Gene architecture and expression analyses provide insights into the role of glutathione peroxidases (GPXs) in bread wheat (Triticum aestivum L.)

Characterization of GPX Gene Family in Pepper (Capsicum annuum L.) under Abiotic Stress and ABA Treatment

Plant glutathione peroxidases (GPXs) are important enzymes for removing reactive oxygen species in plant cells and are closely related to the stress resistance of plants. This study identified the GPX gene family members of pepper (Capsicum annuum L.), "CM333", at the whole-genome level to clarify their expression patterns and enzyme activity changes under abiotic stress and ABA treatment. The results showed that eight CaGPX genes were unevenly distributed across four chromosomes and one scaffold of the pepper genome, and their protein sequences had Cys residues typical of the plant GPX domains. The analysis of collinearity, phylogenetic tree, gene structure, and conserved motifs indicated that the CaGPX gene sequence is conserved, structurally similar, and more closely related to the sequence structure of Arabidopsis. Meanwhile, many cis elements involved in stress, hormones, development, and light response were found in the promoter region of the CaGPX gene. In addition, CaGPX1/4 and CaGPX6 were basically expressed in all tissues, and their expression levels were significantly upregulated under abiotic stress and ABA treatment. Subcellular localization showed that CaGPX1 and CaGPX4 are localized in chloroplasts. Additionally, the variations in glutathione peroxidase activity (GSH-Px) mostly agreed with the variations in gene expression. In summary, the CaGPXs gene may play an important role in the development of peppers and their response to abiotic stress and hormones.

The selenium-independent phospholipid hydroperoxide glutathione peroxidase from Theobroma cacao (TcPHGPX) protects plant cells against damages and cell death

Proteins from the glutathione peroxidase (GPX) family, such as GPX4 or PHGPX in animals, are extensively studied for their antioxidant functions and apoptosis inhibition. GPXs can be selenium-independent or selenium-dependent, with selenium acting as a potential cofactor for GPX activity. However, the relationship of plant GPXs to these functions remains unclear. Recent research indicated an upregulation of Theobroma cacao phospholipid hydroperoxide glutathione peroxidase gene (TcPHGPX) expression during early witches' broom disease stages, suggesting the use of antioxidant mechanisms as a plant defense strategy to reduce disease progression. Witches' broom disease, caused by the hemibiotrophic fungus Moniliophthora perniciosa, induces cell death through elicitors like MpNEP2 in advanced infection stages. In this context, in silico and in vitro analyses of TcPHGPX's physicochemical and functional characteristics may elucidate its antioxidant potential and effects against cell death, enhancing understanding of plant GPXs and informing strategies to control witches' broom disease. Results indicated TcPHGPX interaction with selenium compounds, mainly sodium selenite, but without improving the protein function. Protein-protein interaction network suggested cacao GPXs association with glutathione and thioredoxin metabolism, engaging in pathways like signaling, peroxide detection for ABA pathway components, and anthocyanin transport. Tests on tobacco cells revealed that TcPHGPX reduced cell death, associated with decreased membrane damage and H2O2 production induced by MpNEP2. This study is the first functional analysis of TcPHGPX, contributing to knowledge about plant GPXs and supporting studies for witches' broom disease control.

Dual RNA-sequencing of Fusarium head blight resistance in winter wheat

Fusarium head blight (FHB) is a devastating fungal disease responsible for significant yield losses in wheat and other cereal crops across the globe. FHB infection of wheat spikes results in grain contamination with mycotoxins, reducing both grain quality and yield. Breeding strategies have resulted in the production of FHB-resistant cultivars, however, the underlying molecular mechanisms of resistance in the majority of these cultivars are still poorly understood. To improve our understanding of FHB-resistance, we performed a transcriptomic analysis of FHB-resistant AC Emerson, FHB-moderately resistant AC Morley, and FHB-susceptible CDC Falcon in response to Fusarium graminearum. Wheat spikelets located directly below the point of inoculation were collected at 7-days post inoculation (dpi), where dual RNA-sequencing was performed to explore differential expression patterns between wheat cultivars in addition to the challenging pathogen. Differential expression analysis revealed distinct defense responses within FHB-resistant cultivars including the enrichment of physical defense through the lignin biosynthesis pathway, and DON detoxification through the activity of UDP-glycosyltransferases. Nucleotide sequence variants were also identified broadly between these cultivars with several variants being identified within differentially expressed putative defense genes. Further, F. graminearum demonstrated differential expression of mycotoxin biosynthesis pathways during infection, leading to the identification of putative pathogenicity factors.

