Glutaredoxin Gene Research Articles

The Roles of Glutaredoxins in Wheat (Triticum aestivum L.) under Biotic and Abiotic Stress Conditions, including Fungal and Hormone Treatments

Glutaredoxins (GRXs) are widely distributed oxidoreductase enzymes that play important roles in plant growth, development, and responses to various stresses. In this study, bioinformatics methods were used to identify and analyze the wheat GRX gene family and predict their properties and potential functions. RNA-seq and RT-qPCR expression analyses were used to investigate their regulatory functions under hormone treatment and fungal diseases. In this study, 86 GRX genes were identified in wheat and classified into CC-type, CGFS-type, and CPYC-type categories with no TaGRX located on chromosome 4B. The results show that TaGRXs regulate wheat transcriptional responses and have an integrative role in biotic and abiotic stress responses. TaGRXs are involved in wheat responses to Fusarium graminearum, Puccinia striiformis, and Erysiphe graminis diseases. TaGRX73-7D, TaGRX20-3A, and TaGRX29-3B play a negative regulatory role in E. graminis infection but a positive regulatory role in F. graminearum and P. striiformis infection. These TaGRXs play potential regulatory functions in wheat responses to the plant hormones and signaling molecules, including IAA, ABA, H2O2, and SA. The findings of this study lay the groundwork for further investigation of the functions of wheat GRX genes and their potential use as candidate genes for molecular breeding of stress-resistant wheat varieties.

Comprehensive Analysis of Genes Associated with the Reactive Oxygen Species Metabolism in Citrus sinensis during Pathogen Infection

Reactive oxygen species (ROS) are pivotal in signal transduction processes in plant–pathogen interactions. The ROS signaling pathways involved in Candidatus Liberibacter asiaticus (CLas) and Xanthomonas citri subspecies citri (Xcc) infections in Citrus sinensis (sweet orange) are unclear. In this study, we comprehensively identified ROS metabolism-associated genes, including 9 NADPH oxidase (RBOH), 14 superoxide dismutase (SOD), 1 catalase (CAT), 9 peroxiredoxin (PrxR), 5 ascorbate peroxidase (APX), 4 glutathione peroxidase (GPX), 3 monodehydroascorbate reductase (MDAR), 2 dehydroascorbate reductase (DHAR), 2 glutathione reductase (GR), 24 thioredoxin (Trx), and 18 glutaredoxin (GLR) genes in C. sinensis. An analysis revealed variable gene structures but conserved motifs and domains in ROS subfamilies. A comparative synteny analysis with Arabidopsis thaliana and Vitis vinifera indicated evolutionary conservation of most ROS metabolism-associated genes, with some originating from gene duplication events post-species divergence in C. sinensis. Expression profiling revealed five up-regulated genes and four down-regulated genes during both CLas and Xcc infections. Promoter analysis revealed numerous stress-responsive elements in the promoter of ROS metabolism-associated genes. Protein–protein interaction network analysis highlighted the involvement of ROS metabolism in various biological processes. A comparison of ROS metabolism-associated genes between C. sinensis and Poncirus trifoliata indicated multiple gene gain and loss events within ROS subfamilies of C. sinensis. This study enhances our understanding of ROS metabolism in C. sinensis and sheds light on citrus–pathogen interactions.

PM2.5 toxicity in blood impairs cardiac redox balance and promotes mitochondrial dysfunction in rat heart that further aggravates ischemia reperfusion injury by modulating PI3K/AKT/mTOR/NF-kB signaling axis.

