Comparative Physiological and Transcriptomic Analyses Reveal Ascorbate and Glutathione Coregulation of Cadmium Toxicity Resistance in Wheat Genotypes

Abstract Background: Understanding the cadmium (Cd) resistance mechanism is crucial for combating the phytotoxicity of Cd and meeting the increasing food demand daily. A classic symptom of Cd toxicity is root growth inhibition. Results: Using two wheat genotypes (Cd tolerant genotype T207 and Cd sensitive genotype S276) with differing root growths in response to Cd, we conducted comparative physiological and transcriptomic analyses and exogenous application tests to interpret Cd detoxification mechanisms. S276 accumulated more H2O2, O2-, and malonaldehyde than T207. Catalase activity and levels of ascorbic acid (AsA) and glutathione (GSH) were higher, whereas superoxide dismutase and peroxidase activities were lower in T207 than in S276. Transcriptome analysis showed that the expression of RBOHA, RBOHC, and RBOHE significantly increased, whereas that of RBOHB markedly decreased by Cd treatment. The transcriptional levels of 22 genes encoding RBOH were higher, and that of 11 genes were lower in T207 than in S276. The transcription of genes involved in the AsA-GSH cycle was profoundly reshaped by Cd treatment; 124 genes were higher and 43 genes were lower in T207 than in S276. Exogenous combined application of AsA and GSH alleviated Cd toxicity by scavenging excess ROS and coordinately modulating root length and branching, especially in S276.Conclusions: These results indicate that the AsA-GSH cycle fundamentally and vigorously influences plant defense against Cd toxicity, which provides valuable information for further clarification of the mechanisms underlying Cd detoxification.

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Combined application of biochar and selenium alleviates cadmium toxicity in peanuts and enriches selenium content in peanut grains.

10.21203/rs.3.rs-1076617/v1 ◽

2021 ◽

Author(s):

Shiwei Shao ◽

Bing Ma ◽

Liuhuan Ai ◽

Lei Zhang

Keyword(s):

Grain Yield ◽

Arachis Hypogaea ◽

Cadmium Toxicity ◽

Selenium Content ◽

Cd Toxicity ◽

Combined Application ◽

Global Concern ◽

Application Methods ◽

Underlying Mechanisms

Abstract Cadmium (Cd) pollution in soil and particularly in peanuts has attracted global concern and requires urgent attention. Selenium (Se) can alleviate Cd toxicity; however, the underlying mechanisms are not completely understood. Therefore, two varieties of peanut (Arachis hypogaea Linn.) Huayu 23 and Huayu 20 were chosen as the target crops for this study. A pot experiment was conducted to investigate the effects of two Se application methods combined with biochar on the accumulation of Cd and Se, and the best application method was identified. In addition, the role of Se in alleviating Cd toxicity in peanuts was studied. The results indicated that both Se and biochar decreased the Cd content in peanuts and alleviated Cd toxicity. However, the combined application of foliar Se and biochar significantly increased the peanut biomass by 71.50–110.46%, increased the grain yield of Huayu 23 by 0.38–0.47 fold, and Huayu 20 by 2.37–3.47 fold. Additionally, Cd content in peanut grains was decreased by 26.68–50.07%, and Se content was increased by 31.57–99.75 folds. Biochar can decrease the absorption of Cd from the soil, while Se can increase the accumulation of Cd in cell vacuoles by increasing glutathione and phytochelatin to decrease the movement of Cd into the grains. Therefore, our results indicate that the combined application of foliar Se and biochar can effectively promote the enrichment of Se in peanuts and suppress Cd toxicity.

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Comparative physiological and transcriptomic analyses reveal ascorbate and glutathione coregulation of cadmium toxicity resistance in wheat genotypes

BMC Plant Biology ◽

10.1186/s12870-021-03225-w ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Tao Zhang ◽

Jingui Xiao ◽

Yongsheng Zhao ◽

Yifan Zhang ◽

Yaqi Jie ◽

...

