Load on Urinary Supersaturation and Phosphate Metablism in Non-stone-forming Asian Individuals.

Introduction Phosphate ion is common in the core of urinary stones and may initiate stone formation. However, the precise role of phosphate in the initiation of stone formation remains obscure. We assessed the effects of dietary phosphate load on urinary stone risk and phosphate metabolism. Methods Ten non-stone-forming healthy volunteers completed this randomized, crossover study. Each subject was provided a high or low phosphate diet for 3 days. After a 2-day equilibration period with a moderate phosphate diet, the participants received a low or high phosphate diet for another 3 days. Serum, fecal and 24-hour urine samples were collected at the end of each intervention. Results High dietary phosphate load increased urinary phosphate excretion, and low dietary phosphate decreased urinary phosphate excretion. In addition, urine pH was lower and supersaturation index of uric acid was higher after high a phosphate diet. There was no significant difference in the supersaturation index for calcium oxalate, brushite and hydroxyapatite, or in 24-hour urinary citrate between the high and the low dietary phosphate. Also, no significant change was observed in fecal phosphate excretion after a high or low phosphate diet. The serum phosphate level increased after a high phosphate diet, but there was no difference in serum phosphate between low phosphate and moderate phosphate diets. Conclusion High dietary phosphate load led to higher urinary phosphate excretion, a higher supersaturation index of uric acid, and lower urine pH. Stone formers should be advised to limit the intake of high phosphate source diet, including high protein diets and phosphate-based food additives.

Association between serum phosphate level and mortality of patients with aneurysmal subarachnoid hemorrhage.

Disorders of serum phosphate, including hyperphosphatemia and hypophosphatemia, have been confirmed to be related to the poor prognosis of specific critically ill patients. No study analyzes the relationship between continuous serum phosphate level and mortality from aneurysmal subarachnoid hemorrhage (aSAH). This study was performed to explore this relationship. aSAH patients were divided into four groups based on serum phosphate quartiles. Significant factors discovered in the univariate Cox regression were included in the multivariate Cox regression to explore the independent relationship between serum phosphate and mortality of aSAH. Kaplan-Meier survival analysis was performed to compare the difference in survival between the four groups. The 60-day mortality of overall aSAH patients was 20.7%. The mortality of the group with the 1st quartile (29.4%) and the 4th quartile (24.7%) had higher mortality than others (p = 0.028). Univariate Cox regression showed the 2nd quartile (p = 0.020) and 3rd quartile (p = 0.017) were associated with lower mortality risk than the 1st quartile. Compared with the 1st quartile, the 4th quartile was not associated with lower mortality risk (p = 0.458). After adjusting confounding effects, multivariate Cox regression showed only the 4th quartile was significantly associated with higher mortality risk (p = 0.009) than the 1st quartile. The unadjusted relationship between serum phosphate and mortality of aSAH is U-shaped. While high serum phosphate even within the normal range is independently related to the mortality of aSAH. Low serum phosphate may be just a marker for the severity of aSAH. Evaluating the initial serum phosphate is useful for risk stratification of aSAH.

A conserved nuclear factor YC subunit, NF-YC3, is essential for arbuscule development.

Establishing reciprocal symbiosis with arbuscular mycorrhizal (AM) fungi is an important evolutionary strategy of most terrestrial plants to adapt to environmental stresses, especially phosphate (Pi) deficiencies. Identifying the key genes essential for AM symbiosis in plants and dissecting their functional mechanisms will be helpful for the breeding of new crop varieties with enhanced nutrient uptake efficiency. Here, we report a nuclear factor YC subunit-encoding gene, OsNF-YC3, whose expression is specifically induced in arbuscule-containing cells, plays an essential role in AM symbiosis. Knockout of OsNF-YC3 resulted in stunted arbuscule morphology and substantially decreased P accumulation, while overexpressing OsNF-YC3 enhanced mycorrhization and Pi uptake efficiency. OsNF-YC3 is directly regulated by OsPHRs, the major regulators of Pi starvation responses. Chromatin immunoprecipitation sequencing analysis uncovered multiple genes with crucial roles in arbuscule development as its potential downstream targets, including the AM-specific Pi transporter gene OsPT11. OsNF-YC3 can form a heterotrimer with the other two NF-Y subunits, OsNF-YA11 and OsNF-YB11, in yeast. Loss of OsNF-YA11 function also severely impaired arbuscule development in its mutants. Overall, our results highlight an essential role of OsNF-YC3 and its potential interacting NF-Y subunit, OsNF-YA11, in regulating AM symbiosis and arbuscule development.

