Inhibition of FoxO1 alleviates polycystic ovarian syndrome by reducing inflammation and the immune response.

The aim of this study was to explore the role of forkhead box transcription Factor O1 (FoxO1) in chronic inflammation in polycystic ovary syndrome (PCOS). A PCOS rat model was constructed as an in vivo model by letrozole induction, and granulosa cells (GCs) from PCOS rats were isolated and cultured as an in vitro cellular model. FoxO1 was knocked down by shRNA and siRNA in the PCOS rat model and GCs model, respectively. H&E staining was conducted to evaluate the effect of FoxO1 inhibition on ovarian pathology and dysfunction in PCOS rats. The levels of inflammatory cytokines in the ovaries and uterus of PCOS rats and in GCs were assessed by ELISA. Flow cytometry was used to evaluate the changes in the contents of neutrophils and macrophages in the peripheral blood and spleen of PCOS rats. CCK-8 assays and Annexin V-FITC/PI staining were performed to evaluate the proliferation and apoptosis of GCs. The expression of genes and proteins related to the TLR4/NF-κB/NLRP3 pathway in GCs was determined by RT-qPCR and Western blotting. The results indicated that FoxO1 was highly expressed in PCOS rat model. Inhibition of FoxO1 significantly mitigated the pathological changes and dysfunction in the ovaries of PCOS rats while also suppressing inflammation and fibrosis in the ovaries and uterus. Moreover, knocking down FoxO1 facilitated the restoration of the normal ratio of neutrophils and macrophages in the peripheral blood and spleen of PCOS rats and promoted M2 polarization of macrophages. Additionally, inhibition of FoxO1 promoted the proliferation of GCs and inhibited the inflammatory response in GCs. Furthermore, FoxO1 knockdown inhibited the activation of the NF-κB pathway and the formation of the NLRP3 inflammasome in GCs. In conclusion, inhibition of FoxO1 can alleviate PCOS by inhibiting the TLR4/NF-κB/NLRP3 pathway to reduce inflammation and the immune response.

Federal learning edge network based sentiment analysis combating global COVID-19.

As one of the important research topics in the field of natural language processing, sentiment analysis aims to analyze web data related to COVID-19, e.g., supporting China government agencies combating COVID-19. There are popular sentiment analysis models based on deep learning techniques, but their performance is limited by the size and distribution of the dataset. In this study, we propose a model based on a federal learning framework with Bert and multi-scale convolutional neural network (Fed_BERT_MSCNN), which contains a Bidirectional Encoder Representations from Transformer modules and a multi-scale convolution layer. The federal learning framework contains a central server and local deep learning machines that train local datasets. Parameter communications were processed through edge networks. The weighted average of each participant's model parameters was communicated in the edge network for final utilization. The proposed federal network not only solves the problem of insufficient data, but also ensures the data privacy of the social platform during the training process and improve the communication efficiency. In the experiment, we used datasets of six social platforms, and used accuracy and F1-score as evaluation criteria to conduct comparative studies. The performance of the proposed Fed_BERT_MSCNN model was generally superior than the existing models in the literature.

Effect of submerged plant coverage on phytoplankton community dynamics and photosynthetic activity in situ.

