Peroxidase Gene Research Articles

Genome-Wide Investigation of Class III Peroxidase Genes in Brassica napus Reveals Their Responsiveness to Abiotic Stresses.

Brassica napus (B. napus) is susceptible to multiple abiotic stresses that can affect plant growth and development, ultimately reducing crop yields. In the past, many genes that provide tolerance to abiotic stresses have been identified and characterized. Peroxidase (POD) proteins, members of the oxidoreductase enzyme family, play a critical role in protecting plants against abiotic stresses. This study demonstrated a comprehensive investigation of the POD gene family in B. napus. As a result, a total of 109 POD genes were identified across the 19 chromosomes and classified into five distinct subgroups. Further, 44 duplicate events were identified; of these, two gene pairs were tandem and 42 were segmental. Synteny analysis revealed that segmental duplication was more prominent than tandem duplication among POD genes. Expression pattern analysis based on the RNA-seq data of B. napus indicated that BnPOD genes were expressed differently in various tissues; most of them were expressed in roots rather than in other tissues. To validate these findings, we performed RT-qPCR analysis on ten genes; these genes showed various expression levels under abiotic stresses. Our findings not only furnish valuable insights into the evolutionary dynamics of the BnPOD gene family but also serve as a foundation for subsequent investigations into the functional roles of POD genes in B. napus.

Temporal dynamics of stress response in Halomonas elongata to NaCl shock: physiological, metabolomic, and transcriptomic insights

BackgroundThe halophilic bacterium Halomonas elongata is an industrially important strain for ectoine production, with high value and intense research focus. While existing studies primarily delve into the adaptive mechanisms of this bacterium under fixed salt concentrations, there is a notable dearth of attention regarding its response to fluctuating saline environments. Consequently, the stress response of H. elongata to salt shock remains inadequately understood.ResultsThis study investigated the stress response mechanism of H. elongata when exposed to NaCl shock at short- and long-time scales. Results showed that NaCl shock induced two major stresses, namely osmotic stress and oxidative stress. In response to the former, within the cell’s tolerable range (1–8% NaCl shock), H. elongata urgently balanced the surging osmotic pressure by uptaking sodium and potassium ions and augmenting intracellular amino acid pools, particularly glutamate and glutamine. However, ectoine content started to increase until 20 min post-shock, rapidly becoming the dominant osmoprotectant, and reaching the maximum productivity (1450 ± 99 mg/L/h). Transcriptomic data also confirmed the delayed response in ectoine biosynthesis, and we speculate that this might be attributed to an intracellular energy crisis caused by NaCl shock. In response to oxidative stress, transcription factor cysB was significantly upregulated, positively regulating the sulfur metabolism and cysteine biosynthesis. Furthermore, the upregulation of the crucial peroxidase gene (HELO_RS18165) and the simultaneous enhancement of peroxidase (POD) and catalase (CAT) activities collectively constitute the antioxidant defense in H. elongata following shock. When exceeding the tolerance threshold of H. elongata (1–13% NaCl shock), the sustained compromised energy status, resulting from the pronounced inhibition of the respiratory chain and ATP synthase, may be a crucial factor leading to the stagnation of both cell growth and ectoine biosynthesis.ConclusionsThis study conducted a comprehensive analysis of H. elongata’s stress response to NaCl shock at multiple scales. It extends the understanding of stress response of halophilic bacteria to NaCl shock and provides promising theoretical insights to guide future improvements in optimizing industrial ectoine production.

Is There a Link between Thyroid Peroxidase Gene Promoter Polymorphisms and Autoimmune Thyroiditis in the Polish Population?

(1) Autoimmune thyroiditis (AIT) is the most common cause of primary hypothyroidism and one of the most frequent organ-specific autoimmune diseases. Its pathogenesis is polygenic and still requires further research. The aim of the study was to assess, for the first time in the Caucasian population, the role of selected TPO gene promoter polymorphisms (rs2071399 G/A, rs2071400C/T, rs2071402 A/G, and rs2071403 A/G) in the development of AIT. A total of 237 patients diagnosed with AIT and 130 healthy controls were genotyped for four TPO gene polymorphisms, and the results were statistically analyzed to check for the role of these polymorphisms. There were no significant differences in the genotype and allele frequencies of the studied TPO gene promoter polymorphisms between patients and controls (p > 0.05). The haplotype distribution (rs2071400-rs2071402-rs2071403) between the two studied groups was similar for the most common variants (CGA, CAG, TGG). Only a rare haplotype (CGG) occurred more frequently among patients compared to controls (p = 0.04). The studied TPO gene promoter polymorphisms did not show an association with susceptibility to AIT in the Caucasian Polish population, contrary to the results in Japanese patients.