Mechanical and microscopic properties of low alkali sulfoaluminate and magnesium phosphate cement slurries modified recycled aggregate concrete

Mechanical and microscopic properties of low alkali sulfoaluminate and magnesium phosphate cement slurries modified recycled aggregate concrete

Clinical management of hypophosphatemic osteomalacia induced by adefovir and tenofovir: Insights from a case report.

Hypophosphatemic osteomalacia is a rare chronic metabolic bone disease characterized by low serum phosphate levels owing to genetic or acquired causes. This article presents a case report of the clinical management, challenges encountered, and prognosis of secondary hypophosphatemic osteomalacia induced by defovir and tenofovir. A 55-year-old male patient had been experiencing persistent dull chest pain and fatigue for more than a year. The patient had chronic hepatitis B infection for over 10 years, with regular use of adefovir dipivoxil capsules for more than 10 years. Five months before admission, the patient was switched to tenofovir alafenamide fumarate tablets. After obtaining clinical manifestations, medical history, and examination results, tumor-induced osteomalacia was excluded, and the final diagnosis was drug-induced hypophosphatemic osteomalacia. Adefovir dipivoxil and tenofovir alafenamide were discontinued, and the patient was switched to entecavir disintegration tablets for antiviral therapy. He was advised to follow a high-phosphate diet, receive phosphorus supplementation and calcitriol capsules to promote calcium absorption, obtain moderate sun exposure, and take measures to prevent falls and fractures. Serum phosphate levels showed a gradual upward trend, with the most recent measurement being 0.85 mmol/L. The bone density gradually improved and reached normal levels in the most recent assessment. The symptoms of fatigue and chest pain were resolved. Accurate diagnosis requires a combination of clinical presentation, medical history, biochemical and radiological findings, and, if available, measurement of fibroblast growth factor 23 (FGF 23). The role of national, provincial, or regional centers for rare diseases is crucial for conducting unconventional tests and providing access to rare medications.

Molecular Mechanisms of Phosphate Use Efficiency in Arabidopsis via Penicillium olsonii TLL1.

Beneficial fungi are promising tools for enhancing plant growth and crop yield in stressful environments. Penicillium olsonii TLL1 (POT1) was identified as a potential biofertilizer enhancing plant growth and phosphate use efficiency especially under phosphate deficiency stress. Hence, we attempted to explore bioinformatic insights into how POT1 enhances plant growth under phosphate starvation. In our study, wild-type Arabidopsis thaliana Columbia-0 roots and shoots cultivated with POT1 under phosphate-limiting conditions were employed for comparative analyses. By integrating transcriptomic and proteomic data, we identified key molecular pathways regulated by POT1 that influenced phosphate acquisition and plant stress tolerance. Comprehensive RNA-seq analysis revealed significant upregulation of genes involved in phosphate transport, root architecture, and stress-related pathways, while proteome profiling further highlighted proteins associated with lipid remodeling, phosphate metabolism, and phytohormone signaling. Bioinformatic analyses of differentially expressed genes (DEGs) and proteins (DEPs) elucidated the complex regulatory networks at both transcriptional and translational levels, with key contributions from auxin and ethylene signaling. Our study demonstrated that POT1-treated plants exhibited enhanced root development and nutrient uptake under phosphate-deficient conditions, driven by the coordinated regulation of phosphate solubilization genes and stress-responsive proteins. Our findings underscore the potential of multi-omics approaches in unraveling the molecular mechanisms behind plant-microbe interactions, with implications for improving sustainable agricultural practices.

