Gene Encoding Glutathione S-transferase Research Articles

Generation of selenium-rich wheat mutants and exploration of responsive genes for selenium accumulation.

Salt tolerance, selenium accumulation and expression of the responsive genes were analyzed in the wheat high selenium mutants. Selenium is an essential trace element for the human body, and its deficiency can lead to various diseases such as Keshan disease and large bone disease. Wheat, being a major staple crop, plays a crucial role in providing dietary selenium supplementation to combat this deficiency. Despite progress in understanding the molecular regulation of selenium accumulation in certain crops, the molecular mechanisms governing selenium accumulation-related gene expression in wheat plants remain poorly understood. In this study, three mutant wheat lines with elevated selenium content were identified. Under the treatment of Na2SeO3 or NaCl, the selenium-rich wheat mutants exhibited decreased sensitivity to both selenium and NaCl compared to the wild type. Additionally, there was an increase in the activities of SOD and POD, while the content of MDA decreased. Through qRT-PCR analysis, the expression of selenium-related genes was affected, revealing that some of these genes not only regulate the response of wheat to salt stress, but also play a role in the process of selenium accumulation. The transcriptome results revealed that the important genes encoding glutathione S-transferases, peroxidases, superoxide dismutases, and UDP-glucosyltransferases may function in the regulation of salt tolerance and selenium accumulation in wheat. These findings significantly contribute to the current understanding of the molecular regulation of selenium accumulation in wheat crops, while also offering novel germplasm resources for cultivating selenium-rich and salt-tolerant wheat lines.

Identification of candidate genes involved with dicamba resistance in waterhemp (Amaranthus tuberculatus) via transcriptomics analyses

AbstractWaterhemp [Amaranthus tuberculatus (Moq.) Sauer] is one of the most troublesome weeds in the United States. An A. tuberculatus population (CHR) was identified in Illinois, USA, as resistant to herbicides from six different site-of-action groups. Recently, the same population was also recognized as dicamba resistant. This study aimed to identify key resistance genes and the putative dicamba resistance mechanism in A. tuberculatus via transcriptomics analysis. Multiple differentially expressed (DE) genes and co-expression gene modules were identified as associated with dicamba resistance. Specifically, genes encoding glutathione S-transferases (GSTs), ATP-binding cassette transporters, peroxidases, and uridine diphosphate (UDP)-glycosyltransferases (UGTs) were identified. Results indicated enhanced oxidative stress tolerance as the primary mechanism for reducing dicamba toxicity. Results also point to potential glycosylation via UGTs and conjugation via GSTs of dicamba and its by-products. This is the first transcriptomics characterization of dicamba resistance in A. tuberculatus. Multiple non-target-site resistance genes were identified, indicating a cross-resistance pattern in the CHR population leading to a putative-enhanced oxidative stress response. Regions of multiple DE genes (i.e., genomic hot spots) across the A. tuberculatus genome corroborate previous results and potentially add to the complexity of non-target-site resistance traits.

Quantitative Proteomic Analysis of Cyanide and Mercury Detoxification by Pseudomonas pseudoalcaligenes CECT 5344.