Comprehensive identification of glutathione peroxidase (GPX) gene family in response to abiotic stress in pepper (Capsicum annuum L.)

Plant glutathione peroxidase (GPX) plays an important role in the maintenance of cell homeostasis and in the antioxidant response in plants. In this study, the peroxidase (GPX) gene family was identified in the whole genome of pepper using bioinformatic method. As a result, a total of 5 CaGPX genes were identified, which were unevenly distributed on 3 of the 12 chromosomes of pepper genome. Based on phylogenetic analysis, 89 GPX genes in 17 species from lower plants to higher plants can be divided into 4 groups GroupⅠ, Group Ⅱ, Group Ⅲ, Group Ⅳ). The MEME Suite analysis of GPX proteins shows that all these proteins contain four highly conserved motifs, as well as other conserved sequences and amino acid residues. Gene structure analysis revealed the conservative exon-intron organization pattern of these genes. In the promoter region of CaGPX genes, many cis elements of plant hormone and abiotic stress response were identified in each of CaGPX proteins. In addition, expression patterns of CaGPX genes in different tissues, developmental stages and responses to abiotic stress were also performed. The results of qRT-PCR showed that the transcripts of CaGPX genes varied greatly under abiotic stress at different time points. There results suggest that the GPX gene family of pepper may play a role in plant development andstress response. In conclusion, our research provides new insights into the evolution of pepper GPX gene family, and understanding for functional of these genes in response to abiotic stresses.

Duplicate Genes Contribute to Variability in Abiotic Stress Resistance in Allopolyploid Wheat

Gene duplication is a universal biological phenomenon that drives genomic variation and diversity, plays a crucial role in plant evolution, and contributes to innovations in genetic engineering and crop development. Duplicated genes participate in the emergence of novel functionality, such as adaptability to new or more severe abiotic stress resistance. Future crop research will benefit from advanced, mechanistic understanding of the effects of gene duplication, especially in the development and deployment of high-performance, stress-resistant, elite wheat lines. In this review, we summarize the current knowledge of gene duplication in wheat, including the principle of gene duplication and its effects on gene function, the diversity of duplicated genes, and how they have functionally diverged. Then, we discuss how duplicated genes contribute to abiotic stress response and the mechanisms of duplication. Finally, we have a future prospects section that discusses the direction of future efforts in the short term regarding the elucidation of replication and retention mechanisms of repetitive genes related to abiotic stress response in wheat, excellent gene function research, and practical applications.

The Glutathione Peroxidase Gene Family in Nitraria sibirica: Genome-Wide Identification, Classification, and Gene Expression Analysis under Stress Conditions

Plant glutathione peroxidases (GPXs) are the main enzymes in the antioxidant defense system that sustain H₂O₂ homeostasis and normalize plant reaction to abiotic stress conditions. However, the genome-wide identification of the GPX gene family and its responses to environmental stresses, especially salt stress, in Nitraria sibirica, which is a shrub that can survive in saline environments, has not yet been reported. Here, we first report the genome-wide analysis of the GPX gene family in N. sibirica, leading to a total of seven NsGPX genes that are distributed on six of the twelve chromosomes. Phylogenetic analysis showed that NsGPX genes were grouped into four major groups (Group I-IV). Three types of cis-acting elements were identified in the NsGPX promoters, mainly related to hormones and stress response. The quantitative real-time PCR (qRT-PCR) analysis indicated that NsGPX1 and NsGPX3 were significantly up-regulated in stem and leaf, while NsGPX7 transcriptionally in root in response to salt stress. The current study identified a total seven NsGPX genes in N. sibirica via genome-wide analysis, and discovered that NsGPXs may play an important role in response to salt stress. Taken together, our findings provide a basis for further functional studies of NsGPX genes, especially in regarding to the resistance to salt stress of this halophyte plant N. sibirica, eventually aid in the discovery of new methods to restore overtly saline soil.