According to the pathophysiological mechanisms linking particulate matter (PM2.5) exposure and cardiovascular diseases, PM2.5 may directly translocate into the blood stream and remote target organs and thereby induce cardiovascular effects. The toxicity of PM2.5 is known to induce oxidative stress in pulmonary tissue, but its impact on the redox state in heart (distant organ) is unknown and how it modulates the cardiac response to ischemia reperfusion (IR) remains unclear. In the present study, we evaluated the toxic effect of PM2.5 on cardiac physiology in the presence and absence of IR after introducing PM2.5 into the blood. Female Wistar rats were injected with diesel particulate matter (DPM) via i.p & i.v routes at a concentration of 10 µg/ml. The toxic impact of PM2.5 not only adversely affects the cardiac ultra-structure (leading to nuclear infiltration, edema, irregularities in heart muscle and nuclear infiltration), but also altered the cellular redox balance, elevated inflammation and promoted the upregulation of proapoptotic mediator genes at the basal level of myocardium. The results showed alterations in cardiac ultrastructure, elevated oxidative stress and significant redox imbalance, increased inflammation and proapoptotic mediators at the basal level of myocardium. Moreover, the cardioprotective pro survival signaling axis was declined along with an increased NF-kB activation at the basal level. IR inflicted further injury with deterioration of cardiac hemodynamic indices (Heart rate [HR], Left ventricular developed pressure [LVDP], Left ventricular end-diastolic pressure [LVEDP] and rate pressure product [RPP]) along with prominent inactivation of signaling pathways. Furthermore, the levels of GSH/GSSG, NADH/NAD, NADPH/NADP were significantly low along with increased lipid peroxidation in mitochondria of PM2.5 treated IR rat hearts. This observation was supported by downregulation of glutaredoxin and peroxiredoxin genes in the myocardium. Similarly the presence of oxidative stress inducing metals was found at a higher concentration in cardiac mitochondria. Thus, the toxic impact of PM2.5 in heart augment the IR associated pathological changes by altering the physiological response, initiating cellular metabolic alterations in mitochondria and modifying the signaling molecules.

Glutaredoxin regulation of primary root growth is associated with early drought stress tolerance in pearl millet.

Seedling root traits impact plant establishment under challenging environments. Pearl millet is one of the most heat and drought tolerant cereal crops that provides a vital food source across the sub-Saharan Sahel region. Pearl millet's early root system features a single fast-growing primary root which we hypothesize is an adaptation to the Sahelian climate. Using crop modeling, we demonstrate that early drought stress is an important constraint in agrosystems in the Sahel where pearl millet was domesticated. Furthermore, we show that increased pearl millet primary root growth is correlated with increased early water stress tolerance in field conditions. Genetics including genome-wide association study and quantitative trait loci (QTL) approaches identify genomic regions controlling this key root trait. Combining gene expression data, re-sequencing and re-annotation of one of these genomic regions identified a glutaredoxin-encoding gene PgGRXC9 as the candidate stress resilience root growth regulator. Functional characterization of its closest Arabidopsis homolog AtROXY19 revealed a novel role for this glutaredoxin (GRX) gene clade in regulating cell elongation. In summary, our study suggests a conserved function for GRX genes in conferring root cell elongation and enhancing resilience of pearl millet to its Sahelian environment.

Glutaredoxin regulation of primary root growth is associated with early drought stress tolerance in pearl millet

Seedling root traits impact plant establishment under challenging environments. Pearl millet is one of the most heat and drought tolerant cereal crops that provides a vital food source across the sub-Saharan Sahel region. Pearl millet’s early root system features a single fast-growing primary root which we hypothesize is an adaptation to the Sahelian climate. Using crop modeling, we demonstrate that early drought stress is an important constraint in agrosystems in the Sahel where pearl millet was domesticated. Furthermore, we show that increased pearl millet primary root growth is correlated with increased early water stress tolerance in field conditions. Genetics including genome-wide association study and quantitative trait loci (QTL) approaches identify genomic regions controlling this key root trait. Combining gene expression data, re-sequencing and re-annotation of one of these genomic regions identified a glutaredoxin-encoding gene PgGRXC9 as the candidate stress resilience root growth regulator. Functional characterization of its closest Arabidopsis homolog AtROXY19 revealed a novel role for this glutaredoxin (GRX) gene clade in regulating cell elongation. In summary, our study suggests a conserved function for GRX genes in conferring root cell elongation and enhancing resilience of pearl millet to its Sahelian environment.