Effect of calcium phosphate modification on the interfacial transition zone of recycled aggregate and concrete

Recycling construction solid waste is an immediate need due to the substantial amount of construction waste that occupies valuable land and poses environmental hazards. In response to challenges related to the performance and interfacial transition zone (ITZ) when using recycled aggregate (RA) in concrete, a modified formulation with low calcium phosphate (CaP) content was developed to enhance RA's performance. It was found that when the mass ratio of CaP to RA reached 0.001 g/g, the physical properties of RA were significantly improved through a precoating treatment, resulting in a 31.52 % increase in the compressive strength of recycled aggregate concrete (RAC) compared to the control group. An in-depth analysis of the mechanism of action of CaP revealed that the active layer formed by CaP on the RA surface promoted the slow hydrolysis-hydration coupling reaction through the sustained release of Ca2+ and PO₄3- ions. This process and the solid-phase reactions of C-S-H gel, carbonation products, and sulfate ions effectively improved the pore structure, increased the specific surface area by 47.36 %, and reduced crack width by 78.95 %. Furthermore, the bond strength test between modified RA and freshly hardened mortar showed a 30.29 % increase in bond strength, directly demonstrating the effectiveness of CaP in enhancing the ITZ in RAC.

Ecology and biogeochemistry of the microbial underworld in two sister soda lakes

BackgroundApproximately 3.7 billion years ago, microbial life may have emerged in phosphate-rich salty ponds. Surprisingly, analogs of these environments are present in alkaline lake systems, recognized as highly productive biological ecosystems. In this study, we investigate the microbial ecology of two Canadian soda lake sediment systems characterized by naturally high phosphate levels.ResultsUsing a comprehensive approach involving geochemistry, metagenomics, and amplicon sequencing, we discovered that groundwater infiltration into Lake Goodenough sediments supported stratified layers of microbial metabolisms fueled by decaying mats. Effective degradation of microbial mats resulted in unexpectedly low net productivity. Evaporation of water from Last Chance Lake and its sediments led to saturation of brines and a habitat dominated by inorganic precipitation reactions, with low productivity, low organic matter turnover and little biological uptake of phosphorus, leading to high phosphate concentrations. Highly alkaline brines were found to be dominated by potentially dormant spore-forming bacteria. These saturated brines also hosted potential symbioses between Halobacteria and Nanoarchaeaota, as well as Lokiarchaea and bacterial sulfate reducers. Metagenome-assembled genomes of Nanoarchaeaota lacked strategies for coping with salty brines and were minimal for Lokiarchaea.ConclusionsOur research highlights that modern analogs for origin-of-life conditions might be better represented by soda lakes with low phosphate concentrations. Thus, highly alkaline brine environments could be too extreme to support origin of life scenarios. These findings shed light on the complex interplay of microbial life in extreme environments and contribute to our understanding of early Earth environments.

Choice of activated sludge microorganisms under phosphate deficiency: Competition for inorganic phosphate or change to organophosphorus metabolism

Phosphorus (P) plays a crucial role in the microbial processes of wastewater treatment. However, the current understanding of P metabolic pathways in wastewater is incomplete, and the mechanisms of microbial P metabolism under P deficient conditions remain unclear. This study explores the succession patterns of activated sludge bacterial communities and their potential P utilization strategies under P-deficient conditions. The results indicate that changes in phosphorus concentration and composition drive microbial community succession. Under P deficiency, microorganisms initially focus on inorganic phosphorus (IP) metabolism, prioritizing competition for IP. Subsequently, the bacterial community shifts to predominantly utilizing organic phosphorus (OP), with over 94% of genomes carrying OP metabolism genes. The OP in the system primarily consists of phosphonates and phosphoester. Consequently, distinct bacterial responses to phosphoester and phosphonates were observed, with the bacterial community transitioning from low modular to highly modular communities with differentiated niches. Phosphoester and phosphonate metabolism emerged as the two main OP metabolic pathways within the community. By reconstructing the P metabolic pathways of dominant genera, including Pannonibacter (Proteobacteria) and f_Saprospiraceae (Bacteroidota), metabolic models of phosphonate and phosphoester were developed in a wastewater treatment system for the first time. This study provides new insights into biological P metabolism in wastewater treatment, expanding our understanding of P metabolic pathways in wastewater.

How Well Do Endemic Wetland Plant Species Perform in Water Purification?