Genome-wide identification and expression analysis of calmodulin and calmodulin-like genes in wheat (Triticum aestivum L.)

Calmodulin (CaM) and calmodulin-like (CML) genes are widely involved in plant growth and development and mediating plant stress tolerance. However, the whole genome scale studies about CaM and CML gene families have not been done in wheat, and the possible functions of most wheat CaM/CML gene members are still unknown. In this study, a total of 18 TaCaM and 230 TaCML gene members were identified in wheat genome. Among these genes, 28 TaCaM/CML gene members have 74 duplicated copies, while 21 genes have 48 transcript variants, resulting in 321 putative TaCaM/CML transcripts totally. Phylogenetic tree analysis showed that they can be classified into 7 subfamilies. Similar gene structures and protein domains can be found in members of the same gene cluster. The TaCaM/CML genes were spread among all 21 chromosomes with unbalanced distributions, while most of the gene clusters contained 3 homoeologous genes located in the same homoeologous chromosome group. Synteny analysis showed that most of TaCaM/CMLs gene members can be found with 1-4 paralogous genes in T. turgidum and Ae. Tauschii. High numbers of cis-acting elements related to plant hormones and stress responses can be observed in the promoters of TaCaM/CMLs. The spatiotemporal expression patterns showed that most of the TaCaM/TaCML genes can be detected in at least one tissue. The expression levels of TaCML17, 21, 30, 50, 59 and 75 in the root or shoot can be up-regulated by abiotic stresses, suggesting that TaCML17, 21, 30, 50, 59 and 75 may be related with responses to abiotic stresses in wheat. The spatiotemporal expression patterns of TaCaM/CML genes indicated they may be involved widely in wheat growth and development. Our results provide important clues for exploring functions of TaCaMs/CMLs in growth and development as well as responses to abiotic stresses in wheat in the future.

Plant Glutathione Peroxidases: Non-Heme Peroxidases with Large Functional Flexibility as a Core Component of ROS-Processing Mechanisms and Signalling

Glutathione peroxidases (GPXs) are non-heme peroxidases catalyzing the reduction of H₂O₂ or organic hydroperoxides to water or corresponding alcohols using glutathione (GSH) or thioredoxin (TRX) as a reducing agent. In contrast to animal GPXs, the plant enzymes are non-seleno monomeric proteins that generally utilize TRX more effectively than GSH but can be a putative link between the two main redox systems. Because of the substantial differences compared to non-plant GPXs, use of the GPX-like (GPXL) name was suggested for Arabidopsis enzymes. GPX(L)s not only can protect cells from stress-induced oxidative damages but are crucial components of plant development and growth. Due to fine-tuning the H₂O₂ metabolism and redox homeostasis, they are involved in the whole life cycle even under normal growth conditions. Significantly new mechanisms were discovered related to their transcriptional, post-transcriptional and post-translational modifications by describing gene regulatory networks, interacting microRNA families, or identifying Lys decrotonylation in enzyme activation. Their involvement in epigenetic mechanisms was evidenced. Detailed genetic, evolutionary, and bio-chemical characterization, and comparison of the main functions of GPXs, demonstrated their species-specific roles. The multisided involvement of GPX(L)s in the regulation of the entire plant life ensure that their significance will be more widely recognized and applied in the future.