Molecular identification and functional characterization of an environmental stress responsive glutaredoxin gene ROXY1 in Quercus glauca

Quercus glauca is a valuable natural resource with both economic and ecological values. It is one of the dominant forest tree species widely distributed in Southern China. As a perennial broadleaf plant, Q. glauca inevitably encounters numerous stresses from environment. Glutaredoxins (GRXs) are a kind of small oxidoreductases that play an important role in response to oxidative stress. CC-type GRXs also known as ROXYs are specific to land plants. In this study, we isolated a CC-type GRX gene, QgROXY1, from Q. glauca. Expression of QgROXY1 is induced by a variety of environmental stimuli. QgROXY1 protein localizes to both cytoplasm and nucleus; whereas the nucleus localized QgROXY1 could physically interact with the basic region/leucine zipper motif (bZIP) transcription factor AtTGA2 from Arabidopsis thaliana. Transgenic A. thaliana ectopically expressing QgROXY1 is hypersensitive to exogenously applied salicylic acid. Induction of plant defense gene is significantly impaired in QgROXY1 transgenic plants that results in enhanced susceptibility to infection of Botrytis cinerea pathogen, indicating the evolutionary conserved function among ROXY homologs in weedy and woody plants. This is the first described function for the ROXYs in tree plants. Through this case study, we demonstrated the feasibility and efficacy of molecular technology applied to characterization of gene function in tree species.

Genome-Wide Identification and Characterization of Glutaredoxin Family Genes in Common Wheat

Glutaredoxins (GRXs) are small-molecular-weight proteins present in a wide range of organisms, and they play a key role in maintaining the redox homeostasis of cells. Most studies on GRXs are conducted in animals and humans, and those conducted on plants are scarce. The number and types of GRX genes vary in different plants. According to the active sites, the GRX family can be further divided into the CPYC, CGFS, and CC subfamilies. The CPYC and CGFS subfamilies are present in eukaryotes. The CC subfamily is exclusively present in higher plants and has the highest number of genes. In this study, 85 GRX genes were identified in common wheat (Triticum aestivum L.) using a bioinformatic method, wherein 12, 9, and 64 belonged to the CPYC, CGFS, and CC subfamilies, respectively. All TaGRX genes were homogeneously distributed in the three subgenomes of wheat. The gene structure analysis revealed that TaGRX members had 1–7 introns. The conserved motif analysis revealed that members of the same TaGRX subfamily had similar motifs. An analysis of cis-regulatory elements of promoters demonstrated that most TaGRX members had auxin-responsive elements; cis-regulatory elements, such as methyl jasmonate (MeJA), MYB, and abscisic acid (ABA), were distributed in all subfamilies, and the cell-cycle regulation element was only observed in the CC and CPYC subfamily members. Additionally, the synteny of the GRX genes in wheat, in wheat and Arabidopsis, and in wheat and barley was analyzed to clarify the evolutionary correlation of TaGRXs. The expression characteristics of TaGRXs were investigated, and TaGRX expression in various tissues and its responses to different abiotic stresses were preliminarily determined. This study provides a reference for the functional analysis of TaGRXs and understanding their role in molecular breeding of wheat.

Glutaredoxin in Rice Growth, Development, and Stress Resistance: Mechanisms and Research Advances

Rice (Oryza sativa L.) is a staple food for more than half of the global population. Various abiotic and biotic stresses lead to accumulation of reactive oxygen species in rice, which damage macromolecules and signaling pathways. Rice has evolved a variety of antioxidant systems, including glutaredoxin (GRX), that protect against various stressors. A total of 48 GRX gene loci have been identified on 11 of the 12 chromosomes of the rice genome; none were found on chromosome 9. GRX proteins were classified into four categories according to their active sites: CPYC, CGFS, CC, and GRL. In this paper, we summarized the recent research advances regarding the roles of GRX in rice development regulation and response to stresses, and discussed future research perspectives related to rice production. This review could provide information for rice researchers on the current status of the GRX and serve as guidance for breeding superior varieties.

