Search Results (61)

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

The present study systematically investigated the cesium (Cs) enrichment characteristics and physiological responses to Cs exposure in radish (Raphanus sativus L.) seedlings under hydroponic conditions through integrated physiological, biochemical, and transcriptome analyses. The results showed that the Cs content in radish roots, stems, and cotyledons increased progressively with rising Cs concentrations (0.25–2 mM), and Cs mainly accumulated in the cotyledon. The transfer factor (TF) increased by 63.29% (TF = 3.87) as the Cs concentration increased from 0.25 to 2 mM, while the biological concentration factor (BCF) decreased by 72.56% (BCF = 14.87). Severe growth inhibition was observed at 2 mM Cs stress, with biomass reduction reaching 29.73%. The carotenoid content decreased by 11.92%; however, the total chlorophyll content did not change significantly, and the photosynthesis of radish was not affected. In addition, Cs exposure disrupted mineral nutrient homeostasis, decreasing potassium (K), sodium (Na), magnesium (Mg), and iron (Fe) content. The superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities, reactive oxygen species (ROS), and malondialdehyde (MDA) content increased under the different Cs treatments, which indicated that Cs exposure induced oxidative stress response in radish seedlings. Transcriptome analysis detected a total of 4326 differentially expressed genes (DEGs), in which altered expression patterns in genes associated with mineral transport, antioxidant systems, and carotenoid biosynthesis pathways in radish under 2 mM Cs treatment were observed. In conclusion, this study comprehensively investigated the physiological and molecular responses of radish to Cs stress, revealing that Cs accumulation exhibited site-specific preference and concentration dependence and induced physiological disturbances, including growth inhibition and photosynthetic pigment metabolism alterations. At the transcription level, Cs activated the enzymatic antioxidant system, related genes, and stress-response pathways. Notably, this study is the first to demonstrate that Cs disrupts plant mineral nutrition homeostasis and inhibits carotenoid biosynthesis. These findings establish a crucial theoretical foundation for utilizing radish in Cs-contaminated phytoremediation strategies. Full article

The CorA/MRS2-type transporters represent a crucial family of magnesium ion transporters widely distributed in plants. Through comprehensive screening and alignment using the Phytozome database, we identified seven magnesium-related MdMRS2 Confirm the deletion of the “Chinese Province” column in the address. genes in apple (MdMRS2-1 to MdMRS2-7), which were distributed across seven distinct chromosomes. Phylogenetic analysis classified these genes into five distinct clades. Tissue-specific expression profiles revealed the differential expression patterns of MdMRS2 members in different tissues such as the apple roots, stems, leaves, seedlings, seeds, flowers, and fruits. Among them, the expression level of MdMRS2-5 was the highest in fruits, while that of MdMRS2-6 was the lowest in seeds. Analysis of cis-regulatory elements in MdMRS2 promoter regions identified numerous light-responsive elements, MYB binding sites, and hormone-responsive elements, suggesting their transcriptional regulation may be influenced by related metabolic pathways or signaling molecules. qRT-PCR results showed that the relative expression levels of all genes were significantly upregulated compared with CK under M3 treatment, while there were no significant differences in other treatments. Among them, the upregulation of MdMRS2-7 was the most significant, increasing by 142% compared with CK. Notably, all MdMRS2 genes were significantly upregulated under 4 mmol·L⁻¹ MgSO₄ treatment. Subcellular localization experiments conducted in tobacco leaves confirmed the membrane and cytoplasmic distribution of these transporters, consistent with bioinformatic predictions. These genes may become candidate genes for subsequent functional studies. This work will provide a basis for future research on the response mechanism and function of the MRS2 gene family in response to magnesium stress. Full article

