Superoxide Dismutase Gene Family Research Articles

Genome-Wide Identification and Characterization of the Superoxide Dismutase (SOD) Gene Family in Pakchoi and the Role of the BchFSD2 Gene in the Salt Stress Toleran

Superoxide dismutase (SOD) is an important antioxidant metalloenzyme present in plants that plays a vital role in plant growth and development, but studies on the SOD gene family in Pakchoi are lacking. In this study, we identified 13 SOD genes from pakchoi, including three MnSODs, five Cu/ZnSODs, and five FeSODs. Through structural analysis, the gene structures and motif patterns in the three subfamilies showed a high degree of conservation. From an evolutionary point of view, gene duplication is an important pathway driving the evolutionary development of the SOD gene family. In addition, by analyzing the structure and function of BchSOD proteins, most of the genes were shown to be involved in different developmental stages of pakchoi, and their expression was shown to be regulated by external conditions such as light, phytohormones, and abiotic stress. qPCR results revealed that BchSODs were expressed in different parts of pakchoi, and most of the genes were expressed in response to abiotic stresses (salt and drought) and hormones (GA and MeJA). In addition, the BchFSD2 gene was studied in depth, and subcellular localization confirmed that the BchFSD2 gene was expressed in plant chloroplasts. Overexpression of BchFSD2 promoted salt tolerance, limited superoxide anion and MDA production, and increased antioxidant enzyme activities in Arabidopsis. In summary, the BchSOD gene family was comprehensively analyzed in this study to provide new insights for a better understanding of BchSOD function and to improve salt tolerance in pakchoi.

Superoxide dismutase gene family in cassava revealed their involvement in environmental stress via genome-wide analysis

Superoxide dismutase (SOD) is a crucial metal-containing enzyme that plays a vital role in catalyzing the dismutation of superoxide anions, converting them into molecular oxygen and hydrogen peroxide, essential for enhancing plant stress tolerance. We identified 8 SOD genes (4 CSODs, 2 FSODs, and 2 MSODs) in cassava. Bioinformatics analyses provided insights into chromosomal location, phylogenetic relationships, gene structure, conserved motifs, and gene ontology annotations. MeSOD genes were classified into two groups through phylogenetic analysis, revealing evolutionary connections. Promoters of these genes harbored stress-related cis-elements. Duplication analysis indicated the functional significance of MeCSOD2/MeCSOD4 and MeMSOD1/MeMSOD2. Through qRT-PCR, MeCSOD2 responded to salt stress, MeMSOD2 to drought, and cassava bacterial blight. Silencing MeMSOD2 increased XpmCHN11 virulence, indicating MeMSOD2 is essential for cassava's defense against XpmCHN11 infection. These findings enhance our understanding of the SOD gene family's role in cassava and contribute to strategies for stress tolerance improvement.

Genome wide analysis for the identification and characterization of Superoxide-dismutase gene family in Rosa chinensis ascertains the role of salinity-responsive RcMSD1 protein and its interaction with peroxyl radical

Abiotic stresses e.g., cold, heat, and salinity affect the quality and yield of Rosa chinensis, a well-known ornamental and medicinal plant. Previously, several attempts have been made to identify the genes that confer resistance to oxidative stressors. Superoxide-dismutase (SOD) is a crucial member of the class metalloenzyme that responds to abiotic stresses and protects plants by countering the reactive-oxygen species (ROS). In this genome-wide association study, the SOD gene family has been investigated in R. chinensis. Seven SOD genes, including three Cu/ZnSODs, two MnSODs, and two FeSODs were identified. Phylogenetic analysis revealed that RcSODs are divided into three clades; (i) CSDs (Cu/ZnSODs) (ii) FSDs (FeSODs) and MSDs (MnSODs). Most of the RcSODs exhibited different exons/introns distribution patterns. Motifs 3 and 5 are conserved in all RcSODs genes. The RNA-seq data analysis and qRT-PCR-based expression profiling indicated that RcSODs exhibit diverse responses under salt stress conditions. The RcCSD1, RcCSD3, and RcFSD3 are significantly up-regulated under salt stress conditions in roots and down-regulated in leaves. This data provides valuable information for further application and function of SODs in R. chinensis under abiotic stresses.