Evolutionary and functional characterisation of glutathione peroxidases showed splicing mediated stress responses in Maize

Maize (Zea mays L) is an important cereal with extensive adaptability and multifaceted usages. However, various abiotic and biotic stresses limit the productivity of maize across the globe. Exposure of plant to stresses disturb the balance between reactive oxygen species (ROS) production and scavenging, which subsequently increases cellular damage and death of plants. Tolerant genotypes have evolved higher output of scavenging antioxidative defence compounds (ADCs) during stresses as one of the protective mechanisms. The glutathione peroxidases (GPXs) are the broad class of ADCs family. The plant GPXs catalyse the reduction of hydrogen peroxide (H₂O₂), lipid hydroperoxides and organic hydroperoxides to the corresponding alcohol, and facilitate the regulation of stress tolerance mechanisms. The present investigation was framed to study the maize GPXs using evolutionary and functional analyses. Seven GPX genes with thirteen splice-variants and sixty-three types of cis-acting elements were identified through whole-genome scanning in maize. Evolutionary analysis of GPXs in monocots and dicots revealed mixed and lineage-specific grouping patterns in phylogeny. The expression of ZmGPX splice variants was studied in drought and waterlogging tolerant (L1621701) and sensitive (PML10) genotypes in root and shoot tissues. Further, the differential expression of splice variants of ZmGPX1, ZmGPX3, ZmGPX6 and ZmGPX7 and regulatory network analysis suggested the splicing and regulatory elements mediated stress responses. The present investigation suggests targeting the splicing machinery of GPXs as an approach to enhance the stress tolerance in maize.

Exploration of glutathione reductase for abiotic stress response in bread wheat (Triticum aestivum L.)

A total of seven glutathione reductase (GR) genes were identified in Triticum aestivum, which were used for comparative structural characterization, phylogenetic analysis and expression profiling with the GR genes of other cereal plants. The modulated gene expression and enzyme activity revealed the role of GRs in abiotic stress response in T. aestivum. Glutathione reductase (GR) is an enzymatic antioxidant that converts oxidized glutathione (GSSG) into reduced glutathione (GSH) through the ascorbate-glutathione cycle. In this study, a total of seven GR genes forming two homeologous groups were identified in the allohexaploid genome of bread wheat (Triticum aestivum). Besides, we identified three GR genes in each Aegilops tauschii, Brachypodium distachyon, Triticum urartu and Sorghum bicolor, which were used for comparative characterization. Phylogenetic analysis revealed the clustering of GR proteins into two groups; class I and class II, which were predicted to be localized in cytoplasm and chloroplast, respectively. The exon-intron and conserved motif patterns were almost conserved in each group, in which a maximum of 10 and 17 exons were present in chloroplastic and cytoplasmic GRs, respectively. The protein structure analysis confirmed the occurrence of conserved pyridine nucleotide disulfide oxidoreductase (Pyr_redox) and pyridine nucleotide disulfide oxidoreductase dimerization (Pyr_redox_dim) domains in each GR. The active site of GR proteins consisted of two conserved cysteine residues separated by four amino acid residues. Promoter analysis revealed the occurrence of growth and stress-related cis-active elements. Tissue-specific expression profiling suggested the involvement of GRs in both vegetative and reproductive tissue development in various plants. The differential expression of TaGR genes and enhanced GR enzyme activity suggested their roles under drought, heat, salt and arsenic stress. Interaction of GRs with other proteins and chemical compounds of the ascorbate-glutathione cycle revealed their coordinated functioning. The current study will provide a foundation for the validation of the precise role of each GR gene in future studies.