Low R:FR light ratio enhances calcium nitrate resistance and stomatal movement in tomato seedlings by regulating H2O2 accumulation

Secondary salinization is a major environmental factor that causes a stress response and growth inhibition in plants in protected agriculture. The positive effect of a low red to far-red light ratio (R:FR) in salt tolerance through antioxidant defense has been reported, while the underlying model remains obscure. In this study, we used physiological and genetic approaches to investigate the relationship between H2O2 signaling and low R:FR-induced salt tolerance and antioxidant capacity in tomato seedlings. This study found that low R:FR treatment with calcium nitrate stress (SL treatment) enhanced the growth of plants and increased the net photosynthetic rate 5 days after stress compared with a higher R:FR ratio and calcium nitrate stress (S treatment). With transcriptomic analysis of tomato leaves at 5 d, compared with CK, most of glutaredoxin genes and antioxidant enzymes were upregulated by S treatment, which were upregulated further by SL treatment. Compared to the S treatment, within 5 days, the H2O2 level was increased faster before 24 h and it was slowed down after 24 h by SL treatment, with less H2O2 accumulation at 5 d than that of S treatment. The enhancement of gene expression of RBOH genes were also shown at 24 h under SL. It was found that stomatal conductance followed the dynamic change of H2O2, with a rapid closure of stomata and decrease at 3 h and an increase after 9 h in SL treatment compared to S treatment, respectively. There was same trend of stomata opening degrees of tomato leaves observed by optical microscope. However, the inhibitor of H2O2 production (DPI pretreatment) weakened the positive effect of low R:FR on the regulation of stomatal movement. In addition, SL treatment increased the antioxidant enzyme activities and proline content and decreased the MDA content as compared to the S treatment, while the enhancement of ROS homeostasis was reduced by the DPI pretreatment. In conclusion, low R:FR improved redox homeostasis and stomatal status under calcium nitrate stress through H2O2 signaling, improving the adaptation of tomato seedlings to soil salinization stress.

Comparative transcriptomic analysis of the chickpea glutaredoxin (CaGrx) gene over-expressed in Arabidopsis thaliana is associated with drought tolerance by modulating the plant defense system

Comparative transcriptomic analysis of the chickpea glutaredoxin (CaGrx) gene over-expressed in Arabidopsis thaliana is associated with drought tolerance by modulating the plant defense system

Identification and adaptive evolution analysis of glutaredoxin genes in Populus spp.

Glutaredoxin (GRX) is a class of small redox proteins widely involved in cellular redox homeostasis and the regulation of various cellular processes. The role of GRX gene in the differentiation of Populus spp. is rarely reported. We compared the similarities and differences of GRX genes among four sections of poplar using bioinformatics, corrected the annotations of some GRX genes, and focused on analysing their transcript profiling and adaptive evolution in Populus spp. A total of 219 GRX genes were identified in four sections of poplar, among which annotations for 13 genes were corrected. Differences in GRX genes were found between sect. Turanga, represented by P. euphratica, and other poplar sections. Most notably, P. euphratica had the smallest number of duplication events for GRX genes (n = 9) and no tandem duplications, whereas there were >25 duplication events for all other poplars. Furthermore, we detected 18 pairs of GRX genes under positive selection pressure in various sections of poplar, and identified two groups of GRX genes in the Salicaceae that potentially underwent positive selection. Expression profiling results showed that the PtrGRX34 and its orthologous genes were upregulated under stress treatments. In summary, the GRX gene family underwent expansion during poplar differentiation, and some genes underwent rapid evolution during this process, which may be beneficial for Populus spp. to adapt to environmental changes. This study may provide more insights into the molecular mechanisms of Populus spp. adaptation to environmental changes and the adaptive evolution of GRX genes.

Genome-Wide Identification, Characterization, and Expression Profiling of the Glutaredoxin Gene Family in Tea Plant (Camellia sinensis)

