Modified Zhizhu Pill improves the loperamide-induced slow transit constipation via gut microbiota and neurotransmitters in microbiota-gut-brain axis.

BACKGROUND: Slow-transmission constipation is a type of intractable constipation with unknown etiology and unclear pathogenesis. OBJECTIVE: The intention of this study was to evaluate the therapeutic effect and possible mechanism of Modified Zhizhu Pills on loperamide-induced slow transit constipation. METHODS: The effects of the Modified Zhizhu Pill were evaluated in a rat model of constipation induced by subcutaneous administration of loperamide. Fecal parameters (fecal count, fecal water content, and fecal hardness) were measured in constipated rats. The substance, target, and pathway basis of the Modified Zhizhu Pill on constipation was investigated using network pharmacology. The microflora in rats was determined. Serum neurotransmitters (acetylcholine and 5-hydroxytryptamine) were measured in rats and their relationship with the gut microbiota was assessed. RESULTS: Modified Zhizhu Pill increased the number of bowel movements and fecal water content, and decreased fecal hardness and transit time. Network pharmacological analysis showed that Modified Zhizhu Pill can target multiple constipation-related targets and pathways through multiple potential active ingredients. Modified Zhizhu Pill alleviated loperamide-induced microbiota dysbiosis. Modified Zhizhu Pill increased serum 5-hydroxytryptamine and acetylcholine. The increase in serum 5-hydroxytryptamine and acetylcholine was associated with rat gut microbiota. CONCLUSION: These results suggest that Modified Zhizhu Pill may increase intestinal motility and ultimately relieve constipation by improving microecological dysbiosis and neurotransmission.

Bactericidal bissulfone B7 targets bacterial pyruvate kinase to impair bacterial biology and pathogenicity in plants.

The prevention and control of rice bacterial leaf blight (BLB) disease has not yet been achieved due to the lack of effective agrochemicals and available targets. Herein, we develop a series of novel bissulfones and a novel target with a unique mechanism to address this challenge. The developed bissulfones can control Xanthomonas oryzae pv. oryzae (Xoo), and 2-(bis(methylsulfonyl)methylene)-N-(4-chlorophenyl) hydrazine-1-carboxamide (B7) is more effective than the commercial drugs thiodiazole copper (TC) and bismerthiazol (BT). Pyruvate kinase (PYK) in Xoo has been identified for the first time as the target protein of our bissulfone B7. PYK modulates bacterial virulence via a CRP-like protein (Clp)/two-component system regulatory protein (regR) axis. The elucidation of this pathway facilitates the use of B7 to reduce PYK expression at the transcriptional level, block PYK activity at the protein level, and impair the interaction within the PYK-Clp-regR complex via competitive inhibition, thereby attenuating bacterial biology and pathogenicity. This study offers insights into the molecular and mechanistic aspects underlying anti-Xoo strategies that target PYK. We believe that these valuable discoveries will be used for bacterial disease control in the future.

Cell number regulator 8 from Salix linearistipularis enhances cadmium tolerance in poplar by reducing cadmium uptake and accumulation.

Trace metals have relatively high density and high toxicity at low concentrations. Willow (Salix genus) is an excellent phytoremediation species for soil contaminated by trace metal ions. This study identified a cell number regulator (CNR) gene family member in Salix linearistipularis exhibiting strong metal ion resistance: SlCNR8. SlCNR8 expression was affected by various metal ions, including cadmium (Cd), zinc (Zn), copper (Cu), iron (Fe), and manganese (Mn). SlCNR8 overexpression enhanced Cd, Zn, Cu, and Fe resistance in transgenic poplar seedlings (84K) compared with the wild-type (WT). Moreover, transgenic poplar seedlings showed lower root Cd uptake and less Cd accumulation than WT under Cd stress. SlCNR8 was primarily localized to the nucleus and the plasma membrane-like cell periphery. Furthermore, SlCNR8 had transcriptional activation activity in yeast. The transcript levels of multiple metal ion transporters were altered in the roots of transgenic poplar seedlings compared to WT roots under Cd stress. These results suggest that SlCNR8 may enhance Cd resistance in transgenic poplar by reducing Cd uptake and accumulation. This may be related to altered transcription levels of other transporters or to itself. Our study suggests that SlCNR8 can be used as a candidate gene for genetic improvement of phytostabilisation of trace metals by genetic engineering.

