Journal of Hazardous Materials

Cadmium (Cd) has long been recognized as toxic pollutant to crops worldwide. The biosynthesis of glutathione-dependent phytochelatin plays crucial roles in the detoxification of Cd in plants. However, its regulatory mechanism remains elusive. Here, we revealed that Arabidopsis transcription factor WRKY45 confers Cd tolerance via promoting the expression of PC synthesis-related genes PCS1 and PCS2, respectively. Firstly, we found that Cd stress induces the transcript levels of WRKY45 and its protein abundance. Accordingly, in contrast to wild type Col-0, the increased sensitivity to Cd is observed in wrky45 mutant, while overexpressing WRKY45 plants are more tolerant to Cd. Secondly, quantitative real-time PCR revealed that the expression of AtPCS1 and AtPCS2 is stimulated in overexpressing WRKY45 plants, but decreased in wrky45 mutant. Thirdly, WRKY45 promotes the expression of PCS1 and PCS2, electrophoresis mobility shift assay analysis uncovered that WRKY45 directly bind to the W-box cis-element of PCS2 promoter. Lastly, the overexpression of WRKY45 in Col-0 leads to more accumulation of PCs in Arabidopsis, and the overexpression of PCS1 or PCS2 in wrky45 mutant plants rescues the phenotypes induced by Cd stress. In conclusion, our results show that AtWRKY45 positively regulate Cd tolerance in Arabidopsis via activating PCS1 and PCS2 expression. Environmental implicationAccumulation of cadmium (Cd) in soils poses a threat to crop productivity and food safety. It has been revealed that phytochelatin (PC) plays an essential role in plants to alleviate Cd toxicity, yet the regulatory mechanisms governing its expression remain unclear. We have demonstrated that the Arabidopsis transcription factor WRKY45 directly activates the expression of PCS1 and PCS2, which encode PC synthase, thereby increasing the content of PC and enhancing Arabidopsis tolerance to Cd stress. These findings offer insights into precise regulation strategies for crop Cd tolerance via modulation of WRKY45 homologue in crops.

Bacteria are continually challenged with variety of synthetic chemicals/xenobiotics in their immediate surroundings, including pesticides. Chlorpyrifos is one of the most commonly used organophosphate pesticides in the world. The non-environmental strain of Escherichia coli, BL21 (DE3) displayed high tolerance to chlorpyrifos but with no/negligible degradation. The intrinsic resistance mechanisms that aid the organism in its high tolerance are probed. Efflux pumps being ubiquitous in nature and capable of conferring resistance against wide variety of xenobiotics were found to be over-expressed in the presence of CP. Also, an efflux pump inhibitor PA{beta}N increased the susceptibility of E. coli to chlorpyrifos due to the intracellular accumulation of CP. The tripartite efflux pump EmrAB-TolC with increased expression in both transcript and protein on CP exposure, might play a major role in CP tolerance. The transcriptional regulators involved in multidrug resistance along with transporters belonging to all the major families conferring antimicrobial resistance were up-regulated. Also up-regulated were the genes involved in phopshonate metabolism and all the genes in the copper or silver export system. The common resistance mechanisms i.e, activation of efflux pumps between CP, antibacterial metals and antibiotics resistance might result in cross-resistance, ultimately increasing the prevalence of multidrug resistant strains, making infections hard to treat.

Microbiota plays a crucial role to protect the intestine contrary to the harmful foreign microorganisms and organize the immune system via numerous mechanisms, which include either direct or indirect environmental factors. The underlying mechanism arsenic (As) influenced immune system and regulates inflammation by altering gut microbiome in ileum remains unclear. However, chronic exposure to arsenic (at doses of 0.15 mg or 1.5 mg or 15 mg As2O3/ L in drinking water) significantly increased mRNA and protein levels of F4/80 and CX3CR1, concurrently, the increased levels of mRNA and protein IFN{gamma}, TNF, IL-18 and decreased levels of IL-10 were found in both 3 and 6 months exposure periods. High-throughput sequencing analysis revealed that gut microbiota at phylum; family and taxonomical levels were showed the abundance of gut microbiota. Evidentially, the ultra-structure of intestinal villi, microbes engulfed and immune cell migration were showed by the transmission electron microscopy. Chronic exposure to As influenced the inflammation by changing immune system and altered gut microbiota. In this study we conclude that chronic exposure to As breakdown the normal gut microbial community and increase the pathogenicity, the resultant risk pathogen direct contact with intestinal immune system and regulate the inflammation.

