Cadmium Minimization in Grains of Maize and Wheat Grown on Smelting-Impacted Land Ameliorated by Limestone.

Cadmium (Cd) contamination in agricultural soils has emerged as a significant concern, particularly due to its potential impact on plant-based food. Soil pH reductions can exacerbate Cd mobility, leading to excessive accumulation in crops. While liming has been demonstrated as an effective method to mitigate Cd accumulation in rice grains in acid soils of southern China, its efficacy in remediating acid soils in northern China remains unclear. In this study, a multi-year field experiment was conducted on farmland impacted by zinc ore smelting at coordinates of 33.92° N 112.46° E to investigate the use of limestone for controlling Cd accumulation in wheat and maize grains. The results indicated that applying 7.5 t ha-1 of limestone significantly raised the soil pH from 4.5 to 6.8 as anticipated. Different rates of limestone application (2.25, 4.45, and 7.50 t ha-1) reduced Cd bioavailability in the soil by 20-54%, and Cd accumulation in wheat grains by 5-38% and maize grains by 21-63%, without yield penalty. The remediation effects were sustained for at least 27 months, highlighting limestone as a promising ameliorant for smelting-affected farmland in northern China.

LncRNA NR2F2-AS1 inhibits the progression of oral squamous cell carcinoma by mediating the miR-32-5p/SEMA3A axis.

Previous studies have supported a tumor-suppressive role of semaphorin 3A (SEMA3A) in several tumors including oral squamous cell carcinoma (OSCC). However, in-depth characterization of the role of SEMA3A in OSCC and the underlying molecular mechanisms is lacking. Gene and protein expressions were detected using quantitative real-time PCR, western blot assay, and immunohistochemistry. OSCC cell metastasis was evaluated using Transwell and angiogenesis of human umbilical vein endothelial cells (HUVECs) was determined using tube formation assay. The interactions among molecules were predicted using bioinformatics analysis and validated using luciferase activity experiment and RNA immunoprecipitation assay. Pulmonary metastasis was evaluated using hematoxylin and eosin staining after constructing a lung metastasis tumor model in mice. SEMA3A expression was decreased in OSCC cells and its overexpression led to suppression of epithelial-mesenchymal transition (EMT), migration, and invasion of OSCC cells and angiogenesis of HUVECs. miR-32-5p was identified as an upstream molecule of SEMA3A and long non-coding RNA NR2F2 antisense RNA 1 (NR2F2-AS1) was validated as an upstream gene of miR-32-5p. Further experiments revealed that the inhibitory effects of NR2F2-AS1 overexpression on EMT, migration, invasion of OSCC cells, and angiogenesis of HUVECs as well as tumor growth and metastasis in mice were mediated via the miR-32-5p/SEMA3A axis. To conclude, NR2F2-AS1 may attenuate OSCC cell metastasis and angiogenesis of HUVECs and suppress tumor growth and metastasis in mice via the miR-32-5p/SEMA3A axis.

HIV knowledge, sexual attitudes, and PrEP-Eligible behaviors among college students in Southwest China: a cross-sectional study.