The cyanide-degrading bacterium Pseudomonas pseudoalcaligenes CECT 5344 uses cyanide and different metal-cyanide complexes as the sole nitrogen source. Under cyanotrophic conditions, this strain was able to grow with up to 100 μM mercury, which was accumulated intracellularly. A quantitative proteomic analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been applied to unravel the molecular basis of the detoxification of both cyanide and mercury by the strain CECT 5344, highlighting the relevance of the cyanide-insensitive alternative oxidase CioAB and the nitrilase NitC in the tolerance and assimilation of cyanide, independently of the presence or absence of mercury. Proteins overrepresented in the presence of cyanide and mercury included mercury transporters, mercuric reductase MerA, transcriptional regulator MerD, arsenate reductase and arsenical resistance proteins, thioredoxin reductase, glutathione S-transferase, proteins related to aliphatic sulfonates metabolism and sulfate transport, hemin import transporter, and phosphate starvation induced protein PhoH, among others. A transcriptional study revealed that from the six putative merR genes present in the genome of the strain CECT 5344 that could be involved in the regulation of mercury resistance/detoxification, only the merR2 gene was significantly induced by mercury under cyanotrophic conditions. A bioinformatic analysis allowed the identification of putative MerR2 binding sites in the promoter regions of the regulatory genes merR5, merR6, arsR, and phoR, and also upstream from the structural genes encoding glutathione S-transferase (fosA and yghU), dithiol oxidoreductase (dsbA), metal resistance chaperone (cpxP), and amino acid/peptide extruder involved in quorum sensing (virD), among others. IMPORTANCE Cyanide, mercury, and arsenic are considered very toxic chemicals that are present in nature as cocontaminants in the liquid residues generated by different industrial activities like mining. Considering the huge amounts of toxic cyanide- and mercury-containing wastes generated at a large scale and the high biotechnological potential of P. pseudoalcaligenes CECT 5344 in the detoxification of cyanide present in these industrial wastes, in this work, proteomic, transcriptional, and bioinformatic approaches were used to characterize the molecular response of this bacterium to cyanide and mercury, highlighting the mechanisms involved in the simultaneous detoxification of both compounds. The results generated could be applied for developing bioremediation strategies to detoxify wastes cocontaminated with cyanide, mercury, and arsenic, such as those generated at a large scale in the mining industry.

A recessive mutation in muscadine grapes causes berry color-loss without influencing anthocyanin pathway

Anthocyanins, a major class of flavonoids, are important pigments of grape berries. Despite the recent discovery of the genetic cause underlying the loss of color, the metabolomic and molecular responses are unknown. Anthocyanin quantification among diverse berry color muscadines suggests that all genotypes could produce adequate anthocyanin quantities, irrespective of berry color. Transcriptome profiling of contrasting color muscadine genotypes proposes a potential deficiency that occurs within the anthocyanin transport and/or degradation mechanisms and might cause unpigmented berries. Genome-wide association studies highlighted a region on chromosome-4, comprising several genes encoding glutathione S-transferases involved in anthocyanin transport. Sequence comparison among genotypes reveals the presence of two GST4b alleles that differ by substituting the conserved amino acid residue Pro171-to-Leu. Molecular dynamics simulations demonstrate that GST4b2–Leu171 encodes an inactive protein due to modifications within the H-binding site. Population genotyping suggests the recessive inheritance of the unpigmented trait with a GST4b2/2 homozygous. A model defining colorless muscadines’ response to the mutation stimulus, avoiding the impact of trapped anthocyanins within the cytoplasm is established.

Transcriptomic analysis reveals the genes involved in tetrodotoxin (TTX) accumulation, translocation, and detoxification in the pufferfish Takifugu rubripes.

Tetrodotoxin (TTX) is a potent marine neurotoxin that exists in a variety of aquatic and terrestrial organisms. Pufferfish in different habitats show great variation in their TTX contents. Exploring the genes involved in TTX metabolism could contribute to our understanding of the molecular mechanisms underlying TTX accumulation, translocation, and detoxification in pufferfish. In this study, transcriptomic analysis was used to identify the functional genes related to TTX metabolism in the blood, liver, and muscle of the toxic and non-toxic tiger puffer (Takifugu rubripes). A total of 6101 differentially expressed genes (DEGs) were obtained after transcriptomic analysis; of these, 2401 were identified in the blood, 2262 in the liver, and 1438 in the muscle. After enrichment analysis, fourteen genes encoding glutathione S-transferases (GSTs), glutathione peroxidase (GPx), thioredoxins (TXNs), superoxide dismutase (SOD), ATP-binding cassettes (ABCs), apolipoproteins (APOs), inhibitors of apoptosis protein (IAP), and solute carrier (SLC), which are mainly antioxidant enzymes, membrane transporters, or anti-apoptotic factors, were revealed in the blood. Thirty-six genes encoding SLCs, ABCs, long-chain-fatty-acid-CoA ligases (ACSLs), interleukin 6 cytokine family signal transducer (IL6ST), endoplasmic reticulum (ER), and heat shock protein family A (Hsp70) were involved in transmembrane transporter activity and innate immune response. Notably, a large number of slc genes were found to play critical and diverse roles in TTX accumulation and translocation in the liver of T. rubripes. Nine genes from the slc, hsp70, complement C5 (c5), acsl, er, and serpin peptidase inhibitor (serpin) gene families were found to participate in the regulation of protein processing and anti-apoptosis. These results reflect the diverse functions of genes closely related to TTX accumulation, translocation, and detoxification in T. rubripes.