Genome-Wide Characterization of Glutathione Peroxidase (GPX) Gene Family in Rapeseed (Brassica napus L.) Revealed Their Role in Multiple Abiotic Stress Response and Hormone Signaling

Plant glutathione peroxidases (GPXs) are the main enzymes in the antioxidant defense system that sustain H₂O₂ homeostasis and normalize plant reaction to abiotic stress conditions. To understand the major roles of the GPX gene family in rapeseed (Brassica napus L.), for the first time, a genome-wide study identified 25 BnGPX genes in the rapeseed genome. The phylogenetic analysis discovered that GPX genes were grouped into four major groups (Group I-Group IV) from rapeseed and three closely interrelated plant species. The universal investigation uncovered that the BnGPXs gene experienced segmental duplications and positive selection pressure. Gene structure and motifs examination recommended that most of the BnGPX genes demonstrated a comparatively well-maintained exon-intron and motifs arrangement within the identical group. Likewise, we recognized five hormones-, four stress-, and numerous light-reactive cis-elements in the promoters of BnGPXs. Five putative bna-miRNAs from two families were also prophesied, targeting six BnGPXs genes. Gene ontology annotation results proved the main role of BnGPXs in antioxidant defense systems, ROS, and response to stress stimulus. Several BnGPXs genes revealed boosted expression profiles in many developmental tissues/organs, i.e., root, seed, leaf, stem, flower, and silique. The qRT-PCR based expression profiling exhibited that two genes (BnGPX21 and BnGPX23) were suggestively up-regulated against different hormones (ABA, IAA, and MeJA) and abiotic stress (salinity, cold, waterlogging, and drought) treatments. In short, our discoveries provide a basis for additional functional studies on the BnGPX genes in future rapeseed breeding programs.

Regulation of Reactive Oxygen Species and Antioxidant Defense in Plants under Salinity

The generation of oxygen radicals and their derivatives, known as reactive oxygen species, (ROS) is a part of the signaling process in higher plants at lower concentrations, but at higher concentrations, those ROS cause oxidative stress. Salinity-induced osmotic stress and ionic stress trigger the overproduction of ROS and, ultimately, result in oxidative damage to cell organelles and membrane components, and at severe levels, they cause cell and plant death. The antioxidant defense system protects the plant from salt-induced oxidative damage by detoxifying the ROS and also by maintaining the balance of ROS generation under salt stress. Different plant hormones and genes are also associated with the signaling and antioxidant defense system to protect plants when they are exposed to salt stress. Salt-induced ROS overgeneration is one of the major reasons for hampering the morpho-physiological and biochemical activities of plants which can be largely restored through enhancing the antioxidant defense system that detoxifies ROS. In this review, we discuss the salt-induced generation of ROS, oxidative stress and antioxidant defense of plants under salinity.

Proteomics of Homeobox7 Enhanced Salt Tolerance in Mesembryanthemum crystallinum

Mesembryanthemum crystallinum (common ice plant) is a halophyte species that has adapted to extreme conditions. In this study, we cloned a McHB7 transcription factor gene from the ice plant. The expression of McHB7 was significantly induced by 500 mM NaCl and it reached the peak under salt treatment for 7 days. The McHB7 protein was targeted to the nucleus. McHB7-overexpressing in ice plant leaves through Agrobacterium-mediated transformation led to 25 times more McHB7 transcripts than the non-transformed wild type (WT). After 500 mM NaCl treatment for 7 days, the activities of superoxide dismutase (SOD) and peroxidase (POD) and water content of the transgenic plants were higher than the WT, while malondialdehyde (MDA) was decreased in the transgenic plants. A total of 1082 and 1072 proteins were profiled by proteomics under control and salt treatment, respectively, with 22 and 11 proteins uniquely identified under control and salt stress, respectively. Among the 11 proteins, 7 were increased and 4 were decreased after salt treatment. Most of the proteins whose expression increased in the McHB7 overexpression (OE) ice plants under high salinity were involved in transport regulation, catalytic activities, biosynthesis of secondary metabolites, and response to stimulus. The results demonstrate that the McHB7 transcription factor plays a positive role in improving plant salt tolerance.

Molecular characterization revealed the role of catalases under abiotic and arsenic stress in bread wheat (Triticum aestivum L.)