MIR1868 negatively regulates rice cold tolerance at both the seedling and booting stages

Low temperature causes rice yield losses of up to 30%–40%, therefore increasing its cold tolerance is a breeding target. Few genes in rice are reported to confer cold tolerance at both the vegetative and reproductive stages. This study revealed a rice-specific 24-nt miRNA, miR1868, whose accumulation was suppressed by cold stress. Knockdown of MIR1868 increased seedling survival, pollen fertility, seed setting, and grain yield under cold stress, whereas its overexpression conferred the opposite phenotype. Knockdown of MIR1868 increased reactive oxygen species (ROS) scavenging and soluble sugar content under cold stress by increasing the expression of peroxidase genes and sugar metabolism genes, and its overexpression produced the opposite effect. Thus, MIR1868 negatively regulated rice cold tolerance via ROS scavenging and sugar accumulation.

MdPRX34L, a class III peroxidase gene, activates the immune response in apple to the fungal pathogen Botryosphaeria dothidea.

MdPRX34L enhanced resistance to Botryosphaeria dothidea by increasing salicylic acid (SA) and abscisic acid (ABA) content as well as the expression of related defense genes. The class III peroxidase (PRX) multigene family is involved in complex biological processes. However, the molecular mechanism of PRXs in the pathogen defense of plants against Botryosphaeria dothidea (B. dothidea) remains unclear. Here, we cloned the PRX gene MdPRX34L, which was identified as a positive regulator of the defense response to B. dothidea, from the apple cultivar 'Royal Gala.' Overexpression of MdPRX34L in apple calli decreased sensitivity to salicylic acid (SA) and abscisic acid（ABA). Subsequently, overexpression of MdPRX34L in apple calli increased resistance to B. dothidea infection. In addition, SA contents and the expression levels of genes related to SA synthesis and signaling in apple calli overexpressing MdPRX34L were higher than those in the control after inoculation, suggesting that MdPRX34L enhances resistance to B. dothidea via the SA pathway. Interestingly, infections in apple calli by B. dothidea caused an increase in endogenous levels of ABA followed by induction of ABA-related genes expression. These findings suggest a potential mechanism by which MdPRX34L enhances plant-pathogen defense against B. dothidea by regulating the SA and ABA pathways.

Ascorbate-glutathione cycle in wheat and rice seedlings under anoxia and subsequent reaeration.

The most important part of the plant antioxidant system is the ascorbate-glutathione cycle (AGC), the activity of which is observed upon exposure to a range of stressors, including lack of O2, and oxidative stress occurring immediately after the restoration of oxygen access, hereafter termed reaeration or post-anoxia. The operation of the AGC (enzymes and low-molecular components) in wheat (Triticum aestivum, cv. Leningradka, non-resistant to hypoxia) and rice (Oryza sativa, cv. Liman, resistant) seedlings after 24 h anoxia and 1 h or 24 h reaeration was studied. Significant accumulation of oxidized forms of ascorbate and glutathione was revealed in the non-resistant plant (wheat) after 24 h of anoxia and reaeration, indicating the development of oxidative stress. In the resistant plant (rice), reduced forms of these antioxidants prevailed both in normoxia and under stress, which may indicate their intensive reduction. In wheat, the activities of ascorbate peroxidase and dehydroascorbate reductase in shoots, and monodehydroascorbate reductase and glutathione reductase in roots decreased under anoxia and reaeration. The activity of antioxidant enzymes was maintained in rice under lack of oxygen (ascorbate peroxidase, glutathione reductase) and increased during post-anoxia (AGC reductases). Anoxia stimulated accumulation of mRNA of the organellar ascorbate peroxidase genes OsAPX3, OsAPX5 in shoots, and OsAPX3-5 and OsAPX7 in roots. At post-anoxia, the contribution of the OsAPX1 and OsAPX2 genes encoding the cytosolic forms of the enzyme increased in the whole plant, and so did that of the OsAPX8 gene for the plastid form of the enzyme. The accumulation of mRNA of the genes OsMDAR2 and OsMDAR4 encoding peroxisomal and cytosolic monodehydroascorbate reductase as well as the OsGR2 and OsGR3 for cytosolic and organellar glutathione reductase was activated during reaeration in shoots and roots. In most cases, O2 deficiency activated the genes encoding the peroxisomal, plastid, and mitochondrial forms of the enzymes, and upon reaeration, an enhanced activity of the genes encoding the cytoplasmic forms was observed. Taken together, the inactivation of AGC enzymes was revealed in wheat seedlings during anoxia and subsequent reaeration, which disrupted the effective operation of the cycle and triggered the accumulation of oxidized forms of ascorbate and glutathione. In rice, anoxia led to the maintenance of the activity of AGC enzymes, and reaeration stimulated it, including at the level of gene expression, which ensured the effective operation of AGC.