Identification and characterization of the novel genes encoding glutathione S-transferases in Mytilus galloprovincialis

The superfamily of glutathione S-transferases (GST) plays an essential role in the xenobiotic metabolism, binding compounds to the glutathione, and is like a cell protector during the influence of various negative external factors. Nevertheless, there are very few works devoted to the investigation of these genes in marine invertebrates. Up to this time, only three classes of cytosolic GSTs for one of the leading commercial molluscs Mytilus galloprovincialis were described. We sequenced the whole transcriptome from the gill tissues and, using bioinformatic analysis, detected ten classes of glutathione S-transferases, which are expressed in the mussel M. galloprovincialis. For the first time, two subfamilies were described: mitochondrial GST (kappa class) and microsomal (MAPEG), as well as five classes of the family of cytosolic GSTs (mu, omega, rho, tau, theta). Omega and sigma GST classes might be rapidly regulated genes due to the lack of introns and this assumption was confirmed by the investigation of short-term hypoxia on M. galloprovincialis. Seven new classes of GST revealed a greater gene variety of this detoxifying enzyme in mussels than expected. The obtained nucleotide sequences are necessary for future investigations of GSTs expression in response to various external factors (pollution, oxygen starvation, infection, etc.).

Genome-Wide Transcriptomic and Proteomic Exploration of Molecular Regulations in Quinoa Responses to Ethylene and Salt Stress.

Quinoa (Chenopodium quinoa Willd.), originated from the Andean region of South America, shows more significant salt tolerance than other crops. To reveal how the plant hormone ethylene is involved in the quinoa responses to salt stress, 4-week-old quinoa seedlings of ‘NL-6′ treated with water, sodium chloride (NaCl), and NaCl with ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) were collected and analyzed by transcriptional sequencing and tandem mass tag-based (TMT) quantitative proteomics. A total of 9672 proteins and 60,602 genes was identified. Among them, the genes encoding glutathione S-transferase (GST), peroxidase (POD), phosphate transporter (PT), glucan endonuclease (GLU), beta-galactosidase (BGAL), cellulose synthase (CES), trichome birefringence-like protein (TBL), glycine-rich cell wall structural protein (GRP), glucosyltransferase (GT), GDSL esterase/lipase (GELP), cytochrome P450 (CYP), and jasmonate-induced protein (JIP) were significantly differentially expressed. Further analysis suggested that the genes may mediate through osmotic adjustment, cell wall organization, reactive oxygen species (ROS) scavenging, and plant hormone signaling to take a part in the regulation of quinoa responses to ethylene and salt stress. Our results provide a strong foundation for exploration of the molecular mechanisms of quinoa responses to ethylene and salt stress.

Insights into enhanced biodegradation of sulfadimethoxine by catalyst: Transcriptomic responses and free radical interactions