Catalases are crucial antioxidant enzymes that reduce the excessive level of H₂O₂ caused by various environmental stresses and metal toxicity and hence protect the plant cells. In this study, a total of ten TaCAT genes, forming three homeologous groups, were identified in the genome of bread wheat (Triticum aestivum L.) and named as per the wheat gene symbolization guidelines. The identified catalases were characterized for various structural and physicochemical features. The proximal active-site (F(D/A)RERIPERVVHAKGASA) and heme-ligand (R(I/V)F(S/A)Y(A/S)DTQ) signature motifs, catalytic residues and peroxisomal targeting peptides were found conserved. Phylogenetic analysis clustered TaCATs into three classes, which showed conserved functional specialization based on their tissue specific expression. Modulated spatio-temporal expression of various TaCAT genes and alteration in total catalase enzyme activity during heat, drought, salt and arsenic (As^III and As^V) treatment suggested their roles in abiotic stress response and arsenic tolerance. Molecular cloning and overexpression of TaCAT3-B gene in Escherichia coli showed tolerance against heat, drought, salt and varied concentrations of As^III and As^V treatments. The results further confirmed their role in stress tolerance and recommended that these genes can be used in future stress management strategies for the development of abiotic and arsenic stress resistant transgenic crops.

Molecular characterization of ascorbate peroxidase (APX) and APX-related (APX-R) genes in Triticum aestivum L

Ascorbate peroxidases (APXs) are heme-dependent H₂O₂ scavenging enzymes involved in myriad biological processes. Herein, a total of 21 TaAPX and six TaAPX-R genes were identified from the A, B and D sub-genomes of Triticum aestivum L. The occurrence of three paralogous gene pairs with unequal evolutionary rate suggested functional divergence. The phylogenetic analysis formed four distinct clades having conserved gene and protein architecture, and sub-cellular localization. The tertiary structure analysis revealed the presence of helices and coils and residues involved in ligand binding. Transcriptional profiling of each TaAPX and TaAPX-R gene suggested their specific role during development and stress response. Modulated transcript expression and APX enzyme activity during various stress conditions indicated their role in stress response. Interaction analyses suggested their association with other genes, miRNAs and various legends. The present study reported numerous features of these genes, and may provide a platform for their detailed functional characterization in future studies.

Genomic dissection and transcriptional profiling of Cysteine-rich receptor-like kinases in five cereals and functional characterization of TaCRK68-A

Cysteine-rich receptor-like kinases (CRK) constitute one of the largest subfamily of receptor-like kinases, which play crucial roles in plant development and stress response. In total, 43, 37, 36, 38 and 170 CRK genes including duplicated genes were identified in the genome of Brachypodium distachyon, Hordeum vulgare, Oryza sativa, Sorghum bicolor and Triticum aestivum, respectively. These CRK proteins were tightly clustered into four phylogenetic groups and exhibited close syntenic relationship among orthologous genes. Majority of CRK proteins contain a transmembrane domain for plasma membrane localization. The organization of exon/intron, domains and motifs were variably conserved. Tissue-specific expression suggested the involvement of certain CRK genes in plant development. Modulated expression revealed their specific stress-responsive functions. Co-expression and interaction analysis indicated their role in signaling. Ks value and divergence time analysis suggested duplication of TaCRK genes before the hybridization of T. aestivum sub-genomes. Expression comparison of duplicated TaCRK genes revealed functional retention, neofunctionalization or pseudo-functionalization. Recombinant expression of a stress-responsive gene TaCRK68-A in Escherichia coli and Saccharomyces cerevisiae displayed enhanced tolerance against heat, drought, cold and salinity stresses. The study suggested vital functions of CRKs during development and stresses, and provides the basis for functional characterization of each gene in future studies.

