Stresses that Raise Np4A Levels Induce Protective Nucleoside Tetraphosphate Capping of Bacterial RNA.

Present in all realms of life, dinucleoside tetraphosphates (Np4Ns) are generally considered signaling molecules. However, only a single pathway for Np4N signaling has been delineated in eukaryotes, and no receptor that mediates the influence of Np4Ns has ever been identified in bacteria. Here we show that, under disulfide stress conditions that elevate cellular Np4N concentrations, diverse Escherichia coli mRNAs and sRNAs acquire a cognate Np4 cap. Purified E. coli RNA polymerase and lysyl-tRNA synthetase are both capable of adding such 5' caps. Cap removal by either of two pyrophosphatases, ApaH or RppH, triggers rapid RNA degradation in E. coli. ApaH, the predominant decapping enzyme, functions as both a sensor and an effector of disulfide stress, which inactivates it. These findings suggest that the physiological changes attributed to elevated Np4N concentrations in bacteria may result from widespread Np4 capping, leading to altered RNA stability and consequent changes in gene expression.

Genetic factors of grain cadmium concentration in Polish wheat (Triticum polonicum L.).

Wheat (Triticum aestivum L.) is one of the most important crops worldwide and a major source of human Cd intake. Limiting grain Cd concentration (Gr_Cd_Conc) in wheat is necessary to ensure food safety. However, the genetic factors associated with Cd uptake, translocation, distribution, and Gr_Cd_Conc in wheat are poorly understood. Here, we mapped quantitative trait loci (QTL) for Gr_Cd_Conc and its related transport pathway using a recombinant inbred line (RIL_DT) population derived from two Polish wheat varieties (dwarf Polish wheat [DPW] and tall Polish wheat [TPW]). We identified 29 novel major QTLs for grain and tissue Cd concentration; 14 novel major QTLs for Cd uptake, translocation, and distribution; and 27 major QTLs for agronomic traits. We also analyzed the pleiotropy of these QTLs. Six novel QTLs (QGr_Cd_Conc-1A, QGr_Cd_Conc-3A, QGr_Cd_Conc-4B, QGr_Cd_Conc-5B, QGr_Cd_Conc-6A and QGr_Cd_Conc-7A) for Gr_Cd_Conc explained 8.16-17.02% of the phenotypic variation. QGr_Cd_Conc-3A, QGr_Cd_Conc-6A and QGr_Cd_Conc-7A pleiotropically regulated Cd transport; three other QTLs were organ-specific for Gr_Cd_Conc. We fine-mapped the locus of QGr_Cd_Conc-4B and identified the candidate gene as Cation/Ca exchanger 2 (TpCCX2-4B), which was differentially expressed in DPW and TPW. It encodes an endoplasmic reticulum membrane/plasma membrane-localized Cd efflux transporter in yeast. Overexpression of TpCCX2-4B reduced Gr_Cd_Conc in rice. The average Gr_Cd_Conc was significantly lower in TpCCX2-4BDPW genotypes than in TpCCX2-4BTPWgenotypes of the RIL_DT population and two other natural populations, based on a KASP marker derived from the different promoter sequences between TpCCX2-4BDPW and TpCCX2-4BTPW. Our study reveals the genetic mechanism of Cd accumulation in wheat and provides valuable resources for genetic improvement of low-Cd-accumulating wheat cultivars.

Understanding Trap States in InP and GaP Quantum Dots through Density Functional Theory.

The widespread application of III-V colloidal quantum dots (QDs) as nontoxic, highly tunable emitters is stymied by their high density of trap states. Here, we utilize density functional theory (DFT) to investigate trap state formation in a diverse set of realistically passivated core-only InP and GaP QDs. Through orbital localization techniques, we deconvolute the dense manifold of trap states to allow for detailed assignment of surface defects. We find that the three-coordinate species dominate trapping in III-V QDs and identify features in the geometry and charge environment of trap centers capable of deepening, or sometimes passivating, traps. Furthermore, we observe stark differences in surface reconstruction between InP and GaP, where the more labile InP reconstructs to passivate three-coordinate indium at the cost of distortion elsewhere. These results offer explanations for experimentally observed trapping behavior and suggest new avenues for controlling trap states in III-V QDs.