The genome-wide characterization and associated cold-tolerance function of the superoxide dismutase in the cold response of the tick Haemaphysalis longicornis

Accumulating evidence suggests that superoxide dismutase (SOD) is the first line of antioxidant defense in organisms and plays an important role in scavenging reactive oxygen species produced during environmental stress. However, limited information is available regarding the response of SOD genes to cold stress in ticks. Therefore, in the present study, SOD genes were cloned and identified from the genome of Haemaphysalis longicornis, and the function of SOD during the cold response was further explored. Seven SOD genes were characterized: HlCCS1, HlCCS2, HlMSD, HlCSD1, HlCSD2, HlCSD3, and HlCSD4. Bioinformatics analysis showed that HlCCS1 and HlCCS2 are copper chaperones of SODs. HlCSD1–HlCSD4 belong to the Cu/Zn SOD, whereas HlMSD belongs to the Mn SOD gene family. Fluorescence quantitative PCR showed that the expression of HlCCS2, HlMSD, and HlCSD1–3 was upregulated, whereas HlCCS1 and HlCSD4 were downregulated during the cold response of H. longicornis. Western blotting confirmed changes in the relative expression of HlCSD3 and HlMSD in H. longicornis after cold treatment. Mortality of H. longicornis increased significantly after dsRNA injection of HlCCS2, HlMSD, HlCSD1, and HlCSD3. The above results show that SODs have different regulatory functions during the cold response in H. longicornis, and there might be an interaction between treatment temperature and duration. Furthermore, the results lay a foundation for subsequent research on the molecular mechanism of cold tolerance in H. longicornis and shed light on the population distribution and diffusion limit of ticks.

Regulation of three subtypes of SOD gene in Aleuroglyphus ovatus (Acari:Acaridae) under lead stress.

Superoxide dismutase (SOD) is an important enzyme that acts as the first line of protection in the mite antioxidant defense system, involved in eliminating reactive oxygen species (ROS) under harsh environmental conditions. Nevertheless, the SOD gene family was yet to be reported in stored grain pest mite (Aleuroglyphus ovatus). In this study, A. ovatus was used to evaluate the response of SOD gene during lead stress. A. ovatus were separately exposed to different concentration lead (12.5, 25, 50, and 100 mg/kg), which induce the dynamic trend of SOD enzyme activity initially increased and then reduced with an increase in lead concentration, whereas they were still substantially higher than the control group. Moreover, after lead stress, it was found that all of the three SOD genes showed enhanced relative messenger RNA expression at high concentrations and decreased relative expression at low concentrations, which indicated that lead stress induces the expression of AoSODs. The present work implies that AoSODs play an important role in resisting oxidative damage caused by lead stress.

Comparative Analyses of Superoxide Dismutase (SOD) Gene Family and Expression Profiling under Multiple Abiotic Stresses in Water Lilies

Plants in their natural habitat frequently face different biotic and abiotic stresses, which lead to the production of reactive oxygen species (ROS) that can damage cell membranes, cause peroxidation and deterioration of macromolecules, and ultimately result in cell death. Superoxide dismutase (SOD), a class of metalloenzymes, is primarily found in living organisms and serves as the principal line of defense against ROS. The SOD gene family has not yet been characterized in any species of water lily from the genus Nymphaea. The present study aims to conduct a genome-wide study to discover SOD genes in four representative water lily species. In our present comparative study, we discovered 43 SOD genes in the genomes of four water lily species. The phylogenetic investigation results revealed that SOD genes from water lily and closely related plant species formed two distinct groups, as determined by their binding domains with high bootstrap values. Enzymatic ion-binding classified the SOD gene family into three groups, FeSOD, Cu/ZnSOD, and MnSOD. The analysis of gene structure indicated that the SOD gene family exhibited a relatively conserved organization of exons and introns, as well as motif configuration. Moreover, we discovered that the promoters of water lily SODs contained five phytohormones, four stress-responsive elements, and numerous light-responsive cis-elements. The predicted 3D protein structures revealed water lily SODs form conserved protein dimer signatures that were comparable to each other. Finally, the RT-qPCR gene expression analysis of nine NcSOD genes revealed their responsiveness to heat, saline, cold, cadmium chloride, and copper sulphate stress. These findings establish a basis for further investigation into the role of the SOD gene family in Nymphaea colorata and offer potential avenues for genetic enhancement of water lily aquaculture.