Previous studies have shown that foliar spraying with a 0.3% CaCl₂ + 0.3% MgCl₂ solution can mitigate the “sugar receding” phenomenon in fruit pulp, partly by regulating sugar conversion in the pulp of ‘Feizixiao’ litchi (Litchi chinensis Sonn.). Given that calcium-dependent protein kinases (CDPKs) in plants regulate sugar metabolism by modulating the activity of key sugar conversion enzymes, this study investigated the expression response of CDPK genes in ‘Feizixiao’ litchi pulp to foliar calcium–magnesium nutrient treatment and their regulatory characteristics on sugar conversion. After the fruit set, ‘Feizixiao’ litchi trees were subjected to three consecutive foliar spray applications of 0.3% CaCl₂ + 0.3% MgCl₂, with water spraying as the control. The dynamic changes in peel h values and soluble sugar and monosaccharides, water-soluble calcium (Ca²⁺) and magnesium (Mg²⁺), plant hormones, and the concentration of CDPKs in the pulp were compared throughout fruit development. Key differentially expressed members of the CDPK gene family were screened through real-time quantitative PCR analysis. The results showed that the peel color transition occurred earlier in the control (CK) than in the treatment (T), but the coloration process accelerated in the treated fruit, leading to no significant difference in peel h values between the groups at 76 days after anthesis (DAA), when both reached the lowest levels. The total of soluble sugar in the pulp peaked at 70 DAA in both groups, but while the CK exhibited a significant decline thereafter, T maintained stable sugar levels, thereby mitigating the “sugar receding” phenomenon. Water-soluble calcium and water magnesium levels were significantly higher in the T at 42 and 63 DAA, with water calcium remaining significantly higher at 70 DAA. Furthermore, sucrose, glucose, fructose, abscisic acid (ABA) contents, and CDPK concentration were significantly higher in the T at 70 and 76 DAA. The CDPK gene family members LcCDPK1, LcCDPK2, LcCDPK3, LcCDPK4, LcCDPK5, LcCDPK9, LcCDPK15, and LcCDPK17 were upregulated in response to T. Among them, LcCDPK1, LcCDPK4, LcCDPK5, LcCDPK9, and LcCDPK17 were identified as key structural genes due to their significant correlation with soluble sugar content and CDPK concentration, as well as their differential expression between T and CK. In conclusion, foliar calcium–magnesium nutrient treatment upregulates the expression of these five CDPK gene family members by increasing the ABA levels in the pulp, leading to more CDPK accumulation. This accumulation inhibits sugar conversion and promotes sucrose and fructose accumulation, thereby mitigating the “sugar receding” phenomenon in ‘Feizixiao’ litchi pulp. Full article

As an endogenous hormone, auxin plays a crucial role in regulating plants’ growth and development, and also in the responses to abiotic stresses. However, the effects and mechanism of auxin and its inhibitors on plant growth and mineral nutrient absorption in citrus have not been thoroughly studied. Therefore, we used trifoliate orange (citrus’s rootstock, Poncirus trifoliata) as the experimental material to supplement the research content in this area. The trifoliate orange seedlings were treated with exogenous auxin (indolebutyric acid, IBA) and auxin inhibitor (2-naphthoxyacetic acid, 2-NOA) in a sand culture system. The results showed that compared to the control, exogenous auxin (1.0 µmol L⁻¹ IBA) significantly enhanced the taproot length, lateral root length, and lateral root number by 17.56%, 123.07%, and 88.89%, respectively, while also markedly elevating the levels of nitrogen (N), phosphorus (P), potassium (K), copper (Cu), and zinc (Zn) by 14.29%, 45.61%, 23.28%, 42.86%, and 59.80%, respectively. Again compared to the control, the auxin inhibitor (50.0 µmol L⁻¹ 2-NOA) dramatically reduced the taproot length, lateral root length, and lateral root number by 21.37%, 10.25%, and 43.33%, respectively, while also markedly decreasing the levels of N, magnesium (Mg), iron (Fe), Cu, and Zn by 7.94%, 10.42%, 24.65%, 39.25%, and 18.76%, respectively. Furthermore, IBA increased auxin accumulation in the root hair, stele, and epidermal tissues of citrus taproots, and promoted the up-regulation of auxin synthesis genes (TAR2, YUC3, YUC4, YUC6, YUC8) and transport genes (ABCB1, ABCB19, AUX1, LAX1, LAX2, PIN1, PIN3, PIN4). In contrast, 2-NOA decreased auxin levels in the root hair, stele, and epidermal tissues of citrus taproots, and was involved in the down-regulation of auxin synthesis genes (TAR2, YUC3, YUC4, YUC6) and transport genes (ABCB1, AUX1, LAX1, LAX2, LAX3, PIN3). Interestingly, 2-NOA dramatically elevated auxin level specifically in the root tip of citrus taproot. Therefore, 2-NOA disrupts auxin reflux from the root tip to root hair and epidermal tissues in citrus taproot through down-regulation of auxin transport genes, thereby creating localized (i.e., root hair zone and epidermal tissues) auxin deficiencies that compromise root system architecture and nutrient acquisition capacity. According to the results of this study, exogenous auxin analogs could regulate citrus growth and mineral nutrient absorption through the auxin synthesis and transport pathways. Full article

