Search Results (112)

Sustained abiotic stress severely impairs fruit crop growth and development. As plants’ primary environmental sensing organ, fruit tree roots experience disrupted morphogenesis and physiological functions, reducing yield, lowering fruit quality, and threatening orchard ecosystem stability. Abiotic stress is diverse: water deficit from drought, extreme temperature fluctuations, and salinization-induced ion imbalance, heavy metal accumulation, or nutrient disorders. Its complexity requires synergistic and crosstalk regulation of multiple root-specific signaling modules and pathways in root stress perception and transduction. When responding to stress, roots activate hormone, reactive oxygen species (ROS), and calcium ion (Ca²⁺) signaling. These pathways mediate early stress recognition and regulate downstream gene expression and physiological metabolic reprogramming via transcription factors (TFs) and other regulators, determining stress tolerance and adaptability. Using typical abiotic stresses as models, this review outlines the composition, activation mechanisms, specificity, and synergistic effects of root-specific signaling modules/pathways, along with modern biotechnologies for decoding these modules and current research limitations, aiming to reveal the root signal network’s integration mode. Full article

Seed biopriming is increasingly recognized as a strategy capable of inducing molecular memory that enhances plant performance under heavy-metal stress. Here, we investigated how biopriming Silene sendtneri seeds with Paraburkholderia phytofirmans PsJN establishes a transcriptional state that predisposes seedlings for improved cadmium (Cd) tolerance. RNA-seq profiling revealed that primed seeds exhibited differential gene expression prior to Cd exposure, with strong upregulation of detoxification enzymes, antioxidant machinery, metal transporters, photosynthetic stabilizers, and osmoprotectant biosynthetic genes. Enrichment of gene ontology categories related to metal ion detoxification, redox homeostasis, phenylpropanoid metabolism, and cell wall organization indicated that biopriming imprints a preparatory transcriptional signature resembling early stress responses. Upon Cd exposure, primed plants displayed enhanced physiological performance, including preserved integrity, elevated antioxidant activity, particularly peroxidases in roots, higher osmolyte accumulation, stabilized micronutrient levels, and substantially increased Cd uptake and sequestration. These coordinated responses demonstrate that biopriming induces a sustained molecular memory that accelerates and strengthens downstream defense activation. These findings demonstrate that PGPR-based biopriming establishes a stable transcriptomic memory in seeds that enhances cadmium tolerance, metal sequestration, and stress resilience, highlighting its potential for improving hyperaccumulator performance in phytoremediation and stress adaptation strategies. Full article

Agricultural systems in Mediterranean-type climates are increasingly threatened by drought, salinity, extreme temperatures, heavy metal contamination, and pathogen pressure, all of which undermine crop productivity and agroecosystem stability. In this context, arbuscular mycorrhizal fungi (AMF), natural symbionts of most terrestrial plants, emerge as key biological agents capable of enhancing crop resilience. Following PRISMA guidelines, this systematic review synthesizes current knowledge on the role of AMF in mitigating abiotic and biotic stresses, highlighting their potential as a central component of sustainable Mediterranean agriculture. The available evidence demonstrates that AMF symbiosis significantly increases plant tolerance to multiple stressors across major crop families, including Poaceae, Fabaceae, Solanaceae, and Asteraceae. Under abiotic constraints, AMF improve water and nutrient uptake via extensive hyphal networks, modulate ion homeostasis under salinity, enhance tolerance to thermal extremes, and reduce heavy metal toxicity by immobilizing contaminants. Regarding biotic stresses, AMF induce systemic resistance to pathogens, stimulate secondary metabolite production that deters herbivores, and suppress parasitic nematode populations. Moreover, co-inoculation with other biostimulants, such as plant growth-promoting rhizobacteria, shows synergistic benefits, further improving crop productivity and resource-use efficiency. Overall, AMF represent an effective and multifunctional nature-based tool for improving the sustainability of Mediterranean agroecosystems. However, further research is required to evaluate AMF performance under simultaneous multiple stress factors, thereby reflecting real-world conditions and enabling a more integrated understanding of their agronomic potential. Full article

Drought, salinity, heavy metal contamination and temperature fluctuations are increasingly constraining crop production. Conventional agronomic and chemical approaches alone often fail to ensure stable yields under these abiotic stresses. Nanomaterials are emerging as complementary tools for improving stress tolerance and helping to stabilize yield because they can interact efficiently with key processes at the rhizosphere, at the leaf surface and within cells. Their high surface area, tunable surface chemistry and functionalization, and controlled-release properties make them suitable for root application, foliar spraying, and seed treatment. These features enable low-dose, efficient, and targeted delivery. This review delineates five mechanistic dimensions: restoring redox homeostasis; enhancing nutrient uptake and maintaining ion balance; modulating signaling factors and hormone levels; influencing gene expression; and improving structural and physiological traits at the root and chloroplast levels. Based on case studies under salinity, drought, and heavy metal conditions, we summarize material- and route-dependent differences in efficacy and define dose boundaries. Moreover, the current limitations arising from limited field evidence and nonuniform evaluation standards are also highlighted. Accordingly, we outline key considerations for material design and application assessment, underscoring the value of this review in integrating mechanisms and guiding the practical translation of nanomaterials for stress alleviation in plants. Full article