O_LICadmium (Cd) is a major environmental pollutant with high toxicity potential. Even though a reduction of growth, including the primary root, is a clear consequence of Cd exposure, a profound understanding of the impact of Cd on the root apical meristem (RAM) and the elongation/differentiation zone (EDZ) is still lacking. C_LIO_LIIn this study, Arabidopsis thaliana roots were subjected to Cd and divided into root tips (RT) and remaining roots (RR) to separately assess the effect of Cd using transcriptomics, ionomics and metabolomics. C_LIO_LIElemental profiling revealed lower Cd accumulation in RT and differences in mineral contents between RT and RR. Transcriptomic analysis demonstrated distinct gene expression patterns in RT and RR, with Cd having less impact in RT. Functional enrichment analysis revealed genes associated with iron and sulfur homeostasis as well as the response to light in both RR and RT. RT-specific responses to Cd included several genes regulated by the transcription factor ELONGATED HYPOCOTYL 5 (HY5) and notably, the hy5 mutant showed increased Cd sensitivity and accumulation compared to the wild type. C_LIO_LIThis study provides comprehensive insights into the inhibitory effects of Cd on primary root growth, elucidating molecular mechanisms involved, particularly highlighting the role of HY5 in Cd accumulation. C_LI

The increasing use of gold nanoparticles (NPs) raises concerns about the potential effect of gold NPs exposure on human health. Therefore, gold NPs exposure is hard to evaluate at the organ level with current measurement technology. The bio-distribution assay showed that intestine was the organ with most gold NPs accumulated in C. elegans. However, our data indicated that 62.8% of the significant altered genes were function in the nervous system using tissue enrichment analysis. Notably, developmental stage analysis has demonstrated that NP exposure interfered with the development of animals. Furthermore, the transcription factors DAF-16 was regulating the oxidative stress genes induced by gold NPs. Therefore, we proposed the localization of the oxidative stress genes in the neuron cells and how their expression affect neuron communication. Our results demonstrate that the gold NPs-induced oxidative stress affects the nervous system via physical damage to the neurons and disruption of cell-to-cell communication. Future toxicology research on gold NPs should focus on neurons. O_FIG O_LINKSMALLFIG WIDTH=120 HEIGHT=200 SRC="FIGDIR/small/699785v2_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@19effeorg.highwire.dtl.DTLVardef@db10d9org.highwire.dtl.DTLVardef@2f4736org.highwire.dtl.DTLVardef@1ec2a52_HPS_FORMAT_FIGEXP M_FIG Graphical abstract C_FIG

Cadmium (Cd) as a heavy metal causes serious environmental pollution and multiple organ and system damage in human. However, little is known about the specific molecular mechanisms of the associated regulatory networks. In this study, we selected Caenorhabditis elegans (C. elegans) to investigate the effects of Cd exposure as it acts as an acknowledged and established genetic model organism. A total of 26 differentially-expressed circular RNA (DEcircRNAs), 143 lncRNAs (DElncRNAs), 69 microRNAs (DEmiRNAs) and 6209 mRNAs (DEmRNAs) were found and identified, which might influence reproductive function, aging processes and nervous system functions through regulating the levels of circRNAs and lncRNAs and the controlling of regulatory networks of circRNA/lncRNA-miRNA-mRNA. Based on quantitative PCR, four DEcircRNAs and three DElncRNAs were confirmed to have different expression levels between the Cd-treated and control group. Further, 5 protein-coding genes might be regulated by DElnRNAs through cis-acting and 114 by trans-acting elements. Additionally, 42 differentially regulative phosphopeptides were detected and 4 novel pairs of transcription factors (TFs)-kinase-substrate that might be influenced by Cd exposure were constructed by phosphoproteomics. Our findings suggest that Cd might influence multi-functions and the aging process of C. elegans and may inhibit the expression of TFs to reduce phosphorylated levels of the corresponding protein. SynopsisCadmium exists widely in soil, water and air. This study manifested the regulatory network involving circRNA, lncRNA and phosphorylated protein in C.elegans after Cd exposure, which revealing the potential molecular mechanism underlying the toxic effect caused by Cd. Graphic Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=82 SRC="FIGDIR/small/486470v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1a012bborg.highwire.dtl.DTLVardef@2dc128org.highwire.dtl.DTLVardef@1e43ebaorg.highwire.dtl.DTLVardef@1d236b8_HPS_FORMAT_FIGEXP M_FIG C_FIG