BACKGROUND: There is an increasing number of human immunodeficiency virus (HIV) reported cases among students in Southwest China. However, the data on HIV/sex-related knowledge, attitude toward sex, sexual behaviors, and correlates of pre-exposure prophylaxis (PrEP)-eligible behaviors among college students in this area is still limited. This study aimed to assess the prevalence of HIV/sex-related knowledge, sexual attitudes, sexual behaviors, and factors associated with PrEP-eligible behaviors among college students. METHOD: An online survey from 2020 to 2021 based on a multistage stratified and cluster sampling method was conducted among college students in Southwest China, and a well-designed questionnaire collected data. Propensity score matching (PSM), logistic, and log-binomial regression were used to identify the determinants of PrEP-eligible behaviors. RESULT: A total of 108,987 students participated in the survey, and 92,946 provided valid responses. 91.6% (85,145/92,946) had good HIV-related knowledge, while only 26.0% (24,137/92,946) reported awareness of sex-related knowledge. Furthermore, more than half of the participants (64.5%) held negative stances towards engaging in "one-night stand", and 58.9% (617/1,047) reported PrEP-eligible behaviors. Log-binomial regression analysis indicated that unaware of HIV-related knowledge (aPR = 1.66, 95% CI:1.22-2.26, P = 0.001), not discussing about sex with their parent(s) (aPR = 1.16, 95% CI:1.01-1.33, P = 0.021), not receiving sex-related education in school(aPR = 1.24, 95% CI: 1.07-1.45, P = 0.005), not participating in HIV/AIDS prevention activities in the past year (aPR = 1.32, 95%CI:1.09-1.60, P = 0.004), experiencing forced sex (aPR = 2.08, 95% CI: 1.19-3.63, P = 0.010), and having the drug abuse (aPR = 22.21, 95% CI:5.59-88.31, P < 0.001) were significantly associated with increased odds of PrEP-eligible behaviors. CONCLUSION: College students in Southwest China exhibited suboptimal HIV/sex-related knowledge, received limited sex education, reported conservative attitudes towards casual sex, and significant PrEP-eligible behaviors. These findings suggest that sexually experienced college students who were unaware of HIV-related knowledge, lacked sex education, experienced forced sex, and reported drug abuse were the key individuals for evaluating eligibility for PrEP initiation, and interventions aimed at increasing awareness of HIV/sex-related knowledge, promoting participation in sex education, addressing issues related to forced sex and tackling drug abuse could contribute to reducing the incidence of PrEP-eligible behaviors among college students.

Engineering active and robust alloy-based electrocatalyst by rapid Joule-heating toward ampere-level hydrogen evolution.

Rational design of bimetallic alloy is an effective way to improve the electrocatalytic activity and stability of Mo-based cathode for ampere-level hydrogen evolution. However, it is still critical to realise desirable syntheses due to the wide reduction potentials between different metal elements and uncontrollable nucleation processes. Herein, we propose a rapid Joule heating method to effectively load RuMo alloy onto MoOx matrix. As-prepared catalyst exhibits excellent stability (2000 h @ 1000 mA cm-2) and ultralow overpotential (9 mV, 18 mV and 15 mV in 1 M KOH, 1 M PBS, 0.5 M H2SO4 solution, respectively) at 10 mA cm-2. Based on first-principle simulations and operando measurements, the impressive electrocatalytic stability and activity are investigated. And the role of rapid Joule heating method is highlighted and discussed in details. This study showcases rapid Joule heating as a feasible strategy to construct highly efficient alloy-based electrocatalysts.

Effect of calcium and phosphorus on ammonium and nitrate nitrogen adsorption onto iron (hydr)oxides surfaces: CD-MUSIC model and DFT computation.

Calcium (Ca2+) and phosphorous (PO43-) significantly influence the form and effectiveness of nitrogen (N), however, the precise mechanisms governing the adsorption of ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3--N) are still lacking. This study employed batch adsorption experiments, charge distribution and multi-site complexation (CD-MUSIC) models and density functional theory (DFT) calculations to elucidate the mechanism by which Ca2+ and PO43- affect the adsorption of NH4+-N and NO3--N on the goethite (GT) surface. The results showed that the adsorption of NH4+-N on the GT exhibited an initial increase followed by a decrease as pH increased, peaking at a pH of 8.5. Conversely, the adsorption of NO3--N decreased with rising pH. According to the CD-MUSIC model, Ca2+ minimally affected the NH4+-N adsorption on the GT but enhanced NO3--N adsorption via electrostatic interaction, promoting the adsorption of ≡FeOH-NO3- and ≡Fe3O-NO3- species. Similarly, PO43- inhibited the adsorption of ≡FeOH-NO3- and ≡Fe3O-NO3- species. However, PO43- boosted NH4+-N adsorption by facilitating the formation of ≡Fe3O-NH4+ via electrostatic interaction and site competition. DFT calculations indicates that although bidentate phosphate (BP) was beneficial to stabilize NH4+-N than monodentate phosphate (SP), SP-NH4+ was the main adsorption configuration at pH 5.5-9.5 owing the prevalence of SP on the GT surface under site competition of NH4+-N. The results of CD-MUSIC model and DFT calculation were verified mutually, and provide novel insights into the mechanisms underlying N fixation and migration in soil.

Case report: A novel PTCH1 frameshift mutation leading to nevoid basal cell carcinoma syndrome.