Heavy metal contamination in water is a critical global environmental challenge. Pontederia crassipes has significant potential in phytoremediation due to its rapid proliferation and high adsorption capacity, and this review aims to synthesize its efficacy and mechanisms in removing heavy metals from water. Bibliometric analysis showed a significant increase in relevant research since 2000, with India and China as major contributors. P. crassipes exhibits high removal efficiencies for Cu (up to 97%), Cr (up to 85.7%), Pb (71.21–85.95%), and Zn (76.0–90.1%), along with 50–79.5% in multi-metal systems. Its remediation mechanisms involve root-dominated synergistic physical (e.g., electrostatic attraction) and chemical (e.g., ion exchange) processes. It has advantages like pH tolerance (3.5–11.0) and low cost, but faces risks of ecological invasion and secondary pollution from biomass, while its derived biochar has a stronger adsorption capacity. P. crassipes is an efficient phytoremediator, but rigorous management strategies are needed to mitigate risks. Future research should focus on improving efficiency and controlling invasion to preserve the ecosystem’s natural biodiversity. Full article

Cobalt (Co) is an essential micronutrient for many organisms, but, at higher concentrations, it becomes harmful, primarily due to competitive interactions with other metal ions. Enzyme inhibition and disruption of nutrient homeostasis may lead to oxidative stress in Co-exposed cells. Compared to other heavy metals, such as Cd, Cu, Cr, Pb, or Ni, this element has been less studied in algae with respect to its toxicity and tolerance. Taking into account Co-induced oxidative stress and antioxidant response, the studies on algae usually did not cover a wider range of antioxidants and ROS-detoxifying enzymes monitored in one model. The aim of this study was to assess the impact of CoCl₂ on the model green microalga Chlamydomonas reinhardtii from a broader perspective. We monitored algal growth, photosynthetic pigment content, the maximum quantum yield of photosystem II (F_v/F_m), the efficiency of nonphotochemical quenching of chlorophyll fluorescence (NPQ), and oxidative stress markers (superoxide production, lipid peroxidation). The measured antioxidants included soluble thiols, ascorbate (Asc), proline (Pro), α-tocopherol (α-Toc), and plastoquinol (PQH₂-9). The superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities were also determined. Exposure to CoCl₂ resulted in increased levels of thiols, Asc, α-Toc, PQH₂-9, and CAT activity. At lower concentrations of CoCl₂, no increase in oxidative stress markers was observed, suggesting efficient antioxidant protection. On the contrary, exposure to higher concentrations of CoCl₂ caused the inhibition of growth and chlorophyll (Chl) synthesis, as well as the reduction in the Chl a/Chl b ratio, the F_v/F_m parameter, the efficiency of NPQ induction, and the levels of lipophilic antioxidants, along with an increase in lipid hydroperoxides. An interesting and novel result is the inhibitory effect of Co toxicity on state transitions in exposed algae. Full article

As a typical heavy metal pollutant, cadmium (Cd) poses significant threats to ecosystems and human health. Giant duckweed (Spirodela polyrhiza), a small aquatic plant characterized by rapid growth and efficient heavy metal accumulation, holds great promise for phytoremediation. However, the mechanisms by which S. polyrhiza enriches Cd—particularly the contributions of its surface-associated microbiota—remain poorly understood. In this study, S. polyrhiza fronds were exposed to 0, 1, and 10 μM Cd, and we observed a concentration-dependent increase in the abundance of epiphytic microorganisms on the frond surfaces. High-throughput 16S rRNA gene sequencing revealed that Cd stress significantly altered the diversity of the frond-epiphytic bacterial community. Notably, the relative abundances of the genera Herbaspirillum, Enterobacter, and Pantoea increased significantly with rising Cd concentrations. Functional prediction using PICRUSt2 indicated enrichment under Cd stress of specific traits—such as the nitrate/nitrite transporter NarK, signal transduction mechanisms, and ion channel proteins—suggesting these taxa may actively participate in Cd uptake and tolerance. Together, our results reveal a synergistic S. polyrhiza–microbiome response to Cd and identify taxa/functions as targets and biomarkers for microbe-augmented remediation. Full article