Airborne nanoplastics constitute an emerging class of environmental contaminants, but their mitoepigenetic effects on human immune cells have not been systematically investigated. Ex vivo human lymphocytes were used to investigate integrated mitochondrial, epigenetic, and inflammatory responses induced by polystyrene (PS), polypropylene (PP), and polyvinyl chloride (PVC) nanoplastics. Fluorescence microscopy at multiple exposure time points and flow cytometry confirmed efficient cellular internalization and progressive intracellular accumulation of nanoplastics. Exposure elicited coordinated transcriptional remodeling of genes regulating mitochondrial dynamics (DRP1, MFN1), mitochondrial DNA encoded oxidative phosphorylation components (MT-ATP6, MT-COX1, MT-ND6), DNA repair (OGG1, APE1), DNA methylation machinery (DNMT1, DNMT3a, DNMT3b), and mitochondrial-associated miRNAs (miR-21, miR-34a, miR-155). Functional analyses revealed polymer and time-dependent disruption of mitochondrial membrane potential and respiratory chain activities, with Complex I identified as the primary site of vulnerability. Correlation analysis showed strong positive associations among DRP1, OMA1, DELE1, and ND6 (r > 0.9, R{superscript 2} > 0.8, p < 0.001), reflecting coordinated mitochondrial stress and epigenetic signaling, while negative correlations between DRP1 and MFN1 (r = -0.54, R{superscript 2} = 0.29, p < 0.01) and between APE and ND6 (r {approx} -0.42, R{superscript 2} {approx} 0.18, p < 0.05) highlight antagonistic regulation and impaired mitochondrial network stability linked to Complex I dysfunction. In silico docking of oxidized nanoplastic oligomers identified high-affinity interactions at the Complex I Fe-S cluster and cofactor-binding sites, suggesting direct interference with electron transfer. A random forest-based model accurately predicted MT-ND6 expression from Complex I activity (R{superscript 2} > 0.85), establishing a data-driven Complex I-ND6 axis. Collectively, these findings demonstrate that airborne nanoplastics induce integrated mitoepigenetic and immunometabolic dysregulation, underpinned by coordinated and antagonistic regulatory interactions in lymphocytes.

Understanding the toxicity of hazardous metals in microalgae is critical for environmental risk assessment and sustainable phycoremediation. Metal-tolerant organisms provide powerful models for dissecting the mechanisms that mitigate metal toxicity. Here, we investigated the cellular and molecular responses to uranium (U) chemotoxicity in the metal-tolerant microalga Coelastrella sp. PCV. We used an integrated multi-omics and high-resolution imaging approach, combined with physiological analyses, to elucidate the mechanisms underlying U tolerance in Coelastrella. Using TEM-EDX, U was localized to the cell wall, polyphosphate bodies within acidocalcisomes, and vacuoles. Three-dimensional cell reconstruction and morphometric analysis using FIB-SEM showed that U-challenged cells displayed increased vacuolization, reflecting sequestration of uranyl ions and autophagy-mediated detoxification. Transcriptome responses were rapid and extensive, characterized by repression of cell division and photosynthesis, and pronounced imbalance in protein turnover and trafficking. Uranium also disrupted the homeostasis of essential elements, with marked rewiring of gene networks governing molybdenum, manganese, phosphate, iron and calcium homeostasis, notably affecting transporters and metal-binding proteins. Coelastrella sp. PCV efficiently sequestered U in acidocalcisomes and vacuoles, while rapidly excluding U from the cell. These coordinated detoxification responses are likely mediated by calcium, iron, ABC, and MATE transporters among the strongly deregulated genes under U stress.