Glutaredoxins (GRXs) are a widely distributed group of small oxidoreductases that play an important role in responding to oxidative stress and maintaining redox homeostasis in living organisms. However, there has been no report on the GRX gene family in tea plants (Camellia sinensis). In this study, we conducted a systematic analysis of the CsGRX gene family in tea plants and identified a total of 86 CsGRX genes. Based on phylogenetic and conserved active site analyses, these genes were classified into four categories: CC-type, CPYC-type, CGFS-type, and GRL-type. These subtypes showed distinct characteristics in terms of gene structure, conserved motif, chromosome distribution, subcellular localization, cis-regulatory elements, and expression pattern, indicating functional differences among CsGRX family members. Collinearity analysis showed that the CsGRX family may have undergone member expansion using tandem and segmental duplication along with overwhelmingly strict purifying selection. Protein tertiary structure analysis supported the conserved site-specific binding of CsGRX family members to glutathione. Protein interaction network analysis revealed that CsGRX may interact with glutathione reductase (GR), 2-Cys Peroxiredoxin BAS1, TGA3, and others to participate in the oxidative stress response in tea plants. GO and KEGG enrichment analyses also supported the important role of the CsGRX family in maintaining intracellular redox homeostasis. Expression analysis based on RNA-seq revealed differential expression patterns of CsGRX genes under drought, cold stress, and in different tissues, which were further confirmed by RT-qPCR analysis, indicating their broad-spectrum functionality. This study provides a new perspective for further exploring the evolution and molecular functions of specific CsGRX genes.

Genome-wide survey of glutaredoxin gene family in four Solanaceae species and exploitation of duplicated CC-type following different environmental stimuli in tomato (Solanum lycopersicum)

Glutaredoxins (GRXs) are ubiquitous oxidoreductases involved in cell signaling, development and plant defense response against oxidative stress. Despite this gene family has been characterized in several species, clues about their evolution, diversification and function in Solanaceae are still in infancy. By exploring genomes of cultivated tomato (Solanum lycopersicum), potato (S. tuberosum) and their wild relatives (S. pennellii, S. commersonii), a total of 237 GRX genes were identified and grouped in CPYC-, CGFS-, GRL- and CC-types. Focusing on cultivated tomato, we highlighted that a higher diversity within CC-type resulted from tandem duplication events, indicating that this latter might be the force driving GRXs evolution. The presence of a rich repertoire of cis-regulatory elements suggested specialized functions of SlGRXs in plant development, hormonal and (a)biotic stress responses, as also confirmed by their different expression patterns observed in various tissues and during fruit development through an in silico approach. qRT-PCR analysis revealed a divergent profile of tandem and segmental duplicated CC-type members in tomato response to abiotic stresses, pathogenic or beneficial microorganisms. This study reported the first insights on the GRX gene family in four Solanaceae species and provided a comprehensive and detailed analysis of their gene structure and role in tomato. The divergent profile of selected duplicated CC-type members against various environmental constraints, highlighted candidate genes that will be used as a reference for functional analysis and genetic improvement not only in tomato but also in related species.

CEP peptide and cytokinin pathways converge on CEPD glutaredoxins to inhibit root growth

C-TERMINALLY ENCODED PEPTIDE (CEP) and cytokinin hormones act over short and long distances to control plant responses to environmental cues. CEP and cytokinin pathway mutants share phenotypes, however, it is not known if these pathways intersect. We show that CEP and cytokinin signalling converge on CEP DOWNSTREAM (CEPD) glutaredoxins to inhibit primary root growth. CEP inhibition of root growth was impaired in mutants defective in trans-zeatin (tZ)-type cytokinin biosynthesis, transport, perception, and output. Concordantly, mutants affected in CEP RECEPTOR 1 showed reduced root growth inhibition in response to tZ, and altered levels of tZ-type cytokinins. Grafting and organ-specific hormone treatments showed that tZ-mediated root growth inhibition involved CEPD activity in roots. By contrast, root growth inhibition by CEP depended on shoot CEPD function. The results demonstrate that CEP and cytokinin pathways intersect, and utilise signalling circuits in separate organs involving common glutaredoxin genes to coordinate root growth.

The bianchetto truffle (Tuber borchii) a lead-resistant ectomycorrhizal fungus increases Quercus cerris phytoremediation potential.