This study aimed to examine the effects of aluminum (Al) stress on the leaves of Shatian pomelo (Citrus maxima “Shatian Yu”) and its underlying response mechanisms. Leaf phenotype analysis, physiological response index determination, transcriptome analysis, and genome verification were employed to investigate the effects of Al toxicity in detail. Al toxicity stress inhibited leaf growth and development, reducing leaf area, girth, and both dry and fresh weights. Antioxidant enzyme activity and soluble protein content in leaves significantly increased with rising Al stress levels. Additionally, Al toxicity caused an accumulation of Al ions in leaves and a decline in boron, magnesium, calcium, manganese, and iron ion content. RNA sequencing identified 4868 differentially expressed genes (DEGs) under 0 mM (Control) and 4 mM (Al stress) conditions, with 1994 genes upregulated and 2874 downregulated, indicating a complex molecular regulatory response. These findings were further validated by real-time quantitative PCR (qPCR). The results provide critical insights into the molecular mechanisms of Shatian pomelo leaf response to Al toxicity and offer a theoretical basis and practical guidance for improving citrus productivity in acidic soils. Full article

Aluminum (Al) toxicity in acidic soils poses significant challenges to crop growth and development. However, the response mechanism of Shatian pomelo (Citrus maxima ‘Shatian Yu’) roots to Al toxicity remains poorly understood. This study employed root phenotype analysis, physiological response index measurement, root transcriptome analysis, and quantitative PCR (qPCR) validation to investigate the effects of Al toxicity on Shatian pomelo roots. The findings revealed that Al toxicity inhibited root growth and development, resulting in reduced root biomass, total root length, total root surface area, root volume, average root diameter, and root tip count. Antioxidant enzyme activities (peroxidase, superoxide dismutase, ascorbate peroxidase, and catalase activity) and soluble protein content increased with rising Al toxicity, whereas malondialdehyde content initially increased and then declined. Additionally, Al toxicity stress increased Al (1439.25%) content and decreased boron (B, 50.64%), magnesium (Mg, 42.04%), calcium (Ca, 46.02%), manganese (Mn, 86.75%), and iron (Fe, 69.92%) levels in the roots. RNA sequencing (RNA-seq) analysis identified 3855 differentially expressed genes (DEGs) between 0 mmol/L Al (control) and 4 mmol/L Al (Al toxicity) concentrations, with 1457 genes up-regulated and 2398 down-regulated, indicating a complex molecular regulatory response. The qPCR results further validated these findings. This study elucidates the response mechanisms of Shatian pomelo roots to Al toxicity stress, providing insights into the regulatory pathways involved. The findings offer valuable reference points for breeding Al-resistant Shatian pomelo varieties. The results of this study provide important genetic tools and technical support for the screening and breeding of highly resistant varieties of Shatian pomelo. On the one hand, by detecting the key indexes (such as antioxidant enzyme activity and nutrient absorption capacity) of Shatian pomelo, varieties with excellent anti-Al toxicity characteristics can be selected. On the other hand, the Al-resistant genes identified in this study, such as TFM1 and ALERTFA0, can be used to develop molecular markers, assisted marker breeding, or transgenic breeding to accelerate the breeding process of Al-resistant strains. Full article

