Characterization of a wheat HSP70 gene and its expression in response to stripe rust infection and abiotic stresses

Evaluation of Tunisian wheat endophytes as plant growth promoting bacteria and biological control agents against Fusarium culmorum

Plant growth-promoting rhizobacteria (PGPR) applications have emerged as an ideal substitute for synthetic chemicals by their ability to improve plant nutrition and resistance against pathogens. In this study, we isolated fourteen root endophytes from healthy wheat roots cultivated in Tunisia. The isolates were identified based from their 16S rRNA gene sequences. They belonged to Bacillota and Pseudomonadota taxa. Fourteen strains were tested for their growth-promoting and defense-eliciting potentials on durum wheat under greenhouse conditions, and for their in vitro biocontrol power against Fusarium culmorum, an ascomycete responsible for seedling blight, foot and root rot, and head blight diseases of wheat. We found that all the strains improved shoot and/or root biomass accumulation, with Bacillus mojavensis, Paenibacillus peoriae and Variovorax paradoxus showing the strongest promoting effects. These physiological effects were correlated with the plant growth-promoting traits of the bacterial endophytes, which produced indole-related compounds, ammonia, and hydrogen cyanide (HCN), and solubilized phosphate and zinc. Likewise, plant defense accumulations were modulated lastingly and systematically in roots and leaves by all the strains. Testing in vitro antagonism against F. culmorum revealed an inhibition activity exceeding 40% for five strains: Bacillus cereus, Paenibacillus peoriae, Paenibacillus polymyxa, Pantoae agglomerans, and Pseudomonas aeruginosa. These strains exhibited significant inhibitory effects on F. culmorum mycelia growth, sporulation, and/or macroconidia germination. P. peoriae performed best, with total inhibition of sporulation and macroconidia germination. These finding highlight the effectiveness of root bacterial endophytes in promoting plant growth and resistance, and in controlling phytopathogens such as F. culmorum. This is the first report identifying 14 bacterial candidates as potential agents for the control of F. culmorum, of which Paenibacillus peoriae and/or its intracellular metabolites have potential for development as biopesticides.

Co-expression network analysis and identification of core genes in the interaction between wheat and Puccinia striiformis f. sp. tritici

The epidemic of stripe rust, caused by the pathogen Puccinia striiformis f. sp. tritici (Pst), would reduce wheat (Triticum aestivum) yields seriously. Traditional experimental methods are difficult to discover the interaction between wheat and Pst. Multi-omics data analysis provides a new idea for efficiently mining the interactions between host and pathogen. We used 140 wheat-Pst RNA-Seq data to screen for differentially expressed genes (DEGs) between low susceptibility and high susceptibility samples, and carried out Gene Ontology (GO) enrichment analysis. Based on this, we constructed a gene co-expression network, identified the core genes and interacted gene pairs from the conservative modules. Finally, we checked the distribution of Nucleotide-binding and leucine-rich repeat (NLR) genes in the co-expression network and drew the wheat NLR gene co-expression network. In order to provide accessible information for related researchers, we built a web-based visualization platform to display the data. Based on the analysis, we found that resistance-related genes such as TaPR1, TaWRKY18 and HSP70 were highly expressed in the network. They were likely to be involved in the biological processes of Pst infecting wheat. This study can assist scholars in conducting studies on the pathogenesis and help to advance the investigation of wheat-Pst interaction patterns.

Genome-wide analysis of Hsp40 and Hsp70 gene family in four cotton species provides insights into their involvement in response to Verticillium dahliae and abiotic stress

Introduction: Cotton is an important economic crop to provide natural fibers as raw materials to textile industry, and is significantly affected by biotic and abiotic stress during the whole growth stage, in which Verticillium wilt (VW) caused by Verticillium dahliae is one of the most destructive disease to lead to a significant yield reduction. Heat shock proteins (Hsps) are important molecular chaperones, and play crucial roles in plant growth, development, resistance to biotic and abiotic stress. Hsp40 and Hsp70 are two key Hsps in cell chaperone network, however, the function and regulatory mechanism of Hsp40 and Hsp70 members in VW resistance and abiotic stress in cotton are largely unknown. Methods and Results: Herein, a systematic and comprehensive analysis of Hsp40s and Hsp70s in four cotton species of Gossypium arboretum, G. raimondii, G. hirsutum, and G. barbadense were performed. A total of 291 Hsp40s and 171 Hsp70s identified in four Gossypium species. Sequence analysis revealed that all Hsp40 proteins contained J domain that provides the binding sites to Hsp70. Protein-protein interaction prediction analysis displayed that GhHsp40-55 might interact with GhHsp70-2 and GhHsp70-13, suggesting their potential function as protein complex. Promoter cis-acting element analysis demonstrated that multiple cis-elements related to disease and stress response consists in GhHsp40 and GhHsp70 promoters. Further expression analysis showed that eight GhHsp40s (Hsp40-2,4,8,11,20,23,53,55) and seven GhHsp70s (Hsp70-2,3,6,8,13,19,22) were up-regulated after V. dahliae infection. In addition, five GhHsp40s (Hsp40-2,8,11,53,55) and four GhHsp70s (Hsp70-3,6,8,13) were up-regulated after salt treatment, six GhHsp40s (Hsp40-4,11,20,23) and three GhHsp70s (Hsp70-2,8,19) were up-regulated after drought treatment, four GhHsp40s (Hsp40-2,11,20,23) and four GhHsp70s (Hsp70-3,6,19,22) were up-regulated after temperature treatment, suggesting these Hsps have possible important function in the process of abiotic stress response. Discussion: Our results lay a foundation for understanding the function of Hsp40 and Hsp70 in the resistance against V. dahliae and abiotic stress, and elucidating the regulatory mechanism of the protein complex, evolution and molecular mechanism under stress.