The occurrence of sulfonamides in the environment is a severe global threat to public health due to the increasing prevalence of antibiotic selection pressure that may lead to the development of antibiotic resistance. We report an enhanced biodegradation of sulfadimethoxine (SDM) by Phanerochaete chrysosporium (Pc) with lignocellulosic biomass (Lb) using Fe3O4-ZSM-5 as a catalyst (Pc/Fe3O4-ZSM-5/Lb). SDM was completely degraded within 4 days at pH 7.0 in the Pc/Fe3O4-ZSM-5/Lb system. Transcriptomic, metabolites and free radical analyses were performed to explore the detailed molecular mechanisms of SDM degradation. A total of 246 genes of Pc in the Pc/Fe3O4-ZSM-5/Lb system exhibited significant upregulation compared to that in Pc alone. Upregulated genes encoding cellulases, cytochrome P450, cellobiose quinone oxidoreductase, and cellobiose dehydrogenase were involved in SDM degradation in the Pc/Fe3O4-ZSM-5/Lb system. In addition, genes encoding glutathione S-transferase and cytochrome P450 genes related to oxidative stress and detoxification were all significantly upregulated (P < 0.01). Electron paramagnetic resonance revealed the generation of OH suggesting a free radical pathway could be catalyzed by Fe3O4-ZSM-5 and the enzymes. These findings of catalyst-assisted SDM biodegradation will be valuable for remediation of antibiotics from contaminated wastewater.

Additive effect of glutathione S-transferase T1 active genotype and infection with Toxoplasma gondii for increasing the risk of schizophrenia

Purpose To determine if Toxoplasma gondii (T. gondii) infection may play a role in the development of schizophrenia in genetically susceptible persons with regard to genes encoding glutathione S-transferase T1 (GSTT1) and M1 (GSTM1). Methods A total of 78 cases with psychiatric diagnosis of schizophrenia were compared with 91 healthy controls. For detection of IgG antibodies, enzyme-linked immunosorbent assay was used. Genotyping of GSTM1 and GSTT1 was performed by multiplex PCR. Chi-square and logistic regression were used for statistical analyses. Results A higher frequency of the GSTT1 active gene in schizophrenic patients was observed. When risk categories based on the combination of T. gondii status and GSTs polymorphisms were compared, risk of schizophrenia increased in T. gondii positive/GSTT1 absent subjects (OR = 4.75, p = 0.05) compared with T. gondii negative/GSTT1 absent group. When T. gondii positive subjects had the GSTT1 active genotype, the risk increased linearly (OR = 10.20, p < 0.001). Odds ratio in T. gondii positive groups were almost the same in combination with the GSTM1 active genotype (OR = 4.45, p = 0.003) or null genotype (OR = 4.37, p = 0.006). Conclusions Our results showed an additive effect for T. gondii and GSTT1 active genotype as risk factors for schizophrenia in Iranian population. This is a small pilot study and replicating the study with larger groups of patients in multinational investigation to clarify these findings is recommended.

A genomic biomarker that identifies human bone marrow-derived mesenchymal stem cells with high scalability.

Although the application of human mesenchymal stem cells (hMSCs) to repair damaged or diseased tissues has proven relatively effective, both the donor-to-donor variability in ex vivo expansion rates and the maintenance of stemness remain a bottleneck to widespread translation. Previous work from this laboratory stratified donors into those yielding hMSCs with high- or low-growth capacity; global transcriptomic analysis revealed that high-growth-capacity hMSCs were characterized by a loss of the gene encoding glutathione S-transferase theta 1 (GSTT1). These GSTT1-null hMSCs demonstrated increased proliferative rates, clonogenic potential, and longer telomeres compared with low-growth capacity hMSCs that were GSTT1-positive. Thus, this study identifies GSTT1 as a novel genomic DNA biomarker for hMSC scalability.

The role of genetic factors in carpal tunnel syndrome etiology: A review.

The direct causes of idiopathic carpal tunnel syndrome (CTS) still remain obscure. It has been suggested that the pathology of tendons and other connective tissue structures within the carpal tunnel may be involved in its etiology. The objective of this study was to review the literature about the potential role of genetic factors in the etiology of CTS. Three different mechanisms are suspected to be involved in genetic predisposition to CTS: collagen synthesis, collagen degradation and protection against oxidative stress effect in connective tissue. Several gene groups are involved in the regulation and modulation of these mechanisms, and the research reviewed in this study showed their possible effect on the development of CTS. Variants within the COL1A1, COL5A1 and COL11A1 genes - encoding the synthesis of minor collagen subtypes - may potentially be involved, as they alter the mechanical properties of tendons and other connective tissue structures within the carpal tunnel. The collagen within connective tissue structures is also remodeled by matrix metalloproteinases (MMPs), so variants of these genes have also been investigated for their possible role in the risk of CTS development. Next, the variants of genes encoding glutathione S-transferase (GST) synthesis were found to be involved in the etiology of CTS. The findings from the abovementioned studies provide reliable information on the potential role of genetic risk factors in the development of CTS.