Drug-eluting nanofibrous wound dressings composed of polycaprolactone and gelatin augment diabetic wounds healing via reducing oxidative stress and inflammation: An in vitro and in vivo study

Diabetes is a prevalent medical condition that often leads to complications, including diabetic wounds that can have serious consequences such as infections, amputations, and death. In the current research, lodoxamide was loaded into electrospun polycaprolacton/gelatin scaffolds In order to improve wound healing in a rat model. Our developed dressings were characterized in vitro using various methods and then applied on a rat model of excisional wound. Study showed that the dressings were not toxic and promoted migration potential of skin-derived fibroblast cells. Wound healing study showed that lodoxamide-loaded dressings had markedly higher healing potential than other scaffolds and augmented collagen deposition and epithelialization. Gene expression studies showed that TNF-α, glutathione peroxidase, and superoxide dismutase genes were significantly downregulated by lodoxamide-loaded scaffolds.

Combining Vitis OneGene causality approach with phylogenetic and cistrome analyses to study the laccase, dirigent and peroxidase gene networks

Combining <i>Vitis</i> OneGene causality approach with phylogenetic and cistrome analyses to study the laccase, dirigent and peroxidase gene networks

Comparative Transcriptome Profiles of the Response of Mycelia of the Genus Morchella to Temperature Stress: An Examination of Potential Resistance Mechanisms.

Temperature and moisture belong to the most important environmental factors affecting the growth and development of fungi. However, the effect of temperature on the mycelia of the edible Morchella mushrooms has not been determined. Here, a comprehensive analysis was performed to determine the influence of culture temperature on 13 strains of mycelia of three Morchella species (Morchella sextelata, Morchella septimelata, and Morchella importuna) at 5 °C, 10 °C, 15 °C, 20 °C, 25 °C, and 30 °C. The mycelial branching and growth rate data showed that 15-20 °C was a suitable temperature range for the mycelial growth of the 13 Morchella strains. RNA sequences revealed that a total of 2843, 2404, 1973, 1572, and 1866 differentially expressed genes (DEGs) were identified at 5 °C, 10 °C, 15 °C, 25 °C, and 30 °C compared with 20 °C. A Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis further indicated that the purine nucleotide and tyrosine metabolism pathways were crucial for mycelium development. Moreover, the enrichment of autophagy of mitochondria, regulation of cell morphogenesis, and piecemeal microautophagy of the nuclei at 25 °C (vs. 20 °C) indicated the damage caused by heat stress in Morchella mycelia. Notably, a total of four unique module eigengenes (MEs) were identified through a weighted gene coexpression network analysis (WGCNA). Among them, 2293 genes in the turquoise module were significantly positively correlated with temperature (r = 0.946, p < 0.001), whereas 739 genes in the blue module were significantly negatively correlated with temperature (r = -0.896, p < 0.001), suggesting that the effect of high temperatures on mycelial genes was significantly greater than that of low temperatures. Moreover, the coexpression network indicated that high culture temperatures accelerated the oxidative stress response and energy metabolism in mycelia, while upregulation of purine nucleotide catabolism and ribosomal protein-related genes were improved by low-temperature tolerance. In addition, the upregulated expression of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and heat shock protein (HSP) genes in mycelia was associated with reactive oxygen species (ROS)-mediated damage at high temperatures. Overall, this study provides an important theoretical basis and application value for optimizing Morchella cultivation techniques.