Transcriptome analysis reveals chrysanthemum flower discoloration under high-temperature stress

Temperature is an important environmental factor affecting plant anthocyanin synthesis. High temperatures are associated with decreased anthocyanin pigmentation in chrysanthemum. To reveal the effects of high temperature on anthocyanin biosynthesis in chrysanthemum, ray florets of the heat-sensitive cultivar "Nannong Ziyunying" (ZYY) were subjected to RNA sequencing. A total of 18,286 unigenes were differentially expressed between the control and treatment groups. Functional annotation and enrichment analyses of these unigenes revealed that the heat shock response and flavonoid pathways were significantly enriched, suggesting that the expression of these genes in response to high temperature is associated with the fading of chrysanthemum flower color. In addition, genes related to anthocyanin synthesis and heat shock response were differentially expressed under high-temperature stress. Finally, to further investigate the molecular mechanism of discoloration under high-temperature stress and facilitate the use of marker-assisted breeding for developing novel heat-tolerant cultivars, these results were used to mine candidate genes by analyzing changes in their transcription levels in chrysanthemum.

ITRAQ-Based Proteomic Analysis of Wheat (Triticum aestivum) Spikes in Response to Tilletia controversa Kühn and Tilletia foetida Kühn Infection, Causal Organisms of Dwarf Bunt and Common Bunt of Wheat

Dwarf bunt and common bunt diseases of wheat are caused by Tilletia controversa Kühn and Tilletia foetida Kühn, respectively, and losses caused by these diseases can reach 70-80% in favourable conditions. T. controversa and T. foetida are fungal pathogens belonging to the Exobasidiomycetes within the basidiomycetous smut fungi (Ustilaginomycotina). In order to illuminate the proteomics differences of wheat spikes after the infection of T. controversa and T. foetida, the isobaric tags for relative and absolute quantification (iTRAQ) technique was used for better clarification. A total of 4553 proteins were differentially detected after T. controversa infection; 4100 were upregulated, and 453 were downregulated. After T. foetida infection, 804 differentially expressed proteins were detected; 447 were upregulated and 357 were downregulated. In-depth data analysis revealed that 44, 50 and 82 proteins after T. controversa and 9, 6 and 16 proteins after T. foetida were differentially expressed, which are antioxidant, plant-pathogen interaction and glutathione proteins, respectively, and 9 proteins showed results consistent with PRM. The top 20 KEGG enrichment pathways were identified after pathogen infection. On the basis of gene ontology, the upregulated proteins were linked with metabolic process, catalytic activity, transferase activity, photosynthetic membrane, extracellular region and oxidoreductase activity. The results expanded our understanding of the proteome in wheat spikes in response to T. controversa and T. foetida infection and provide a basis for further investigation for improving the defense mechanism of the wheat crops.

Genome-wide analysis of the VQ motif-containing gene family and expression profiles during phytohormones and abiotic stresses in wheat (Triticum aestivum L.)

BACKGROUND

VQ motif-containing (VQ) proteins are cofactors of transcriptional regulation that are widely involved in plant growth and development and respond to various stresses. The VQ gene family has been identified and characterized for many plants, but there is little research on VQ gene family proteins in wheat (Triticum aestivum L.).

RESULTS

In this study, 113 TaVQ genes (40 homoeologous groups) were identified in the wheat genome. TaVQ proteins all contain the conserved motif FxxhVQxhTG, and most of the TaVQ genes do not contain introns. Phylogenetic analysis demonstrated that TaVQ proteins can be divided into 8 subgroups (I-VIII). The chromosomal location mapping analysis indicated that TaVQ genes are disproportionally distributed on 21 wheat chromosomes. Gene duplication analysis revealed that segmental duplication significantly contributes to the expansion of the TaVQ gene family. Gene expression analysis demonstrated that the expression pattern of TaVQ genes varies in different tissues. The results of quantitative real-time PCR (qRT-PCR) found that TaVQ genes displayed different expression levels under different phytohormones and abiotic stresses. The cis-elements analysis of the promoter region demonstrated that stress responses, hormone responses, growth and development, and WRKY binding elements are all widely distributed. Additionally, a potential regulatory network between TaVQ proteins and WRKY transcription factors was visualized.