Rising anthropogenic-induced nutrient enrichment of surface waters is of great concern globally as it jeopardizes the ecological integrity and functioning of freshwater ecosystems. Floating wetlands have been successfully used to treat nutrient enriched wastewater in developing nations, and provide additional co-benefits. We aimed to quantify the nutrient removal efficiency of high-potential, endemic wetland species on floating wetlands in different conditions and to understand whether the nutrient uptake process was characterised by key plant functional traits. Two experiments were run under Mediterranean-climate conditions of the Western Cape of South Africa: (1) a closed, oligotrophic mesocosm experiment representing local conditions and (2) a real-life (in-situ) eutrophic application. The mesocosm experiment conducted under oligotrophic local conditions yielded low nitrate, phosphate and ammonium removal rates (34.8–35.2 mgNO3-Nm− 2.d− 1, 10.4–10.7 mgPO4-Pm− 2.d− 1 and 3.6–3.8 mgNH4-Nm−2.d− 1) in comparison to other floating wetland studies globally, yet high removal efficiencies (> 90%). However the eutrophic in-situ experiment demonstrated the potential for these same endemic plants to remove up to 312 g.m− 2 of nitrogen and 47 g.m− 2 of phosphorus per year– which is relatively high compared to similar global research. Cyperus textilis had the highest daily nutrient uptake and content followed by Prionium serratum and Juncus lomatophyllus, while J. lomatophyllus had the greatest nutrient uptake efficiency. Two of the three species (C. textilis and P. serratum) stored significantly more total nutrients in their shoot tissue compared to their root tissue, suggesting that the permanent removal of nutrients from the system is possible through shoot harvesting. Floating wetlands planted with endemic plant species have the potential to remove nutrients effectively and sustainably from eutrophic water and can thus be implemented as low-cost nature-based solutions to mitigate pollution of lentic systems.

Ethylene modulates wheat response to phosphate deficiency.

Ethylene involves in the response to P deficiency in some model plants, but its relevance to wheat remains limited. Following our recent study demonstrating the role of differentially expressed genes (DEGs) encoding ethylene response factors (ERFs) in response to P starvation in wheat, this study aims to investigate the remodelling of ethylene pathway and the physiological roles of ethylene in wheat under P deficiency using transcriptome analysis and the addition of exogenous ethylene analogue ethephon or ethylene inhibitors. ERFs with at least a two-fold change upon P deficiency were biasedly enriched on chromosome 4 B. A group of genes encoding ACC synthase and ACC oxidase were upregulated under P starvation, indicating an increase in ACC and ethylene content, which was verified by biochemical measurements and gas chromatography-mass spectrometry analysis. Under P deficiency, both root and shoot biomass decreased with the application of exogenous ethephon or ethylene inhibitors, while root fork numbers and root surface area decreased upon ethephon treatment. The phosphate (Pi) concentrations in roots and old leaves increased with ethephon treatment, and it's redistribution in roots and younger leaves was altered under Pi starvation. Our findings could serve as a guideline for breeding germplasm with high Pi efficiency.

Insight into heterovalent metal modification for lanthanum carbonate to enhance phosphate removal at trace levels

Reducing phosphate concentrations from low levels to ultra-low levels (e.g., below 0.01 mg P/L) is crucial for preventing and treating eutrophication. Adsorption is promising but still challenged by the limited adsorption capacity at low phosphate concentrations, which leads to high costs. Herein, we propose a heterovalent metal modification strategy using Fe(II) to improve the adsorption capacity of lanthanum (La) carbonate for low-level phosphate removal. A La:Fe(II) molar ratio of 7:1 enabled the partial substitution of Fe(II) for La, resulting in a La/Fe carbonate with a high adsorption capacity. La/Fe carbonate exhibited fast adsorption kinetics, excellent applicability in a pH range of 5–7, and good reusability at low phosphate concentrations. Its adsorption capacity at low phosphate levels surpassed previously reported adsorbents. La/Fe carbonate demonstrated high resistance to complex water matrices and cost-effectiveness, achieving an effluent concentration below 0.01 mg P/L in real wastewater treatment. Mechanism analysis revealed that Fe(II) substitution led to super-saturated coordination and Fe(II) → Fe(III) conversion for charge compensation. The self-conversion of Fe(II) → Fe(III) donated electrons to neighboring La active sites, activating these active centers, which caused a positive shift in the d-band center of La active sites and enhanced interfacial electron transport between La/Fe carbonate and phosphate. This work offers an efficient, easy-to-operate, and low-cost approach to achieve ultra-low phosphate concentrations through adsorption, and fills the research gap on the mechanism of heterovalent metal modulation to enhance the phosphate adsorption capacity.