Restoration of submerged plants in eutrophic lakes can reduce nutrients and phytoplankton biomass in the water body. However, the effect of submerged plants on phytoplankton communities and their photosynthetic activity in situ are still poorly understood. Here, we studied the response of phytoplankton community structure and fluorescence parameters to different submerged plants coverage, the relationship of phytoplankton community and fluorescence parameters with submerged plants coverage and water physicochemical parameters were analysed in sampling area of Hangzhou West Lakes. The results showed that the coverage and biomass of submerged plants were negatively correlated with nitrogen and phosphorus contents in water body but positively correlated with total phenol content. The ratio of nitrogen to phosphorus in the study site changed greatly (32.25-124.54). In spring and summer, Oscillatoria and Leptolyngbya (Cyanophyta) were the dominant species, while in autumn and winter, the dominant species were Cyclotella (Chlorophyta), and Melosira and Cymbella (Bacillariophyta). Compared with Chlorophyta and Bacillariophyta, fluorescence parameters of Cyanophyta were more sensitive to total phosphorus, N:P ratio, total phenols, pH, and electric conductivity. Fluorescence parameters of Chlorophyta and Bacillariophyta were only affected by underwater light. Total phosphorus (TP) and N:P had a negative effect on the maximum photochemical electron yield of Cyanophyta. Furthermore, Cyanophyta was inhibited by total phenols from submerged plants. When phytoplankton were under stress, photochemical electron yield decreased significantly, whereas non-photochemical quenching increased. The structural equation model showed that the coverage of submerged plants might indirectly affect the fluorescence parameters of Cyanophyta by affecting nitrogen, phosphorus, and total phenol contents in the water body. These findings contribute to the understanding of the mechanisms underlying the impact of submerged plant restoration on phytoplankton community dynamics in subtropical eutrophic shallow lakes and provide a theoretical basis for the management of lakes.

Single and combined effects of microplastics and lead on the freshwater algae Microcystis aeruginosa.

Recently, the pollution of microplastics (MPs) in the global freshwater environment has become increasingly problematic, but there are few studies on the freshwater environment risks of MPs. The present study, therefore, has investigated the single and combined effects of MPs and lead (Pb) on the freshwater algal Microcystis aeruginosa. Results showed that Pb-only (>0.05 mg·L-1) promoted the growth of algal cells, while MPs-only (1 mg L-1) resulted in growth inhibition. However, compared with the corresponding concentration of Pb-only groups, the growth of algal cells was promoted in MPs + Pb treatments. MPs-only and Pb-only (0.5 mg L-1) both reduced the content of photosynthetic pigments and affected algal photosynthesis. The MPs-only treatment and MPs + Pb2+ (no pretreatment, 0.5 mg L-1 Pb2+) treatments showed significant cell aggregation. At the same time, MPs-only caused a significant increase in bound extracellular polysaccharides (bEPS), while 0.5 mg L-1 Pb reduced bEPS. Furthermore, under high Pb stress (0.5 mg L-1), the effects of combined MPs and Pb on chlorophyll content, antioxidant enzyme activity (peroxidase (POD), catalase (CAT)), and damage to algal cells were less compared to individual effects, and the combination of MPs and Pb had a synergistic effect on promoting aggregations of M. aeruginosa. These results demonstrate that single and combined effects of MPs and Pb can induce differential responses in the freshwater algal M. aeruginosa, which can have a significant impact on aquatic ecosystems.

A beta-glucosidase gene from Stevia rebaudiana may be involved in the steviol glycosides catabolic pathway.

We herein report the preparation of a full-length raucaffricine-O-beta-D-glucosidase gene of stevia rebaudiana Bertoni (named SrRG1, GenBank accession number MK920450). Sequence analysis indicated SrRG1 consists of a 1650 bp open reading frame encoding a protein of 549 amino acids. Its deduced amino acid sequence showed a high identity of 82% with a raucaffricine-O-beta-D-glucosidase from H. annuus of glycoside hydrolase family 1. The expression pattern analyzed by real-time quantitative PCR showed no significant difference among different tissues, developmental stages, and cultivars under normal growth conditions. Furthermore, the gene function of SrRG1 was preliminarily studied by agrobacterium-mediated transformation on instantaneous expression. In the test of agrobacterium-mediated transformation on instantaneous expression, it was observed that overexpression of SrRG1 increased the accumulation of steviol content and decreased the major components and total SGs contents. Such results demonstrated that SrRG1 may participate in the steviol glycosides catabolic pathway. However, the effect of silencing construct infiltration on steviol and SGs content was not significant and its expression pattern was constitutive, which most probably, attributed the hydrolysis of SGs to the secondary activity of SrRG1. This study firstly identified the bate-glucosidase in stevia and advances our understanding of steviol glycosides hydrolyzation.