Populus euphratica plant cadmium resistance 2 mediates Cd tolerance by root efflux of Cd ions in poplar.

KEY MESSAGE: Populus euphratica PePCR2 increases Cd resistance by functioning as a Cd extrusion pump and by mediating the expression of genes encoding other transporters. Cadmium (Cd) is a non-essential, toxic metal that negatively affects plant growth. Plant cadmium resistance (PCR) proteins play key roles in the response to heavy metal stress. In this study, we isolated the gene PePCR2 encoding a plant PCR from Populus euphratica. PePCR2 gene transcription was induced by Cd, and its transcript level peaked at 24 h after exposure, at a level approximately 18-fold higher than that at 0 h. The PePCR2 protein was localized to the plasma membrane. Compared with yeast cells harboring the empty vector, yeast cells expressing PePCR2 showed enhanced Cd tolerance and a lower Cd content. Compared with wild-type (WT) plants, poplar overexpressing PePCR2 showed higher Cd resistance. Net Cd2+ efflux measurements showed that Cd2+ efflux from the roots was 1.5 times higher in the PePCR2-overexpressing plants than in WT plants. Furthermore, compared with WT plants, the PePCR2-overexpressing plants showed increased transcript levels of ABCG29, HMA5, PDR2, YSL7, and ZIP1 and decreased transcript levels of NRAMP6, YSL3, and ZIP11 upon exposure to Cd. These data show that PePCR2 increased Cd resistance by acting as a Cd extrusion pump and/or by regulating other Cd2+ transporters to decrease Cd toxicity in the cytosol. The results of this study identify a novel plant gene with potential applications in Cd removal, and provide a theoretical basis for reducing Cd toxicity and protecting food safety.

Plant cadmium resistance 10 enhances tolerance to toxic heavy metals in poplar.

Toxic heavy metals originating from human activities have caused irreversible harm to the environment. Toxic heavy metal ions absorbed by crop plants can seriously threaten human health. Therefore, decreasing heavy metal contents in crop plants is an urgent need. The plant cadmium resistance protein (PCR) is a heavy metal ion transporter. In this study, PePCR10 was cloned from Populus euphratica. Bioinformatics analyses revealed its transmembrane structure and gene sequence motifs. The transcript profile of PePCR10 was analyzed by RT-qPCR, and its transcript levels increased under toxic heavy metal (cadmium, lead, aluminum) treatments. Subcellular localization analyses in tobacco cells revealed that PePCR10 localizes at the plasma membrane. Compared with wild type (WT), PePCR10-overexpressing lines showed significantly higher values for plant height, root length, fresh weight, and dry weight under heavy metal stress. Electrolyte leakage, nitroblue tetrazolium staining, and chlorophyll fluorescence analyses indicated that Cd/Al tolerance in PePCR10-overexpressing lines was stronger than that in WT. The Cd/Al contents were lower in the PePCR10-overexpressing lines than in WT under Cd/Al stress. Our results show that PePCR10 can reduce the heavy metal content in poplar and enhance its Cd/Al tolerance. Hence, PePCR10 is a candidate genetic resource for effectively reducing heavy metal accumulation in crops.

Populus euphratica plant cadmium tolerance PePCR3 improves cadmium tolerance.

