Search Results (149)

The natural resistance-associated macrophage proteins (NRAMPs) gene family represents a group of membrane transporter proteins with wide distribution in plants. This family of membrane transporters plays a pivotal role in mediating plant responses to metal stress by coordinating ion transport processes and maintaining cellular metal homeostasis, thereby effectively mitigating the detrimental effects of metal ion stress on plant growth and development. This study conducted a comprehensive genome-wide analysis of the NRAMP gene family in A. tauschii using integrated bioinformatics approaches, as well as the expression pattern when exposed to heavy metal-induced stress. By means of phylogenetic investigation, eleven AetNRAMP proteins were categorized into five distinct subgroups. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis revealed that the majority of NRAMP genes exhibited marked differential expression patterns under specific stress treatments. Subsequently, yeast cells were employed to validate the functions of AetNRAMP1 and AetNRAMP3. It was confirmed that AetNRAMP1 functioned in copper transport, and AetNRAMP3 showed an increase in its expression level under manganese stress. These findings establish a molecular foundation for elucidating the functional specialization of NRAMP gene family members in A. tauschii’s heavy metal detoxification pathways, providing critical genetic evidence for their stress-responsive regulatory networks. Nevertheless, significant knowledge gaps persist regarding its functions in A. tauschii. Research on metal stress resistance in this wheat progenitor species may establish a theoretical foundation for enhancing wheat tolerance and developing improved cultivars. Full article

The primary worldwide variables limiting plant development and agricultural output are the ever-present threat that environmental stressors such as salt (may trigger osmotic stress plus ions toxicity, which impact on growth and yield of the plants), drought (provokes water stress, resulting in lowering photosynthesis process and growth rate), heavy metals (induced toxicity, hindering physiological processes also lowering crop quantity and quality), and pathogens (induce diseases that may significantly affect plant health beside productivity). This review explores the integrated effects of these stressors on plant productivity and growth rate, emphasizing how each stressor exceptionally plays a role in physiological responses. Owing to developments in technology that outclass traditional breeding methods and genetic engineering techniques, powerful alleviation strategies are vital. New findings have demonstrated the remarkable role of nanoparticles in regulating responses to these environmental stressors. In this review, we summarize the roles and various applications of nanomaterials in regulating abiotic and biotic stress responses. This review discusses and explores the relationship between various types of nanoparticles (metal, carbon-based, and biogenic) and their impact on plant physiology. Furthermore, we assess how nanoparticle technology may play a role in practices of sustainable agriculture by reducing the amount of compounds used, providing them with a larger surface area, highly efficient mass transfer abilities, and controlled, targeted delivery of lower nutrient or pesticide amounts. A review of data from several published studies leads to the conclusion that nanoparticles may act as a synergistic effect, which can effectively increase plant stress tolerance and their nutritional role. Full article

In recent decades, heavy metal pollution has become a significant environmental stress factor. Plants are characterized by high biochemical plasticity and can adjust their metabolism to ensure survival under a changing environment. Here we report, to our knowledge, the first gas chromatography-mass spectrometry (GC-MS)-based metabolomics study of Zn-induced stress responses in Amaranthus caudatus plants. The study was performed with root and leaf aqueous methanolic extracts after their lyophilization and sequential derivatization with methoxylamine hydrochloride and N-methyl-N-(trimethylsilyl)trifluoroacetamide. In total, 419 derivatives were detected in the samples, and 144 of them could be putatively annotated. The metabolic shifts in seven-week-old A. caudatus plants in response to a seven-day treatment with 300 µmol/L ZnSO₄·7H₂O in nutrient solution were organ-specific and more pronounced in roots. Most of the responsive metabolites were up-regulated and dominated by sugars and sugar acids. The revealed effects could be attributed to the involvement of these metabolites in osmotic regulation, antioxidant protection and Zn²⁺ complexation. A 59-fold up-regulation of gluconic acid in roots distinctly indicated enhanced glucose oxidation due to oxidative stress upon the Zn treatment. Gluconic acid might be further employed in Zn²⁺ complexation. Pronounced Zn-induced up-regulation of salicylic acid in roots and shoots suggested a key role of this hormone in stress signaling and activation of Zn stress tolerance mechanisms. Overall, our study provides the first insight into the general trends of Zn-induced biochemical rearrangements and main adaptive metabolic shifts in A. caudatus. Full article