Identification of GH1 gene family fgt members in Stevia rebaudiana and their expression when grown in darkness.

Stevia rebaudiana Bertoni is an important economic crop that is well known for its secondary metabolites, steviol glycosides (SGs), found in leaves. Because the enzymes of deglycosylation (glycoside hydrolases) play important roles in SGs biosynthetic processes, our study is focused on the functions of ß-glucosidases in SGs catabolism in stevia. We cloned and characterized 19 stevia GH1 genes based on transcriptomic sequences. The 19 genes were divided into five putative subfamilies in Arabidopsis. Conserved motifs in the SrGH1 proteins were analysed using the online motif-based sequence analysis tool, MEME. Most of the identified proteins contain the conserved 'TFNEP' motif (contains the catalytic acid/base) and 'ITENG' motif (contains the catalytic nucleophile). Furthermore, the steviol glycoside content and expression of these 19 genes were characterized under constant darkness. The dark treatment lowered the steviol glycoside content significantly, while SrBGLU16 responded to darkness and was markedly upregulated. This study is the first transcriptome-wide analysis of the GH1 family in Stevia rebaudiana. The sequences of 19 SrGH1 members and their expression when grown in darkness were characterized. Among the 19 genes, SrBGLU16 was markedly upregulated by darkness. Thus, we identified SrBGLU16 for further investigation as a possible steviol glycoside beta-glucosidase.

Response of the submerged macrophytes Vallisneria natans to snails at different densities.

The study investigated the responses of the submerged macrophyte Vallisneria natans (V. natans) to snails (Bellamya aeruginosa) at different densities, with changes in physiological parameters, morphology, leaf-epiphytic bacteria community and water quality parameters examined. The changes of water quality parameters (pH, total nitrogen (TN), total phosphorus (TP) and total organic carbon (TOC)) indicated that snails secreted nutrients into water. Changes in morphological and physiological parameters (fresh weight, root length, shoot height, chlorophyll, malondialdehyde (MDA), activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD)) demonstrated that the presence of snails were beneficial to the growth of submerged macrophytes. Microbial diversity analyses indicated that snails could decrease microbial community richness and diversity. At medium densities (340 ind. m-2), an increase in snail density was beneficial to the growth of submerged macrophytes. The results of this study provide theoretical guidance and technical support for the maintenance and restoration of submerged macrophytes.

The evolutionary history of the sucrose synthase gene family in higher plants.

BACKGROUND: Sucrose synthase (SUS) is widely considered a key enzyme participating in sucrose metabolism in higher plants and regarded as a biochemical marker for sink strength in crops. However, despite significant progress in characterizing the physiological functions of the SUS gene family, knowledge of the trajectory of evolutionary processes and significance of the family in higher plants remains incomplete. RESULTS: In this study, we identified over 100 SUS genes in 19 plant species and reconstructed their phylogenies, presenting a potential framework of SUS gene family evolution in higher plants. Three anciently diverged SUS gene subfamilies (SUS I, II and III) were distinguished based on their phylogenetic relationships and unique intron/exon structures in angiosperms, and they were found to have evolved independently in monocots and dicots. Each subfamily of SUS genes exhibited distinct expression patterns in a wide range of plants, implying that their functional differentiation occurred before the divergence of monocots and dicots. Furthermore, SUS III genes evolved under relaxed purifying selection in dicots and displayed narrowed expression profiles. In addition, for all three subfamilies of SUS genes, the GT-B domain was more conserved than the "regulatory" domain. CONCLUSIONS: The present study reveals the evolution of the SUS gene family in higher plants and provides new insights into the evolutionary conservation and functional divergence of angiosperm SUS genes.

Incidence and Risk Factors of Pressure Injuries in Surgical Spinal Patients: A Retrospective Study.

