Search Results (43)

As a plant-specific peroxidase family, class III peroxidase (PRX) plays an important role in plant growth, development, and stress response. In this study, a preliminary functional analysis of CqPRX9L1 was conducted. Bioinformatics analysis revealed that CqPRX9L1 encodes a 349-amino acid protein belonging to the plant-peroxidase-like superfamily, featuring a transmembrane domain and cytoplasmic localization. The promoter region of CqPRX9L1 harbors various cis-acting elements associated with stress responses, hormone signaling, light regulation, and meristem-specific expression. The tissue-specific expression pattern of the CqPRX9L1 gene and its characteristics in response to different stresses were explored using subcellular localization, quantitative real-time PCR (qRT-PCR), and heterologous transformation into Arabidopsis thaliana. The results showed that CqPRX9L1, with a transmembrane structure, was localized in the cytoplasm, which encodes 349 amino acids and belongs to the plant-peroxisome-like superfamily. The promoter region contains stress-response elements, hormone-response elements, light-response elements, and meristem expression-related elements. The expression of CqPRX9L1 was relatively higher in ears and roots at the panicle stage than in stems and leaves. CqPRX9L1 showed a dynamic expression pattern of first decreasing and then increasing under abiotic stresses such as 15% PEG 6000, low temperature, and salt damage, with differences in response time and degree. CqPRX9L1 plays an important role in response to abiotic stress by affecting the activity of antioxidant enzymes such as superoxide dismutase (SOD) and peroxidase (POD), as well as the synthesis and decomposition of proline (Pro). CqPRX9L1 also affects plant bolting and flowering by regulating key flowering genes (such as FT and AP1) and gibberellin (GA)-related pathways. The results establish a foundation for revealing the functions and molecular mechanisms of the CqPRX9L1 gene. Full article

Class III peroxidases (PODs) are plant-specific enzymes that play crucial roles in plant growth, development and responses to stress. However, the POD gene family in the radish (Raphanus sativus L.) has not been comprehensively investigated to date. In this study, a total of 95 RsPODs were identified in the radish genome, which were classified into six subgroups based on a phylogenetic analysis. The gene structures and conserved motifs of the RsPODs were highly conserved within each subgroup. An intraspecific collinearity analysis revealed 7 tandem and 40 segmental duplication events. An expression analysis across diverse tissues and developmental stages demonstrated that the RsPODs were functionally involved in radish development. Using a chimeric-colored radish mutant, this study revealed significantly higher POD activity in the green tissues compared to purple tissues. Through transcriptome sequencing, two RsPOD genes (RsPOD14 and RsPOD28) were identified as candidate genes related to the anthocyanin metabolism. Our study provides a genome-wide perspective on the RsPOD genes in the radish and highlights their potential roles in the anthocyanin metabolism. These findings establish a critical foundation for future research aimed at uncovering the functional roles of specific RsPOD genes, with a particular emphasis on elucidating the molecular mechanisms that regulate anthocyanin degradation in the radish. Full article

Class III peroxidases are plant-specific enzymes that play indispensable roles in catalyzing oxidative–reductive reactions, which are integral to numerous biochemical processes in plants. In this study, we identified 69 members of the class III peroxidase (POD) gene family in the Populus simonii genome and classified them into four subfamilies based on phylogenetic analysis. Chromosomal localization revealed that these PsPOD genes are unevenly distributed across 19 chromosomes, with chromosomes 3 and 7 harboring the highest densities. Conserved domain and motif analyses demonstrated that all PsPOD proteins contain the characteristic peroxidase domain and share highly conserved motif structures. Cis-acting element analysis of promoter regions revealed the presence of numerous regulatory elements associated with light responsiveness, phytohormone signaling, stress responses, and plant growth and development. Transcriptome data showed that the expression of PsPOD genes varies significantly across different tissues and organs and under various stress conditions, suggesting their involvement in both developmental processes and abiotic stress responses. These findings were further validated by qRT-PCR analysis of selected PsPOD genes. Notably, PsPOD45, PsPOD69, PsPOD33, and PsPOD64 were identified as central hub genes in the protein–protein interaction network, making them promising candidates for further functional characterization. Overall, this study provides a comprehensive overview of the PsPOD gene family in P. simonii, laying a solid foundation for future functional studies and offering valuable insights for comparative research in other plant species. Full article