CONCLUSION

This study systematically analyzed the wheat TaVQ gene family, providing a reference for further functional characterization of TaVQ genes in wheat.

In Silico and Transcription Analysis of Trehalose-6-phosphate Phosphatase Gene Family of Wheat: Trehalose Synthesis Genes Contribute to Salinity, Drought Stress and Leaf Senescence

Trehalose-6-phosphate phosphatase (TPP) genes take part in trehalose metabolism and also in stress tolerance, which has been well documented in many species but poorly understood in wheat. The present research has identified a family of 31 TPP genes in Triticum aestivum L. through homology searches and classified them into five clades by phylogenetic tree analysis, providing evidence of an evolutionary status with Hordeum vulgare, Brachypodium distachyon and Oryza sativa. The exon-intron distribution revealed a discrete evolutionary history and projected possible gene duplication occurrences. Furthermore, different computational approaches were used to analyze the physical and chemical properties, conserved domains and motifs, subcellular and chromosomal localization, and three-dimensional (3-D) protein structures. Cis-regulatory elements (CREs) analysis predicted that TaTPP promoters consist of CREs related to plant growth and development, hormones, and stress. Transcriptional analysis revealed that the transcription levels of TaTPPs were variable in different developmental stages and organs. In addition, qRT-PCR analysis showed that different TaTPPs were induced under salt and drought stresses and during leaf senescence. Therefore, the findings of the present study give fundamental genomic information and possible biological functions of the TaTPP gene family in wheat and will provide the path for a better understanding of TaTPPs involvement in wheat developmental processes, stress tolerance, and leaf senescence.

Identification and expression analysis of heat-shock proteins in wheat infected with powdery mildew and stripe rust

Heat-shock proteins (HSPs), which are encoded by conserved gene families in plants, are crucial for development and responses to diverse stresses. However, the wheat (Triticum aestivum L.) HSPs have not been systematically classified, especially those involved in protecting plants from disease. Here, we classified 119 DnaJ (Hsp40) proteins (TaDnaJs; encoded by 313 genes) and 41 Hsp70 proteins (TaHsp70s; encoded by 95 genes) into six and four groups, respectively, via a phylogenetic analysis. An examination of protein sequence alignment revealed diversity in the TaDnaJ structural organization, but a highly conserved J-domain, which was usually characterized by an HPD motif followed by DRD or DED motifs. The expression profiles of HSP-encoding homologous genes varied in response to Blumeria graminis f. sp. tritici (Bgt) and Puccinia striiformis f. sp. tritici (Pst) stress. A quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated a lack of similarity in the expression of DnaJ70b, Hsp70-30b, and Hsp90-4b in Bgt-infected resistant and susceptible wheat. Furthermore, a direct interaction between DnaJ70 and TaHsp70-30 was not detected in a yeast two-hybrid (Y2H) assay, but screening cDNA library and Y2H evidence supported that TaHsp70-30 not only interacts directly with heat-shock transcription factor (HSF) A9-like protein but also interacts with TaHsp90-4 by HSP organizing protein. This study revealed the structure and expression profiles of the HSP-encoding genes in wheat, which may be useful for future functional elucidation of wheat HSPs responses to fungal infections.

Wheat Thioredoxin (TaTrxh1) Associates With RD19-Like Cysteine Protease TaCP1 to Defend Against Stripe Rust Fungus Through Modulation of Programmed Cell Death

Thioredoxins (Trxs) function within the antioxidant network through modulation of one or more redox reactions involved in oxidative-stress signaling. Given their function in regulating cellular redox, Trx proteins also fulfill key roles in plant immune signaling. Here, TaTrxh1, encoding a subgroup h member of the Trx family, was identified and cloned in wheat (Triticum aestivum), which was rapidly induced by Puccinia striiformis f. sp. tritici invasion and salicylic acid (SA) treatment. Overexpression of TaTrxh1 in tobacco (Nicotiana benthamiana) induced programmed cell death. Silencing of TaTrxh1 in wheat enhanced susceptibility to P. striiformis f. sp. tritici in different aspects, including reactive oxygen species accumulation and pathogen-responsive or -related gene expression. Herein, we observed that the cellular concentration of SA was significantly reduced in TaTrxh1-silenced plants, indicating that TaTrxh1 possibly regulates wheat resistance to stripe rust through a SA-associated defense signaling pathway. Using a yeast two-hybrid screen to identify TaTrxh1-interacting partners, we further show that interaction with TaCP1 (a RD19-like cysteine protease) and subsequent silencing of TaCP1 reduced wheat resistance to P. striiformis f. sp. tritici. In total, the data presented herein demonstrate that TaTrxh1 enhances wheat resistance against P. striiformis f. sp. tritici via SA-dependent resistance signaling and that TaTrxh1 interaction with TaCP1 is required for wheat resistance to stripe rust.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Genome-wide analysis of Hsp70 and Hsp100 gene families in Ziziphus jujuba