PURPOSE: The purpose of this study was to measure the incidence and identify risk factors of pressure injury development during the perioperative period in patients undergoing spinal surgery requiring intraoperative positioning in the prone position. DESIGN: Review of medical records. SUBJECTS AND SETTING: The sample comprised 3834 patients; 52.2% (n = 2006) were male and 65.5% (n = 2516) were older than 60 years. Most patients underwent surgery of the lumbosacral spinal segments (43.4%, n = 1667) followed by cervical (32.3%, n = 1241) and thoracic spinal segments (24.2%, n = 932). The study setting was the First Affiliated Hospital of Nanchang University, Jiang XI Province in southeastern China. METHODS: We reviewed charts of patients who underwent spinal surgery requiring intraoperative positioning in the prone position from November 2013 to July 2016. Demographic data, Braden Scale for Pressure Sore Risk cumulative score (measured before preoperative transport), body mass index (BMI), duration of surgery, preoperative time (time between preoperative transport from the inpatient unit to when the operation began), postoperative time (time between when the operation was over and postoperative transport to the inpatient unit), and development of any pressure injury were collected using a standardized form. Factors associated with an increased or decreased likelihood of pressure injury were initially evaluated with χ and independent t tests. Logistic regression was then used to identify potential risk factors for perioperative pressure injury in patients undergoing open spinal surgery requiring placement in the supine position during surgery. RESULTS: One hundred eighty-four of 3840 patients (4.7%) developed pressure injuries. Multivariate analysis indicated that factors associated with intraoperative pressure injury development were older than 60 years (odds ratio [OR] = 1.05, 95% confidence interval [CI] = 1.02-2.17), BMI under 18 kg/m (OR = 2.45, 95% CI = 4.05-5.21), cumulative Braden Scale score 13 or less (OR = 6.59, CI = 2.23-3.98), prolonged preoperative time (OR = 5.99, 95% CI = 3.21-6.12), and prolonged postoperative time (OR = 14.23, 95% CI = 10.23-21.19). CONCLUSIONS: Based on these findings we recommend extending preventive interventions for pressure injury to incorporate the time from preoperative transport to the surgical suite to inpatient care unit following surgery.

Furfural-tolerant Zymomonas mobilis derived from error-prone PCR-based whole genome shuffling and their tolerant mechanism.

Furfural-tolerant strain is essential for the fermentative production of biofuels or chemicals from lignocellulosic biomass. In this study, Zymomonas mobilis CP4 was for the first time subjected to error-prone PCR-based whole genome shuffling, and the resulting mutants F211 and F27 that could tolerate 3 g/L furfural were obtained. The mutant F211 under various furfural stress conditions could rapidly grow when the furfural concentration reduced to 1 g/L. Meanwhile, the two mutants also showed higher tolerance to high concentration of glucose than the control strain CP4. Genome resequencing revealed that the F211 and F27 had 12 and 13 single-nucleotide polymorphisms. The activity assay demonstrated that the activity of NADH-dependent furfural reductase in mutant F211 and CP4 was all increased under furfural stress, and the activity peaked earlier in mutant than in control. Also, furfural level in the culture of F211 was also more rapidly decreased. These indicate that the increase in furfural tolerance of the mutants may be resulted from the enhanced NADH-dependent furfural reductase activity during early log phase, which could lead to an accelerated furfural detoxification process in mutants. In all, we obtained Z. mobilis mutants with enhanced furfural and high concentration of glucose tolerance, and provided valuable clues for the mechanism of furfural tolerance and strain development.

Transcriptome analysis reveals complex response of the medicinal/ornamental halophyte Iris halophila Pall. to high environmental salinity.