Formation and Transformation of CdS Clusters during the Prenucleation Stage and in a Dilute Dispersion at Room Temperature.

The formation and transformation of colloidal semiconductor clusters remain poorly understood. With CdS as a model system, we show that, in the reaction of cadmium myristate (Cd(MA)2) and S powder in 1-octadecene (ODE), clusters form in the prenucleation stage of quantum dots (QDs). Called precursor compounds (PCs), the clusters can transform to magic-size clusters (MSCs) in reaction at a relatively high temperature (MSC-322 displaying optical absorption peaking at 322 nm) or in a dispersion at room temperature (MSC-360). When the reaction temperature is increased, PC-360 forms at 140 °C, while PC-322 and MSC-322 form at 180 °C. In a dispersion of cyclohexane and octylamine, MSC-322 transforms to MSC-360 via MSC-345. The MSC-345 to MSC-360 transformation displays continuous and discontinuous shifts in the optical absorption. The PCs and MSCs are a group of isomers. The present findings bring insight into the cluster formation and isomerization in the prenucleation stage of QDs and in a dispersion.

Overexpression of vacuolar transporters OsVIT1 and OsVIT2 reduces cadmium accumulation in rice.

Excessive cadmium in rice grain in agricultural production is an important issue to be addressed in some southern regions of China. In this study, we constructed transgenic rice overexpressing OsVIT1 and OsVIT2 driven by 35S promoter in the cultivar ZH11. Compared with ZH11, OsVIT1 expression in leaves was significantly increased by 3-6.6 times and OsVIT2 expression in leaves was significantly increased by 2-2.5 times. Hydroponic experiments showed that overexpression of OsVIT1 and OsVIT2 increased the tolerance to Fe deficiency, significantly reduced Cd content in shoot and xylem sap, and had no effect on Cd tolerance in rice. Two years of field trials showed that the Fe content in the grain of OsVIT1 and OsVIT2 overexpressed materials was significantly reduced by 20-40% and the straw Fe content was significantly increased by 10-45%, and the grain Fe content distribution ratio was significantly decreased and the straw Fe distribution ratio was significantly increased compared with the wild type. The OsVIT1 and OsVIT2 overexpressed materials significantly reduced the Cd content of grain by 40-80% and the Cd content of straws by 37-77%, and the bioconcentration factor of Cd was significantly reduced in both grains and straw of OsVIT1 and OsVIT2 overexpressed materials. Overexpression of OsVIT1 and OsVIT2 did not affect the concentration of other metal ions in rice straw and grain. qRT-PCR analysis showed that the expression of the low affinity cation transporter OsLCT1 was significantly downregulated in the OsVIT1 and OsVIT2 overexpressed materials. In conclusion, overexpression of OsVIT1 and OsVIT2 reduced Cd accumulation in straw and grains, providing a strategy for Cd reduction in rice.

Cadmium Stress Signaling Pathways in Plants: Molecular Responses and Mechanisms.

Heavy metal (HM) pollution, specifically cadmium (Cd) contamination, is a worldwide concern for its consequences for plant health and ecosystem stability. This review sheds light on the intricate mechanisms underlying Cd toxicity in plants and the various strategies employed by these organisms to mitigate its adverse effects. From molecular responses to physiological adaptations, plants have evolved sophisticated defense mechanisms to counteract Cd stress. We highlighted the role of phytochelatins (PCn) in plant detoxification, which chelate and sequester Cd ions to prevent their accumulation and minimize toxicity. Additionally, we explored the involvement of glutathione (GSH) in mitigating oxidative damage caused by Cd exposure and discussed the regulatory mechanisms governing GSH biosynthesis. We highlighted the role of transporter proteins, such as ATP-binding cassette transporters (ABCs) and heavy metal ATPases (HMAs), in mediating the uptake, sequestration, and detoxification of Cd in plants. Overall, this work offered valuable insights into the physiological, molecular, and biochemical mechanisms underlying plant responses to Cd stress, providing a basis for strategies to alleviate the unfavorable effects of HM pollution on plant health and ecosystem resilience.