Keyword(s):

Transcriptional Profiling ◽

Cadmium Toxicity ◽

Resistance Mechanisms ◽

Differentially Expressed ◽

Growth Responses ◽

Cd Toxicity ◽

Wheat Genotypes ◽

Exogenous Application ◽

Daily Food ◽

Human Food Chain

Abstract Background Cadmium (Cd) is a heavy metal with high toxicity that severely inhibits wheat growth and development. Cd easily accumulates in wheat kernels and enters the human food chain. Genetic variation in the resistance to Cd toxicity found in wheat genotypes emphasizes the complex response architecture. Understanding the Cd resistance mechanisms is crucial for combating Cd phytotoxicity and meeting the increasing daily food demand. Results Using two wheat genotypes (Cd resistant and sensitive genotypes T207 and S276, respectively) with differing root growth responses to Cd, we conducted comparative physiological and transcriptomic analyses and exogenous application tests to evaluate Cd detoxification mechanisms. S276 accumulated more H2O2, O2−, and MDA than T207 under Cd toxicity. Catalase activity and levels of ascorbic acid (AsA) and glutathione (GSH) were greater, whereas superoxide dismutase (SOD) and peroxidase (POD) activities were lower in T207 than in S276. Transcriptomic analysis showed that the expression of RBOHA, RBOHC, and RBOHE was significantly increased under Cd toxicity, and two-thirds (22 genes) of the differentially expressed RBOH genes had higher expression levels in S276 than inT207. Cd toxicity reshaped the transcriptional profiling of the genes involving the AsA-GSH cycle, and a larger proportion (74.25%) of the corresponding differentially expressed genes showed higher expression in T207 than S276. The combined exogenous application of AsA and GSH alleviated Cd toxicity by scavenging excess ROS and coordinately promoting root length and branching, especially in S276. Conclusions The results indicated that the ROS homeostasis plays a key role in differential Cd resistance in wheat genotypes, and the AsA-GSH cycle fundamentally and vigorously influences wheat defense against Cd toxicity, providing insight into the physiological and transcriptional mechanisms underlying Cd detoxification.

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Efflux-Related Resistance to Norfloxacin, Dyes, and Biocides in Bloodstream Isolates of Staphylococcus aureus

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00430-07 ◽

2007 ◽

Vol 51 (9) ◽

pp. 3235-3239 ◽

Cited By ~ 122

Author(s):

Carmen E. DeMarco ◽

Laurel A. Cushing ◽

Emmanuel Frempong-Manso ◽

Susan M. Seo ◽

Tinevimbo A. A. Jaravaza ◽

...

Keyword(s):

Gene Expression ◽

Staphylococcus Aureus ◽

Efflux Pump ◽

Resistance Mechanism ◽

Efflux Pump Inhibitor ◽

Qrt Pcr ◽

Reverse Transcription Pcr ◽

Environmental Surfaces ◽

Genes Encoding ◽

High Level

ABSTRACT Efflux is an important resistance mechanism in Staphylococcus aureus, but its frequency in patients with bacteremia is unknown. Nonreplicate bloodstream isolates were collected over an 8-month period, and MICs of four common efflux pump substrates, with and without the broad-spectrum efflux pump inhibitor reserpine, were determined (n = 232). A reserpine-associated fourfold decrease in MIC was considered indicative of efflux. Strains exhibiting efflux of at least two of the four substrates were identified (“effluxing strains” [n = 114]). For these strains, MICs with or without reserpine for an array of typical substrates and the expression of mepA, mdeA, norA, norB, norC, and qacA/B were determined using quantitative real-time reverse transcription-PCR (qRT-PCR). A fourfold or greater increase in gene expression was considered significant. The most commonly effluxed substrates were ethidium bromide and chlorhexidine (100 and 96% of effluxing strains, respectively). qRT-PCR identified strains overexpressing mepA (5 [4.4%]), mdeA (13 [11.4%]), norA (26 [22.8%]), norB (29 [25.4%]), and norC (19 [16.7%]); 23 strains overexpressed two or more genes. Mutations probably associated with increased gene expression included a MepR-inactivating substitution and norA promoter region insertions or deletions. Mutations possibly associated with increased expression of the other analyzed genes were also observed. Effluxing strains comprised 49% of all strains studied (114/232 strains), with nearly half of these overexpressing genes encoding MepA, MdeA, and/or NorABC (54/114 strains). Reduced susceptibility to biocides may contribute to persistence on environmental surfaces, and efflux of drugs such as fluoroquinolones may predispose strains to high-level target-based resistance.