Contamination of soils with toxic heavy metals is a major environmental problem. Growing crop plants that can promote the efflux of heavy metals is an effective strategy in contaminated soils. The plant cadmium resistance (PCR) protein is involved in the translocation of heavy metals, specifically zinc and cadmium (Cd). In this study, yeast expressing Populus euphratica PCR3 (PePCR3) showed enhanced Cd tolerance and decreased Cd accumulation under Cd treatment. Real-time quantitative PCR analyses revealed up-regulation of PePCR3 in poplar seedlings under Cd stress. Localization analysis revealed that PePCR3 localizes at the plasma membrane. The plant growth and biomass were greater in PePCR3-overexpressing (OE) transgenic hybrid poplar lines than in wild type (WT). Physiological parameters analyses indicated that, compared with WT, PePCR3-OE transgenic lines were more tolerant to Cd. In addition, more Cd was excreted in the roots of the PePCR3-OE transgenic lines than in those of WT, but the remaining Cd in transgenic lines was more translocated into the stems and leaves. Eight genes encoding transporters showed increased transcript levels in PePCR3-OE transgenic lines under Cd treatment, implying that PePCR3 interacts with other transporters to translocate Cd. Thus, PePCR3 may be an important genetic resource for generating new lines that can enhance Cd translocation to phytoremediation in contaminated soils.

Potential candidate genes and pathways related to cytoplasmic male sterility in Dianthus spiculifolius as revealed by transcriptome analysis.

KEY MESSAGE: We introduced the candidate gene DsHSP70 into Arabidopsis thaliana, resulting in male gametophyte sterility and abnormal degeneration of sepals and petals. Cytoplasmic male sterility (CMS) is a useful tool for hybrid production. However, the regulatory mechanism of CMS in Dianthus spiculifolius remains unclear. In this study, we investigated whether male-sterile line of D. spiculifolius has a malformed tapetum and fails to produce normal fertile pollen. RNA sequencing technology was used to compare the gene expression patterns of the D. spiculifolius male-sterile line and its male fertility maintainer line during anther development. A total of 12,365 differentially expressed genes (DEGs) were identified, among which 1765 were commonly expressed in the S1, S2 and S3 stages. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses indicated that these DEGs were mainly involved in oxidation-reduction processes, signal transduction and programmed cell death. Additionally, weighted correlation network analysis (WGCNA) showed that three modules may be related to male sterility. A putative regulatory pathway for the male sterility traits was constructed based on the reproductive development network. After introducing the candidate DsHSP70 gene into Arabidopsis thaliana, we found that overexpressing plants showed anther abortion and shorter filaments, and accompanied by abnormal degeneration of sepals and petals. In summary, our results identified potential candidate genes and pathways related to CMS in D. spiculifolius, providing new insights for further research on the mechanism of male sterility.

Analysis of the Spatial Differentiation and Promotion Potential for Agricultural Eco-Efficiency-Evidence of Pollution's Strong Disposability.

Agricultural eco-efficiency is an important indicator used to measure agriculture's high-quality and sustainable development. Therefore, this paper uses the EBM-Super-ML method with strong disposability of undesired output to calculate Chinese agricultural eco-efficiency and uses a geographical detector to measure the driving force of the factor. The research conclusions are mainly reflected in three aspects. Firstly, from the perspective of eco-efficiency changes, the overall mean value of agricultural eco-efficiency increased by 3.5%, and the regional heterogeneity is significant, with the fastest growth in the eastern region. Secondly, the results of driving force analysis show that the main driving factors of agricultural eco-efficiency divergence are capital inputs, total carbon emissions, labor inputs, agricultural film residues, fertilizer use, and pesticide residues, with driving forces of 0.43, 0.37, 0.34, 0.31, 0.28, and 0.20, respectively. Finally, from the perspective of eco-efficiency improvement potential, the mean value of output improvement potential is 5%, and the input factor is 7%. Among the non-desired outputs, the reduction rate of agricultural films can reach 40%. Among the input factors, labor input has the highest potential for intensive use, while agricultural machinery has a negative effect. Therefore, strengthening the development of the agricultural service industry is of great significance to improve the utilization rate of mechanical equipment and reduce the undesired output of agriculture.

Carbon effect calculation and upgrading strategy of agricultural land consolidation project in urban edge of Three Gorges Reservoir Area.