Prediagnostic whole blood cadmium and molybdenum associated with pancreatic cancer in an American cohort.

Environmental exposures such as cadmium might be contributing to the increasing incidence of pancreatic cancer. Few prospective studies have examined the association between trace elements and pancreatic ductal adenocarcinoma (PDAC). We conducted a nested case-control study in participants aged 55-74 years at baseline from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial cohort to examine the association between 12 trace elements measured in predignostic whole blood and PDAC. From May 1998 through December 2014, 318 incident PDAC cases were identified during follow-up to 16.7 years. Two controls (n = 636) alive when each case was diagnosed were selected and matched by age (+ 5 years), sex, calendar date of blood draw (2-month blocks), and race and ethnic group. We used multivariable adjusted conditional logistic regression to calculate odds ratios (OR) and 95% confidence intervals (CI). Cadmium and molybdenum were associated with PDAC [highest compared to lowest quintile: cadmium OR=1.81; 95% CI: 01.12, 2.95; P-trend = 0.03; molybdenum OR=0.50; 95% CI: 0.32, 0.80; P-trend = 0.02]. The inverse molybdenum association was only observed among ever smokers (OR=0.31, 95% CI: 0.17, 0.58, P-trend= 0.003, P-interaction=0.03) with no association in never smokers. Lead, arsenic, and other trace elements were not associated with PDAC. Our results support that increasing prediagnostic whole blood cadmium increases while molybdenum reduces PDAC risk.

Loss of mutant p53 in HaCaT keratinocytes promotes cadmium-induced keratin 17 expression and cell death.

BACKGROUND: Cadmium exposure induces dermatotoxicity and epidermal barrier disruption and leads to the development of various pathologies. HaCaT cells are immortalized human keratinocytes that are widely used as alternatives to primary human keratinocytes, particularly for evaluating cadmium toxicity. HaCaT cells bear two gain-of-function (GOF) mutations in the TP53 gene, which strongly affect p53 function. Mutant forms of p53 are known to correlate with increased resistance to various stimuli, including exposure to cytotoxic substances. In addition, keratin 17 (KRT17) was recently shown to be highly expressed in HaCaT cells in response to genotoxic stress. Moreover, p53 is a direct transcriptional repressor of KRT17. However, the impact of TP53 mutations in HaCaT cells on the regulation of cell death and keratin 17 expression is unclear. In this study, we aimed to evaluate the impact of p53 on the response to Cd-induced cytotoxicity. METHODS AND RESULTS: Employing the MTT assay and Annexin V/propidium iodide staining, we demonstrated that knockout of TP53 leads to a decrease in the sensitivity of HaCaT cells to the cytotoxic effects of cadmium. Specifically, HaCaT cells with TP53 knockout (TP53 KO HaCaT) exhibited cell death at a cadmium concentration of 10 µM or higher, whereas wild-type cells displayed cell death at a concentration of 30 µM. Furthermore, apoptotic cells were consistently detected in TP53 KO HaCaT cells upon exposure to low concentrations of cadmium (10 and 20 µM) but not in wild-type cells. Our findings also indicate that cadmium cytotoxicity is mediated by reactive oxygen species (ROS), which were significantly increased only in TP53 knockout cells treated with 30 µM cadmium. An examination of proteomic data revealed that TP53 knockout in HaCaT cells resulted in the upregulation of proteins involved in the regulation of apoptosis, redox systems, and DNA repair. Moreover, RT‒qPCR and immunoblotting showed that cadmium toxicity leads to dose-dependent induction of keratin 17 in p53-deficient cells but not in wild-type cells. CONCLUSIONS: The connection between mutant p53 in HaCaT keratinocytes and increased resistance to cadmium toxicity was demonstrated for the first time. Proteomic profiling revealed that TP53 knockout in HaCaT cells led to the activation of apoptosis regulatory circuits, redox systems, and DNA repair. In addition, our data support the involvement of keratin 17 in the regulation of DNA repair and cell death. Apparently, the induction of keratin 17 is p53-independent but may be inhibited by mutant p53.