Genetic Diversity in Natural Populations of Rhodiola Species of Different Adaptation Strategies.

Representatives of the Crassulaceae family's genus Rhodiola are succulents, making them distinctive in a changing environment. One of the most significant tools for analyzing plant resources, including numerous genetic processes in wild populations, is the analysis of molecular genetic polymorphism. This work aimed to look at the polymorphisms of allelic variations of the superoxide dismutase (SOD) and auxin response factor (ARF) gene families, as well as the genetic diversity of five Rhodiola species, using the retrotransposons-based fingerprinting approach. The multi-locus exon-primed intron-crossing (EPIC-PCR) profiling approach was used to examine allelic variations in the SOD and ARF gene families. We implemented the inter-primer binding site (iPBS) PCR amplification technique for genome profiling, which demonstrated a significant level of polymorphism in the Rhodiola samples studied. Natural populations of Rhodiola species have a great capacity for adaptation to unfavorable environmental influences. The genetic variety of wild populations of Rhodiola species leads to their improved tolerance of opposing environmental circumstances and species evolutionary divergence based on the diversity of reproductive systems.

Regulation of three subtypes of SOD gene in Aleuroglyphus ovatus (Acari: Acaridae) under lead stress

Superoxide dismutase (SOD) is an important enzyme that acts as the first line of protection in the mite antioxidant defense system and involves in eliminating reactive oxygen species (ROS) under harsh environmental conditions. Lead pollution is becoming increasingly serious and poses a serious hazard to the health and survival and reproduction of organisms. Nevertheless, the SOD gene family was yet to be reported in stored grain pest mite (Aleuroglyphus ovatus). In the present study, A. ovatus was reared on artificial diets treated with different concentrations of lead (12.5, 25, 50 and 100 mg/kg); the treatment fed on artificial diet without lead was marked as the control group (CK). Then three different subtypes of SOD were cloned, including AoSOD1 (Cu-ZnSOD), AoSOD2 and AoSOD3 (MnSOD). Enzyme activity of the egg stage was the lowest, and that of the protonymph stage was the highest. The enzyme activity of A. ovatus increased initially before dropping with increasing lead concentration, nevertheless, it was still substantially higher than that in CK. The analysis of SOD enzyme activity specified that it was higher at 25 mg/kg lead in each mite stage compared to other concentration groups. All three genes were up-regulated and thereafter reduced in the embryonic stage, according to an examination of mRNA expression levels; tritonymphs, in particular, attained the highest level. The expression level of the SOD genes also changed with lead concentration. It increased after an initial decline trend with increasing lead concentration, and then peaked in the 100 mg/kg lead group, which were 3.1 times (AoSOD1), 4.1 times (AoSOD2), and 2.3 times (AoSOD3) the control group, respectively. In this study, three AoSOD genes had developmental stage-specific mRNA expressions, and the expression of SOD enzyme activity was encouraged by the higher lead concentration, and the mRNA expression level of the AoSODs genes was not synchronized with the enzyme activity.

Genome-wide identification of the rubber tree superoxide dismutase (SOD) gene family and analysis of its expression under abiotic stress.