The remediation and subsequent use of saline-alkaline land are of great significance to ecological environment construction and sustainable agricultural development. Iris halophila Pall. is a salt-tolerant medicinal and ornamental plant, which has good application prospects in the ecological construction of saline-alkaline land; therefore, study of the molecular mechanisms of salt tolerance in I. halophila has important theoretical and practical value. To evaluate the molecular mechanism of the response of I. halophila to salt toxicity, I. halophila seedlings were treated with salt (300 mM NaCl) and subjected to deep RNA sequencing. The clean reads were obtained and assembled into 297,188 unigenes. Among them, 1120 and 100 salt-responsive genes were identified in I. halophila shoots and roots, respectively. Among them, the key flavonoid and lignin biosynthetic genes, hormone signaling genes, sodium/potassium ion transporter genes, and transcription factors were analyzed and summarized. Quantitative reverse-transcription PCR analysis strengthened the reliability of the RNA sequencing results. This work provides an overview of the transcriptomic responses to salt toxicity in I. halophila and identifies the responsive genes that may contribute to its reduced salt toxicity. These results lay an important foundation for further study of the molecular mechanisms of salt tolerance in I. halophila and related species.

Iris lactea var. chinensis (Fisch.) cysteine-rich gene llCDT1 enhances cadmium tolerance in yeast cells and Arabidopsis thaliana.

IlCDT1, a cysteine-rich protein, was isolated from Iris lactea var. chinensis (Fisch.) (I. lactea var. chinensis). Its transcription was up-regulated by the exogenous application of Cd. The truncated IlCDT1 (25-54) containing 14 Cys residues confers Cd tolerance to yeast as the intact IlCDT1, indicating that Cys residues are required for Cd tolerance presumably by chelating Cd. When the gene was constitutively expressed in A. thaliana, root length of transgenic lines was longer than that of wild-type under 100 µM or 200 µM Cd stress. However, Cd absorption in wild-type was more than in two trangenic lines under 100 µM Cd exposure. IlCDT1 may directly bind Cd, through chelating Cd and avoiding the Cd uptake into the cells. Together, IlCDT1 may be a promising gene for the Cd tolerance improvement. SUMMARY: Cysteine-rich gene llCDT1 enhances cadmium tolerance in yeast cells and Arabidopsis thaliana.

Exogenous glutathione increased lead uptake and accumulation in Iris lactea var. chinensis exposed to excess lead.

Long- and short-term hydroponic experiments were conducted to study the effect of different concentrations of exogenous glutathione (GSH) on Pb uptake, translocation, and gene expresses in Iris lactea var. chinensis exposed to excess lead (Pb). Exogenous GSH remarkedly promoted Pb uptake and translocation in long-term (14 d) experiment, and the GSH-dose-dependent increases in shoot and root Pb contents existed obviously when GSH concentrations were lower than 800 mg·L-1. The fresh weight in gradual rise in plants was observed with the increase of exogenous GSH concentration. In short-term (24 h) experiment, Pb contents in roots under Pb with L-buthionine sulfoximine (BSO, a known inhibitor of GSH biosynthesis) treatments were significantly lower than that under Pb exposure alone. The transcript levels of three genes (Ilγ-ECS, IlGS, and IlPCS) involved in GSH synthesis and metabolism, showed no significant change in expression pattern except that upregulation after 24 h of treatment with Pb and GSH in comparison with that of the single Pb treatment. Further, the level of IlGS transcript after exposure for 4 h was much higher than that of Ilγ-ECS and IlPCS transcripts. All these results obtained here suggest that exogenous GSH can increase Pb accumulation, detoxification, and translocation to the shoot.

De novo characterization of the Iris lactea var. chinensis transcriptome and an analysis of genes under cadmium or lead exposure.