Background: Rheumatoid arthritis (RA) is a common systemic autoimmune inflammatory disease that can cause joint damage. We have recently reported that oral magnesium supplementation significantly reduces disease severity and joint damage in models of RA. Methods: In the present study, we analyzed the transcriptome of spleens and synovial tissues obtained from mice with KRN serum-induced arthritis (KSIA) consuming either a high Mg supplemented diet (Mg2800; n = 7) or a normal diet (Mg500; n = 7). Tissues were collected at the end of a 15-day KSIA experiment. RNA was extracted and used for sequencing and analyses. Results: There was an enrichment of differentially expressed genes (DEGs) belonging to Reactome and Gene Ontology (GO) pathways implicated in RA pathogenesis such as RHO GTPases, the RUNX1 pathway, oxidative stress-induced senescence, and the senescence-associated secretory phenotype. Actc1 and Nr4a3 were among the genes with the highest expression, while Krt79 and Ffar2 were among the genes with the lowest expression in synovial tissues of the Mg2800 group compared with the Mg500 group. Spleens had an enrichment for the metabolism of folate and pterines and the HSP90 chaperone cycle for the steroid hormone receptor. Conclusions: We describe the tissue transcriptomic consequences of arthritis-protecting Mg supplementation in KSIA mice. These results show that oral Mg supplementation may interfere with the response to oxidative stress and senescence and other processes known to participate in RA pathogenesis. We provide new evidence supporting the disease-suppressing effect of increased Mg intake in arthritis and its potential to become a new addition to the therapeutic options for RA and other autoimmune and inflammatory diseases. Full article

The three-amino-loop-extension (TALE) family involves key transcription factors vital for maintaining different aspects of growth including leaf, flower, and fruit development and responses to stressful stimulus. Thus far, a deep understanding of the TALE gene family in wax gourd subjected to low calcium and magnesium stress has been missing. Here, we isolated 24 BhTALE genes from a wax gourd genome database. Comprehensive bioinformatic analysis, including evolutionary tree, gene structures, conserved motifs, and chemical properties, provide structural and functional insights into the BhTALE gene family. Gene ontology (GO) analysis of TALE genes unveils their involvement in growth and stress responses. Promoter analysis indicates that hormones and stresses can influence the expression of BhTALE genes. Tissue-specific expression under low calcium and magnesium stress showed that BhTALE genes were more active in the leaves and roots. Notably, BhTALE7, BhTALE10, and BhTALE14 were expressed differentially in leaves under low calcium and magnesium applications. Similarly, the induced expression pattern of BhTALE4 was recorded in the roots under low calcium and magnesium applications. Our findings underscore the pivotal role of the BhTALE gene family in dealing with low calcium and magnesium stress in the wax gourd. Full article

Olive trees worldwide suffer from a number of devastating fungal diseases that affect production. One such serious disease is olive leaf spot caused by Venturia oleaginea. Recently, we applied magnesium hydroxide porous micron-scale particles (PMPs) on tomatoes and observed potent antimicrobial activity, reducing the fungal load of the treated phyllosphere. To assess the effectiveness of the compound on olive fungal disease, we applied it for two consecutive seasons. One particular olive tree exhibited extreme manifestations of fungal disease and was destined for removal. A single application of Mg(OH)₂ PMP reversed all symptoms of the disease and eliminated the Venturia pathogen, curing the tree of disease. Venturia oleaginea appears to be exceptionally susceptible to treatment compared to other species in the fungal leaf community. The beneficial fungus Aureobasidium pullulans increased in relative abundance in all the sprayed trees. No toxicity and leaf loss were observed, and the compound retention exceeded 47 days. All trees sprayed showed drastic reductions in the total fungal load and compared favorably to the commercial copper compound. Spraying induced a moderate expression of key indicator genes associated with stress responses. No leaf chlorosis or shedding were observed. Overall, Mg(OH)₂ PMP treatment appears to be a highly promising tool for combating plant fungal disease. Full article