BackgroundThe rubber tree (Hevea brasiliensis) is the only species capable of producing high-quality natural rubber for commercial use, and is often subjected to various abiotic stresses in non-traditional rubber plantation areas. Superoxide dismutase (SOD) is a vital metalloenzyme translated by a SOD gene family member and acts as a first-line of protection in plant cells by catalysing the disproportionation of reactive oxygen species (ROS) to produce H2O2 and O2. However, the SOD gene family is not reported in rubber trees.MethodsHere, we used hidden markov model (HMM) and BLASTP methods to identify SOD genes in the H. brasiliensis genome. Phylogenetic tree, conserved motifs, gene structures, cis elements, and gene ontology annotation (GO) analyses were performed using MEGA 6.0, MEME, TBtools, PlantCARE, and eggNOG database, respectively. HbSOD gene expression profiles were analysed using quantitative reverse transcription polymerase chain reaction (qRT-PCR).ResultsWe identified nine HbSOD genes in the rubber tree genome, including five HbCSDs, two HbFSDs, and two HbMSDs. Phylogenetic relationship analysis classified the SOD proteins from the rubber tree and other related species into three subfamilies. The results of gene structure and conserved motif analysis illustrated that most HbSOD genes have similar exon-intron numbers and conserved motifs in the same evolutionary branch. Five hormone-related, four stress-related, and light-responsive elements were detected in the HbSODs’ promoters. HbSODs were expressed in different tissues, gradually increased with leaf development, and were abundantly expressed in mature leaves. HbCSD2 and HbCSD4 was significantly upregulated under low and high temperatures, and salt stress, except for HbCSD2, by heat. Furthermore, most HbSOD genes were significantly upregulated by drought, except HbMSD2. These findings imply that these genes may play vital roles in rubber tree stress resistance. Our results provide a basis for further studies on the functions of HbSOD genes in rubber trees and stress response mechanisms.

Genome-Wide Characterization of Superoxide Dismutase (SOD) Genes in Daucus carota: Novel Insights Into Structure, Expression, and Binding Interaction With Hydrogen Peroxide (H2O2) Under Abiotic Stress Condition.

Superoxide dismutase (SOD) proteins are important antioxidant enzymes that help plants to grow, develop, and respond to a variety of abiotic stressors. SOD gene family has been identified in a number of plant species but not yet in Daucus carota. A total of 9 DcSOD genes, comprising 2 FeSODs, 2 MnSODs, and 5 Cu/ZnSODs, are identified in the complete genome of D. carota, which are dispersed in five out of nine chromosomes. Based on phylogenetic analysis, SOD proteins from D. carota were categorized into two main classes (Cu/ZnSODs and MnFeSODs). It was predicted that members of the same subgroups have the same subcellular location. The phylogenetic analysis was further validated by sequence motifs, exon–intron structure, and 3D protein structures, with each subgroup having a similar gene and protein structure. Cis-regulatory elements responsive to abiotic stresses were identified in the promoter region, which may contribute to their differential expression. Based on RNA-seq data, tissue-specific expression revealed that DcCSD2 had higher expression in both xylem and phloem. Moreover, DcCSD2 was differentially expressed in dark stress. All SOD genes were subjected to qPCR analysis after cold, heat, salt, or drought stress imposition. SODs are antioxidants and play a critical role in removing reactive oxygen species (ROS), including hydrogen peroxide (H2O2). DcSODs were docked with H2O2 to evaluate their binding. The findings of this study will serve as a basis for further functional insights into the DcSOD gene family.

The Superoxide Dismutase Gene Family in Nicotiana tabacum: Genome-Wide Identification, Characterization, Expression Profiling and Functional Analysis in Response to Heavy Metal Stress.

Superoxide dismutases (SODs) play an important role in protecting plants against ROS toxicity induced by biotic and abiotic stress. Recent studies have shown that the SOD gene family is involved in plant growth and development; however, knowledge of the SOD gene family in tobacco is still limited. In the present study, the SOD gene family was systematically characterized in the tobacco genome. Based on the conserved motif and phylogenetic tree, 15 NtSOD genes were identified and classified into three subgroups, including 5 NtCSDs, 7 NtFSDs and 3 NtMSDs. The predicted results of the transport peptide or signal peptide were consistent with their subcellular localization. Most NtSOD genes showed relatively well-maintained exon-intron and motif structures in the same subgroup. An analysis of cis-acting elements in SOD gene promoters showed that NtSOD expression was regulated by plant hormones, defense and stress responses, and light. In addition, multiple transcription factors and miRNAs are predicted to be involved in the regulation of NtSOD gene expression. The qPCR results indicated specific spatial and temporal expression patterns of the NtSOD gene family in different tissues and developmental stages, and this gene family played an important role in protecting against heavy metal stress. The results of functional complementation tests in the yeast mutant suggested that NtCSD1a, NtFSD1e and NtMSD1b scavenge ROS produced by heavy metal stress. This study represents the first genome-wide analysis of the NtSOD gene family, which lays a foundation for a better understanding of the function of the NtSOD gene family and improving the tolerance of plants to heavy metal toxicity.