The heavy metal-associated (HMA) domain-harboring proteins constitute critical players involved in the transport of various metal ions in plants, and are associated with development and stress responses. Herein, a total of 243 TaHMA genes were identified in the bread wheat genome, each of which had a characteristic molecular profile and a distinct chromosomal localization. The TaHMA proteins were distributed in five clades in phylogeny, which differed with respect to the distribution of the key HMA domain. Sub-cellular localization was variable for the TaHMA proteins. Gene structure analysis yielded similar results when compared with the orthologous counterparts. Cis-regulatory element analysis produced a range of promoter elements, suggesting their diverse biological roles. Gene duplication analysis revealed a crucial role played by tandem and segmental duplication events in the expansion of TaHMA genes. Synteny analysis highlighted the evolutionary relatedness of TaHMA genes with those derived from Arabidopsis and rice. Expression analysis provided crucial information about the role of TaHMAs in mediating vital responses in the plant body, including the development of tissues and the regulation of various abiotic stress conditions. Overall, the study provides significant cues and evidence to functionally annotate and characterize the differentially expressed TaHMAs in order to validate their role. Full article

Background: Phytoremediation is an efficient approach for remediating heavy metal-contaminated soils. Heavy metal-associated isoprenylated plant proteins (HIPPs)—crucial for metal ion homeostasis—are unique to vascular plants, featuring a heavy metal-associated (HMA) domain and an isoprenylated CaaX motif. However, ZmHIPP genes have not been systematically or functionally characterized in maize. Methods: This study characterizes ZmHIPP at the genome-wide level, including phylogenetic classification, motif/gene structure, chromosome location, gene duplication events, promoter elements, and tissue expression patterns. Cadmium (Cd) responses were evaluated by specific ZmHIPP expression and Cd accumulation in shoots and roots under Cd treatment. Results: A total of 66 ZmHIPPs were distributed unevenly across ten chromosomes, classified into five phylogenetic groups phylogenetically. Gene collinearity revealed 26 pairs of segmental duplications in ZmHIPPs. Numerous synteny genes were detected in rice and sorghum, but none in Arabidopsis, suggesting high conservation of HIPP genes in crop evolution. Transcriptomic analysis revealed tissue-specific expression patterns of ZmHIPP members in maize. Cis-acting element analysis linked several binding elements to abscisic acid, MeJA response, and MYB and MYC transcription factors. Under Cd stress, 53 out of 66 ZmHIPP genes were significantly induced, exhibiting three expression patterns. Cd exposure confirmed that the expression of ZmHIPP11, ZmHIPP30, and ZmHIPP48 was generally higher in shoots than roots, while ZmHIPP02 and ZmHIPP57 exhibited the opposite. Cd accumulation was higher in roots than shoots, peaking at 72 h (96 mg/kg) in shoots and exceeding 1000 mg/kg in roots after 120 h. Conclusions: This study not only provides fundamental genetic and molecular insights into HIPP function in maize but also identifies specific ZmHIPP genes as promising genetic resources for breeding Cd-tolerant maize, aiding in phytoremediation of Cd-contaminated soils. Full article

Salinity and heavy metal stress significantly reduce agricultural productivity in arable lands, particularly affecting crops like rice (Oryza sativa L.). This study aimed to evaluate the efficacy of heavy metal-tolerant plant growth-promoting rhizobacteria (HMT-PGPR) in mitigating the harmful effects of salt (NaCl), chromium (Cr), and combined NaCl + Cr stress on rice plants. Two pre-isolated and well-characterized heavy metal-tolerant epiphytic (Ochrobactrum pseudogrignonense strain P14) and endophytic (Arthrobacter woluwensis strain M1R2) PGPR were tested. The LSD test (p ≤ 0.05) was used to assess the statistical significance between treatment means. Stresses caused by NaCl, Cr, and their combination were found to impair plant growth and biomass accumulation through mechanisms, including osmotic stress, oxidative damage, ionic imbalance, reduced photosynthetic pigment, lowered relative water content, and compromised antioxidant defense systems. Conversely, inoculation with HMT-PGPR alleviated these adverse effects by reducing oxidative stress indicators, including malondialdehyde (MDA), hydrogen peroxide (H₂O₂) content and electrolyte leakage (EL) and enhancing plant growth, osmolyte synthesis, and enzymatic antioxidant activity under single- and dual-stress conditions. The application of HMT-PGPR notably restricted Na⁺ and Cr⁶⁺ uptake, with an endophytic A. woluwensis M1R2 demonstrating superior performance in reducing Cr⁶⁺ translocation (38%) and bioaccumulation (42%) in rice under dual stress. The findings suggest that A. woluwensis effectively mitigates combined salinity and chromium stress by maintaining ion homeostasis and improving the plant’s antioxidant defenses. Full article