Tuber borchii is a European edible truffle which forms ectomycorrhizas with several soft- and hardwood plants. In this article, the effects of high level of Pb on the in vitro growth of five T. borchii strains and the molecular mechanisms involved in Pb tolerance were studied. Moreover, the effects of the Pb treatment on T. borchii ectomycorrhizas and on the growth, element uptake and distribution in different organs of Quercus cerris seedlings were investigated. The results showed an extraordinary tolerance of T. borchii mycelium to Pb: all the tested strains were able to grow at Pb concentration over 4000 mg L-1 . The mechanisms of tolerance seem related to Pb sequestration in the vacuole and its immobilization as crystal of Pb oxalate outside the hyphae rather than detoxification processes, considering the low expression of glutaredoxin and thioredoxin genes. T. borchii-Q. cerris mycorrhizas tolerate a soil concentration of Pb from 1869 to 4030 mg kg-1 although, at these Pb concentrations, T. borchii showed a reduced ability to colonize roots. T. borchii mycorrhization increased the uptake of Pb by Q. cerris. Mycorrhization and Pb treatment also significantly influenced the uptake and translocation in the plant of other elements.

Genome-wide identification, characterization and expression analysis of glutaredoxin gene family (Grxs) in Phaseolus vulgaris

Glutaredoxins (Grxs) are ubiquitous oxidoreductase proteins implicated in development and abiotic stress response mainly through maintaining redox homoeostasis. Here, we conducted the first systematic analysis of the Grx gene family (PvGrx) in the most popular legume Phaseolus vulgaris (common bean). A total of 50 PvGrx genes were identified, and divided into four classes (CC-type, CGFS-type, CPYC-type and Grl-type) based on the phylogenetic analysis. The different classes have different introns-exons structures and conserved motifs, indicating functional divergence in the PvGrx family. Both tandem and segmental duplications were found to be involved in the expansion of PvGrx family that underwent a purifying selection by excluding the deleterious loss-of-function mutations. Cis-acting regulatory elements and gene ontology analyses predicted their role of distinctive members in abiotic stress response and hormonal signalling. RNA-seq based expression analysis revealed their differential expression pattern during plant development. On the other hand, RT q-PCR analysis revealed that target PvGrx isoforms were associated with nodule organogenesis and symbiosis based on their expression profiles. In addition, a battery of PvGrx candidates were markedly upregulated by different abiotic stressors suggesting their broad spectrum of functions. These findings serve as a reference for functional analysis and genetic improvement in P. vulgaris and related legume species.

Enhanced resistance in ‘shatang’ mandarin fruit against Penicillium italicum caused by 2-methoxy-1,4-naphthoquinone

Blue mold caused by Penicillium italicum leads to considerable postharvest losses in citrus fruit. The 2-methoxy-1,4-naphthoquinone (MNQ), a natural compound from Chinese medicinal plant, had strong in vitro antifungal activity. Therefore, we investigated the in vivo effect of MNQ treatment against blue mold on ‘shatang’ mandarin fruit caused by P. italicum and the underlying mechanisms. Our results found that MNQ could suppress disease development, indicated by less severe incidence and symptoms of fruit disease. MNQ treatment maintained redox status via enhancing antioxidant enzyme activities to decrease hydrogen peroxide (H2O2) content and up-regulating sulfoxide reductase, glutaredoxin and thioredoxin gene expression to keep protein repair ability. Meanwhile, MNQ alleviated membrane damage and protein carbonylation caused by oxidative stress. Additionally, MNQ increased the activities of defense-related enzymes (phenylalanine ammonia lyase, β-1,3-glucanase and chitinase) and accumulation of lignin, phenolic compounds and flavonoids. Moreover, we found that MNQ treatment could up-regulate abscisic acid (ABA) synthetic gene expression resulting in higher ABA content. In summary, MNQ was effective as a potential agent controlling the postharvest diseases.

CGFS-type glutaredoxin mutations reduce tolerance to multiple abiotic stresses in tomato.