Combined application of arbuscular mycorrhizal fungi and selenium fertilizer increased wheat biomass under cadmium stress and shapes rhizosphere soil microbial communities.

BACKGROUND: Selenium (Se) fertilizer and arbuscular mycorrhizal fungi (AMF) are known to modulate cadmium (Cd) toxicity in plants. However, the effects of their co-application on wheat growth and soil microbial communities in Cd-contaminated soil are unclear. RESULTS: A pot experiment inoculation with two types of AMF and the application of Se fertilizer under Cd stress in wheat showed that inoculation AMF alone or combined with Se fertilizer significantly increased wheat biomass. Se and AMF alone or in combination significantly reduced available Cd concentration in wheat and soil, especially in the Se combined with Ri treatment. High throughput sequencing of soil samples indicated that Se and AMF application had stronger influence on bacterial community compared to fungal community and the bacterial network seemed to have more complex interconnections than the fungal network, and finally shaped the formation of specific microflora to affect Cd availability. CONCLUSION: These results indicate that the application of Se and AMF, particularly in combination, could successfully decrease soil Cd availability and relieve the harm of Cd in wheat by modifying rhizosphere soil microbial communities.

Microplastics increase cadmium absorption and impair nutrient uptake and growth in red amaranth (Amaranthus tricolor L.) in the presence of cadmium and biochar.

Microplastic (MP) pollution in terrestrial ecosystems is gaining attention, but there is limited research on its effects on leafy vegetables when combined with heavy metals. This study examines the impact of three MP types-polyethylene (PE), polyethylene terephthalate (PET), and polystyrene (PS)-at concentrations of 0.02, 0.05, and 0.1% w/w, along with cadmium (Cd) and biochar (B), on germination, growth, nutrient absorption, and heavy metal uptake in red amaranth (Amaranthus tricolor L.). We found that different MP types and concentrations did not negatively affect germination parameters like germination rate, relative germination rate, germination vigor, relative germination vigor, and germination speed. However, they increased phytotoxicity and decreased stress tolerance compared to an untreated control (CK1). The presence of MPs, particularly the PS type, reduced phosphorus and potassium uptake while enhancing Cd uptake. For example, treatments PS0.02CdB, PS0.05CdB, and PS0.1CdB increased Cd content in A. tricolor seedlings by 158%, 126%, and 44%, respectively, compared to the treatment CdB (CK2). Additionally, MP contamination led to reduced plant height, leaf dry matter content, and fresh and dry weights, indicating adverse effects on plant growth. Moreover, the presence of MPs increased bioconcentration factors and translocation factors for Cd, suggesting that MPs might act as carriers for heavy metal absorption in plants. On the positive side, the addition of biochar improved several root parameters, including root length, volume, surface area, and the number of root tips in the presence of MPs, indicating potential benefits for plant growth. Our study shows that the combination of MPs and Cd reduces plant growth and increases the risk of heavy metal contamination in food crops. Further research is needed to understand how different MP types and concentrations affect various plant species, which will aid in developing targeted mitigation strategies and in exploring the mechanisms through which MPs impact plant growth and heavy metal uptake. Finally, investigating the potential of biochar application in conjunction with other amendments in mitigating these effects could be key to addressing MP and heavy metal contamination in agricultural systems.

Conjoint analysis of physio-biochemical, transcriptomic, and metabolomic reveals the response characteristics of solanum nigrum L. to cadmium stress.