Under the background of promoting the construction of ecological civilization and the goal of carbon peak and carbon neutralization, it is of great significance to explore the measurement method and improvement strategy of the carbon effect of agricultural land consolidation. Based on a quantitative analysis and the whole life cycle of land consolidation, this study constructed a carbon effect accounting and analysis framework of agricultural land consolidation project from three stages of project initiation and design, project implementation, and operation management. Taking the agricultural land consolidation project in the Shiyan town on the urban edge of the Three Gorges Reservoir Area as a case, this study made empirical analysis and calculation and analyzed the carbon effect and influencing factors in different consolidation stages. The results showed that the overall carbon effect in the project area was a carbon source. The net carbon emission generated by the project construction was 8358t, which was mainly from workers input and concrete carbon emission; the carbon storage brought about by the adjustment of land use structure was 2,378.20t, which mainly came from the carbon storage increment of newly cultivated land; the carbon storage generated by the agricultural ecosystem was 1,100.04t, which was mainly based on the increase of cultivated land and the improvement of cultivated land quality; the carbon emission from agricultural production activities was 18.18t. Research conclusions: ① the carbon source effect of engineering construction is obvious. Artificial input and concrete are the main carbon sources in the hilly area at the edge of the metropolis; ② the adjustment of land use structure is manifested as a carbon sink effect, which mainly comes from the contribution of carbon storage of newly increased cultivated land; ③ the carbon effect of project operation and management may be a carbon source in the short term, and the long-term effect should be exerted; and ④ based on the concept of whole life cycle, promoting ecological land consolidation, optimizing project design, reasonably arranging consolidation projects, and strengthening operation management are effective measures to improve the carbon effect of land consolidation projects, which are conducive to the realization of the "double carbon" goal.

Genetic Variants in MIR3142HG Contribute to the Predisposition of IgA Nephropathy in a Chinese Han Population.

BACKGROUND: The study aimed to evaluate the association of genetic variants in MIR3142HG with the predisposition of IgA nephropathy (IgAN) in a Chinese Han population. METHODS: Six single-nucleotide polymorphisms (SNPs) in MIR3142HG were chosen for genotyping among 417 IgAN cases and 424 healthy controls using Agena MassARRAY technique. Logistic regression models adjusted for age and gender were used to calculate odds ratios (ORs) and 95% confidence intervals (CI). Haploview and multifactor dimensionality reduction analysis were used to analyze the role of combined SNPs in IgAN risk. RESULTS: Rs17057846-AA genotype (OR = 2.11, 95% CI: 1.04-4.27, p = 0.039) and rs58747524-CC genotype (OR = 1.89, 95% CI: 1.06-3.38, p = 0.032) had the higher risk for IgAN developing in the overall. Interestingly, rs7727115 had a reduced risk for IgAN in females, while rs17057846, rs2961920, and rs58747524 were related to the increased susceptibility to IgAN in females and the subjects with age ≤35 years; moreover, rs17057846 and rs58747524 conferred to the higher risk for Lee's grade ≥III IgAN (p < 0.05 for all). Besides, the combination of rs1582417, rs7727115, and rs2961920 was the best model (testing accuracy = 0.5468, CVC = 10/10, p < 0.001) to predict IgAN predisposition compared to the single SNP alone. CONCLUSIONS: Our study firstly indicated that rs17057846 and rs58747524 in MIR3142HG contributed to the elevated risk for IgAN in a Chinese Han population. These results might provide a new insight for the molecular mechanism in the progression of IgAN.

lncRNA TUG1 regulates hyperuricemia-induced renal fibrosis in a rat model.

Renal fibrosis is most common among chronic kidney diseases. Molecular studies have shown that long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) participate in renal fibrosis, while the roles of lncRNA taurine upregulated gene 1 (TUG1) and miR-140-3p in hyperuricemia-induced renal fibrosis remain less investigated. In this study, a rat hyperuricemia model is constructed by oral administration of adenine. TUG1, miR-140-3p, and cathepsin D (CtsD) expression levels in rat models are measured. After altering TUG1, miR-140-3p, or CtsD expression in modelled rats, biochemical indices, including uric acid (UA), serum creatine (SCr), blood urea nitrogen (BUN), and 24-h urine protein are detected, pathological changes in the renal tissues, and renal fibrosis are examined. In renal tissues from hyperuricemic rats, TUG1 and CtsD are upregulated, while miR-140-3p is downregulated. Inhibiting TUG1 or CtsD or upregulating miR-140-3p relieves renal fibrosis in hyperuricemic rats. Downregulated miR-140-3p reverses the therapeutic effect of TUG1 reduction, while overexpression of CtsD abolishes the role of miR-140-3p upregulation in renal fibrosis. Collectively, this study highlights that TUG1 inhibition upregulates miR-140-3p to ameliorate renal fibrosis in hyperuricemic rats by inhibiting CtsD.