Cadmium (Cd) contamination poses significant threats to aquatic ecosystems. Heavy metal-associated isoprenylated plant proteins (HIPPs) are plant-specific chaperones involved in metal ion homeostasis and stress adaptation. Lotus is an aquatic plant with high biomass and Cd accumulation capacity, showing great potential in water remediation. However, the functional characterization of HIPPs in lotus remains unexplored, limiting its application in phytoremediation. We conducted comprehensive characterization of NnHIPP genes in lotus, integrating comparative genomics, Cd-stress transcriptomics, and heterologous expression assays in transgenic yeast. This study identified 33 NnHIPP genes classified into five subfamilies with conserved motifs and structures. Synteny analysis revealed closer evolutionary relationships with dicots (Arabidopsis and Medicago sativa) than monocots. Abundant stress-responsive elements were found in NnHIPPs promoters. Tissue-specific expression profilings indicated functional diversification across organs and developmental stages. Our transcriptome analysis revealed that most NnHIPPs responded to Cd stress, with stronger induction in roots than leaves. Four Cd-induced NnHIPPs (NnHIPP10/14/21/33) showed both plasma membrane and nuclear localization. Notably, NnHIPP14, NnHIPP21, and NnHIPP33 conferred varying degrees of Cd tolerance when overexpressed in yeast. Our study demonstrates that NnHIPPs participate in Cd stress response. Three candidate NnHIPP genes are proposed for genetic engineering to enhance phytoremediation efficiency in lotus. Full article

Heavy metal pollution is becoming increasingly severe, and cadmium (Cd) is one of the most threatening pollutants. The PCR (Plant cadmium resistance) gene encodes a class of small transmembrane proteins containing the PLAC8 motif, which confer cadmium tolerance to plants through multiple mechanisms such as efflux, compartmentalization, chelation, and antioxidant activity, and regulate fruit size and ion homeostasis. This study systematically integrated the PLAC8/PCR gene families from mosses, monocots, and dicots, revealing their structural and functional relationships, evolutionary trajectories, and functional diversification patterns through phylogenetic and motif analyses, providing a theoretical basis for cadmium-resistant breeding and environmental remediation. Future research should further integrate multi-omics and gene editing technologies to deeply elucidate the transport mechanism of the PCR protein pentamer and the functional differences of key motifs (CCXXXXCPC, CCXXCAL, and CCXXG), and conduct field trials to assess their ecological safety and crop application potential. Full article

Plants are frequently exposed to a range of abiotic stresses, including drought, salinity, extreme temperatures, and heavy metals, that severely impair their growth and productivity. Among the adaptive mechanisms that plants have evolved, the accumulation of glycine betaine (GB), a naturally occurring, zwitterionic, and chemically stable osmoprotectant, has been widely recognized as a key strategy for stress tolerance. In higher plants, GB is primarily synthesized via the two-step oxidation of choline, catalyzed by choline monooxygenase (CMO) and betaine aldehyde dehydrogenase (BADH). GB contributes to cellular homeostasis by modulating osmotic balance, regulating ion flux, scavenging reactive oxygen species (ROS), enhancing antioxidant defense systems, and stabilizing proteins and membrane structures. Both exogenous application of GB and genetic engineering approaches aimed at enhancing endogenous GB biosynthesis have been shown to significantly improve plant tolerance to a variety of abiotic stresses. In this review, we provide a comprehensive overview of recent advances in the understanding of GB biosynthesis, its regulatory mechanisms, and its multifaceted roles in plant stress responses. We also highlight emerging prospects for leveraging GB-centered strategies to enhance crop resilience in challenging environmental conditions. Full article

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

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

Suaeda salsa, a halophytic plant species, exhibits a remarkable salt tolerance and demonstrates a significant phytoremediation potential through its capacity to absorb and accumulate saline ions and heavy metals from soil substrates, thereby contributing to soil quality amelioration. Furthermore, this species serves as a critical habitat component for avifauna populations and represents a keystone species in maintaining ecological stability within estuarine and coastal wetland ecosystems. With the development and maturity of UAV remote sensing technology in recent years, the advantages of using UAV imagery to extract weak targets are becoming more and more obvious. In this paper, for Suaeda salsa, which is a weak target with a sparse distribution and inconspicuous features, relying on the high-resolution and spatial information-rich features of UAV imagery, we establish an adaptive contextual information extraction deep learning semantic segment model (ACI-Unet), which can solve the problem of recognizing Suaeda salsa from high-precision UAV imagery. The precise extraction of Suaeda salsa was completed in the coastal wetland area of Dongying City, Shandong Province, China. This paper achieves the following research results: (1) An Adaptive Context Information Extraction module based on large kernel convolution and an attention mechanism is designed; this module functions as a multi-scale feature extractor without altering the spatial resolution, enabling a seamless integration into diverse network architectures to enhance the context-aware feature representation. (2) The proposed ACI-Unet (Adaptive Context Information U-Net) model achieves a high-precision identification of Suaeda salsa in UAV imagery, demonstrating a robust performance across heterogeneous morphologies, densities, and scales of Suaeda salsa populations. Evaluation metrics including the accuracy, recall, F1 score, and mIou all exceed 90%. (3) Comparative experiments with state-of-the-art semantic segmentation models reveal that our framework significantly improves the extraction accuracy, particularly for low-contrast and diminutive Suaeda salsa targets. The model accurately delineates fine-grained spatial distribution patterns of Suaeda salsa, outperforming existing approaches in capturing ecologically critical structural details. Full article