Screening and Expression Analysis of POD Gene in POD-H2O2 Pathway on Bud Dormancy of Pear (Pyrus pyrifolia)

Bud endodormancy represents a pivotal and intricate biological process influenced by both genetic and epigenetic factors, the exact mechanism of which remains elusive. Hydrogen peroxide (H2O2) functions as a signalling molecule in the regulation of dormancy, with peroxidase (POD) playing a crucial role in governing H2O2 levels. Our prior transcriptomic and metabolomic investigations into diverse pear dormancy phases posited that POD predominantly oversees pear bud dormancy. In this study, we utilised qRT-PCR to screen the most significantly expressed gene, Pyrus pyrifolia POD4-like (PpPOD4-like), from seven POD genes. Subsequently, H2O2 test kits, overexpression methods, and subcellular localisation techniques were employed to assess changes in H2O2 content, POD activity, PpPOD4-like expression, and its cellular positioning during pear bud dormancy. Subcellular localisation experiments revealed that PpPOD4-like is situated on the cell membranes. Notably, H2O2 content exhibited a rapid increase during endodormancy and decreased swiftly after ecodormancy. The fluctuation pattern of POD activity aligned with that of H2O2 content. Additionally, PpPOD4-like expression was markedly upregulated, displaying an overall upward trajectory. Our findings indicate that PpPOD4-like modulates H2O2 levels by regulating POD activity, thereby actively participating in the intricate regulation of pear dormancy processes.

Soil drought during the development of cotton ovule destroyed the antioxidant balance of cotton pistil to hinder the ovule formation

AbstractReproductive failure in cotton caused by drought has been reported to be closely associated with alterations in pistil fertility; however, the mechanism of the effect of drought on pistil fertility in cotton is less studied. We hypothesized that drought would inhibit the ovule formation to alter pistil potential fertility. To address this hypothesis, we conducted a water deficit induction experiment with a cotton cultivar, Dexiamian 1. Results showed that drought damaged the cytological structure of the developing ovules. This resulted in a lower ovule number, finally leading to lower cottonseed number and boll weight. And the decreased ovule number was closely related to the reactive oxygen species (ROS) accumulation in pistil during ovule development. Further analysis of antioxidant metabolism found that in the enzymatic antioxidant system, drought decreased the activities of superoxide dismutase (SOD) and catalase (CAT), resulting in the accumulation of superoxide anion () and hydrogen peroxide (H2O2). Regarding the non‐enzymatic antioxidant system, the elevated glutathione reductase gene (GhGR) expression under drought promoted the glutathione (GSH) accumulation; however, the decreased dehydroascorbate reductase gene (GhDHAR2) expression under drought inhibited the conversion of GSH to ascorbic acid (AsA). Although the increased monodehydroascorbate reductase gene (GhMDHAR) expression under drought promoted AsA accumulation, drought‐induced reduced ascorbate peroxidase gene (GhAPX) expression inhibited the reduction of H2O2 by AsA, which ultimately led to higher AsA content and H2O2 content. We conclude that drought impedes the ovule formation by disturbing pistil's antioxidant metabolic homeostasis to destruct the cytological structure of the developing ovules.

Comparative Transcriptome Analysis Reveals the Genes and Pathways Related to Wheat Root Hair Length.

Tube-like outgrowths from root epidermal cells, known as root hairs, enhance water and nutrient absorption, facilitate microbial interactions, and contribute to plant anchorage by expanding the root surface area. Genetically regulated and strongly influenced by environmental conditions, longer root hairs generally enhance water and nutrient absorption, correlating with increased stress resistance. Wheat, a globally predominant crop pivotal for human nutrition, necessitates the identification of long root hair genotypes and their regulatory genes to enhance nutrient capture and yield potential. This study focused on 261 wheat samples of diverse genotypes during germination, revealing noticeable disparities in the length of the root hair among the genotypes. Notably, two long root hair genotypes (W106 and W136) and two short root hair genotypes (W90 and W100) were identified. Transcriptome sequencing resulted in the development of 12 root cDNA libraries, unveiling 1180 shared differentially expressed genes (DEGs). Further analyses, including GO function annotation, KEGG enrichment, MapMan metabolic pathway analysis, and protein-protein interaction (PPI) network prediction, underscored the upregulation of root hair length regulatory genes in the long root hair genotypes. These included genes are associated with GA and BA hormone signaling pathways, FRS/FRF and bHLH transcription factors, phenylpropanoid, lignin, lignan secondary metabolic pathways, the peroxidase gene for maintaining ROS steady state, and the ankyrin gene with diverse biological functions. This study contributes valuable insights into modulating the length of wheat root hair and identifies candidate genes for the genetic improvement of wheat root traits.