Numerous autism spectrum disorder (ASD) risk genes are associated with Wnt signaling, suggesting that brain development may be especially sensitive to genetic perturbation of this pathway. Additionally, valproic acid, which modulates Wnt signaling, increases risk for ASD when taken during pregnancy. We previously found that an autism-linked gain-of-function UBE3AT485A mutant construct hyperactivated canonical Wnt signaling, providing a genetic means to elevate Wnt signaling above baseline levels. To identify environmental use chemicals that enhance or suppress Wnt signaling, we screened the ToxCast Phase I and II libraries in cells expressing this autism linked UBE3AT485 gain-of-function mutant construct. Using structural comparisons, we identify classes of chemicals that stimulated Wnt signaling, including ethanolamines, as well as chemicals that inhibited Wnt signaling, such as agricultural pesticides, and synthetic hormone analogs. To prioritize chemicals for follow-up, we leveraged predicted human exposure data, and identified diethanolamine (DEA) as a chemical that both stimulates Wnt signaling in UBE3AT485A-transfected cells and has a high potential for prenatal exposure in humans. DEA also enhanced proliferation in two primary human neural progenitor cell lines. Overall, this study identifies chemicals with the potential for human exposure that influence Wnt signaling in human cells.

Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic chemicals extensively used as plastic additives. Their environmental persistence and potential for bioaccumulation have raised significant toxicological concerns. This study evaluates the cytotoxic and molecular effects of Perfluorooctanoic acid (PFOA) and its replacement compound, Perfluoro(2-methyl-3-oxohexanoic) acid (GenX), in human-derived skin (A375), liver (HepG2), kidney (SN12C), and colon (SW620) cell lines. The experimental design assessed cell viability, gene expression, and perturbations in key cellular stress pathways, with a particular focus on TGF-{beta}/SMAD-mediated inflammation and the p53-driven DNA damage response. Our results demonstrate compound- and cell-type-specific toxicity, with GenX displaying reduced cytotoxicity compared to PFOA across all cell types. Molecular analyses revealed that both PFAS compounds induced alterations in the TGF-{beta}/SMAD pathway, consistent with a pro-inflammatory cellular state. Additionally, we observed activation of the DNA damage response, as evidenced by increased expression of ATM, ATR, and p53, alongside ribosomal stress-related changes in RPL5 and RPL11. Notably, while skin and liver cells exhibited similar response profiles, kidney and colon cells showed divergent modulation of SMAD signaling, suggesting tissue-specific susceptibility and mechanistic differences. These findings contribute to a deeper understanding of the differential toxicological profiles of legacy and replacement PFAS, with implications for health risk assessment and regulatory policy. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=112 SRC="FIGDIR/small/652004v2_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@ce20aaorg.highwire.dtl.DTLVardef@c29608org.highwire.dtl.DTLVardef@1081ae6org.highwire.dtl.DTLVardef@11e0401_HPS_FORMAT_FIGEXP M_FIG C_FIG

Uranium (U) is a non-essential and toxic metal for plants, which have the ability to take up uranyl ions from the soil and preferentially accumulate them in the roots. We showed that the bulk of the radionuclide accumulates in the root insoluble proteome of Arabidopsis plants challenged with U. Therefore, to elucidate new molecular mechanisms related to U stress response and tolerance, we used label-free quantitative proteomics to analyze the dynamics of the root membrane- and cell wall-enriched proteome under U stress. Of the 2,802 proteins identified, 458 showed differential accumulation in response to U. Biological processes affected by U include response to stress, amino acid metabolism, and previously unexplored functions associated with membranes and the cell wall. Indeed, our analysis supports a dynamic and complex reorganization of the cell wall in response to U stress, including lignin and suberin synthesis, pectin modifications, polysaccharide hydrolysis, and Casparian strips formation. Water flux through aquaporins and vesicular trafficking were also significantly perturbed by U stress. Finally, the abundance of metal transporters and iron, calcium, and other metal-binding proteins was affected by U. These proteins may play a role in controlling the fate and toxicity of U in plants.