A patient presenting with several basal cell carcinomas, pigmented nevi, and developmental defects was diagnosed with nevoid basal cell carcinoma syndrome. Gene panel sequencing and Sanger sequencing were used to identify a novel heterozygous frameshift mutation, c.1312dupA:p.Ser438Lysfs, in exon 9 of PTCH1. I-Tasser and PyMol analyses indicated that the mutated protein patched homolog 1 (PTCH1) lacked 12 transmembrane domains and the intracellular and extracellular rings of ECD2 compared with the wild-type protein, resulting in a remarkably different structure from that of the wild-type protein. This case extends our knowledge of the mutation spectrum of NBCCS.

Phalaenopsiszhanhouana (Orchidaceae, Vandeae), a new species from Yunnan, China.

A new species of Orchidaceae, Phalaenopsiszhanhouana, from Xichou County, Yunnan, China, is described and illustrated. The novelty is close to P.taenialis, P.wilsonii, and P.stobartiana, but differs from them by having a distinct, fleshy anterior callus with a deeply lobed apex at the base of the labellum and lateral lobes of labellum reflexed and facing outward.

Supplementing two wheat genotypes with ZnSO4 and ZnO nanoparticles showed differential mitigation of Cd phytotoxicity by reducing Cd absorption, preserving root cellular ultrastructure, and regulating metal-transporter gene expression.

Cadmium (Cd) contamination is a serious challenge in agricultural soils worldwide, resulting in Cd entering the food chain mainly through plant-based food and threatening human health. Minimizing Cd bioaccumulation in wheat is an important way to prevent Cd hazards to humans. Hydroponic and pot experiments were conducted to comprehensively evaluate the effects of zinc sulfate (ZnSO4) and zinc oxide nanoparticles (nZnO) on Cd uptake, translocation, subcellular distribution, cellular ultrastructure, and gene expression in two wheat genotypes that differ in grain Zn accumulation. Results showed that high-dose nZnO significantly reduced root Cd concentration (52.44%∼56.85%) in two wheats, in contrast to ZnSO4. The S216 exhibited higher tolerance to Cd compared to Z797. Importantly, Zn supplementation enhanced Cd sequestration into vacuoles and binding to cell walls, which conferred stability to ultracellular structures and photosynthetic apparatus. Down-regulation of influx transporter (TaHMA2 and TaLCT1) and up-regulation of efflux transporters (TaTM20 and TaHMA3) in Z797 might contribute to Zn-dependent alleviation of Cd toxicity and enhance its Cd tolerance. Down-regulation of ZIP transporters (TaZIP3, -5, and -7) might contribute to an increase in root Zn concentration and inhibit Cd absorption. Additionally, soil Zn provided an effective strategy for the reduction of grain Cd concentrations in both wheats, with a reduction of 26%∼32% (high ZnSO4) and 11%∼67% (high nZnO), respectively. Collectively, these findings provide new insights and perspectives on the mechanisms of Cd mitigation in wheats with different Zn fertilizers and demonstrate that the effect of nZnO in mitigating Cd stress is greater than that of ZnSO4 fertilizers.

Dual oxidase 2 (duox 2) participates in the intestinal antibacterial innate immune responses of Procambarus clarkii by regulating ROS levels.

Dual oxidase (Duox) a member of the nicotinamide adenine dinucleotide phosphate oxidase (NOX) family can induce the production of reactive oxygen species (ROS). In vertebrates, the duox gene was indicated to be associated with the mucosal immunity. The roles of the duox gene in invertebrates were mainly studied in insects for the function of maintaining intestinal flora balance. In recent years, some studies have reported that Duox is involved in regulating the production of ROS and plays an important role in defending against the intestinal pathogen infection. However, the molecular mechanism has not been fully illuminated. In this study, a duox 2 involved in the production of H2O2 was identified for the first time in P. clarkii. Mature Pc-Duox 2 is a 7-transmembrane protein molecule that includes PHD, FAD, and NAD domains. Pc-duox 2 was mainly expressed in hemocytes and intestinal tissue. Its expression levels were obviously upregulated after intramuscular or oral infection with V. harveyi. In the RNAi assay, the upregulated trends of H2O2 and total ROS levels in crayfish intestine were significantly suppressed when Pc-duox 2 was knocked down. Compared with the slightly affected SOD activity, the upregulated CAT activity was suppressed more obviously in the crayfish intestine. Furthermore, Pc-duox 2 had an important effect on the maintenance of the structural stability of crayfish the intestine. Further research revealed that the knockdown of Pc-duox 2 could cause an obvious suppression in the upregulated levels of Toll signalling pathway-related genes, including Pc-toll 1, Pc-toll 3, Pc-dorsal, Pc-ALF 5, Pc-crustin 1, and Pc-lysozyme. Ultimately, these changes triggered the accelerated death of crayfish. Overall, we speculated that Pc-duox 2 played an important role in antibacterial innate immunity in the crayfish intestine by regulating the total ROS level.