Iris lactea var. chinensis (I. lactea var. chinensis) is tolerant to accumulations of cadmium (Cd) and lead (Pb). In this study, the transcriptome of I. lactea var. chinensis was investigated under Cd or Pb stresses. Using the gene ontology database, 31,974 unigenes were classified into biological process, cellular component and molecular function. In total, 13,132 unigenes were involved in enriched Encyclopedia of Genes and Genomes (KEGG) metabolic pathways, and the expression levels of 5904 unigenes were significantly changed after exposure to Cd or Pb stresses. Of these, 974 were co-up-regulated and 1281 were co-down-regulated under the two stresses. The transcriptome expression profiles of I. lactea var. chinensis under Cd or Pb stresses obtained in this study provided a resource for identifying common mechanisms in the detoxification of different heavy metals. Furthermore, the identified unigenes may be used for the genetic breeding of heavy-metal tolerant plants.

Dibutyl Phthalate Inhibits the Effects of Follicle-Stimulating Hormone on Rat Granulosa Cells Through Down-Regulation of Follicle-Stimulating Hormone Receptor.

Dibutyl phthalate (DBP) is used worldwide in solvents and plasticizers. The cytotoxicity and potential tumorigenic effect of DBP have been reported. DBP has also been shown to impact reproductive function. In this study, to further evaluate the effects of DBP on granulosa cells (GCs), we treated rat GCs in vitro with DBP before evaluation of the biological alterations of these GCs. We found that DBP did not induce significant GC death at the tested concentrations. However, follicle-stimulating hormone (FSH)-induced KIT ligand (KITLG) expression in GCs was significantly reduced at both mRNA and protein levels by DBP treatment in a dose-dependent manner. The down-regulation of KITLG was due to the down-regulation of expression of FSH receptor (FSHR) in GCs. Down-regulation of FSHR impaired FSH-induced intracellular signaling in GCs, demonstrated by decreased phosphorylation of AKT and mechanistic target of rapamycin (mTOR). Furthermore, DBP treatment also reduced FSH-induced expression of hypoxia-inducible factor 1-alpha (HIF1A), which is an important signaling component for KITLG expression. Other FSH-induced biological effects, such as production of estradiol and progesterone, as well as GC proliferation, were also suppressed by DBP. Therefore, our study discovered a unique mechanism underlying the toxicity of DBP on GCs. These findings may initiate the development of novel therapeutic interventions for DBP-induced damage to GCs.

Isolation and characterization of butanol-tolerant Staphylococcus aureus.

OBJECTIVES: A new solvent-tolerant species, Staphylococcus aureus, was isolated and characterized during the screening of butanol-tolerant microorganisms. RESULTS: Three isolates of S. aureus were obtained as contaminants during improvement of butanol tolerance of E. coli K12. Their cell dry weights were 135 % that of K12 in the absence of butanol stress. S. aureus had a growth advantage over K12 when cultured with various concentrations of butanol. It can tolerate up to 3 % (v/v) butanol, while most solventogenic bacteria can tolerate only 2 % (v/v) butanol. The addition of 10-20 g glucose/l enhanced its butanol tolerance. The relative cell biomass of the S. aureus was 71-306 % that of E. coli under 5.5-10 % (v/v) ethanol stress, indicating ethanol resistance. CONCLUSIONS: This is the first study to observe butanol-tolerant S. aureus. As this organism can be genetically manipulated, it could have a wide array of applications.

Activation of salicylic acid metabolism and signal transduction can enhance resistance to Fusarium wilt in banana (Musa acuminata L. AAA group, cv. Cavendish).

Fusarium wilt caused by the fungus Fusarium oxysporum f. sp. cubens (Foc) is the most serious disease that attacks banana plants. Salicylic acid (SA) can play a key role in plant-microbe interactions. Our study is the first to examine the role of SA in conferring resistance to Foc TR4 in banana (Musa acuminata L. AAA group, cv. Cavendish), which is the greatest commercial importance cultivar in Musa. We used quantitative real-time reverse polymerase chain reaction (qRT-PCR) to analyze the expression profiles of 45 genes related to SA biosynthesis and downstream signaling pathways in a susceptible banana cultivar (cv. Cavendish) and a resistant banana cultivar (cv. Nongke No. 1) inoculated with Foc TR4. The expression of genes involved in SA biosynthesis and downstream signaling pathways was suppressed in a susceptible cultivar and activated in a resistant cultivar. The SA levels in each treatment arm were measured using high-performance liquid chromatography. SA levels were decreased in the susceptible cultivar and increased in the resistant cultivar. Finally, we examined the contribution of exogenous SA to Foc TR4 resistance in susceptible banana plants. The expression of genes involved in SA biosynthesis and signal transduction pathways as well as SA levels were significantly increased. The results suggest that one reason for banana susceptibility to Foc TR4 is that expression of genes involved in SA biosynthesis and SA levels are suppressed and that the induced resistance observed in banana against Foc TR4 might be a case of salicylic acid-dependent systemic acquired resistance.