Identification, characterization and expression profiling of cation-proton antiporter superfamily in Triticum aestivum L. and functional analysis of TaNHX4-B

The monovalent cation proton antiporter (CPA) superfamily comprises Na⁺/H⁺ exchanger (NHX), K⁺ efflux antiporter (KEA), and cation/H⁺ exchanger (CHX) family proteins, which play vital functions in plants. A total of 107 TaCPA proteins were identified in Triticum aestivum, and phylogenetically classified into 35 TaNHX, 24 TaKEA and 48 TaCHX proteins. These families had representatives derived from all three sub-genomes. TaKEA genes consisted of higher number of exons, followed by TaNHXs and TaCHXs. The occurrence of about 10 transmembrane regions and higher composition of helices and coils support their membrane-bound and hydrophobic nature. Diverse expression in various tissues and modulated expression under stress conditions suggested their role in development and in response to stress. Co-expression analyses revealed their complex interaction networks. Expression of TaNHX4-B.1 and TaNHX4-B.4 facilitated differential abiotic stress tolerance to Escherichia coli. Our study provides comprehensive information about CPA genes, which would be useful in their future functional characterization.

Identification and Characterization of the Glutathione Peroxidase (GPX) Gene Family in Watermelon and Its Expression under Various Abiotic Stresses

Plant glutathione peroxidase (GPX) is an important antioxidant enzyme to maintain H2O2 homeostasis and regulate plant response to abiotic stress. In this paper, we present the first report of a genome-wide identification of GPX genes in watermelon. A total of six genes (ClGPX1–ClGPX6) were identified, which were unevenly located on four chromosomes of the watermelon genome. Based on phylogenetic analysis, the GPX genes of Arabidopsis, rice, cucumber, and sorghum were classified into four groups. Through analyzing the promoter regions of ClGPX genes, many development-, stress-, and hormone-responsive cis-acting regulatory elements were also identified. Expression pattern analysis by qRT-PCR indicated that all ClGPX genes were actively expressed in flowers and fruits, and exhibited relatively lower expression in other tissues, particularly roots and stems. In addition, the expression of ClGPX genes was significantly induced by salt, drought, and cold stresses, as well as abscisic acid (ABA) treatment at different time points, suggesting that they may be involved in response to abiotic stress and ABA. Taken together, our findings demonstrated that ClGPX genes might function in watermelon development, especially in flower and fruit tissue, as well as in response to abiotic stress and hormones.

Molecular characterization and differential expression suggested diverse functions of P-type II Ca2+ATPases in Triticum aestivum L

Background

Plant P-type II Ca²⁺ATPases are formed by two distinct groups of proteins (ACAs and ECAs) that perform pumping of Ca²⁺ outside the cytoplasm during homeostasis, and play vital functions during development and stress management. In the present study, we have performed identification and characterisation of P-type II Ca²⁺ATPase gene family in an important crop plant Triticum aestivum.

Results

Herein, a total of 33 TaACA and 9 TaECA proteins were identified from the various chromosomes and sub-genomes of Triticum aestivum. Phylogenetic analysis revealed clustering of the homoeologous TaACA and TaECA proteins into 11 and 3 distinct groups that exhibited high sequence homology and comparable structural organization as well. Both TaACA and TaECA group proteins consisted of eight to ten transmembrane regions, and their respective domains and motifs. Prediction of sub-cellular localization was found variable for most of the proteins; moreover, it was consistent with the evolutionarily related proteins from rice and Arabidopsis in certain cases. The occurrence of assorted sets of cis-regulatory elements indicated their diverse functions. The differential expression of various TaACA and TaECA genes during developmental stages suggested their roles in growth and development. The modulated expression during heat, drought, salt and biotic stresses along with the occurrence of various stress specific cis-regulatory elements suggested their association with stress response. Interaction of these genes with numerous development and stress related genes indicated their decisive role in various biological processes and signaling.

Conclusion

T. aestivum genome consisted of a maximum of 42 P-type II Ca²⁺ATPase genes, derived from each A, B and D sub-genome. These genes may play diverse functions during plant growth and development. They may also be involved in signalling during abiotic and biotic stresses. The present study provides a comprehensive insight into the role of P-type II Ca²⁺ATPase genes in T. aestivum. However, the specific function of each gene needs to be established, which could be utilized in future crop improvement programs.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-4792-9) contains supplementary material, which is available to authorized users.