Non-invasive Micro-test Technology (NMT) represents a pioneering approach in the study of physiological functions within living organisms. This technology possesses the remarkable capability to monitor the flow rates and three-dimensional movement directions of ions or molecules as they traverse the boundaries of living organisms without sample destruction. The advantages of NMT are multifaceted, encompassing real-time, non-invasive assessment, a wide array of detection indicators, and compatibility with diverse sample types. Consequently, it stands as one of the foremost tools in contemporary plant physiological research. This comprehensive review delves into the applications and research advancements of NMT within the field of plant abiotic stress physiology, including drought, salinity, extreme temperature, nutrient deficiency, ammonium toxicity, acid stress, and heavy metal toxicity. Furthermore, it offers a forward-looking perspective on the potential applications of NMT in plant physiology research, underscoring its unique capacity to monitor the flux dynamics of ions/molecules (e.g., Ca²⁺, H⁺, K⁺, and IAA) in real time, reveal early stress response signatures through micrometer-scale spatial resolution measurements, and elucidate stress adaptation mechanisms by quantifying bidirectional nutrient transport across root–soil interfaces. NMT enhances our understanding of the spatiotemporal patterns governing plant–environment interactions, providing deeper insights into the molecular mechanism of abiotic stress resilience. Full article

This study evaluated the response of two willow varieties, Salix × smithiana Willd. and Salix viminalis L. var. Gigantea, to selected heavy metals and elevated soil salinity, simulating complex environmental conditions during phytoremediation. Plants propagated from stem cuttings were cultivated in pots under field conditions in soil artificially contaminated with a mixture of Cd, Ni, Cu, Zn, and Pb salts at two concentration levels representing lower and higher guideline thresholds. Sodium chloride was added to induce salinity stress. S. × smithiana exhibited enhanced growth under combined metal and salinity stress, suggesting efficient tolerance mechanisms. This was reflected in elevated relative water content (RWC) and increased accumulation of Zn and Cd in shoots. In contrast, Gigantea showed growth inhibition and primarily sequestered metals in roots, indicating a stress-avoidance strategy and reduced metal translocation. While salinity alone negatively affected both varieties, its combination with metals mitigated growth reduction in S. × smithiana, possibly due to improved ion homeostasis or cross-tolerance. Zn and Cd displayed the highest bioconcentration and mobility. Based on bioconcentration factor (BCF) and translocation factor (TF), S. × smithiana appears suitable for phytoextraction, whereas S. viminalis var. Gigantea appears suitable for phytostabilization. These results support species-specific approaches to phytoremediation in multi-contaminant environments. Full article

Mercury (Hg) pollution has led to a serious decline in crop yields. Methyl jasmonate (MJ), as a plant hormone, regulates plant responses to heavy metal stress. Nonetheless, the pathways by which MJ modulates Hg tolerance in plants are still not well elucidated. Our study aimed to elucidate the positive impacts of MJ in alleviating Hg-induced toxicity in maize (Zea mays L.) seedlings using an integrated approach combining physiological assessments and transcriptomic analysis. The findings indicated that exogenous MJ mitigated Hg-induced inhibition of photosynthetic performance by up-regulating photosynthesis-related and light-harvesting-related genes and increasing chlorophyll content. Under Hg stress, MJ enhances proline accumulation in maize seedlings by up-regulating essential genes in the proline biosynthesis pathway and down-regulating critical genes in the proline degradation pathway. MJ also elevates the expression of key enzymes involved in phenylpropanoid biosynthesis in maize seedlings, decreases malondialdehyde (MDA) content, and enhances root vitality. In addition, MJ may exert a detoxification effect on maize seedlings under Hg stress by regulating the expression of various genes linked to basic nutrient transport proteins, as well as those involved in the transport, influx, and distribution of metal ions. These findings indicate that MJ is essential for enhancing plant tolerance to Hg stress, thereby establishing a theoretical framework for the advancement and utilization of environmentally friendly agricultural methods involving plant hormones. Full article