A diagnostic biomarker that predicts human bone marrow-derived mesenchymal stem cell scalability

Background & Aim Extreme donor-to-donor variability in scalability and the maintenance of stemness remain a major bottleneck to the therapeutic application of human mesenchymal stem cells (hMSCs). Current best practice monitors stemness by an array of cell-based assays that are lengthy and poorly differentiate between donor hMSCs of varying quality. To date, no markers can reliably determine the therapeutic quality of hMSCs during ex vivo expansion. To address this limitation, the study aimed to identify markers of MSC potency. Methods, Results & Conclusion Global transcriptomic analysis on high- and low-growth capacity donor hMSCs, stratified according to their in vitro proliferative potential revealed that high-growth capacity hMSCs lacked the expression of the gene encoding glutathione S-transferase theta 1 (GSTT1) as a result of gene deletion. Further characterization of these hMSCs demonstrated increased proliferative rate, clonogenicity, and longer telomere length compared to low-growth capacity GSTT1-positive hMSCs. In addition, detailed molecular profiling on GSTT1-homozygous negative and positive hMSCs showed that genes related to proliferation, inflammation and Wnt signaling were differentially regulated between them. This study identifies GSTT1 as a novel genomic DNA biomarker for MSC scalability. We advocate the further development of this biomarker as a tool to screen donors prior to painful and expensive surgical harvesting of their bone marrow.

Are genetic polymorphisms of glutathione S-Transferase P1 gene associated with urothelial carcinoma of the urinary bladder?

Background: Polymorphisms in genes encoding glutathione S-transferase (GST) may affect susceptibility to develop urothelial carcinomas (UCs). One of the extensively studied genes in this group is GST P1 (GSTP1), but studies of the relationship of polymorphisms of GSTP1 and UC of the bladder have been equivocal. Hence, we assessed the association between genetic polymorphism of GSTP1 gene and the development of UC of the urinary bladder. Materials and Methods: This prospective, case–control study was conducted in the departments of urology and clinical genetics at a tertiary care teaching hospital in South India, which included 52 patients with histopathologically confirmed UC bladder and matched with 46 controls from August 2012 to July 2013. The study participants provided a single venous blood sample for extraction of genomic DNA. Laboratory personnel was blinded to sample groups. The primary outcome of the study was to detect association of genetic polymorphism of GSTP1 gene with UC of the bladder. The secondary outcome was to assess if the risk of urothelial bladder cancer is increased in smokers with polymorphism of GSTP1 gene. Statistical Analysis Used: We used the Chi-square or Fisher's (F) exact test to compare discrete variables. Unconditional logistic regression was used to estimate adjusted odds ratios and 95% confidence intervals. Results: Although the heterozygous polymorphic genotype ile/val (AG) was seen more frequently in cancer group (34.6% vs. 23.9%), the difference was not statistically significant (P = 0.202). None of the smokers had homozygous polymorphic valine allele and GSTP1 did not add to the susceptibility of UC bladder even among smokers. Conclusions: A lack of association between GSTP1 313 G/G polymorphism and urothelial cancer of bladder was observed.

Acclimatization of Rhizophagus irregularis Enhances Zn Tolerance of the Fungus and the Mycorrhizal Plant Partner.