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Comparative Transcriptome Profiling Reveals Defense-Related Genes against Meloidogyne incognita Invasion in Tobacco

Molecules ◽

10.3390/molecules23082081 ◽

2018 ◽

Vol 23 (8) ◽

pp. 2081 ◽

Cited By ~ 4

Author(s):

Xiaohui Li ◽

Xuexia Xing ◽

Pei Tian ◽

Mingzhen Zhang ◽

Zhaoguang Huo ◽

...

Keyword(s):

Transcription Factor ◽

Meloidogyne Incognita ◽

Resistance Mechanism ◽

Transcriptome Profiling ◽

Ethylene Response Factor ◽

Sequencing Analysis ◽

Cell Wall Modification ◽

Resistance Response ◽

Helix Loop Helix ◽

Genes Encoding

Root-knot nematodes Meloidogyne incognita are one of the most destructive pathogens, causing severe losses to tobacco productivity and quality. However, the underlying resistance mechanism of tobacco to M. incognita is not clear. In this study, two tobacco genotypes, K326 and Changbohuang, which are resistant and susceptible to M. incognita, respectively, were used for RNA-sequencing analysis. An average of 35 million clean reads were obtained. Compared with their expression levels in non-infected plants of the same genotype, 4354 and 545 differentially expressed genes (DEGs) were detected in the resistant and susceptible genotype, respectively, after M. incognita invasion. Overall, 291 DEGs, involved in diverse biological processes, were common between the two genotypes. Genes encoding toxic compound synthesis, cell wall modification, reactive oxygen species and the oxidative burst, salicylic acid signal transduction, and production of some other metabolites were putatively associated with tobacco resistance to M. incognita. In particular, the complex resistance response needed to overcome M. incognita invasion may be regulated by several transcription factors, such as the ethylene response factor, MYB, basic helix–loop–helix transcription factor, and indole acetic acid–leucine-resistant transcription factor. These results may aid in the identification of potential genes of resistance to M. incognita for tobacco cultivar improvement.

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Minimization of energy transduction confers resistance to phosphine in the rice weevil, Sitophilus oryzae

Scientific Reports ◽

10.1038/s41598-019-50972-w ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Kyeongnam Kim ◽

Jeong Oh Yang ◽

Jae-Yoon Sung ◽

Ji-Young Lee ◽

Jeong Sun Park ◽

...

Keyword(s):

Cancer Metabolism ◽

Insect Pests ◽

Sitophilus Oryzae ◽

Resistance Mechanism ◽

Energy Transduction ◽

Metabolic Reprogramming ◽

Rice Weevil ◽

Altered Expression ◽

Synonymous Mutations ◽

Genes Encoding

Abstract Infestation of phosphine (PH3) resistant insects threatens global grain reserves. PH3 fumigation controls rice weevil (Sitophilus oryzae) but not highly resistant insect pests. Here, we investigated naturally occurring strains of S. oryzae that were moderately resistant (MR), strongly resistant (SR), or susceptible (wild-type; WT) to PH3 using global proteome analysis and mitochondrial DNA sequencing. Both PH3 resistant (PH3–R) strains exhibited higher susceptibility to ethyl formate-mediated inhibition of cytochrome c oxidase than the WT strain, whereas the disinfectant PH3 concentration time of the SR strain was much longer than that of the MR strain. Unlike the MR strain, which showed altered expression levels of genes encoding metabolic enzymes involved in catabolic pathways that minimize metabolic burden, the SR strain showed changes in the mitochondrial respiratory chain. Our results suggest that the acquisition of strong PH3 resistance necessitates the avoidance of oxidative phosphorylation through the accumulation of a few non-synonymous mutations in mitochondrial genes encoding complex I subunits as well as nuclear genes encoding dihydrolipoamide dehydrogenase, concomitant with metabolic reprogramming, a recognized hallmark of cancer metabolism. Taken together, our data suggest that reprogrammed metabolism represents a survival strategy of SR insect pests for the compensation of minimized energy transduction under anoxic conditions. Therefore, understanding the resistance mechanism of PH3–R strains will support the development of new strategies to control insect pests.