In this study, the growth morphology of FJ21 strain was observed, and its 16S rRNA and whole genome were sequenced. Then, related software was used to make genome assembly, gene structure and function annotation, genome phylogenetic tree analysis, genome collinearity analysis and prediction of secondary metabolic gene cluster analysis. Finally, the single acute toxicity of five heavy metals to FJ21 strain was detected. There were luxC, luxD, luxA, luxB, luxF, luxE and luxG genes in FJ21, and the protein encoded by lux operon had certain hydrophilicity. The genome of this strain FJ21 contains a chromosome with a total length of 4853277bp and a GC content of 39.23%. The genome of FJ21 was compared with that of Photobacterium kishitanii ATCCBAA-1194, Photobacterium phosphoreum JCM21184, Photobacterium aquimaris LC2-065, Photobacterium malacitanum CECT9190, and Photobacterium carnosum TMW 2.2021. The average nucleotide identity(ANI), tetra nucleotide signatures (Tetra), comparative genome, and phylogenetic analysis proposed that FJ21 is a strain of Photobacterium kishitanii. In the acute toxicity test, the toxicity of heavy metals to the strain FJ21 is Pb(NO3)2 > ZnSO4{middle dot}7H2O > CdCl2{middle dot}2.5H2O > CuSO4{middle dot}5H2O > K2Cr2O7.

Man-made chemicals are a significant contributor to the ongoing deterioration of ecosystems. Currently, risk assessment of these chemicals is based on observations in a single generation of animals, despite potential adverse intergenerational effects. Here, we investigate the effect of the fungicide prochloraz across three generations of Daphnia magna. We studied both the effects of continuous exposure over all generations and the effects of first-generation (F0) exposure on two subsequent, non-exposed, generations. Effects at different levels of biological organization were monitored. Acclimation to prochloraz was found after continuous exposure. Following F0-exposure, non-exposed F1-offspring showed no significant effects. However, in the F2 animals, several parameters differed significantly from controls. A direct association between grandmaternal effects and toxic mode of action of prochloraz was found, showing that chemicals can be harmful not only to the exposed generation, but also to subsequent generations and that effects may even skip a generation.

Uranium (U) pollution of terrestrial and aquatic ecosystems poses a significant threat to the environment and human health because this radionuclide is chemotoxic. Characterization of organisms that tolerate and accumulate U is critical to decipher the mechanisms evolved to cope with the radionuclide and to propose new effective strategies for bioremediation of U-contaminated environments. Here, we isolated a unicellular green microalga of the genus Coelastrella from U-contaminated wastewater. We showed that Coelastrella sp. PCV is much more tolerant to U than Chlamydomonas reinhardtii and Chlorella vulgaris. Coelastrella is able to accumulate U very rapidly, then gradually release it into the medium, behaving as an excluder to limit the toxic effects of U. The ability of Coelastrella to accumulate U is remarkably high, with up to 600 mg U sorbed per g dry biomass. Coelastrella is able to grow and maintain high photosynthesis in natural metal-contaminated waters from a wetland near a reclaimed U mine. Over a single one-week growth cycle, Coelastrella is able to capture 25-55% of U from contaminated waters and demonstrates lipid droplet accumulation. Coelastrella sp. PCV is a very promising microalga for the remediation of polluted waters with valorization of algal biomass that accumulates lipids. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=176 SRC="FIGDIR/small/546994v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@1ff356corg.highwire.dtl.DTLVardef@c53d0org.highwire.dtl.DTLVardef@15284eborg.highwire.dtl.DTLVardef@946d49_HPS_FORMAT_FIGEXP M_FIG C_FIG