Cadmium (Cd) is a nonessential element in plants and has adverse effects on the growth and development of plants. However, the molecular mechanisms of Cd phytotoxicity, tolerance and accumulation in hyperaccumulators Solanum nigrum L. has not been well understood. Here, physiology, transcriptome, and metabolome analyses were conducted to investigate the influence on the S. nigrum under 0, 25, 50, 75 and 100 µM Cd concentrations for 7 days. Pot experiments demonstrated that compared with the control, Cd treatment significantly inhibited the biomass, promoted the Cd accumulation and translocation, and disturbed the balance of mineral nutrient metabolism in S. nigrum, particularly at 100 µM Cd level. Moreover, the photosynthetic pigments contents were severely decreased, while the content of total protein, proline, malondialdehyde (MDA), H2O2, and antioxidant enzyme activities generally increased first and then slightly declined with increasing Cd concentrations, in both leaves and roots. Furthermore, combined with the previous transcriptomic data, numerous crucial coding-genes related to mineral nutrients and Cd ion transport, and the antioxidant enzymes biosynthesis were identified, and their expression pattern was regulated under different Cd stress. Simultaneously, metabolomic analyses revealed that Cd treatment significantly changed the expression level of many metabolites related to amino acid, lipid, carbohydrate, and nucleotide metabolism. Metabolic pathway analysis also showed that S. nigrum roots activated some differentially expressed metabolites (DEMs) involved in energy metabolism, which may enhance the energy supply for detoxification. Importantly, central common metabolism pathways of DEGs and DEMs, including the "TCA cycle", "glutathione metabolic pathway" and "glyoxylate and dicarboxylate metabolism" were screened using conjoint transcriptomics and metabolomics analysis. Our results provide some novel evidences on the physiological and molecular mechanisms of Cd tolerance in hyperaccumulator S. nigrum plants.

Genome-wide identification and evolutionary analysis of the NRAMP gene family in the AC genomes of Brassica species.

BACKGROUND: Brassica napus, a hybrid resulting from the crossing of Brassica rapa and Brassica oleracea, is one of the most important oil crops. Despite its significance, B. napus productivity faces substantial challenges due to heavy metal stress, especially in response to cadmium (Cd), which poses a significant threat among heavy metals. Natural resistance-associated macrophage proteins (NRAMPs) play pivotal roles in Cd uptake and transport within plants. However, our understanding of the role of BnNRAMPs in B. napus is limited. Thus, this study aimed to conduct genome-wide identification and bioinformatics analysis of three Brassica species: B. napus, B. rapa, and B. oleracea. RESULTS: A total of 37 NRAMPs were identified across the three Brassica species and classified into two distinct subfamilies based on evolutionary relationships. Conservative motif analysis revealed that motif 6 and motif 8 might significantly contribute to the differentiation between subfamily I and subfamily II within Brassica species. Evolutionary analyses and chromosome mapping revealed a reduction in the NRAMP gene family during B. napus evolutionary history, resulting in the loss of an orthologous gene derived from BoNRAMP3.2. Cis-acting element analysis suggested potential regulation of the NRAMP gene family by specific plant hormones, such as abscisic acid (ABA) and methyl jasmonate (MeJA). However, gene expression pattern analyses under hormonal or stress treatments indicated limited responsiveness of the NRAMP gene family to these treatments, warranting further experimental validation. Under Cd stress in B. napus, expression pattern analysis of the NRAMP gene family revealed a decrease in the expression levels of most BnNRAMP genes with increasing Cd concentrations. Notably, BnNRAMP5.1/5.2 exhibited a unique response pattern, being stimulated at low Cd concentrations and inhibited at high Cd concentrations, suggesting potential response mechanisms distinct from those of other NRAMP genes. CONCLUSIONS: In summary, this study indicates complex molecular dynamics within the NRAMP gene family under Cd stress, suggesting potential applications in enhancing plant resilience, particularly against Cd. The findings also offer valuable insights for further understanding the functionality and regulatory mechanisms of the NRAMP gene family.

Differential responses of chili varieties grown under cadmium stress.