Rapid carbothermal shocking fabrication of iron-incorporated molybdenum oxide with heterogeneous spin states for enhanced overall water/seawater splitting.

Molybdenum dioxide (MoO2) has been considered as a promising hydrogen evolution reaction (HER) electrocatalyst. However, the active sites are mainly located at the edges, resulting in few active sites and poor activity in the HER. Herein, we first reported on an efficient strategy to incorporate Fe into MoO2 nanosheets on Ni foam (Fe-MoO2/NF) using a rapid carbothermal shocking method (820 °C for 127 s). Notably, the different spin states between Fe and Mo atoms could lead to rich lattice dislocations in Fe-MoO2/NF, exposing abundant oxygen vacancies and the low-oxidation-state of Mo sites during the rapid Joule heating process. As tested, the catalyst exhibited superior activity with ultralow overpotentials (HER: 17 mV@10 mA cm-2; oxygen evolution reaction (OER): 310 mV@50 mA cm-2) and high OER selectivity in alkaline seawater splitting. Meanwhile, this catalyst was equipped in a home-made anion exchange membrane (AEM) seawater electrolyzer, which achieved a low energy consumption (5.5 kW h m-3). More importantly, Fe-MoO2/NF also coupled very well with a solar-driven electrolytic system and turned out a solar-to-hydrogen (STH) efficiency of 13.5%. Theoretical results also demonstrated that Fe incorporated and abundant oxygen vacancies in MoO2 can distort the distance of the Mo-O bonds and regulate the electronic structure, thus optimizing the binding energy of H*/OOH* adsorption. This method can be extended to other heterogeneous spin states in MoO2-based catalysts (e.g. Ni-MoO2/NF, Co-MoO2/NF) for seawater splitting, and provide a simple, efficient and universal strategy to prepare highly-efficient MoO2-based electrocatalysts.

[Effects of P on the Uptake and Transport of Cd and As in Wheat Seedlings].

The aim of this study was to explore the effect of P on the physiological mechanism of Cd and As uptake and transport of wheat seedlings. Taking Bainong 207 as the test material, we investigated the effects of exogenous P supply and P deficiency treatment on the growth, root morphology, photosynthetic parameters, antioxidant system, ion content, and rhizome transfer coefficient of wheat seedlings under Cd and As stress using hydroponic experiments. The results showed that compared with that in the P deficiency treatment, the supply of exogenous P significantly increased the chlorophyll content of wheat seedlings under As stress, promoted the growth and development of roots, and increased biomass, whereas there were no significant effects on the growth of wheat seedlings under Cd stress. The contents of P and Cd in the root system under the condition of Cd stress were significantly increased by the supply of exogenous P, and the contents of P and Cd in the aboveground part were reduced. At the same time, the P and As content in the shoot and the transfer coefficient of As from the root to the shoot under As stress were significantly improved. Therefore, the effects of P on the poisoning of wheat Cd and As in this study showed obvious differences. Under As stress, exogenous P supply mainly promoted the growth of wheat seedlings by improving the transport of As from the root to the shoot and the CAT activity in the root system, reducing the poisoning of As in wheat. Under Cd stress, P and Cd showed a certain synergistic effect, and the toxic effect of Cd on wheat was aggravated to a certain extent after the supply of P.

Alicyclic polyimides with large band gaps exhibit superior high-temperature capacitive energy storage.