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Identification and profiling of microRNAs responsive to cadmium toxicity in hepatopancreas of the freshwater crab Sinopotamon henanense

Hereditas ◽

10.1186/s41065-019-0110-z ◽

2019 ◽

Vol 156 (1) ◽

Author(s):

Peng Xu ◽

Huiqin Guo ◽

Huihui Wang ◽

Yuxin Xie ◽

Shao Chin Lee ◽

...

Keyword(s):

Transcriptional Regulatory Network ◽

Cadmium Toxicity ◽

Functional Adaptation ◽

Differentially Expressed ◽

Portunus Trituberculatus ◽

Freshwater Crab ◽

Cd Toxicity ◽

Qrt Pcr ◽

Differentially Expressed Mirnas ◽

Sinopotamon Henanense

Abstract Background Cadmium (Cd) is a ubiquitous environmental toxicant for aquatic animals. The freshwater crab, Sinopotamon henanense (S. henanense), is a useful model for monitoring Cd exposure since it is widely distributed in sediments whereby it tends to accumulate several toxicants, including Cd. In the recent years, the toxic effects of Cd in the hepatopancreas of S. henanense have been demonstrated by a series of biochemical analysis and ultrastructural observations as well as the deep sequencing approaches and gene expression profile analysis. However, the post-transcriptional regulatory network underlying Cd toxicity in S.henanense is still largely unknown. Results The miRNA transcriptional profile of the hepatopancreas of S. henanense was used to investigate the expression levels of miRNAs in response to Cd toxicity. In total, 464 known miRNAs and 191 novel miRNAs were identified. Among these 656 miRNAs, 126 known miRNAs could be matched with the miRNAs of Portunus trituberculatus, Eriocheir sinensis and Scylla paramamosain. Furthermore, a total of 24 conserved miRNAs were detected in these four crab species. Fifty-one differentially expressed miRNAs were identified in the Cd-exposed group, with 31 up-regulated and 20 down-regulated. Eight of the differentially expressed miRNAs were randomly selected and verified by the quantitative real-time PCR (qRT-PCR), and there was a general consistency (87.25%) between the qRT-PCR and miRNA transcriptome data. A total of 5258 target genes were screened by bioinformatics prediction. GO term analysis showed that, 17 GO terms were significantly enriched, which were mainly related to the regulation of oxidoreductase activity. KEGG pathway analysis showed that 18 pathways were significantly enriched, which were mainly associated with the biosynthesis, modification and degradation of proteins. Conclusion In response to Cd toxicity, in the hepatopancreas of S. henanense, the expressions of significant amount of miRNAs were altered, which may be an adaptation to resist the oxidative stress induced by Cd. These results provide a basis for further studies of miRNA-mediated functional adaptation of the animal to combat Cd toxicity.

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Effect of manganese on cadmium toxicity in maize seedlings

Plant Soil and Environment ◽

10.17221/3358-pse ◽

2011 ◽

Vol 52 (No. 4) ◽

pp. 143-149 ◽

Cited By ~ 21

Author(s):

P. Paľove-Balang ◽

A. Kisová ◽

J. Pavlovkin ◽

MistríkI

Keyword(s):

Root Growth ◽

Nitrate Uptake ◽

Reductase Activity ◽

Cadmium Toxicity ◽

Uptake System ◽

Maize Seedlings ◽

Cd Toxicity ◽

Maize Plants ◽

Pre Treatment ◽

Free Media

The interaction of manganese with cadmium (Cd) toxicity was studied on maize plants grown in hydroponics. Manganese supplied as MnSO<sub>4</sub>clearly alleviated the toxic effect of cadmium on the root growth of maize seedlings. The magnitude of alleviation was dose dependant and total abolition of 10µM Cd toxicity on root growth was observed at Mn/Cd ratio of 20:1. The 12 h pre-treatment with 10μM Cd was generally toxic for nitrate uptake and reduction (both determined in Cd-free media). The beneficial effect of 100μM Mn on this toxicity was confirmed for the low-affinity nitrate uptake system, but on the other hand, Mn alone seems to be slightly toxic for high affinity nitrate uptake system and on the nitrate reductase activity.