Sessile organisms such as plants have adopted diverse reactive oxygen species (ROS) scavenging mechanisms to mitigate damage under abiotic stress conditions. Though CGFS-type glutaredoxin (GRX) genes are important regulators of ROS homeostasis, each of their functions in crop plants have not yet been well understood. We performed a targeted mutagenesis analysis of four CGFS-type GRXs (SlGRXS14, SlGRXS15, SlGRXS16, and SlGRXS17) in tomato plants (Solanum lycopersicum) using a multiplex clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system and found that Slgrxs mutants were more sensitive to various abiotic stresses compared with the wild-type tomatoes. Slgrxs15 mutants were embryonic lethal. Single, double, and triple combinations of Slgrxs14, 16, and 17 mutants were examined under heat, chilling, drought, heavy metal toxicity, nutrient deficiency, and short photoperiod stresses. Slgrxs14 and 17 mutants showed hypersensitivity to almost all stresses while Slgrxs16 mutants were affected by chilling stress and showed milder sensitivity to other stresses. Additionally, Slgrxs14 and 17 mutants showed delayed flowering time. Our results indicate that the CGFS-type SlGRXs have specific roles against abiotic stresses, providing valuable resources to develop tomato and, possibly, other crop species that are tolerant to multiple abiotic stresses by genetic engineering.

Identification and expression analyzes of CC-type glutaredoxin in cucumber (Cucumis sativus L.) under abiotic stress

Glutaredoxins (GRXs) are key regulators in the cellular redox state and play pivotal roles in both plant development and responses to stress stimuli. Here, we found 45 GRX gene members in cucumber, 16 of which were classified as CC-type. These CC-type GRXs were shown to be highly conserved among cucumber, Arabidopsis thaliana, and rice, according to our bioinformatic analyzes results. Cucumber CC-type GRX (CsGRX) genes showed varying expression levels in different plant organs and in response to different abiotic stresses. CsGRX1, CsGRX5, CsGRX9, CsGRX13, and CsGRX16 expression was induced from 3 to 6 h by salicylic acid (SA) treatments, whereas CsGRX1, CsGRX3, CsGRX8, CsGRX13, CsGRX14, and CsGRX17 expression was induced from 3 to 12 h with methyl jasmonate (MeJA) treatments. Moreover, CsGRX11 expression was strongly induced from 0 to 24 h by MeJA treatment, whereas CsGRX3 and CsGRX11 expression was strongly induced at the early stages of 42 °C treatments and at the later stages of the methyl viologen treatments. CsGRX4, CsGRX6, CsGRX7, CsGRX13 and CsGRX11 expression was induced by PEG and NaCl treatments. These results indicated the versatile roles of GRX genes in response to stress stimuli. The subcellular localization results for three CsGRX–green fluorescent protein (GFP) fusion proteins indicated that some orthologs were localized to the nucleus. CsGRX4 that responded to salt stress were heterologously expressed in Arabidopsis, and its transgenic lines demonstrated salt sensitivity, showing lower seed germination rate and shorter root length than their wild type counterparts under salt stress. Our results provide a foundation for future studies on GRX genes in cucumber.

Lycopene Modulates Placental Health and Fetal Development Under High‐Fat Diet During Pregnancy of Rats

Lycopene plays an important role in improving immunity, promoting antioxidant capacity, and regulating fat metabolism. The placenta, an important organ for nutrients exchange between mother and child during pregnancy, directly affects fetal development. This study aims to characterize effects of lycopene on placental health and fetal development under a high-fat diet, and utilize RNA sequencing (RNA-seq) to investigate and integrate the differences of molecular pathways and biological processes in placenta. For placental health, high-fat diet during pregnancy increases placental oxidative stress, inflammation, and fat deposition. However, lycopene reduces the negative effects of high-fat diet on placenta to some extent, and further promotes fetal development. Under high-fat diet, lycopene reduces the levels of Interleukin 17 (IL-17), Interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α) in placenta (p < 0.05) through the IL-17 pathway. Furthermore, lycopene supplementation in high-fat diet increases Glutaredoxin (Glrx) gene and protein expression in the placenta (p < 0.05), increases Glutathione peroxidase (GSH-Px) and Total antioxidant capacity (T-AOC) levels (p < 0.05), decreases reactive oxygen species (ROS) (p < 0.01) and Hydrogen peroxide (H2 O2 ) levels (p < 0.05) in placenta. In addition, lycopene supplementation in high fat diet increases the expression of Lep gene and protein in placenta and increases the level of leptin (p < 0.05). In terms of fetal development, the average fetal weight and fetal litter weight are increased by lycopene compared to high-diet treatment.