Flexible polymer dielectrics for capacitive energy storage that can function well at elevated temperatures are increasingly in demand for continuously advancing and miniaturizing electrical devices. However, traditional high-resistance polymer dielectrics composed of aromatic backbones have a compromised band gap (Eg) and hence suffer from low breakdown strength and a huge loss at high temperatures. Here, based on the density functional theory (DFT) calculations, rigid and non-coplanar alicyclic segments are introduced into the polyimide backbone to overcome the incompatibility of a high glass transition temperature (Tg) and large Eg. Thanks to the large optical Eg (∼4.6 eV) and high Tg (∼277 °C), the all-alicyclic polyimide at 200 °C delivers a maximum discharge energy density (Ue) of 5.01 J cm-3 with a charge-discharge efficiency (η) of 78.1% at 600 MV m-1, and a record Ue of 2.55 J cm-3 at η = 90%, which is 10-fold larger than that of the state-of-art commercial polyetherimides (PEIs). In addition, compared with aromatic polyimides, the all-alicyclic polyimide possesses a better self-clearing characteristic due to a smaller ratio of carbon to hydrogen and oxygen, which facilitates its long-term reliability in practical applications.

Nickel-Catalyzed Reductive Dicarbofunctionalizations of Alkenes for the Synthesis of Difluorocarbonyl Oxindoles and Isoquinoline-1,3-diones.

A novel and efficient strategy for the construction of difluorocarbonyl-oxindole and difluorocarbonyl-isoquinoline-1,3-dione derivatives involving nickel-catalyzed intramolecular Heck-type cyclizations followed by intermolecular cross-couplings has been developed. This approach features high functional group tolerance, broad substrate scope, and operational simplicity under mild conditions, thus providing a new method for the rapid difluorocarbonyl-functionalization of alkenes to construct the structurally diversified five- and six-membered heterocycles.

Meta-Viromic Sequencing Reveals Virome Characteristics of Mosquitoes and Culicoides on Zhoushan Island, China.

Mosquitoes and biting Culicoides species are arbovirus vectors. Effective virome profile surveillance is essential for the prevention and control of insect-borne diseases. From June to September 2021, we collected eight species of female mosquito and Culicoides on Zhoushan Island, China, and used meta-viromic sequencing to analyze their virome compositions and characteristics. The classified virus reads were distributed in 191 genera in 66 families. The virus sequences in mosquitoes with the largest proportions were Iflaviridae (30.03%), Phasmaviridae (23.09%), Xinmoviridae (21.82%), Flaviviridae (13.44%), and Rhabdoviridae (8.40%). Single-strand RNA+ viruses formed the largest proportions of viruses in all samples. Blood meals indicated that blood-sucking mosquito hosts were mainly chicken, duck, pig, and human, broadly consistent with the habitats where the mosquitoes were collected. Novel viruses of the Orthobunyavirus, Narnavirus, and Iflavirus genera were found in Culicoides by de-novo assembly. The viruses with vertebrate hosts carried by mosquitoes and Culicoides also varied widely. The analysis of unclassified viruses and deep-learning analysis of the "dark matter" in the meta-viromic sequencing data revealed the presence of a large number of unknown viruses. IMPORTANCE The monitoring of the viromes of mosquitoes and Culicoides, widely distributed arbovirus transmission vectors, is crucial to evaluate the risk of infectious disease transmission. In this study, the compositions of the viromes of mosquitoes and Culicoides on Zhoushan Island varied widely and were related mainly to the host species, with different host species having different core viromes. and many unknown sequences in the Culicoides viromes remain to be annotated, suggesting the presence of a large number of unknown viruses.

Clinical and Molecular Characterizations of Carbapenem-Resistant Klebsiella pneumoniae Causing Bloodstream Infection in a Chinese Hospital.