Arbuscular mycorrhizal (AM) fungi confer heavy metal tolerance to plants, but this characteristic differs between different AM fungal strains. We tested the hypotheses if acclimatization of an AM fungus to Zn stress is possible and if this leads also to higher Zn tolerance of mycorrhizal plants. The AM fungus Rhizophagus irregularis was acclimatized in root organ cultures (Daucus carota L.) to Zn resulting in an acclimatized (Acc+) strain. The non-acclimatized (Acc-) strain remained untreated. Fungal development and RNA accumulation of a set of stress-related genes were analyzed in root organ cultures and the capacity of conferring Zn tolerance to maize plants was investigated in pot cultures. Development of Acc+ strain was significantly higher than Acc- strain, when strains were grown in Zn-enriched root organ cultures, whereas the growth of the Acc+ strain was reduced on normal medium probably due to a higher Zn demand compared to the Acc- strain. RNA accumulation analyses revealed different expression patterns of genes encoding glutathione S-transferase (RiGST), superoxide dismutase (RiSOD) and glutaredoxin (RiGRX) between the two strains. Plants inoculated with the Acc+ strain showed higher biomass and lower Zn content than those inoculated with the Acc- strain. The results showed that R. irregularis can be acclimatized to increased amounts of Zn. This acclimatization leads not only to improved fungal development in Zn-stress conditions, but also to an increase of mycorrhiza-induced Zn tolerance of colonized plants.

Identification of a gene encoding glutathione S-transferase that is related to anthocyanin accumulation in buckwheat (Fagopyrum esculentum)

Anthocyanins are a group of flavonoids found in buckwheat (Fagopyrum esculentum) and many other plant species; however; little is known about their mechanisms of synthesis and regulation in buckwheat. We previously reported a spontaneous mutant buckwheat line that shows the green stem phenotype; this line does not accumulate anthocyanins but synthesizes flavonol and proanthocyanidin in the stem. Here, we used this line and lines developed by this line to search for genes related to anthocyanin accumulation in buckwheat. The lines with green stem showed flavonoid-3-O-glucosyltransferase activity against UDP-glucose, indicating that the flavonoid-3-O-glucosyltransferase gene was not controlling the green stem trait. We therefore searched the buckwheat genome database for a gene encoding glutathione S-transferase (GST), a flavonoid-binding protein that transports flavonoids to the vacuole, and identified a candidate gene, FeGST1. Expression analysis showed that FeGST1 was expressed in wild type buckwheat but not in the green stem lines. Linkage analysis with an F2 segregating population produced by crossing between the green stem line and a self-compatible line showed that FeGST1 segregated with stem color without any recombination. This indicates that the green stem trait could be caused by homozygous non-functional alleles of the FeGST1 locus.

Transcriptome analysis of Valsa mali reveals its response mechanism to the biocontrol actinomycete Saccharothrix yanglingensis Hhs.015

BackgroundApple canker is a devastating branch disease caused by Valsa mali (Vm). The endophytic actinomycete Saccharothrix yanglingensis Hhs.015 (Sy Hhs.015) can effectively inhibit the growth of Vm. To reveal the mechanism, by which Vm respond to Sy Hhs.015, the transcriptome of Vm was analyzed using RNA-seq technology.ResultsCompared with normal growing Vm in the control group, 1476 genes were significantly differentially expressed in the Sy Hhs.015’s treatment group, of which 851 genes were up-regulated and 625 genes were down-regulated. Combined gene function and pathway analysis of differentially expressed genes (DEGs) revealed that Sy Hhs.015 affected the carbohydrate metabolic pathway, which is utilized by Vm for energy production. Approximately 82% of the glycoside hydrolase genes were down-regulated, including three pectinase genes (PGs), which are key pathogenic factors. The cell wall structure of Vm was disrupted by Sy Hhs.015 and cell wall-related genes were found to be down-regulated. Of the peroxisome associated genes, those encoding catalase (CAT) and superoxide dismutase (SOD) which scavenge reactive oxygen species (ROS), as well as those encoding AMACR and ACAA1 which are related to the β-oxidation of fatty acids, were down-regulated. MS and ICL, key genes in glyoxylate cycle, were also down-regulated. In response to the stress of Sy Hhs.015 exposure, Vm increased amino acid metabolism to synthesize the required nitrogenous compounds, while alpha-keto acids, which involved in the TCA cycle, could be used to produce energy by deamination or transamination. Retinol dehydrogenase, associated with cell wall dextran synthesis, and sterol 24-C-methyltransferase, related to cell membrane ergosterol synthesis, were up-regulated. The genes encoding glutathione S-transferase, (GST), which has antioxidant activity and ABC transporters which have an efflux function, were also up-regulated.ConclusionThese results show that the response of Vm to Sy Hhs.015 exposure is a complicated and highly regulated process, and provide a theoretical basis for both clarifying the biocontrol mechanism of Sy Hhs.015 and the response of Vm to stress.