Evolutionary Analysis of Six Gene Families Part of the Reactive Oxygen Species (ROS) Gene Network in Three Brassicaceae Species.

Climate change is expected to intensify the occurrence of abiotic stress in plants, such as hypoxia and salt stresses, leading to the production of reactive oxygen species (ROS), which need to be effectively managed by various oxido-reductases encoded by the so-called ROS gene network. Here, we studied six oxido-reductases families in three Brassicaceae species, Arabidopsis thaliana as well as Nasturtium officinale and Eutrema salsugineum, which are adapted to hypoxia and salt stress, respectively. Using available and new genomic data, we performed a phylogenomic analysis and compared RNA-seq data to study genomic and transcriptomic adaptations. This comprehensive approach allowed for the gaining of insights into the impact of the adaptation to saline or hypoxia conditions on genome organization (gene gains and losses) and transcriptional regulation. Notably, the comparison of the N. officinale and E. salsugineum genomes to that of A. thaliana highlighted changes in the distribution of ohnologs and homologs, particularly affecting class III peroxidase genes (CIII Prxs). These changes were specific to each gene, to gene families subjected to duplication events and to each species, suggesting distinct evolutionary responses. The analysis of transcriptomic data has allowed for the identification of genes related to stress responses in A. thaliana, and, conversely, to adaptation in N. officinale and E. salsugineum.

Genome-Wide Identification of Ascorbate Peroxidase Gene Family in Two Contrasting Barley (Hordeum vulgare L.) Cultivars in Response to Abiotic Stresses

Genome-Wide Identification of Ascorbate Peroxidase Gene Family in Two Contrasting Barley (Hordeum vulgare L.) Cultivars in Response to Abiotic Stresses

Dietary lysozyme and avilamycin modulate gut health, immunity, and growth rate in broilers

BackgroundAttempts to use dietary lysozyme (LYZ) as an alternative to antibiotics in broilers have been successful, but further research is needed for effective use. Here, we compared the differences between LYZ and avilamycin (AVI) feed additives for growth performance, gut health and immunity of broilers. One-day old, one hundred and twenty broiler chicks (Ross 308) were randomly allocated into three groups consisting forty birds in each group. Standard diet without supplementation was applied as the control group (I), while the chicks of the other groups were supplemented with 100 mg of AVI per kg diet (AVI, group II), and 90 mg LYZ per kg diet (LYZ, group III) for five consecutive weeks.ResultsBody weight, feed conversion ratio, body weight gain, and European production efficiency factor were markedly (p < 0.05) increased in both AVI and LYZ groups in relation to CON group, but the feed intake and protein efficiency ratio were not affected. Both AVI and LYZ significantly (p < 0.001) upregulated the mRNA expression of ileal interleukin-18 (IL-18), interferon-gamma (IFN-γ), and interleukin-10 (IL-10), interleukin-2 (IL-2), and glutathione peroxidase (GSH-PX) genes compared to CON group. However, IL-2, IL-10, IL-18, and GSH-PX genes were markedly (p < 0.01) upregulated in LYZ compared to the AVI group. LYZ treated group had a significant increase (p < 0.05) in the serological haemagglutination inhibition titers of H5N1 vaccination and a significant decrease (p < 0.0001) in coliform counts compared to control and AVI groups, but all growth parameters were nearly similar between AVI and LYZ groups. The VH and VH/CD were markedly higher in LYZ than AVI and control groups.ConclusionExogenous dietary lysozyme supplementation by a dose of 90 mg/kg broilers’ diet induced better effects on intestinal integrity, fecal bacterial counts, immune response, and growth performance which were comparable to avilamycin. Therefore, dietary lysozyme could safely replace avilamycin in the broiler chickens’ diet. However, further experimental studies regarding the use of lysozyme in commercial broilers, both in vitro and in vivo, targeting more communities of intestinal microbiome and explaining more details about its beneficial effects need to be conducted.