Zinc protects sperm from being damaged by reactive oxygen species in assisted reproduction techniques.

The aim of this study was to explore the effect of zinc on hydrogen peroxide-induced sperm damage in assisted reproduction techniques. First, sperms were selected from semen samples of 20 healthy men prepared by density gradient centrifugation. Selected sperm were treated with either 0.001% H(2)O(2), 12.5 nM ZnCL(2), 0.001% H(2)O(2) + 12.5 nM ZnCL(2) or 0.9% NaCl(2) (control). After this treatment, the motility, viability, membrane integrity and DNA fragmentation of sperms in each group were analysed by Goodline sperm detection system, optical microscopy and sperm DNA fragmentation assay. Poorer motility, vitality, membrane integrity and more DNA damage were found in sperms treated by H(2)O(2), compared with control. When sperms were treated with both H(2)O(2) and zinc, however, all indicators were improved compared with H(2)O(2) alone. There was a close association between oxidative stimulation and sperm injury; zinc could inhibit hydrogen peroxide-induced damage of sperm in assisted reproductive technology. However, the presence of zinc in culture medium can decrease the sperm quality without addition of peroxide.

Transcriptome Profiling of Louisiana iris Root and Identification of Genes Involved in Lead-Stress Response.

Louisiana iris is tolerant to and accumulates the heavy metal lead (Pb). However, there is limited knowledge of the molecular mechanisms behind this feature. We describe the transcriptome of Louisiana iris using Illumina sequencing technology. The root transcriptome of Louisiana iris under control and Pb-stress conditions was sequenced. Overall, 525,498 transcripts representing 313,958 unigenes were assembled using the clean raw reads. Among them, 43,015 unigenes were annotated and their functions classified using the euKaryotic Orthologous Groups (KOG) database. They were divided into 25 molecular families. In the Gene Ontology (GO) database, 50,174 unigenes were categorized into three GO trees (molecular function, cellular component and biological process). After analysis of differentially expressed genes, some Pb-stress-related genes were selected, including biosynthesis genes of chelating compounds, metal transporters, transcription factors and antioxidant-related genes. This study not only lays a foundation for further studies on differential genes under Pb stress, but also facilitates the molecular breeding of Louisiana iris.

The heterologous expression of the Iris lactea var. chinensis type 2 metallothionein IlMT2b gene enhances copper tolerance in Arabidopsis thaliana.

Iris lactea var. chinensis (I. lactea var. chinensis) is a widely adapted perennial species with a high level of copper tolerance. To evaluate the role of metallothioneins (MTs) in copper tolerance in I. lactea var. chinensis, a full-length cDNA homologue of MT2, designated IlMT2b (GenBank accession No. AB907788), was cloned using the RACE-PCR method. The expression level of IlMT2b in the leaves and roots of I. lactea var. chinensis was induced in response to copper (Cu) treatment. Ectopic expression of IlMT2b in Arabidopsis thaliana increased the Cu concentration and reduced H2O2 production in the transgenic plants. After treatment with 50 and 100 µM Cu, the root length of two transgenic seedlings was respectively about 1.5- and 3-fold longer than that of the wild-type. Together, these results suggested that IlMT2b may represent a useful target gene for the phytoremediation of Cu-polluted soil.