Heavy metal cadmium (Cd) naturally occurs in soil and is a hazardous trace contaminant for humans, animals, and plants. The main sources of Cd pollution in soil include overuse of phosphatic fertilizers, manure, sewage sludge, and aerial deposition. That's why an experiment was conducted to analyze the effect of Cd toxicity in Capsicum annuum L. by selecting its seven varieties: Hybrid, Desi, Sathra, G-916, BR-763, BG-912, and F1-9226. Cadmium was spiked in soil with four levels, i.e., (0, 3, 4, and 5 mg Cd kg- 1 of soil) for a week for homogeneous dispersion of heavy metal. Chili seeds were sown in compost-filled loamy soil, and 25-day-old seedlings were transplanted into Cd-spiked soil. Cadmium increasing concentration in soil decreased chili growth characteristics, total soluble sugars, total proteins, and amino acids. On the other hand, the activities of antioxidant enzymes were increased with the increasing concentration of Cd in almost all the varieties. Treatment 5 mg Cd/kg application caused - 197.39%, -138.78%, -60.77%, -17.84%, -16.34%, -11.82% and - 10.37% decrease of carotenoids level in chili V2 (Desi) followed by V4 (G-916), V1 (Hy7brid), V7 (F1-9226), V6 (BG-912), V5 (BR-763) and V3 (Sathra) as compared to their controls. The maximum flavonoids among varieties were in V5 (BR-763), followed by V6 (BG-912), V7 (F1-9226), V3 (Sathra) and V1 (Hybrid). Flavonoids content was decreased with - 37.63% (Sathra), -34.78% (Hybrid), -33.85% (G-916), -31.96% (F1-9226), -31.44% (Desi), -30.58% (BR-763), -22.88% (BG-912) as compared to their control at 5 mg Cd/kg soil stress. The maximum decrease in POD, SOD, and CAT was - 31.81%, -25.98%, -16.39% in chili variety V7 (F1-9226) at 5 mg Cd/kg stress compared to its control. At the same time, maximum APX content decrease was - 82.91%, followed by -80.16%, -65.19%, -40.31%, -30.14%, -10.34% and - 6.45% in V4 (G-916), V2 (Desi), V3 (Sathra), V6 (BG-912), V1 (Hybrid), V7 (F1-9226) and V5 (BR-763) at 5 mg Cd/kg treatment as compared to control chili plants. The highest CAT was found in 5 chili varieties except Desi and G-916. Desi and G-916 varieties. V5 (BR-763) and V6 (BG-912) were susceptible, while V1 (Hybrid), V3 (Sathra), and V7 (F1-9226) were with intermediate growth attributes against Cd stress. Our results suggest that Desi and G-916 chili varieties are Cd tolerant and can be grown on a large scale to mitigate Cd stress naturally.

Pathway of Room-Temperature Formation of CdSeS Magic-Size Clusters from Mixtures of CdSe and CdS Samples.

The synthetic application of prenucleation-stage samples of colloidal semiconductor quantum dots (QDs) is in its infancy. It is shown that when two prenucleation-stage samples of binary CdSe and CdS are mixed, ternary CdSeS magic-size clusters (MSCs) grow at room temperature in dispersion. As the amount of the CdS sample increases, the optical absorption of the CdSeS MSCs blueshifts from ≈380 to ≈360 nm. It is proposed that the cluster in the CdSe sample reacts with the CdS monomer from the CdS sample. The monomer substitution reaction of CdSe by CdS can proceed continuously; thus, CdSeS MSCs with tunable compositions are obtained. The present study provides compelling evidence that clusters formed in the prenucleation stage of QDs. The clusters are precursor compounds (PCs) of MSCs, transforming at room temperature with the thermoneutrality principle of isodesmic reactions. The nucleation and growth of QDs follows a multi-step non-classical instead of one-step classical nucleation model.

Amino-Induced CO2 Spillover to Boost the Electrochemical Reduction Activity of CdS for CO Production.