Plant cadmium resistance 6 from Salix linearistipularis (SlPCR6) affects cadmium and copper uptake in roots of transgenic Populus.

Phytoextraction in phytoremediation is one of the environmentally friendly methods used for restoring soils contaminated by heavy metals (HMs). The screening and identification of HM-resistant plants and their regulatory genes associated with HM ion transport are the key research aims in this field. In this study, a plant cadmium (Cd) resistance (PCR) gene family member, SlPCR6, was identified in roots of Salix linearistipularis, which exhibits strong HM resistance. The results revealed that SlPCR6 expression was induced in S. linearistipularis roots in response to Cd stress. Furthermore, SlPCR6 was mainly localized on the plasma membrane. Compared with the wild type, SlPCR6 overexpression reduced the Cd and copper (Cu) contents in the transgenic poplar (84 K) and increased its Cd and Cu resistance. The roots of transgenic poplar seedlings had lower net Cd and Cu uptake rates than wild type roots. Further investigation revealed that the transcript levels of multiple HM ion transporters were not significantly different between the roots of the wild type and those of the transgenic poplar. These results suggest that SlPCR6 is directly involved in Cd and Cu transport in S. linearistipularis roots. Therefore, SlPCR6 can serve as a candidate gene to improve the phytoextraction of the HMs Cd and Cu through genetic engineering.

AaZFP3, a Novel CCCH-Type Zinc Finger Protein from Adonis amurensis, Promotes Early Flowering in Arabidopsis by Regulating the Expression of Flowering-Related Genes.

CCCH-type zinc finger proteins (ZFP) are a large family of proteins that play various important roles in plant growth and development; however, the functions of most proteins in this family are uncharacterized. In this study, a CCCH-type ZFP, AaZFP3, was identified in the floral organ of Adonis amurensis. Quantitative real-time PCR (qPCR) analysis revealed that AaZFP3 was widely expressed in the flowers of A.amurensis. Subcellular localization analysis showed that the AaZFP3 protein was mainly localized to the cytoplasm in tobacco and Arabidopsis. Furthermore, the overexpression of AaZFP3 promoted early flowering in Arabidopsis under both normal and relatively low-temperature conditions. RNA-sequencing and qPCR analyses revealed that the expression of multiple key flowering-time genes was altered in transgenic Arabidopsis overexpressing AaZFP3 compared to wild-type. Of these genes, FLOWERING LOCUS T (AtFT) expression was most significantly up-regulated, whereas FLOWERING LOCUS C (AtFLC) was significantly down-regulated. These results suggest that the overexpression of AaZFP3 promotes early flowering in Arabidopsis by affecting the expression of flowering-time genes. Overall, our study indicates that AaZFP3 may be involved in flowering regulation in A.amurensis and may represent an important genetic resource for improving flowering-time control in other ornamental plants or crops.

New insights into the accumulation of vitamin B3 in Torreya grandis nuts via ethylene induced key gene expression.

Vitamin B3, derived primarily from plant sources, is an essential nutrient for humans. Torreya grandis is rich in vitamin B3, however, the mechanism underlying the biosynthesis and regulation of vitamin B3 in T. grandis remains unclear. A systematic transcriptomic investigation was thus conducted to identify the gene expression pattern of vitamin B3 biosynthesis in 10 T. grandis cultivars. The findings suggest that biosynthesis occurs mainly via the aspartate pathway. Expression and correlation analyses indicate that aspartate oxidase (AOX) and quinolinate synthase (QS) may play important roles in vitamin B3 accumulation. Furthermore, co-expression network and ethephon treatments indicate that the ethylene response factor (ERF) may be involved in the regulation of vitamin B3 biosynthesis in T. grandis nuts. Our findings not only help to elucidate the biosynthesis of vitamin B3, but also provide valuable resource material for future genomic research and molecular-assisted breeding to develop genotypes with higher vitamin B3 levels.