The class III peroxidase (POD) gene family encodes redox enzymes involved in the catalytic processes of hydrogen peroxide, phenolic compounds, and reactive oxygen species. These enzymes play crucial roles in lignin biosynthesis and stress responses. To explore the functions of the oat (Avena sativa) POD (AsPOD) gene family in resistance to powdery mildew, we performed a genome-wide analysis and bioinformatics characterization. A total of 97 AsPOD genes were identified, unevenly distributed across 21 chromosomes. Structural predictions indicated that α-helices are the predominant structural components of AsPOD proteins, and phylogenetic analysis revealed six clades of AsPOD proteins, with high homology to POD proteins in the Poaceae family. Cis-regulatory element analysis revealed that three AsPOD genes are associated with hormone signaling, light response, and stress resistance. Analysis of duplication events in the oat POD gene family indicates that there are a total of 55 pairs of gene segment duplications among the 69 AsPOD genes. Expression profiling of powdery mildew-infected oat varieties showed significant up- or downregulation of several AsPOD genes (AsPOD51, AsPOD55, AsPOD63, AsPOD89), identifying them as key candidates for disease resistance studies. Furthermore, resistant oat varieties exhibited higher lignin content than susceptible ones. Correlation analysis indicated that AsPOD51, AsPOD55, AsPOD63, AsPOD88, and AsPOD89 showed a stronger positive association with lignin content in resistant varieties. After inoculation with the powdery mildew pathogen, the H₂O₂ content rapidly increases, and POD activity first rises and then decreases. Those findings provide a foundation for further research into the role of AsPOD genes in oat disease resistance. Full article

Grafting is a horticultural technique that involves a healing process that requires grafted plants to develop physiological responses to overcome oxidative stress. In this study, oxidative damage, total antioxidant capacity and antioxidant enzymatic activities were analysed in functional and non-functional tomato autografts for eight days after grafting, considering scion and rootstock tissues separately. The results showed that oxidative damage, measured as lipid peroxidation, was controlled, especially in functional grafts. Scion tissues showed significant increases in total antioxidant capacity and activities of key antioxidant enzymes, including superoxide dismutase and catalase. Non-functional grafts showed elevated levels of class III peroxidase, potentially related to defensive suberisation and lignification. Principal component analysis revealed that antioxidant activities correlated dynamically with grafting stages, highlighting their critical role in stress mitigation. These results suggest that an efficient and asymmetric antioxidant response is essential for successful graft healing in tomato plants. Furthermore, different patterns in non-functional grafts underline the importance of redox balance in determining graft success. Full article

Osmotic stress impacts the cell wall properties in plants. This study aimed to elucidate the mechanisms involved in cell wall remodeling in etiolated (dark-grown) rice (Oryza sativa L.) shoots grown under polyethylene glycol (PEG)-induced osmotic stress conditions. Shoot growth was inhibited by 70% by the treatment with 60 mM PEG for 2 days. However, when the stressed seedlings were transferred to a solution without PEG, their shoot growth rate increased significantly. A measurement of the cell wall mechanical properties revealed that the cell walls of the stressed shoots became looser and more extensible than those of unstressed shoots. Among the cell wall constituents, the amounts of cell wall-bound phenolic acids, such as ferulic acid (FA), p-coumaric acid (p-CA), and diferulic acid (DFA), per shoot and per unit of matrix polysaccharide content were significantly reduced in the stressed shoots compared to those in the unstressed shoots. Concerning the formation of cell wall-bound phenolic acids, the activity of cell wall-bound peroxidase (CW-PRX) per unit of cell wall content, which is responsible for the coupling reaction of FA to produce DFA, was 3.5 times higher in stressed shoots than in unstressed shoots, while the activity was reduced by 20% on a shoot basis in stressed shoots compared to that in unstressed shoots. The expression levels of the major class III peroxidase genes in stressed shoots were either comparable to or slightly lower than those in unstressed shoots. Conversely, the phenylalanine ammonia-lyase (PAL) activity, which contributes to the biosynthesis of FA and p-CA, was reduced by 55% and 30% on a shoot and unit-of-protein-content basis, respectively, in stressed shoots compared to that in unstressed shoots. The expression levels of abundantly expressed PAL genes decreased by 14–46% under osmotic stress. Moreover, the gene expression levels of specific BAHD acyltransferases, which are responsible for the addition of FA and p-CA to form ester-linked moieties on cell wall constituents, decreased by 15–33% under osmotic stress. These results suggest that the downregulation of the expression of specific PAL and BAHD acyltransferase genes in osmotically stressed rice shoots is responsible for a reduction in the formation of cell wall-bound phenolic acid monomers. This, in turn, may result in a decrease in the levels of DFAs. The reduction in the formation of DFA-mediated cross-linking structures within the cell wall may contribute to an increase in the mechanical extensibility of the cell wall. The remodeling of cell walls in an extensible and loosened state could assist in maintaining the growth capacity of etiolated rice shoots grown under osmotic stress and contribute to rapid growth recovery following the alleviation of osmotic stress. Full article