Since genetic mutations during brain development play a significant role in the genesis of epilepsy, and such genetically determined epilepsies are the most difficult to treat, there is a need to study the mechanisms of epilepsy development with deletions of various transcription factors. We utilized heterozygous mice (Sip1^wt/fl) with a neuronal deletion of the transcription factor Sip1 (Smad interacting protein 1) in the cerebral cortex. These mice are characterized by cognitive impairment and are prone to epilepsy. It is known that the brain-derived neurotrophic factor (BDNF) has a neuroprotective effect in various neurodegenerative diseases. Therefore, we created and applied an adeno-associated construct carrying the BDNF sequence selectively in neurons. Using in vitro and in vivo research models, we were able to identify a key gen, the disruption of whose expression accompanies the deletion of Sip1 and contributes to hyperexcitation of neurons in the cerebral cortex. Overexpression of BDNF in cortical neurons eliminated epileptiform activity in neurons obtained from heterozygous Sip1 mice in a magnesium-free model of epileptiform activity (in vitro). Using PCR analysis, it was possible to identify correlations in the expression profile of genes encoding key proteins responsible for neurotransmission and neuronal survival. The effects of BDNF overexpression on the expression profiles of these genes were also revealed. Using BDNF overexpression in cortical neurons of heterozygous Sip1 mice, it was possible to achieve 100% survival in the pilocarpine model of epilepsy. At the level of gene expression in the cerebral cortex, patterns were established that may be involved in the protection of brain cells from epileptic seizures and the restoration of cognitive functions in mice with Sip1 deletion. Full article

High temperatures during the crop growing season are becoming more frequent and unpredictable, resulting in reduced crop productivity and quality. Heat stress disrupts plant metabolic processes that affect cell membrane composition and integrity. Cell membrane permeability, ion leakage, and heat shock proteins have been evaluated to screen for heat tolerance in plants. In potatoes, it is unclear whether leaf membrane stability under heat stress is correlated with underground tuber productivity and quality. The main goal of this study was to evaluate if leaf membrane relative electrolyte conductivity (REC) under high temperatures could be used to identify heat-tolerant potato genotypes. Electrolyte leakage assays, correlation estimations, and genome-wide association studies were carried out in 215 genotypes. Expression levels of small heat shock protein 18 (sHSP18) were evaluated in the heat-sensitive potato variety Russet Burbank and compared with those of the heat-tolerant variety Vanguard Russet using Western blotting. Significant differences were observed among genotypes for leaf membrane REC under extreme heat (50°C); REC values ranged from 47.0–99.5%. Leaf membrane REC was positively correlated with tuber external and internal defects and negatively correlated with yield. REC was negatively correlated with the content of several tuber minerals, such as nitrogen, magnesium, and manganese. Eleven quantitative trait loci (QTLs) were identified for leaf membrane REC, explaining up to 13.8% of the phenotypic variance. Gene annotation in QTL areas indicated associations with genes controlling membrane solute transport and plant responses to abiotic stresses. Vanguard Russet had lower leaf REC and higher expression of sHSP18 under high-temperature stress. Our findings indicate that leaf membrane REC under high temperatures can be used as an indicator of potato heat tolerance. Full article