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Signature Arsenic Detoxification Pathways in Halomonas sp. Strain GFAJ-1

mBio ◽

10.1128/mbio.00515-18 ◽

2018 ◽

Vol 9 (3) ◽

Cited By ~ 8

Author(s):

Shuangju Wu ◽

Lianrong Wang ◽

Rui Gan ◽

Tong Tong ◽

Hao Bian ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Resistance Mechanism ◽

Mono Lake ◽

Arsenate Reductase ◽

Simultaneous Occurrence ◽

Arsenic Resistance ◽

Content Type ◽

Arsenic Detoxification ◽

Detoxification Mechanisms ◽

High Arsenic

ABSTRACT Since the original report that Halomonas sp. strain GFAJ-1 was capable of using arsenic instead of phosphorus to sustain growth, additional studies have been conducted, and GFAJ-1 is now considered a highly arsenic-resistant but phosphorus-dependent bacterium. However, the mechanisms supporting the extreme arsenic resistance of the GFAJ-1 strain remain unknown. In this study, we show that GFAJ-1 has multiple distinct arsenic resistance mechanisms. It lacks the genes to reduce arsenate, which is the essential step in the well-characterized resistance mechanism of arsenate reduction coupled to arsenite extrusion. Instead, GFAJ-1 has two arsenic resistance operons, arsH1 - acr3 - 2 - arsH2 and mfs1 - mfs2 - gapdh , enabling tolerance to high levels of arsenate. mfs2 and gapdh encode proteins homologous to Pseudomonas aeruginosa ArsJ and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), respectively, which constitute the equivalent of an As(V) efflux system to catalyze the transformation of inorganic arsenate to pentavalent organoarsenical 1-arseno-3-phosphoglycerate and its subsequent extrusion. Surprisingly, the arsH1 - acr3 - 2 - arsH2 operon seems to consist of typical arsenite resistance genes, but this operon is sufficient to confer both arsenite and arsenate resistance on Escherichia coli AW3110 even in the absence of arsenate reductase, suggesting a novel pathway of arsenic detoxification. The simultaneous occurrence of these two unusual detoxification mechanisms enables the adaptation of strain GFAJ-1 to the particularly arsenic-rich environment of Mono Lake. IMPORTANCE Halomonas sp. strain GFAJ-1 was previously reported to use arsenic as a substitute for phosphorus to sustain life under phosphate-limited conditions. Although this claim was later undermined by several groups, how GFAJ-1 can thrive in environments with high arsenic concentrations remains unclear. Here, we determined that this ability can be attributed to the possession of two arsenic detoxification operons, arsH1 - acr3 - 2 - arsH2 and mfs1 - mfs2 - gapdh . mfs2 and gapdh encode proteins homologous to ArsJ and GAPDH in Pseudomonas aeruginosa ; these proteins create an arsenate efflux pathway to reduce cellular arsenate accumulation. Interestingly, the combination of acr3 - 2 with either arsH gene was sufficient to confer resistance to both arsenite and arsenate in E. coli AW3110, even in the absence of arsenate reductase, suggesting a new strategy for bacterial arsenic detoxification. This study concludes that the survival of GFAJ-1 in high arsenic concentrations is attributable to the cooccurrence of these two unusual arsenic detoxification mechanisms.

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Effects of exogenous nitric oxide on cadmium toxicity in black poplar (Populus nigra): physiological approaches

Acta Botanica Croatica ◽

10.2478/botcro-2019-0018 ◽

2019 ◽

Vol 78 (2) ◽

pp. 116-124 ◽

Cited By ~ 1

Author(s):

Yakup Cikili ◽

Semsettin Kulac ◽

Halil Samet ◽

Ertugrul Filiz

Keyword(s):