Physiological and biochemical responses of Leersia hexandra Swartz to nickel stress: Insights into antioxidant defense mechanisms and metal detoxification strategies

Phytoremediation is widely considered as a cost-effective method for managing heavy metal soil pollution. Leersia hexandra Swartz shows a promising potential for the remediation of heavy metals pollution, including chromium (Cr), copper (Cu), and nickel (Ni). It is vital to understand the physiological and biochemical responses of L. hexandra to Ni stress to elucidate the mechanisms underlying Ni tolerance and accumulation. Here, we examined the metabolic and transcriptomic responses of L. hexandra exposed to 40 mg/L Ni for 24 h and 14 d. After 24-h Ni stress, gene expression of glutathione metabolic cycle (GSTF1, GSTU1 and MDAR4) and superoxide dismutase (SODCC2) was significantly increased in plant leaves. Furthermore, after 14-d Ni stress, the ascorbate peroxidase (APX7), superoxide dismutase (SODCP and SOD1), and catalase (CAT) gene expression was significantly upregulated, but that of glutathione metabolic cycle (EMB2360, GSTU1, GSTU6, GSH2, GPX6, and MDAR2) was downregulated. After 24-h Ni stress, the differentially expressed metabolites (DEMs) were mainly flavonoids (45%) and flavones (20%). However, after 14-d Ni stress, the DEMs were mainly carbohydrates and their derivatives (34%), amino acids and derivatives (15%), and organic acids and derivatives (8%). Results suggest that L. hexandra adopt distinct time-dependent antioxidant and metal detoxification strategies likely associated with intracellular reduction–oxidation balance. Novel insights into the molecular mechanisms responsible for Ni tolerance in plants are presented.

RNAi-Mediated Suppression of OsBBTI5 Promotes Salt Stress Tolerance in Rice.

This study explores the impact of RNAi in terms of selectively inhibiting the expression of the OsBBTI5 gene, with the primary objective of uncovering its involvement in the molecular mechanisms associated with salt tolerance in rice. OsBBTI5, belonging to the Bowman-Birk inhibitor (BBI) family gene, is known for its involvement in plant stress responses. The gene was successfully cloned from rice, exhibiting transcriptional self-activation in yeast. A yeast two-hybrid assay confirmed its specific binding to OsAPX2 (an ascorbate peroxidase gene). Transgenic OsBBTI5-RNAi plants displayed insensitivity to varying concentrations of 24-epibrassinolide in the brassinosteroid sensitivity assay. However, they showed reduced root and plant height at high concentrations (10 and 100 µM) of GA3 immersion. Enzyme activity assays revealed increased peroxidase (POD) and superoxide dismutase (SOD) activities and decreased malondialdehyde (MDA) content under 40-60 mM NaCl. Transcriptomic analysis indicated a significant upregulation of photosynthesis-related genes in transgenic plants under salt stress compared to the wild type. Notably, this study provides novel insights, suggesting that the BBI gene is part of the BR signaling pathway, and that OsBBTI5 potentially enhances stress tolerance in transgenic plants through interaction with the salt stress-related gene OsAPX2.

Comprehensive genomic exploration of class III peroxidase genes in guava unravels physiology, evolution, and postharvest storage responses

Peroxidases (PRXs) play multifaceted roles in plant growth, development, and stress responses. Here, we present a comprehensive analysis of the PRX gene family in guava, a globally significant fruit. In the guava genome, we identified 37 PRX genes, a number lower than that of Arabidopsis, suggesting a distinctive gene family expansion pattern. Phylogenetic analysis unveiled close relationships with Arabidopsis PRXs, with 12 PgPRX genes forming ortholog pairs, indicating a specific expansion pattern. Predictions placed most PRX proteins in the chloroplast and extracellular regions. Structural analysis of PgPRX proteins revealed commonalities in domain structures and motif organization. Synteny analysis underscored the dynamic role of segmental duplication in the evolution of guava's PRX genes. We explored the dynamic expression of PgPRX genes across guava tissues, exposing functional diversity. Furthermore, we examined changes in peroxidase levels and gene expressions during postharvest fruit storage, providing insights for preserving fruit quality. This study offers an initial genome-wide identification and characterization of Class III peroxidases in guava, laying the foundation for future functional analyses.