Bloodstream infection (BSI) caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) is a serious and urgent threat for hospitalized patients. This study aims to describe the clinical and molecular characteristics of CRKP causing BSI in a tertiary-care hospital in Beijing, China. A total of 146 CRKP strains and 39 carbapenem-susceptible K. pneumoniae (CSKP) strains collected in the hospital from 2017 to 2020 were sent for whole-genome sequencing. Univariate and multivariate analyses were used to evaluate risk factors for in-hospital mortality of CRKP-BSI cases. Thirty (20.5%) of 146 CRKP-BSI patients and three (7.7%) of 39 CSKP-BSI patients died at discharge (χ2 = 3.471, P = 0.062). Multivariate logistic regression analysis indicated that age and use of urinary catheters were independent risk factors for the death of CRKP-BSI. The 146 CRKP isolates belonged to 9 sequence types (STs) and 11 serotypes, while the 39 CSKP isolates belonged to 23 STs and 27 serotypes. The mechanism of carbapenem resistance for all the CRKP strains was the acquisition of carbapenemase, mainly KPC-2 (n = 127). There were 2 predominant serotypes for ST11 CRKP, namely, KL47 (n = 82) and KL64 (n = 42). Some virulent genes, including rmpA2, iucABCD and iutA, and repB gene, which was involved in plasmid replication, were detected in all ST11-KL64 strains. Evolutionary transmission analysis suggested that ST11 CRKP strains might have evolved from KL47 into KL64 and were accompanied by multiple outbreak events. This study poses an urgent need for enhancing infection control measures in the hospital, especially in the intensive care unit where the patients are at high-risk for acquiring CRKP-BSI. IMPORTANCE CRKP-BSI is demonstrated to cause high mortality. In this study, we demonstrated that ST11 CRKP strains might carry many virulent genes. Meanwhile, outbreak events occurred several times in the strains collected. Carbapenemase acquisition (mainly KPC-2 carbapenemase) was responsible for carbapenem resistance of all the 146 CRKP strains. As 2 predominant strains, all ST11-KL64 strains, but not ST11-KL47 strains, carried rmpA2, iucABCD, iutA, as well as a plasmid replication initiator (repB). Our study suggested that the occurrence of region-specific recombination events manifested by the acquisition of some virulence genes might contribute to serotype switching from ST11-KL47 to ST11-KL64. The accumulation of virulent genes in epidemic resistant strains poses a great challenge for the prevention and treatment of BSI caused by K. pneumoniae in high-risk patients.

Genomic Evolution of ST11 Carbapenem-Resistant Klebsiella pneumoniae from 2011 to 2020 Based on Data from the Pathosystems Resource Integration Center.

(1) Objective: ST11 carbapenem-resistant Klebsiella pneumoniae (CRKP) is widespread throughout the world, and the mechanisms for the transmission and evolution of major serotypes, ST11-KL47 and ST11-KL64, were analyzed to investigate the global distribution and evolutionary characteristics of ST11 CRKP; (2) Methods: The Pathosystems Resource Integration Center (PATRIC) database was downloaded and all K. pneumoniae from 2011 to 2020 were screened to obtain ST11 CRKP genome assemblies with basic information. The relationship of serotype evolution between KL47 and KL64 was then investigated using statistical and bioinformatic analysis; (3) Results: In total, 386 ST11 CRKP isolates were included for analysis. Blood (31.09%, 120/386), respiratory tract (23.06%, 89/386), and feces (20.21%, 78/386) were the major sources of samples. China was the leading country where ST11 CRKP was isolated. KL47 and KL64 were found to be the most prevalent serotypes. ST11-KL64 CRKP [median 78(P25~P75: 72~79.25)] had remarkably more virulence genes than the KL47 [median 63(P25~P75: 63~69)], and the distinction was statistically significant (p < 0.001). A differential comparison of virulence genes between KL47 and KL64 revealed 35 differential virulence genes, including rmpA/rmpA2, iucABCD, iutA, etc. The comparison of the recombination of serotype-determining regions between the two serotypes revealed that KL64 CRKP carried more nucleotide sequences in the CD1-VR2-CD2 region than KL47 CRKP. More nucleotide sequences added approximately 303 base pairs (bp) with higher GC content (58.14%), which might facilitate the evolution of the serotype toward KL64; (4) Conclusions: KL47 and KL64 have become the predominant serotypes of ST11 CRKP. KL64 CRKP carries more virulence genes than KL47 and has increased by approximately 303 bp through recombinant mutations, thus facilitating the evolution of KL47 to KL64. Stricter infection prevention and control measures should be developed to deal with the epidemic transmission of ST11-KL64 CRKP.

Effect of boron on cadmium uptake and expression of Cd transport genes at different growth stages of wheat (Triticum aestivum L.).