Rice, one of the global staple food crops, is significantly affected in its growth by cadmium (Cd) contamination in soil. This study comprehensively investigated the impact of Cd stress on the root exudates and rhizospheric soil microorganisms of rice through non-targeted metabolomics and high-throughput 16S rRNA sequencing technologies, as well as the ecological regulatory mechanisms between them. Root exudates reflect proactive plant defenses and enhance these capabilities by attracting beneficial microorganisms, which play a pivotal role in plant detoxification. There were significant changes in root exudates under Cd stress, their chelation and rejection of Cd ions diminished the bioavailability within the plant system, thereby mitigating the phytotoxic effects of heavy metal stress and safeguarding the overall health of plants. Moreover, Proteobacteria (Lysobacter, Pseudaminobacter, and Sphingomonas) were recruited by the root exudates from rice as potential participants in plant tolerance and detoxification processes. These findings offer novel insights into the ecological adaptability mechanisms of rice under heavy metal stress and provide potential biomarkers and microbial resources for agricultural environmental regulation. Full article

Ensuring food security is essential for achieving sustainable global development, requiring a balance between sufficient food production and maintaining its safety and nutritional value. However, this objective faces considerable challenges due to the infiltration of toxic metal species into the food supply. Heavy metals and metalloids, depending on their molecular form and daily dose, exhibit varying degrees of toxicity, making the precise identification of their species essential for assessing their impact on human health and the environment. This study focuses on identifying the primary anthropogenic sources and dissemination pathways of heavy metal pollutants, with an emphasis on their speciation and bioavailability. It examines how toxic metal species, such as Pb²⁺, Cd²⁺, Hg²⁺, and various arsenic species (AsIII and AsV), infiltrate ecosystems, bioaccumulate within the food chain, and ultimately compromise food safety and nutritional value. Furthermore, the research explores the physiological and biochemical disruptions caused by these toxic metal species, including the displacement of essential ions from enzymatic active sites and transport proteins due to competitive binding by pollutants, oxidative stress induced by reactive oxygen species generation, and cellular dysfunction affecting metabolic pathways and signaling cascades, all of which contribute to both chronic and acute health conditions. By providing a detailed analysis of exposure routes and toxicological processes, this paper highlights the far-reaching consequences of heavy metal contamination on public health and agricultural sustainability. Special attention is given to the need for precise terminology, as the toxicity of metals is inherently linked to their daily dose and chemical species rather than their elemental form. Finally, this study advocates for integrated, multidisciplinary strategies aimed at mitigating these risks, enhancing ecosystem stability, and ensuring long-term food security in the face of environmental challenges. Full article

Fusarium oxysporum is one of the main pathogens causing rice seedling blight disease. Revealing its pathogenic mechanism is of great significance for formulating prevention and control strategies for rice seedling blight disease. Copper transporting P-type ATPases (Cu-ATPase) is a large class of proteins located on the plasma membrane that utilize the energy provided by ATP hydrolysis phosphorylation to transport substrates across the membrane. It plays a crucial role in signal transduction, the maintenance of cell membrane stability, and material transport. The main function of Cu-ATPase is to maintain the homeostasis of copper in cells, which is essential for the normal growth and development of organisms. This study utilized the ATMT-mediated gene knockout method to obtain the knockout mutant ∆FoCrpA and the complementation strain ∆FoCrpA-C, which are highly homologous to the P-type heavy metal transport ATPase family in F. oxysporum. The results showed that, compared with the wild-type strain, the knockout mutant ∆FoCrpA had a lighter colony color; a reduced tolerance to copper ion, osmotic, and oxidative stress; a weakened ability to penetrate glass paper; and decreased pathogenicity. However, there was no significant difference in pathogenicity and other biological phenotypes between the complementation strain ∆FoCrpA-C and the wild-type strain. In summary, the FoCrpA gene is involved in osmotic and oxidative stress, affecting the invasion and penetration ability and pathogenicity of F. oxysporum, laying a theoretical foundation for understanding the development and pathogenic mechanism of F. oxysporum. Full article

Background: Heavy metal contamination significantly threatens crop growth and global food security. Understanding plant responses to such stress is crucial to developing stress-tolerant crops. This study explores the physiological and biochemical responses of Vigna radiata (L.) R. Wilczek to mercury, lead, and copper stress, focusing on the role of soluble sugar accumulation and biomass enhancement in conferring heavy metal tolerance. Methods: Commercially available V. radiata seeds were exposed to varying concentrations (50, 150, and 300 mg/L) of mercurous nitrate, lead nitrate, and copper chloride under controlled conditions. The germination rates, seedling growth, and physiological parameters such as the soluble sugar and protein content were analyzed using spectrophotometry and statistical methods, including ANOVA. Results: The results demonstrated that lead ion stress significantly increased the seedling dry weight, while all the tested heavy metals promoted soluble sugar accumulation. Although the heavy metals inhibited germination and growth at higher concentrations, Vigna radiata exhibited strong tolerance at moderate stress levels. Conclusion: This study highlights the adaptive strategies of V. radiata, including soluble-sugar-mediated osmotic adjustment and enhanced biomass allocation, which contribute to its resilience under heavy metal stress. These findings provide insights for breeding stress-resistant crops and managing heavy-metal-contaminated environments. Full article