Nitric Oxide ◽

Plant Biomass ◽

Cadmium Toxicity ◽

Populus Nigra ◽

No Donor ◽

Cd Toxicity ◽

Physiological Processes ◽

Black Poplar ◽

Randomized Design ◽

Metallic Contaminant

Abstract Cadmium (Cd) is a highly toxic metallic contaminant that negatively affects plant metabolism and causes reductions in productivity. Nitric oxide (NO) is a signaling molecule that regulates various physiological processes and is involved in response to biotic/abiotic stresses. This work investigated the effects of exogenous sodium nitroprusside (SNP), a nitric oxide (NO) donor, application on Cd toxicity in black poplar (Populus nigra). Black poplars were exposed to individual/combined CdCl2 and SNP treatments for 21 days by complete randomized design with three replications. Cd concentrations increased in leaves, bark, and roots at Cd treatments, whereas Cd + SNP applications had alleviative effects on Cd exposures, except for leaves. Photosynthetic pigments (chlorophyll a, b, a + b and carotenoids) reduced with Cd treatments in leaves, while they increased in Cd + SNP applications. Similarly, plant biomass was reduced with Cd treatments, but Cd + SNP application prevented these reductions. SNP also alleviated malondialdehyde (MDA) and hydrogen peroxide (H2O2) accumulation in leaves under Cd treatments. Catalase (CAT, EC 1.11.1.6) and ascorbate peroxidase (APX, EC 1.11.1.11) activities were also affected by Cd and Cd + SNP applications. Cd exposure also decreased Zn2+, Fe2+ and Mn2+ levels in leaves, bark and roots, while it increased Cu2+ level in leaves and roots. This study concludes that Cd toxicity caused a reduction of plant growth and mineral nutrition parameters. However, SNP indicates great potentials for improving the growth under Cd toxicity in P. nigra.

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hCNT1 in Waldenström’s macroglobulinemia (WM) and small lymphocytic lymphoma (SLL) patients (pts): A possible predictive biomarker of 2-chloro-2`-deoxyadenosine (2-CDA) clinical activity

Journal of Clinical Oncology ◽

10.1200/jco.2006.24.18_suppl.13087 ◽

2006 ◽

Vol 24 (18_suppl) ◽

pp. 13087-13087

Author(s):

C. Rabascio ◽

L. Saronni ◽

P. Antoniotti ◽

V. Raia ◽

F. Bertolini ◽

...

Keyword(s):

Gene Expression ◽

Resistance Mechanism ◽

Threshold Value ◽

Predictive Biomarker ◽

Clinical Activity ◽

Nucleoside Transporter ◽

Concentrative Nucleoside Transporter ◽

Genes Encoding ◽

Deoxyguanosine Kinase ◽

Pcr Method

13087 Background: The resistance mechanism to 2-CDA is not completely known. In this study we used pharmacogenomic to identify genetic factors that influence drug response and to better investigate 2-CDA complex intracellular metabolism. Methods: Using Real-time PCR method (ABI-PRISM 7000 machine) we amplified seven genes, encoding for equilibrative and concentrative nucleoside transporter (hENT1, hCNT1), deoxycytidine and deoxyguanosine kinase (dCK, dGK), 5`-nucleotidase (5`NT), ribonucleotide reductase catalytic and regulatory (RR1, RR2) subunits, in bone marrow (BM) at baseline of 17 pts with WM or SLL in order to verify the correlation between gene expression and clinical outcome. All pts were treated with a combination therapy (2-CDA 0.1 mg/kg sc injection and Rituximab at standard schedule). Quantitation was performed using the Delta CT calculation: the value of gene expression was normalised to the calibrator (healthy tissue cells). Results: hCNT1 and 5’NT gene expression analysis has shown lower values in pts than in controls. The other markers didn’t show any significance. Two pts achieving partial remission (PR) presented 100 times lower hCNT1 levels (median 6.8*10−4, range 6.8–6.9*10−4) than pts (n = 10) in complete remission (median 7.9*10−2, range 0.1–4.6*10−1; p = 0.03). Conclusions: hCNT1 seems to be the most important gene involved in 2-CDA clinical activity and its expression may correlate with prognosis. Compared to controls, the low plasmatic RNA level of hCNT1 exhibited by our pts doesn’t seem to be predictive of lack of clinical activity of 2-CDA. However the lower level of hCNT1 plasmatic expression detected in the two pts who achieved only PR could suggest a possible relationship between reduced hCNT1 plasmatic expression and a diminished clinical activity of 2-CDA. Thus it might be important to explore the possibility of standardizing a quantitative method in order to identify a threshold value which could be predictive of drug resistance. No significant financial relationships to disclose.

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