In Silico Study of Superoxide Dismutase Gene Family in Potato and Effects of Elevated Temperature and Salicylic Acid on Gene Expression.

Potato (Solanum tuberosum L.) is the most important vegetable crop globally and is very susceptible to high ambient temperatures. Since heat stress causes the accumulation of reactive oxygen species (ROS), investigations regarding major enzymatic components of the antioxidative system are of the essence. Superoxide dismutases (SODs) represent the first line of defense against ROS but detailed in silico analysis and characterization of the potato SOD gene family have not been performed thus far. We have analyzed eight functional SOD genes, three StCuZnSODs, one StMnSOD, and four StFeSODs, annotated in the updated version of potato genome (Spud DB DM v6.1). The StSOD genes and their respective proteins were analyzed in silico to determine the exon-intron organization, splice variants, cis-regulatory promoter elements, conserved domains, signals for subcellular targeting, 3D-structures, and phylogenetic relations. Quantitative PCR analysis revealed higher induction of StCuZnSODs (the major potato SODs) and StFeSOD3 in thermotolerant cultivar Désirée than in thermosensitive Agria and Kennebec during long-term exposure to elevated temperature. StMnSOD was constitutively expressed, while expression of StFeSODs was cultivar-dependent. The effects of salicylic acid (10−5 M) on StSODs expression were minor. Our results provide the basis for further research on StSODs and their regulation in potato, particularly in response to elevated temperatures.

Characterization of SOD and GPX Gene Families in the Soybeans in Response to Drought and Salinity Stresses.

Plant stresses causing accumulation of reactive oxidative species (ROS) are scavenged by effective antioxidant defense systems. Therefore, the present study performed genome-wide identification of superoxide dismutase (SOD) and glutathione peroxidase (GPX) gene families in cultivated and wild soybeans, and 11 other legume species. We identified a total of 101 and 95 genes of SOD and GPX, respectively, across thirteen legume species. The highest numbers of SODs and GPXs were identified in cultivated (Glycine max) and wild (Glycine soja). A comparative phylogenetic study revealed highest homology among the SODs and GPXs of cultivated and wild soybeans relative to other legumes. The exon/intron structure, motif and synteny blocks were conserved in both soybean species. According to Ka/Ks, purifying the selection played the major evolutionary role in these gene families, and segmental duplication are major driving force for SODs and GPXs expansion. In addition, the qRT-PCR analysis of the G. max and G. soja SOD and GPX genes revealed significant differential expression of these genes in response to oxidative, drought and salinity stresses in root tissue. In conclusion, our study provides new insights for the evolution of SOD and GPX gene families in legumes, and provides resources for further functional characterization of these genes for multiple stresses.

Genome-Wide Evolution and Comparative Analysis of Superoxide Dismutase Gene Family in Cucurbitaceae and Expression Analysis of Lagenaria siceraria Under Multiple Abiotic Stresses.

Superoxide dismutase (SOD) is an important enzyme that serves as the first line of defense in the plant antioxidant system and removes reactive oxygen species (ROS) under adverse conditions. The SOD protein family is widely distributed in the plant kingdom and plays a significant role in plant growth and development. However, the comprehensive analysis of the SOD gene family has not been conducted in Cucurbitaceae. Subsequently, 43 SOD genes were identified from Cucurbitaceae species [Citrullus lanatus (watermelon), Cucurbita pepo (zucchini), Cucumis sativus (cucumber), Lagenaria siceraria (bottle gourd), Cucumis melo (melon)]. According to evolutionary analysis, SOD genes were divided into eight subfamilies (I, II, III, IV, V, VI, VII, VIII). The gene structure analysis exhibited that the SOD gene family had comparatively preserved exon/intron assembly and motif as well. Phylogenetic and structural analysis revealed the functional divergence of Cucurbitaceae SOD gene family. Furthermore, microRNAs 6 miRNAs were predicted targeting 3 LsiSOD genes. Gene ontology annotation outcomes confirm the role of LsiSODs under different stress stimuli, cellular oxidant detoxification processes, metal ion binding activities, SOD activity, and different cellular components. Promoter regions of the SOD family revealed that most cis-elements were involved in plant development, stress response, and plant hormones. Evaluation of the gene expression showed that most SOD genes were expressed in different tissues (root, flower, fruit, stem, and leaf). Finally, the expression profiles of eight LsiSOD genes analyzed by qRT-PCR suggested that these genetic reserves responded to drought, saline, heat, and cold stress. These findings laid the foundation for further study of the role of the SOD gene family in Cucurbitaceae. Also, they provided the potential for its use in the genetic improvement of Cucurbitaceae.