Molecular Characterization of a Tolerant Saline-Alkali Chlorella Phosphatidate Phosphatase That Confers NaCl and Sorbitol Tolerance.

The gene encoding a putative phosphatidate phosphatase (PAP) from tolerant saline-alkali (TSA) Chlorella, ChPAP, was identified from a yeast cDNA library constructed from TSA Chlorella after a NaCl treatment. ChPAP expressed in yeast enhanced its tolerance to NaCl and sorbitol. The ChPAP protein from a GFP-tagged construct localized to the plasma membrane and the lumen of vacuoles. The relative transcript levels of ChPAP in Chlorella cells were strongly induced by NaCl and sorbitol as assessed by northern blot analyses. Thus, ChPAP may play important roles in promoting Na-ion movement into the cell and maintaining the cytoplasmic ion balance. In addition, ChPAP may catalyze diacylglycerol pyrophosphate to phosphatidate in vacuoles.

Thin-film nanocomposite NF membrane with GO on macroporous hollow fiber ceramic substrate for efficient heavy metals removal.

The ceramic membrane has been widely used in the wastewater treatment based on the chemical resistance and superior separation performance. A robust and defect-free thin-film nanocomposite (TFN) nanofiltration (NF) membrane on the macroporous hollow fiber ceramic (HFC) substrate was novelly developed for heavy metals removal. Before interfacial polymerization (IP), the aqueous solution of graphene oxide (GO) grafted with ethylenediamine (EDA) was deposited on the HFC substrate by vacuum filtration. Then, a thin polyamide (PA) film was fabricated by EDA and 1,3,5-trimesoyl chloride (TMC), followed by heat treatment. The effects of GO content and EDA concentration on the performance of the NF membrane have been systematically investigated. The results showed that when the GO content was 0.015 mg·mL-1 and the EDA concentration was 0.75 wt.%, the as-prepared eGO3/PA-HFC membrane had a rejection rate of 94.12% for MgCl2 and a pure water flux of 18.03 L·m-2·h-1. Additionally, the removal ability of eGO3/PA-HFC membranes for heavy metal ions was satisfactory (93.33%, 92.73%, 90.45% and 88.35% for Zn2+, Cu2+, Ni2+ and Pb2+, respectively). The study explored further that it was efficient and stable for heavy metal ions removal during 30 h in the simulated tap water and mining wastewater, which indicated that the eGO/PA-HFC membrane has great application potential in wastewater treatment.

Identification of a Blood-Based Protein Biomarker Panel for Lung Cancer Detection.

Lung cancer is the deadliest cancer worldwide, mainly due to its advanced stage at the time of diagnosis. A non-invasive method for its early detection remains mandatory to improve patients' survival. Plasma levels of 351 proteins were quantified by Liquid Chromatography-Parallel Reaction Monitoring (LC-PRM)-based mass spectrometry in 128 lung cancer patients and 93 healthy donors. Bootstrap sampling and least absolute shrinkage and selection operator (LASSO) penalization were used to find the best protein combination for outcome prediction. The PanelomiX platform was used to select the optimal biomarker thresholds. The panel was validated in 48 patients and 49 healthy volunteers. A 6-protein panel clearly distinguished lung cancer from healthy individuals. The panel displayed excellent performance: area under the receiver operating characteristic curve (AUC) = 0.999, positive predictive value (PPV) = 0.992, negative predictive value (NPV) = 0.989, specificity = 0.989 and sensitivity = 0.992. The panel detected lung cancer independently of the disease stage. The 6-protein panel and other sub-combinations displayed excellent results in the validation dataset. In conclusion, we identified a blood-based 6-protein panel as a diagnostic tool in lung cancer. Used as a routine test for high- and average-risk individuals, it may complement currently adopted techniques in lung cancer screening.