Metal(loid) salts have been used to treat infectious diseases due to their exceptional biocidal properties at low concentrations. However, the mechanism of their toxicity has yet to be fully elucidated. The production of reactive oxygen species (ROS) has been linked to the toxicity of soft metal(loid)s such as Ag(I), Au(III), As(III), Cd(II), Hg(II), and Te(IV). Nevertheless, few reports have described the direct, or ROS-independent, effects of some of these soft-metal(loid)s on bacteria, including the dismantling of iron-sulphur clusters [4Fe-4S] and the accumulation of porphyrin IX. Here, we used genome-wide genetic, proteomic, and biochemical approaches under anaerobic conditions to evaluate the direct mechanisms of toxicity of these metal(loid)s in Escherichia coli. We found that certain soft-metal(loid)s promote protein aggregation in a ROS-independent manner. This aggregation occurs during translation in the presence of Ag(I), Au(III), Hg(II), or Te(IV) and post-translationally in cells exposed to Cd(II) or As(III). We determined that aggregated proteins were involved in several essential biological processes that could lead to cell death. For instance, several enzymes involved in amino acid biosynthesis were aggregated after soft-metal(loid) exposure, disrupting intracellular amino acid concentration. We also propose a possible mechanism to explain how soft-metal(loid)s act as proteotoxic agents.

With the rise of resistance to last resort antibiotics, metal-based antimicrobials have re-emerged as an alternative to prevent and manage infections. The group 11 metals (copper, silver, gold), historically known for their usage in coins and similar chemical properties, have demonstrated promising bactericidal activity. Despite their efficiency, we do not have a complete understanding for how bacteria are eradicated by metal ions and how they respond to metal-induced stress. One understudied aspect of these metal-bacteria interactions are prolonged exposure models, as other studies tend to focus on the acute toxic response of antimicrobial metals. We used RNA-seq profiling to understand the Escherichia coli physiological response to sublethal inhibitory antimicrobial coinage metal stress after 10 hours of incubation. Gene expression patterns of the adaptive and intrinsic response elicited by each metal were identified, including increased essential metal uptake (Ag, Cu, Au), cysteine biosynthesis (Cu, Au), change of the metal ion oxidation state (Cu, Au), efflux of metal stressor (Cu), protein translation and ribosome biogenesis (Au), and cell envelope stress response (Ag). In this paper, we highlight the remarkable differences and similarities in the transcriptomic response profile of E. coli to these antimicrobial metal elements. IMPORTANCEDogma has existed that all antimicrobial metals kill bacteria the same way, leading to the assumption that bacteria respond the same way to metal toxicity. Nowadays, we have a better understanding why some metal elements are more toxic than others, but questions remain in relation to how bacteria adapt to survive and thrive when challenged by different metal-based antimicrobials. Our study advances the field by characterizing the type of bacterial response(s) to acclimate and grow during a prolonged exposure of silver, copper and gold - metallic elements that are known for their antimicrobial activity. Taking advantage of well-characterized Escherichia coli, we propose a model that summarizes our findings after comparing the shared and unique responses to each of these metals. This information enhances our understanding of bacterial tolerance to metal-based antimicrobials, which can lead to improved drug development strategies as society continues to search for alternatives against antibiotic-resistant pathogens.

Tyrosinases (EC 1.14.18.1) are type-3 copper metalloenzymes with strong oxidative capacities and low allosteric selectivity to phenolic and non-phenolic aromatic compounds that have been used as biosensors and biocatalysts to mitigate the impacts of environmental contaminants over aquatic ecosystems. However, the widespread use of these polyphenol oxidases is limited by elevated production costs and restricted knowledge on their spectrum of action. Here, six tyrosinase homologs were identified and characterized from the genomes of 4 widespread freshwater ciliates using bioinformatics. Binding energies between 3D models of these homologs and ~1000 contaminants of emerging concern (CECs), including fine chemicals, pharmaceuticals, personal care products, illicit drugs, natural toxins, and pesticides were estimated through virtual screening, suggesting their spectrum of action and potential uses in environmental biotechnology might be considerably broader than previously thought. Moreover, considering that many ciliates, including those caring tyrosinase genes within their genomes are fast-growing unicellular microeukaryotes that can be efficiently culturable at large-scales under in vitro conditions, should be regarded as potential low-cost sources for the production of relevant biotechnological molecules.