Insilco identification and characterization of superoxide dismutase gene family in Brassica rapa.

Superoxide Dismutase SODs are defense associated proteins that detoxify ROS and primarily serve as scavengers. They have been described in numerous plant species, but their in-depth characterization in Brassica rapa has not been reported. Therefore, the present investigation on genome wide study of SOD gene family was conducted to identify BrSOD genes, their domain-based organization, gene structure analysis, phylogenetic analysis, intron-exon structure of genes and expression analysis. The sequence characterization of Super oxide dismutase gene family in Brassica rapa, their syntenic associateship of conserved motifs and phylogenetic correlationship, prediction of cis-elements and determing the expression analysis in distinct tissues namely plant callus, root, stem, leaf, flower, and silique under abiotic conditions have been analysed using different software’s. The study on SOD gene family identified 17 BrSOD genes which were grouped into eight BrCu-ZnSODs and nine BrFe-MnSODs domain-based organization. Furthermore, the conserved character of BrSODs were confirmed by intron-exon organisation, motif arrangements and domain architectural investigations. Expression analysis using RNA Sequence data of different developmental stages proclaimed that genes were manifested in all six tissues with an exception of BrCu-ZnSOD3, which was not manifested in roots; however, whose transcript was detected in all other tested tissues. The study has genome wide insight into the occurrence and functional specifications of BrSOD gene family in Brassica rapa that can be potentially utilized in breeding program for resilience to climate change and abiotic stresses tolerance Brassica variety.

Genome-Wide Analysis and Expression Profile of Superoxide Dismutase (SOD) Gene Family in Rapeseed (Brassica napus L.) under Different Hormones and Abiotic Stress Conditions.

Superoxide dismutase (SOD) is an important enzyme that acts as the first line of protection in the plant antioxidant defense system, involved in eliminating reactive oxygen species (ROS) under harsh environmental conditions. Nevertheless, the SOD gene family was yet to be reported in rapeseed (Brassica napus L.). Thus, a genome-wide investigation was carried out to identify the rapeseed SOD genes. The present study recognized 31 BnSOD genes in the rapeseed genome, including 14 BnCSDs, 11 BnFSDs, and six BnMSDs. Phylogenetic analysis revealed that SOD genes from rapeseed and other closely related plant species were clustered into three groups based on the binding domain with high bootstrap values. The systemic analysis exposed that BnSODs experienced segmental duplications. Gene structure and motif analysis specified that most of the BnSOD genes displayed a relatively well-maintained exon–intron and motif configuration within the same group. Moreover, we identified five hormones and four stress- and several light-responsive cis-elements in the promoters of BnSODs. Thirty putative bna-miRNAs from seven families were also predicted, targeting 13 BnSODs. Gene ontology annotation outcomes confirm the BnSODs role under different stress stimuli, cellular oxidant detoxification processes, metal ion binding activities, SOD activity, and different cellular components. Twelve BnSOD genes exhibited higher expression profiles in numerous developmental tissues, i.e., root, leaf, stem, and silique. The qRT-PCR based expression profiling showed that eight genes (BnCSD1, BnCSD3, BnCSD14, BnFSD4, BnFSD5, BnFSD6, BnMSD2, and BnMSD10) were significantly up-regulated under different hormones (ABA, GA, IAA, and KT) and abiotic stress (salinity, cold, waterlogging, and drought) treatments. The predicted 3D structures discovered comparable conserved BnSOD protein structures. In short, our findings deliver a foundation for additional functional investigations on the BnSOD genes in rapeseed breeding programs.

Comparative analysis of the superoxide dismutase gene family in Cetartiodactyla.