In China, soil contamination by heavy metals is a widespread issue, with substantial increases in lead(Pb), cadmium(Cd), copper(Cu), and zinc(Zn) levels observed across various regions. Particularly, the concentrations of Pb and Cd significantly exceed their natural background levels. P-ATPases, a group of proteins, utilize energy from ATP hydrolysis to support the transmembrane movement of metal ions. This group encompasses several Heavy Metal Associated Transporter (HMA) ATPases. Studies on hyperaccumulators have shown the critical role of HMAs in the movement and reduction in Zn and Cd toxicity in plant systems. This research identifies a protein encoded by the SpHMA gene from Sedum plumbizincicola, a species noted for aiding Zn/Cd hyperaccumulators, which enhances tolerance to Cd and Zn. We detail a protein encoded by SpH/A within the HMA family that enhances Cd tolerance. Real-time fluorescence quantification (RT-PCR) indicates that SpHMA3 expression in Arabidopsis thaliana and Zea mays KN5585 correlates with high Cd tolerance, linked to Cd accumulation in Zea mays. In addition, homozygous Arabidopsis thaliana AtHMA3 mutants exhibited increased Cd sensitivity compared to the wild type (WT). Notably, plants of Arabidopsis thaliana and maize overexpressing SpHMA3 showed enhanced Cd stress tolerance compared to WT. Enhanced Cd accumulation in tissues was observed when SpHMA3 was overexpressed, as revealed by subcellular distribution analysis. We propose that SpHMA3 augments maize tolerance to Cd and Zn stresses through enhanced cellular uptake and translocation of Cd ions. This investigation clarifies the gene function of SpHMA3 in Cd and Zn stress response, offering insights for enhancing heavy metal absorption traits in maize varieties and phytoremediation methods for soils contaminated with heavy metals. Full article

Aegilops tauschii, a monocotyledonous annual grass, recognized as a pivotal progenitor of modern wheat (Triticum aestivum L.), serves as the D-genome donor in hexaploid wheat. This diploid species (2n = 2x = 14, DD) harbors a substantial reservoir of genetic diversity, particularly in terms of biotic and abiotic stress resistance traits. The extensive allelic variation present in its genome has been increasingly utilized for wheat genetic enhancement, particularly through introgression breeding programs aimed at improving yield potential and stress resilience. Heavy metal ATPases (HMAs), which belong to the P-type ATPase superfamily and are also known as P1B-type ATPases, play a crucial role in transporting heavy metals and maintaining metal ion homeostasis in plant cells. HMAs have been extensively studied in model plants like Arabidopsis thaliana and rice. However, this family has not been reported in A. tauschii. Here, we conducted the genome-wide identification and bioinformatics analysis of the AetHMA gene family in A. tauschii, resulting in the discovery of a total of nine AetHMA members. Among AetHMA genes, six pairs are large-block duplication genes, which mainly occur among the four genes of AetHMA2, AetHMA4, AetHMA8, and AetHMA9. Additionally, there is one pair that consists of tandem duplication genes (AetHMA6: AetHMA7). All AetHMAs can be classified into six groups (I–VI), which are further divided into two branches: the copper subclasses and the zinc subclasses. Initially, A. tauschii was grown in a 1/2 Hoagland nutrient solution and subsequently exposed to four heavy metals: zinc (Zn), copper (Cu), manganese (Mn), and cadmium (Cd). Following this treatment, the expression profiles of nine AetHMA genes were assessed. The results indicated that, under zinc and manganese stress, the HMA family members exhibited enhanced expression in the leaves, whereas the expression of most members in the roots was downregulated. In the roots, except for AetHMA2, AetHMA5, and AetHMA8, the expression levels of other members were upregulated in response to Cd exposure. Furthermore, AetHMA4 diminishes the tolerance of yeast to Mn by increasing the absorption of Mn, while AetHMA8 increases the tolerance of yeast to Cd by reducing the absorption of Cd. This study provides experimental data regarding the function of the AetHMA gene in the transport, regulation, and detoxification of heavy metal elements in A. tauschii. Full article