Cadmium (Cd) is a toxic pollutant in soil and water affecting plants, animals, and humans. Autophagy, a cellular recycling process, is crucial for different biotic and abiotic plant stress responses. This study explores the autophagy role in Arabidopsis under Cd stress, using wild-type, autophagy-deficient mutants (atg5, and atg7) and overexpressing lines (35S:ATG5, 35S:ATG7). Cd exposure induced autophagy, as evidenced by ATG8a and ATG8a-PE accumulation, GFP-ATG8a fluorescence, and upregulation of ATG genes and proteins. Responses differed between Col-0 and Ws backgrounds, with Ws showing higher Cd tolerance. atg5 mutants were more sensitive to Cd, indicating the autophagy protective role, whereas ATG5/ATG7 overexpression did not significantly enhance Cd tolerance. Although oxidative stress may activate autophagy, ATG5/ATG7 overexpression did not significantly change the oxidative stress response. Notably, atg5 mutants displayed marked disruptions in metal/ion homeostasis under control and Cd conditions, reinforcing autophagys role inion homeostasis. In contrast, atg7 showed no significant differences from its WT (Ws), suggesting genotype-specific effects. Transcriptional analysis of metal transporters and ion flux analyses indicates that autophagy can regulate metal/ion accumulation through transcriptional control and post-translational modifications (e.g., ROS) with a differential response being observed between Ws and Col-0 plants.

Metabolic pathways are targets of environmental contaminants underlying a large variability of toxic effects throughout biodiversity. However, the systematic reconstruction of metabolic pathways remains limited in environmental sentinel species due to the lack of available genomic data in many taxa of animal diversity. In order to improve the knowledge of the metabolism of sentinel species, in this study we used a multi-omics approach to reconstruct the most comprehensive map of metabolic pathways for a crustacean model in biomonitoring, the amphipod Gammarus fossarum. We revisited the assembly of RNA-seq data by de novo approaches drastically reducing RNA contaminants and transcript redundancy. We also acquired extensive mass spectrometry shotgun proteomic data on several organs from G. fossarum males and females to identify organ-specific metabolic profiles. The G. fossarum metabolic pathway reconstruction (available through the metabolic database GamfoCyc) was performed by adapting the genomic tool CycADS and we identified 377 pathways representing 7,630 annotated enzymes, 2,610 enzymatic reactions and the expression of 858 enzymes was experimentally validated by proteomics. Our analysis shows organ-specific metabolic profiles, such as an elevated abundance in enzymes involved in ATP biosynthesis and fatty acid beta-oxidation indicative of the high-energy requirement of the gills, or the key anabolic and detoxification role of the hepatopancreatic caeca, as exemplified by the specific expression of the retinoid biosynthetic pathways and glutathione synthesis. In conclusion, the multi-omics data integration performed in this study provides new resources to investigate metabolic processes in crustacean amphipods and their role in mediating the effects of environmental contaminant exposures in sentinel species.

Aluminum (Al) toxicity and low pH are major factors limiting plant growth in acidic soils. Sensitive to Proton Rhizotoxicity 1 (STOP1) transcription factor respond to these stresses by regulating the expression of multiple Al- or low pH-responsive genes. ZmSTOP1-A, a STOP1-like protein from maize (Zea mays), was localized to the nucleus and had transactivation activity. ZmSTOP1-A was expressed moderately in both roots and shoots of maize seedlings, but was not induced by Al stress or low pH. Overexpression of ZmSTOP1-A in Arabidopsis Atstop1 mutant partially restored Al tolerance and completely low pH tolerance with respect to root growth. Regarding Al tolerance, ZmSTOP1-A/Atstop1 plants showed clear upregulation of organic acid transporter genes, and leading to increased organic acid secretion and reduced Al accumulation in roots. Besides, the antioxidant enzyme activity in roots and shoots of ZmSTOP1-A/Atstop1 plants was significantly enhanced, ultimately alleviating Al toxicity via scavenging reactive oxygen species. Similarly, ZmSTOP1-A could directly activate ZmMATE1 expression in maize, positively correlated with the number of Al-responsive GGNVS cis-element in the ZmMATE1 promoter. Our results revealed that ZmSTOP1-A antagonizes Al toxicity by enhancing organic acid secretion and reactive oxygen species scavenging in Arabidopsis, demonstrating that it is an important transcription factor conferring Al tolerance. Our findings help to comprehensively elucidate the role of STOP1-like transcript factor in enabling plants to detoxifying Al.