A considerable challenge in CO2 reduction reaction (CO2RR) to produce high-value-added chemicals comes from the adsorption and activation of CO2 to form intermediates. Herein, an amino-induced spillover strategy aimed at significantly enhancing the CO2 adsorption and activation capabilities of CdS supported on N-doped mesoporous hollow carbon sphere (NH2-CdS/NMHCS) for highly efficient CO2RR is presented. The prepared NH2-CdS/NMHCS exhibits a high CO Faradaic efficiency (FECO) exceeding 90% from -0.8 to -1.1 V versus reversible hydrogen electrode (RHE) with the highest FECO of 95% at -0.9 V versus RHE in H cell. Additional experimental and theoretical investigations demonstrate that the alkaline -NH2 group functions as a potent trapping site, effectively adsorbing the acidic CO2, and subsequently triggering CO2 spillover to CdS. The amino modification-induced CO2 spillover, combined with electron redistribution between CdS and NMHCS, not only readily achieves the spontaneous activation of CO2 to *COOH but also greatly reduces the energy required for the conversion of *COOH to *CO intermediate, thus endowing NH2-CdS/NMHCS with significantly improved reaction kinetics and reduced overpotential for CO2-to-CO conversion. It is believed that this research can provide valuable insights into the development of electrocatalysts with superior CO2 adsorption and activation capabilities for CO2RR application.

Encapsulation of Cadmium-Free InP-based Quantum Dots in Cross-Linked Core-Shell Microparticles via Coaxial Electrospraying.

Quantum dots (QDs) are inorganic semiconductor nanocrystals capable of emitting light. The current major challenge lies in the use of heavy metals, which are known to be highly toxic to humans and pose significant environmental risks. Researchers have turned to indium (In) as a promising option for more environmentally benign QDs, specifically indium phosphide (InP). A significant obstacle remains in sustaining the long-term photostability of InP-based QDs when exposed to the environment. To tackle this, electrospraying is used in this work to protect indium phosphide/zinc selenide/zinc sulfide (InP/ZnSe/ZnS) QDs by embedding them within polymer core-shell microparticles of poly[(lauryl methacrylate)-co-(ethylene glycol dimethacrylate)]/poly(methyl methacrylate) (poly(LMA-co-EGDMA)/PMMA). During the flight of droplets, the liquid monomer core of LMA and EGDMA with QDs is encapsulated by the solid shell of PMMA formed due to solvent evaporation, resulting in a liquid-core/solid-shell particle structure. After that, the captured core of monomers is polymerized into a cross-linked polymer with the embedded QDs via a thermal initiation. They demonstrate how a successful core-shell particle formation is achieved to produce structures for initially liquid monomer systems via coaxial electrospraying that are used for cross-linked polymers, which are of major interest for the encapsulation of InP-based QDs for generally improved photostability over pristine QDs.

SbYS1 and SbWRKY72 regulate Cd tolerance and accumulation in sweet sorghum.

MAIN CONCLUSION: SbYS1 and its upstream transcription factor SbWRKY72 were involved in Cd tolerance and accumulation and are valuable for developing sweet sorghum germplasm with high-Cd tolerance or accumulation ability through genetic manipulation. Cadmium (Cd) is highly toxic and can severely affect human health. Sweet sorghum, as an energy crop, shows great potential in extracting cadmium from Cd-contaminated soils. However, its molecular mechanisms of Cd-tolerance and -accumulation remain largely unknown. Here, we isolated a YSL family gene SbYS1 from the sweet sorghum genotype with high Cd accumulation ability and the expression of SbYS1 in roots was induced by cadmium. GUS staining experiment exhibited that SbYS1 was expressed in the epidermis and parenchyma tissues of roots. Further subcellular localization analysis suggested that SbYS1 was localized in the endoplasmic reticulum and plasma membrane. Yeast transformed with SbYS1 exhibited a sensitive phenotype compared to the control when exposed to Cd-NA (chelates of cadmium and nicotianamine), indicating that SbYS1 may absorb cadmium in the form of Cd-NA. Arabidopsis overexpressing SbYS1 had a longer root length and accumulated less Cd in roots and shoots. SbWRKY72 bound to the promoter of SbYS1 and negatively regulated the expression of SbYS1. Transgenic Arabidopsis of SbWRKY72 showed higher sensitivity to cadmium and increased cadmium accumulation in roots. Our results provide references for improving the phytoremediation efficiency of sweet sorghum by genetic manipulation in the future.

GhRCD1 promotes cotton tolerance to cadmium by regulating the GhbHLH12-GhMYB44-GhHMA1 transcriptional cascade.