Cetacea, whales, dolphins and porpoises form an order of mammals adapted to aquatic life. Their transition to an aquatic habitat resulted in exceptional protection against cellular insults, including oxidative and osmotic stress. Here, we considered the structure and molecular evolution of the superoxide dismutase (SOD) gene family, which encodes essential enzymes in the mammalian antioxidant system, in the superorder Cetartiodactyla. To this end, we juxtaposed cetaceans and their closest extant relatives (order Artiodactyla). We identified 94 genes in 23 species, of which 70 are bona fide intact genes. Although the SOD gene family is conserved in Cetartiodactyla, lineage-specific gene duplications and deletions were observed. Phylogenetic analyses show thatthe SOD2 subfamily diverged from a clade containing SOD1 and SOD3, suggesting that cytoplasmic, extracellular and mitochondrial SODs have started down independent evolutionary paths. Specific-amino acid changes (e.g. K130N in SOD2) that may enhance ROS elimination were identified in cetaceans. In silico analysis suggests that the core transcription factor repertoire of cetartiodactyl SOD genes may include Sp1, NF-κB, Nrf2 and AHR. Putative transcription factors binding sites responding to hypoxia were (e.g. Suppressor of Hairless; Su(H)) found in the cetaceanSOD1gene. We found significant evidence for positive selection in cetaceans using codon models. Cetaceans with different diving abilities also show divergent evolution of SOD1 and SOD2. Our genome-wide analysis ofSODgenes helps clarify their relationship and evolutionary trajectory and identify putative functional changes in cetaceans.

Genome-wide identification of superoxide dismutase gene families and their expression patterns under low-temperature, salt and osmotic stresses in watermelon and melon.

The online version contains supplementary material available at 10.1007/s13205-021-02726-7.

Genome-wide identification of the SOD gene family and expression analysis under drought and salt stress in barley

Superoxide dismutase (SOD) plays a vital role in the removal of active oxygen in plant. In this study, bioinformatics research and expression analysis of SOD gene family under drought and salt stress has been done in barley (Hordeum vulgare L., Hv). Seven SOD genes were identified, including four Cu/Zn-SODs, two Fe-SODs and one Mn-SOD. Those three kinds of SOD genes were distributed in 2, 4 and 7 chromosomes, respectively. Phylogenetic analysis revealed that SODs of barley, rice and Arabidopsis thaliana can be divided into three subfamilies (A–C). Motif analysis founded six conservative motifs. Most SOD genes had relatively conservative intron/exon and motif composition, but the number of intron/exons varied greatly among different genes. Based on RNA-seq data and qRT-PCR analysis of expression changes of barley SOD family gene under stress, HvCSD1, HvCSD4 and HvFSD1 were more valuable for in-depth research due to their significant changes in their expression after stress treatment. These outcomes help to lay the foundation for studying the gene function of barley SOD family and provide the improvement of drought and salt tolerance barley genetic breeding.

Genome-wide analysis of the maize superoxide dismutase (SOD) gene family reveals important roles in drought and salt responses.

Superoxide dismutase proteins (SODs) are antioxidant enzymes with important roles in abiotic stress responses. The SOD gene family has been systematically analyzed in many plants; however, it is still poorly understood in maize. Here, a bioinformatics analysis of maize SOD gene family was conducted by describing gene structure, conserved motifs, phylogenetic relationships, gene duplications, promoter cis-elements and GO annotations. In total, 13 SOD genes were identified in maize and five members were involved in segmental duplication. Phylogenetic analysis indicated that SODs from maize and other plants comprised two groups, which could be further classified into different subgroups, with most members in the same subgroup having the same subcellular localization. The ZmSOD promoters contained 2-10 stress-responsive cis-elements with different distributions. Heatmap analysis indicated that ZmSODs were expressed in most of the detected tissues and organs. The expression patterns of ZmSODs were investigated under drought and salt treatments by qRT-PCR, and most members were responsive to drought or salt stress, especially some ZmSODs with significant expression changes were identified, such as ZmCSD2 and ZmMSD2, suggesting the important roles of ZmSODs in abiotic stress responses. Our results provide an important basis for further functional study of ZmSODs in future study.