Exploring putative genetic determinants of inter-individual phenotypic heterogeneity in sickle cell disease: A cross-sectional Jamaican cohort-based study

Patients with sickle cell disease (SCD) display puzzling inter-individual phenotypic heterogeneity, conceivably related to inherent differences in antioxidant protection, hemoglobin binding, bilirubin catabolism and methyl group handling. Therefore, we explored putative associations between clinically important phenotypic measures and functional polymorphisms within specific candidate genes encoding glutathione S-transferase, haptoglobin, uridine 5′-diphospho-glucuronosyltransferase 1A1, methyl tetrahydrofolate reductase, 5-methyltetrahydrofolate-homocysteine methyltransferase, and cystathionine beta-synthase. Two-hundred and thirty SCD participants (mean age 25.1 ± 2.8) were recruited from Jamaica's Annual Sickle Cell Unit Cohort Review – two-hundred and five had homozygous hemoglobin SS (HbSS) disease, twenty-five had hemoglobin SC (HbSC) disease. Regression analyses revealed some novel genotype-phenotype associations. HbSC participants had significantly lower mean lactate dehydrogenase (p = 0.01) and glutathione (p < 0.001) values than HbSS participants. Glutathione S-transferase P1 (GSTP1) was significantly associated with mean corpuscular hemoglobin concentration using univariate (p = 0.044) and multivariable regression (p = 0.012). 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR) was significantly associated with hemoglobin F % using univariate (p = 0.010) and multivariable regression (p = 0.009). In conclusion, this exploratory cross-sectional study generated novel, useable, and informative genotype-phenotype estimates of association, but larger studies are needed to determine whether these specific variants are related to inter-individual phenotypic variability in SCD.

Effects of vitro sucrose on quality components of tea plants (Camellia sinensis) based on transcriptomic and metabolic analysis

BackgroundTea plants [Camellia sinensis (L.) O. Kuntze] can produce one of the three most widely popular non-alcoholic beverages throughout the world. Polyphenols and volatiles are the main functional ingredients determining tea’s quality and flavor; however, the biotic or abiotic factors affecting tea polyphenol biosynthesis are unclear. This paper focuses on the molecular mechanisms of sucrose on polyphenol biosynthesis and volatile composition variation in tea plants.ResultsMetabolic analysis showed that the total content of anthocyanins, catechins, and proanthocyanidins(PAs) increased with sucrose, and they accumulated most significantly after 14 days of treatment. Transcriptomic analysis revealed 8384 and 5571 differentially expressed genes in 2-day and 14-day sucrose-treated tea plants compared with control-treated plants. Most of the structural genes and transcription factors (TFs) involved in polyphenol biosynthesis were significantly up-regulated after 2d. Among these transcripts, the predicted genes encoding glutathione S-transferase (GST), ATP-binding cassette transporters (ABC transporters), and multidrug and toxic compound extrusion transporters (MATE transporters) appeared up regulated. Correspondingly, ultra-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-QQQ-MS/MS) analysis revealed that the content of non-galloylated catechins and oligomeric PAs decreased in the upper-stem and increased in the lower-stem significantly, especially catechin (C), epicatechin (EC), and their oligomeric PAs. This result suggests that the related flavonoids were transported downward in the stem by transporters. GC/MS data implied that four types of volatile compounds, namely terpene derivatives, aromatic derivatives, lipid derivatives, and others, were accumulated differently after in vitro sucrose treatment.ConclusionsOur data demonstrated that sucrose regulates polyphenol biosynthesis in Camellia sinensis by altering the expression of transcription factor genes and pathway genes. Additionally, sucrose promotes the transport of polyphenols and changes the aroma composition in tea plant.