Boron (B) is an essential microelement for plant growth and has been shown to reduce cadmium (Cd) toxicity in wheat through modulating gene expression. However, there is not enough information about the effects of different applications of B fertilizer on the accumulation of Cd, particularly throughout the wheat growth period. This experiment employed two different B fertilization methods. The soil application method utilized 1.5 mg B kg-1 soil (Cd+B) and foliar application utilized 0.1% (F0.1%), 0.3% (F0.3%), and 0.6% (F0.6%) B concentrations along with 4 mg kg-1 Cd. The results showed that B application in the soil reduced Cd concentrations per plant by 43.9% at the seedling stage, 74.59% in the roots, and 52.11% in the shoots at the elongation stage. At the same time, Cd concentrations in the roots were higher by B application at the anthesis and maturity stages, suggesting that B retains more Cd in the roots. The gray correlation analysis showed that the gray relational coefficients followed the following order: F0.3% > F0.1% > Cd+B > F0.6%. According to quantitative real-time PCR analysis, the six Cd transporters were mostly expressed in the roots at the seedling stage and anthesis stage. In addition, the expression of TCONS1113, TRIAE1060, and TRIAE5370 showed a negative correlation relationship with Cd concentration at the seedling stage, both in roots and shoots. At the anthesis stage, the expression of TCONS1113 and TRIAE5370 in roots was higher in Cd-treated plants compared to B-treated plants, and a similar tendency was noted for the expression of TRIAE5770 and TRIAE1060 in shoots as well. These results suggest that B application could significantly inhibit Cd uptake and translocation by regulating the expression of Cd transporter genes, especially at the seedling stage and the elongation phase in wheat.

A comparison study of physiological response and TaZIPs expression in seedlings of two wheat (Triticum aestivum L.) cultivars with contrasting grain zinc accumulation.

Screening and breeding of high-Zn-accumulating wheat cultivars have received increasing attention in recent years. However, the exact mechanism of Zn uptake and accumulation in wheat is not fully understood. Here, we investigated the physiological responses and TaZIPs gene expression in a low (Zhengmai0856, ZM0856) and a high (Aikang58, AK58) grain-Zn-accumulating wheat cultivars under hydroponic conditions with different levels of Zn supply. Results showed that AK58 was a Zn sensitive cultivar with better growth advantage, while ZM0856 was a Zn tolerant cultivar with higher capacity of Zn uptake. In addition, gene expression analysis showed that, the expression levels of the TaZIP3, TaZIP5, and TaZIP7 in roots were increased in both cultivars under Zn deficiency. In shoots, TaZIP3 and TaZIP6 transcript accumulation was lower in AK58 than ZM0856, whereas TaZIP7 showed the opposite effect. Moreover, multivariate statistical analysis (Pearson's correlation and PCA) showed that the mechanisms involved in Zn uptake and translocation was closely related to subcellular biosynthesis and ZIP gene expression regulation, whereas adequate Zn supply improved the Zn uptake and root-to-shoot translocation. These novel findings might be helpful for the molecular-assisted selecting and breeding of Zn-rich wheat cultivars.

Metabolomic and antioxidant enzyme activity changes in response to cadmium stress under boron application of wheat (Triticum aestivum).

Boron (B) has previously been shown to inhibit cadmium (Cd) uptake in wheat. Here, we investigated the physiological response of external B application (C for no B added, B for B added, B+Cd for B and Cd added, B/Cd for B 24 h pretreatment before Cd added, B and Cd were 46.2 µM and 5 µM, respectively) on wheat growth under Cd stress. The results showed that the wheat growth was significantly weaker under Cd treatment, while B application did not significantly improve the wheat growth under Cd stress. However, B application decreased Cd concentrations and malondialdehyde (MDA) concentrations of shoot and root. The key enzyme activities including superoxide dismutase (SOD) and peroxidase (POD) significantly increased under Cd treatments while decreased under B treatments. Further, a total of 198, 680 and 204 of the differential metabolites were isolated between B and C treatment, Cd and C treatment and B+Cd and Cd treatment, respectively. The metabolites with up-accumulation in B application (B+Cd) roots were mainly galactaric acid, citric acid, N6-galacturonyl-L-lysine, D-glucose, while the metabolites with down-accumulation were mainly threoninyl-tryptophan and C16 sphinganine. The differential metabolic pathways were mainly concentrated in linoleic acid metabolism, galactose metabolism, sphingolipid metabolism, glycolysis/gluconeogenesis, propanoate metabolism in diabetic complications between B+Cd treatment and B treatment. The results indicate that B alleviates Cd toxicity in winter wheat by inhibiting Cd uptake, increasing antioxidant enzyme activity and changing metabolites.