Heavy metal pollution poses a significant risk to human health and wreaks havoc on agricultural productivity. Phytoremediation, a plant-based, environmentally benign, and cost-effective method, is employed to remove heavy metals from contaminated soil, particularly in agricultural or heavy metal-sensitive lands. However, the phytoremediation capacity of various plant species and germplasm resources display significant genetic diversity, and the mechanisms underlying these differences remain hitherto obscure. Given its potential benefits, genetic improvement of plants is essential for enhancing their uptake of heavy metals, tolerance to harmful levels, as well as overall growth and development in contaminated soil. In this study, we uncover a molecular cascade that regulates cadmium (Cd2+) tolerance in cotton, involving GhRCD1, GhbHLH12, GhMYB44, and GhHMA1. We identified a Cd2+-sensitive cotton T-DNA insertion mutant with disrupted GhRCD1 expression. Genetic knockout of GhRCD1 by CRISPR/Cas9 technology resulted in reduced Cd2+ tolerance in cotton seedlings, while GhRCD1 overexpression enhanced Cd2+ tolerance. Through molecular interaction studies, we demonstrated that, in response to Cd2+ presence, GhRCD1 directly interacts with GhbHLH12. This interaction activates GhMYB44, which subsequently activates a heavy metal transporter, GhHMA1, by directly binding to a G-box cis-element in its promoter. These findings provide critical insights into a novel GhRCD1-GhbHLH12-GhMYB44-GhHMA1 regulatory module responsible for Cd2+ tolerance in cotton. Furthermore, our study paves the way for the development of elite Cd2+-tolerant cultivars by elucidating the molecular mechanisms governing the genetic control of Cd2+ tolerance in cotton.

Multiomics and biotechnologies for understanding and influencing cadmium accumulation and stress response in plants.

Cadmium (Cd) is one of the most toxic heavy metals faced by plants and, additionally, via the food chain, threatens human health. It is principally dispersed through agro-ecosystems via anthropogenic activities and geogenic sources. Given its high mobility and persistence, Cd, although not required, can be readily assimilated by plants thereby posing a threat to plant growth and productivity as well as animal and human health. Thus, breeding crop plants in which the edible parts contain low to zero Cd as safe food stuffs and harvesting shoots of high Cd-containing plants as a route for decontaminating soils are vital strategies to cope with this problem. Recently, multiomics approaches have been employed to considerably enhance our understanding of the mechanisms underlying (i) Cd toxicity, (ii) Cd accumulation, (iii) Cd detoxification and (iv) Cd acquisition tolerance in plants. This information can be deployed in the development of the biotechnological tools for developing plants with modulated Cd tolerance and detoxification to safeguard cellular and genetic integrity as well as to minimize food chain contamination. The aim of this review is to provide a current update about the mechanisms involved in Cd uptake by plants and the recent developments in the area of multiomics approach in terms of Cd stress responses, as well as in the development of Cd tolerant and low Cd accumulating crops.

Production of grains with ultra-low heavy metal accumulation by pyramiding novel Alleles of OsNramp5 and OsLsi2 in two-line hybrid rice.

Ensuring rice yield and grain safety quality are vital for human health. In this study, we developed two-line hybrid rice (TLHR) with ultra-low grain cadmium (Cd) and arsenic (As) accumulation by pyramiding novel alleles of OsNramp5 and OsLsi2. We first generated low Cd accumulation restorer (R) lines by editing OsNramp5, OsLCD, and OsLCT in japonica and indica. After confirming that OsNramp5 was most efficient in reducing Cd, we edited this gene in C815S, a genic male sterile line (GMSL), and screened it for alleles with low Cd accumulation. Next, we generated R and GMSL lines with low As accumulation by editing OsLsi2 in a series of YK17 and C815S lines. When cultivated in soils that were heavily polluted with Cd and As, the edited R, GMSL, and TLHR plants showed significantly reduced heavy metal accumulation, while maintaining a relatively stable yield potential. This study provides an effective scheme for the safe production of grains in As- and/or Cd-polluted paddy fields.