Transcriptome analysis providing novel insights for Cd-resistant tall fescue responses to Cd stress

Cadmium (Cd) is a severely toxic heavy metal and environmental pollutant. Tall fescue is a cold season turf grass which has high resistance to Cd as well as the ability to enrich it. To investigate the molecular mechanism underlying the adaptability of tall fescue to Cd stress, RNA-Seq was used to examine Cd stress responses of tall fescue at a transcriptional level. A total of 12 cDNA libraries were constructed from the total RNA of roots or leaves of tall fescue with or without Cd treatments. A total of 2594 (1768 up- and 826 down-regulated) differentially expressed genes (DEGs) were detected in the roots of Cd-stressed tall fescue compared with control roots (R_cd vs R_ck), while only 52 (29 up- and 23 down-regulated) DEGs were found in the leaves of Cd-stressed plants versus the controls (L_cd vs L_ck). The genes encoding glutathione S-transferase (GST), transporter proteins including the ABC transporter, ZRT/IRT-like protein, potassium transporter/channel, nitrate transporter, putative iron-phytosiderophore transporter, copper-transporting ATPase or transporter and multidrug and toxic compound extrusion (MATE) proteins, and numerous transcription factors were found to be significantly induced in Cd-treated roots. In addition, pathogenesis/disease-related gene mRNAs were accumulated in Cd-treated roots of tall fescue. Furthermore, the significantly enriched KEGG pathways in roots were related to ‘Glutathione metabolism’, ‘Ribosome’, ‘alpha-Linolenic acid metabolism’, ‘Diterpenoid biosynthesis’, ‘Sulfur metabolism’, ‘Phenylpropanoid biosynthesis’, ‘Protein processing in endoplasmic reticulum’, ‘Protein export’ and ‘Nitrogen metabolism’. The study provides novel insights for further understanding the molecular mechanisms of tall fescue responses to Cd stress.

Development of a molecular marker tightly linked to the C locus conferring a white bulb color in onion (Allium cepa L.) using bulked segregant analysis and RNA-Seq

To develop molecular markers linked to the C locus determining a white bulb color in onion (Allium cepa L.), a combination of bulked segregant analysis (BSA) and RNA-Seq was performed using bulked RNAs extracted from 12 plants each of yellow and white F2 bulbs. Ninety-seven genes showed at least five-fold increased expression in the yellow bulk. Eleven previously isolated structural genes were identified from these genes. Two homologous genes coding for phenylalanine ammonia lyase (PAL) and chalcone isomerase (CHI) were also identified. In addition, three glycosyltransferase genes and two acyltransferase genes showed increased transcription in the yellow bulk. Increased expression of 18 structural genes in the yellow F2 individuals were further confirmed by reverse transcription polymerase chain reaction (RT-PCR). Regarding regulatory genes, a gene encoding a WRKY transcription factor was most significantly down-regulated in the white bulk. In the MBW complex, known to control a flavonoid biosynthetic pathway, 47, four, and eight genes encoding putative MYB, bHLH, and WD40 proteins, respectively, were identified from transcriptome. Among them, two MYB-, one bHLH-, and one WD40-coding gene(s) showed up-regulation in the yellow bulk and high similarity with other known regulators of flavonoid biosynthesis. Among 1829 contigs containing single nucleotide polymorphisms (SNPs) or InDels, five contigs were shown to be linked to the C locus. In addition, SNPs in the gene encoding glutathione S-transferase (GST) also showed a linkage relationship. Six molecular markers were developed and a linkage map was constructed using 586 F2:3 individuals. The GST1 marker based on the GST-coding gene showed perfect linkage to the C locus.