As a plant-specific gene family, class III peroxidases (PODs) play an important role in plant growth, development, and stress responses. However, the POD gene family has not been systematically studied in Paeonia ostii. In this study, a total of 57 PoPOD genes were identified in the P. ostii genome. Subsequently, phylogenetic analysis and chromosome mapping revealed that PoPODs were classified into six subgroups and were unevenly distributed across five chromosomes. The gene structure and conserved motifs indicated the potential for functional divergence among the different subgroups. Meanwhile, four PoPODs were identified as tandem duplicated genes, with no evidence of segmental duplication. Using RNA-seq data from eight different tissues, multiple PoPODs exhibited enhanced expression in apical and adventitious roots (ARs). Next, RNA-seq data from AR development combined with trend analysis showed that PoPOD30/34/43/46/47/57 are implicated in the formation of ARs in tree peony. Through WGCNA based on RNA-seq, two key genes, PoPOD5/15, might be involved in heat tolerance via ABA and MeJA signaling. In addition, real-time quantitative PCR (qRT-PCR) analysis indicated that PoPOD23 may play an important role in flower senescence. These findings deepened our understanding of POD-mediated AR development, heat tolerance, and petal senescence in tree peony. Full article

Maize is among the world’s three most important cereals because it is used for human consumption and agricultural feed. The embryo in monocotyledons contains a cotyledon that is the scutellum, which in Chalqueño maize constitutes approximately 80% of the embryo’s mass. The activation of metabolism during germination is accompanied by the production of reactive oxygen species, which must be maintained at a low level to avoid damage. Little is known about the oxidative state of the scutellum, but it is important to understand the control of oxidative stress during the final phase of germination and the embryo–seedling transition. Among the enzymes involved are class III peroxidase (POX), catalase (CAT), and superoxide dismutase (SOD), which were observed in the scutella of isolated imbibed embryos between 0 and 36 h. The activity of SOD fluctuated over a baseline value. The activity of class III POX was greater than that of CAT, showing differences between them in germination and postgermination. The activities of CAT and POX increased during germination (0 to 18 h), stabilized towards the final phase of germination (18 to 24 h), and then increased again in postgermination (24 to 36 h). The POX activity is a biochemical marker of the scutellum metabolism and marks the transition from germination to the embryo–seedling transition. Full article

Lettuce cultivation requires high fertilizer inputs, which impact the environment and costs. Arbuscular mycorrhizal symbiosis (AMS) can reduce fertilizer use, enhance plant nutrition (especially phosphorus), and promote healthier plants. Class III peroxidases (PRXs) play crucial roles in various physiological processes and stress responses. However, their role in AMS and phosphorous (P) deficiency is still unclear. Our study identified 91 PRX genes in the lettuce genome (LsPRXs) and clustered them into eight subfamilies based on phylogenetic relationships. Evolutionary analysis indicated that tandem duplication was the main driver for LsPRX gene family expansion. Synteny analysis showed orthologous relationships of the PRX gene family between lettuce and potato, Arabidopsis, and maize, identifying 39, 28, and 3 shared PRXs, respectively. Transcriptomic data revealed that most LsPRX genes were more expressed in roots than in leaves and differentially expressed LsPRXs were found in response to AMS and P supply. Notably, 15% of LsPRX genes were differentially expressed in roots during mycorrhization. Gene expression network analysis highly correlated five LsPRXs (LsPRX17, LsPRX23, LsPRX24, LsPRX64, and LsPRX79) with genes involved in cell wall remodeling and reorganization during mycorrhization. Our results provide insights into the evolutionary history and functional roles of PRX genes in lettuce and identify candidate gene targets that may enhance the bio-stimulant effects of AMS and help to cope with P deficiency. Full article