PtHSFA4a gene play critical roles in the adaptation of Arabidopsis thaliana plants to high-Zinc stress.

Heat shock transcription factors (HSFs) play pivotal roles in various abiotic stresses. However, only one of the studies on HSFs that participated in excess zinc (Zn) stress in our previous study in Populus ussuriensis. Here, overexpression of P. trichocarpa PtHSFA4a gene in Arabidopsis thaliana significantly improved excess Zn tolerance. It was found that PtHSFA4a-OE lines have higher seed germination rate than wild type (WT) when exposed to excess Zn. Also, PtHSFA4a-OE lines exhibit high viability and stronger root growth than WT in soil. PtHSFA4a reduced the intracellular concentration of free zinc ion of roots when overexpressed in A. thaliana. Our data indicate PtHSFA4a is the candidate gene to act as positive regulators in the resistance to excess Zn, extending our knowledge of excess Zn tolerance transcription factors.

PuHSFA4a Enhances Tolerance To Excess Zinc by Regulating Reactive Oxygen Species Production and Root Development in Populus.

Zinc (Zn) is an essential micronutrient but in excess is highly toxic to plants. Plants regulate Zn homeostasis and withstand excess Zn through various pathways; these pathways are generally tightly regulated by a specific set of genes. However, the transcription factors involved in excess Zn tolerance have yet to be identified. Here, we characterized a Populus ussuriensis heat shock transcription factor A4a (PuHSFA4a) that acts as a positive regulator of excess Zn tolerance in P ussuriensis We used overexpression (PuHSFA4a-OE) and chimeric dominant repressor (PuHSFA4a-SRDX) lines to identify the targets of PuHSFA4a PuHSFA4a transcription is specifically induced in roots by high Zn. Overexpression of PuHSFA4a conferred excess Zn tolerance and a dominant repressor version of PuHSFA4a increased excess Zn sensitivity in P ussuriensis by regulating the antioxidant system in roots. PuHSFA4a coordinately activates genes related to abiotic stress responses and root development and directly binds to the promoter regions of glutathione-s-transferase U17 (PuGSTU17) and phospholipase A2 (PuPLA2 ). PuGSTU17 overexpression significantly increased GST activity and reduced reactive oxygen species levels in roots while PuGSTU17-RNA interference lines exhibited the opposite phenotype. Furthermore, PuPLA2 overexpression promoted root growth under high Zn stress. Taken together, we provide evidence that PuHSFA4a coordinately activates the antioxidant system and root development-related genes and directly targets PuGSTU17 and PuPLA, thereby promoting excess Zn tolerance in P ussuriensis roots.

Accumulation of Heavy Metals in Roadside Soil in Urban Area and the Related Impacting Factors.

Heavy metal contamination in roadside soil due to traffic emission has been recognized for a long time. However, seldom has been reported regarding identification of critical factors influencing the accumulation of heavy metals in urban roadside soils due to the frequent disturbances such as the repair of damaged roads and green belt maintanance. Heavy metals in the roadside soils of 45 roads in Xihu district, Hangzhou city were investigated. Results suggested the accumulation of Cu, Pb, Cd, Cr, and Zn in roadside soil was affected by human activity. However, only two sites had Pb and Zn excessing the standards for residential areas, respectively, according to Chinese Environmental Quality Standards for soils. The concentrations of Cu, Pb, Cd, and Zn were significantly and positively correlated to soil pH and organic matter. An insignificant correlation between the age of the roads or vegetation cover types and the concentration of heavy metals was found although they were reported closely relating to the accumulation of heavy metals in roadside soils of highways. The highest Pb, Cd, and Cr taking place in sites with heavy traffic and significant differences in the concentrations of Cu, Pb, Cd, and Zn among the different categories of roads suggested the contribution of traffic intensity. However, it was difficult to establish a quantitative relationship between traffic intensity and the concentrations of heavy metals in the roadside soil. It could be concluded that impaction of traffic emission on the accumulation of heavy metals in roadside soils in urban area was slight and soil properties such as pH and organic matters were critical factors influencing the retention of heavy metals in soils.