Heterologous expression of Arabidopsis laccase2, laccase4 and peroxidase52 driven under developing xylem specific promoter DX15 improves saccharification in populus

BackgroundSecondary cell wall holds considerable potential as it has gained immense momentum to replace the lignocellulosic feedstock into fuels. Lignin one of the components of secondary cell wall tightly holds the polysaccharides thereby enhancing the recalcitrance and complexity in the biomass. Laccases (LAC) and peroxidases (PRX) are the major phenyl-oxidases playing key functions during the polymerization of monolignols into lignin. Yet, the functions of laccase and peroxidases gene families remained largely unknown. Hence, the objective of this conducted study is to understand the role of specific LAC and PRX in Populus wood formation and to further investigate how the altered Lac and Prx expression affects biomass recalcitrance and plant growth. This study of heterologous expression of Arabidopsis Lac and Prx genes was conducted in poplar to avoid any otherwise occurring co-suppression mechanism during the homologous overexpression of highly expressed native genes. In the pursuit of optimizing lignocellulosic biomass for biofuel production, the present study focuses on harnessing the enzymatic potential of Arabidopsis thaliana Laccase2, Laccase4, and Peroxidase52 through heterologous expression.ResultsWe overexpressed selected Arabidopsis laccase2 (AtLac2), laccase4 (AtLac4), and peroxidase52 (AtPrx52) genes, based on their high transcript expression respective to the differentiating xylem tissues in the stem, in hybrid poplar (cv. 717) expressed under the developing xylem tissue-specific promoter, DX15 characterized the transgenic populus for the investigation of growth phenotypes and recalcitrance efficiency. Bioinformatics analyses conducted on AtLac2 and AtLac4 and AtPrx52, revealed the evolutionary relationship between the laccase gene and peroxidase gene homologs, respectively. Transgenic poplar plant lines overexpressing the AtLac2 gene (AtLac2-OE) showed an increase in plant height without a change in biomass yield as compared to the controls; whereas, AtLac4-OE and AtPrx52-OE transgenic lines did not show any such observable growth phenotypes compared to their respective controls. The changes in the levels of lignin content and S/G ratios in the transgenic poplar resulted in a significant increase in the saccharification efficiency as compared to the control plants.ConclusionsOverall, saccharification efficiency was increased by 35–50%, 21–42%, and 8–39% in AtLac2-OE, AtLac4-OE, and AtPrx52-OE transgenic poplar lines, respectively, as compared to their controls. Moreover, the bioengineered plants maintained normal growth and development, underscoring the feasibility of this approach for biomass improvement without compromising overall plant fitness. This study also sheds light on the potential of exploiting regulatory elements of DX15 to drive targeted expression of lignin-modifying enzymes, thereby providing a promising avenue for tailoring biomass for improved biofuel production. These findings contribute to the growing body of knowledge in synthetic biology and plant biotechnology, offering a sustainable solution to address the challenges associated with lignocellulosic biomass recalcitrance.

Effect of cryopreservation on motility, DNA integrity and gene expression in grey mullet, Mugil cephalus sperm

This study documents the effect of cryopreservation on motility, DNA integrity, and gene expression in Mugil cephalus sperm. Fresh sperm were cryopreserved using V2 extender (V2E) or 0.3 M glucose, each in combination with one of three cryoprotective agents (CPAs), i.e., 10 % of dimethylsulfoxide, ethylene glycol, or glycerol, all at once. After two different storage (7- vs 60- day) periods in liquid nitrogen, sperm samples were thawed. Single-cell gel electrophoresis was used to detect the DNA integrity. Heat shock proteins (HSPs), HSP70, HSP90 and glutathione peroxidase (GPx2) genes mRNA expression levels was documented using qRT-PCR. The results demonstrated that among 0.3 M glucose + CPAs combinations, EG recorded higher frozen-thawed motility 69 % (7- day) and 59 % (60- day). Similarly, in V2E + CPAs combinations, EG recorded higher frozen-thawed motility 31 % (7- day) and 26 % (60- day). The DNA integrity of all thawed sperm (both periods) did not differ from that of fresh sperm. The qRT-PCR results revealed that in the combination of 0.3 M glucose + CPAs, the level of HSP90 and GPx2 gene expression was found to be upregulated in frozen-thawed sperm on both periods. Whereas, the expression level of the HSP70 gene was down-regulated. On the contrary, in the combination of V2E + CPAs, the expression levels of HSP70, HSP90 and GPx2 genes could not be detected on both periods. Overall, the findings of this study demonstrate that the cryomedium (extender + cryoprotectant) has a more influential role in the motility and levels of gene expression in the frozen-thawed sperm of M. cephalus.