Plant class III peroxidases (PRXs) catalyze generation of reactive oxygen species and oxidation of various compounds including lignin precursors. PRXs function in cell wall metabolism, defense, and stress responses. However, gene redundancy and catalytic versatility have impeded detailed functional characterization of PRX genes. The genome of the model moss Physcomitrium patens harbors a relatively small number (49) of PRX genes. Conserved architecture of four exons and three ‘001’ introns, found in some algal PRX genes and in the PpPRX family, suggests that this architecture predated divergence of the green algal and land plant lineages. The PpPRX family expanded mainly through whole-genome duplications. All duplicated pairs but one were under purifying selection and generally exhibited similar expression profiles. An expanded phylogenetic tree revealed a conserved land plant-wide clade that contained PRXs implicated in stress responses in non-lignifying cells, providing a clue to ancient functions of land plant PRXs. Functional clustering was not observed, suggesting convergent evolution of specific PRX functions (e.g., lignification) in different plant lineages. With its small complement of PRXs, P. patens may be useful for functional characterization of land plant PRXs. Several PpPRXs were proposed for further study, including PpPRX34 and PpPRX39 in the ancient land plant-wide clade. Full article

Ginger, valued for its medicinal properties and economic significance, is vulnerable to environmental stressors such as intense light and high temperatures, which can hinder its growth and development. Class III peroxidases (PRXs) are plant-specific oxidoreductases essential for plant development, growth, and stress responses. Despite their importance, there is limited information available on the function of the class III peroxidase gene family in ginger (ZoPRX). In this study, 103 ZoPRX members within the ginger genome were identified, unevenly distributed across 11 chromosomes. The identified ZoPRX members were categorized into five subfamilies based on gene structures, protein motifs, and phylogenetic analysis. Gene duplication analysis revealed that ZoPRX has primarily undergone segmental duplication. Interspecies homology analysis between ginger and Arabidopsis thaliana, Oryza sativa, and Musa acuminata suggested most ZoPRXs in ginger originated after the divergence of dicotyledon and monocotyledon. Analysis of promoter cis-acting elements identified defense and stress response elements in 39 genes and hormone response elements in 95 genes, indicating their potential roles in responding to environmental stresses. Quantitative Real-Time PCR (qRT-PCR) analysis confirmed that the majority of ZoPRX members are responsive to high temperature and intense light stress. This study provides a comprehensive understanding of the PRX family in ginger, thereby laying the groundwork for future investigations into the functional role of ZoPRX genes under high-temperature and intense light-stress conditions. Full article

Class III peroxidases (CIII PRXs) are plant-specific enzymes with high activity that play key roles in the catalysis of oxidation-reduction reactions. In plants, CIII PRXs can reduce hydrogen peroxide to catalyze oxidation–reduction reactions, thereby affecting plant growth, development, and stress responses. To date, no systematic analysis of the CIII PRX gene family in litchi (Litchi chinensis Sonn.) has been documented, although the genome has been reported. In this study, a total of 77 CIII PRX (designated LcPRX) gene family members were predicted in the litchi genome to provide a reference for candidate genes in the responses to abiotic stresses during litchi growth and development. All of these LcPRX genes had different numbers of highly conserved PRX domains and were unevenly distributed across fifteen chromosomes. They were further clustered into eight clades using a phylogenetic tree, and almost every clade had its own unique gene structure and motif distribution. Collinearity analysis confirmed that there were eleven pairs of duplicate genes among the LcPRX members, and segmental duplication (SD) was the main driving force behind the LcPRX gene expansion. Tissue-specific expression profiles indicated that the expression levels of all the LcPRX family members in different tissues of the litchi tree were significantly divergent. After different abiotic stress treatments, quantitative real-time PCR (qRT-PCR) analysis revealed that the LcPRX genes responded to various stresses and displayed differential expression patterns. Physicochemical properties, transmembrane domains, subcellular localization, secondary structures, and cis-acting elements were also analyzed. These findings provide insights into the characteristics of the LcPRX gene family and give valuable information for further elucidating its molecular function and then enhancing abiotic stress tolerance in litchi through molecular breeding. Full article

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. Full article

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. Full article