Common beans (Phaseolus vulgaris L.), besides being an important source of nutrients such as iron, magnesium, and protein, are crucial for food security, especially in developing countries. Common bean cultivation areas commonly face production challenges due to drought occurrences, mainly during the reproductive period. Dry spells last approximately 20 days, enough time to compromise production. Hence, it is crucial to understand the genetic and molecular mechanisms that confer drought tolerance to improve common bean cultivars’ adaptation to drought. Sixty six RNASeq libraries, generated from tolerant and sensitive cultivars in drought time sourced from the R5 phenological stage at 0 to 20 days of water deficit were sequenced, generated over 1.5 billion reads, that aligned to 62,524 transcripts originating from a reference transcriptome, as well as 6673 transcripts obtained via de novo assembly. Differentially expressed transcripts were functionally annotated, revealing a variety of genes associated with molecular functions such as oxidoreductase and transferase activity, as well as biological processes related to stress response and signaling. The presence of regulatory genes involved in signaling cascades and transcriptional control was also highlighted, for example, LEA proteins and dehydrins associated with dehydration protection, and transcription factors such as WRKY, MYB, and NAC, which modulate plant response to water deficit. Additionally, genes related to membrane and protein protection, as well as water and ion uptake and transport, were identified, including aquaporins, RING-type E3 ubiquitin transferases, antioxidant enzymes such as GSTs and CYPs, and thioredoxins. This study highlights the complexity of plant response to water scarcity, focusing on the functional diversity of the genes involved and their participation in the biological processes essential for plant adaptation to water stress. The identification of regulatory and cell protection genes offers promising prospects for genetic improvement aiming at the production of common bean varieties more resistant to drought. These findings have the potential to drive sustainable agriculture, providing valuable insights to ensure food security in a context of climate change. Full article

Aluminum (Al) toxicity in acidic soils can significantly reduce peanut yield. The physiological response of peanut leaves to Al poisoning stress still has not been fully explored. This research examined the influences of Al toxicity on peanut leaves by observing the leaf phenotype, scanning the leaf area and perimeter, and by measuring photosynthetic pigment content, physiological response indices, leaf hormone levels, and mineral element accumulation. Fluorescence quantitative RT–PCR (qPCR) was utilized to determine the relative transcript level of specific genes. The results indicated that Al toxicity hindered peanut leaf development, reducing their biomass, surface area, and perimeter, although the decrease in photosynthetic pigment content was minimal. Al toxicity notably affected the activity of antioxidative enzymes, proline content, and MDA (malondialdehyde) levels in the leaves. Additionally, Al poisoning resulted in the increased accumulation of iron (Fe), potassium (K), and Al in peanut leaves but reduced the levels of calcium (Ca), manganese (Mn), copper (Cu), zinc (Zn), and magnesium (Mg). There were significant changes in the content of hormones and the expression level of genes connected with hormones in peanut leaves. High Al concentrations may activate cellular defense mechanisms, enhancing antioxidative activity to mitigate excess reactive oxygen species (ROS) and affecting hormone-related gene expression, which may impede leaf biomass and development. This research aimed to elucidate the physiological response mechanisms of peanut leaves to Al poisoning stress, providing insights for breeding new varieties resistant to Al poisoning. Full article

Nerve guidance conduits for peripheral nerve injuries can be improved using bioactive materials such as magnesium (Mg) and its alloys, which could provide both structural and trophic support. Therefore, we investigated whether exposure to Mg and Mg-1.6wt%Li thin films (Mg/Mg-1.6Li) would alter acute Schwann cell responses to injury. Using the RT4-D6P2T Schwannoma cell line (SCs), we tested extracts from freeze-killed cells (FKC) and nerves (FKN) as in vitro injury stimulants. Both FKC and FKN induced SC release of the macrophage chemoattractant protein 1 (MCP-1), a marker of the repair SC phenotype after injury. Next, FKC-stimulated cells exposed to Mg/Mg-1.6Li reduced MCP-1 release by 30%, suggesting that these materials could have anti-inflammatory effects. Exposing FKC-treated cells to Mg/Mg-1.6Li reduced the gene expression of the nerve growth factor (NGF), glial cell line-derived neurotrophic factor (GDNF), and myelin protein zero (MPZ), but not the p75 neurotrophin receptor. In the absence of FKC, Mg/Mg-1.6Li treatment increased the expression of NGF, p75, and MPZ, which can be beneficial to nerve regeneration. Thus, the presence of Mg can differentially alter SCs, depending on the microenvironment. These results demonstrate the applicability of this in vitro nerve injury model, and that Mg has wide-ranging effects on the repair SC phenotype. Full article