The Ziziphus species are naturally tolerant to a range of abiotic stresses. Therefore, it is expected that they are an enriched source of genes conferring stress tolerance. Heat shock proteins (Hsps) play a significant role in plants in imparting tolerance against abiotic stress conditions. To get an insight into potential Hsp function in Ziziphus, we performed a genome-wide analysis and expression study of Hsp70 and Hsp100 gene families in Ziziphus jujuba. We identified 21 and 6 genes of the ZjHsp70 and ZjHsp100 families, respectively. Physiochemical properties, chromosomal location, gene structure, motifs, and protein domain organization were analysed for structural and functional characterization. We identified the contribution of tandem and segmental gene duplications in expansions of ZjHsp70s and ZjHsp100s in Z. jujuba. Promoter analysis suggested that ZjHsp70s and ZjHsp100s perform diverse functions related to abiotic stress. Furthermore, expression analyses revealed that most of the Z. jujuba Hsp genes are differentially expressed in response to heat, drought, and salinity stress. Our analyses suggested ZjHsp70-3, ZjHsp70-5, ZjHsp70-6, ZjHsp70-16, ZjHsp70-17, ZjHsp70-20, ZjHsp100-1, ZjHsp100-2, and ZjHsp100-3 are potential candidates for further functional analysis and with regard to breeding new more resilient strains. The present analysis laid the foundation for understanding the molecular mechanism of Hsps70 and Hsp100 gene families regulating abiotic stress tolerance in Z. jujuba.

Genome-wide identification, classification and expression analysis of the Hsf and Hsp70 gene families in maize

Heat shock factors (Hsfs) and heat shock proteins (Hsps) play a critical role in the molecular mechanisms such as plant development and defense against abiotic. As an important food crop, maize is vulnerable to adverse environment such as heat stress and water logging, which leads to a decline in yield and quality. To date, very little is known regarding the structure and function of Hsf and Hsp genes in maize. Although some Hsf and Hsp genes have been characterized in maize, analysis of the entire Hsf and Hsp70 gene families were not completed following Maize (B73) Genome Sequencing Project. Therefore, studying their molecular mechanism and revealing their biological function in plant stress resistance process will contribute to reveal important theoretical significance and application value for improving corn yield and quality. In this study, we have identified 25 ZmHsf and 22 ZmHsp70 genes in maize. The structural characteristics and phylogenetic relationships of the Hsf and Hsp70 gene families of Arabidopsis thaliana, rice and maize were compared. The final 25 ZmHsf proteins and 22 ZmHsp70 proteins were divided into three and four subfamilies, respectively. In addition, chromosomal localization indicated that the ZmHsf and ZmHsp70 genes were unevenly distributed on the chromosome, and the gene structure map revealed the characteristics of their structures. Finally, transcriptome analysis indicated that most of the ZmHsf and ZmHsp70 genes showed different expression patterns at different developmental stages of maize. Further, by semi-quantitative RT-PCR and quantitative real-time PCR analysis, all 25 ZmHsf and 22 ZmHsp70 genes were confirmed to respond to heat stress treatment, indicating that they have potential effects in heat stress response. The analyses performed by combining co-expression network with protein-protein interaction network among the members of the Hsf and Hsp70 gene families in maize further enabled us to recognize components involved in the regulatory network associated with hsfs and hsp70s complex. The predicted subcellular location revealed that maize Hsp70 proteins exhibited a various subcellular distribution, which may be associated with functional diversification in heat stress response. Taken together, our study provides comprehensive information on the members of Hsf and Hsp70 gene families and will help in elucidating their exact function in maize.

TaYS1A, a Yellow Stripe-Like Transporter Gene, Is Required for Wheat Resistance to Puccinia striiformis f. sp. Tritici

Yellow stripe-like (YSL) transporters are required for the transportation of metal-phytosiderophores and are structurally related to metal-nicotianamine complexes. Some studies also reported the involvement of YSL transporters in pathogen-induced defense. However, the molecular mechanisms of YSL genes involved in biotic stress responses are still not clear, especially in cereal crops. This study aimed to functionally characterize TaYS1A during the interaction of wheat and Puccinia striiformis f. sp. tritici (Pst), the causal agent of stripe rust disease. TaYS1A was localized in the cell membrane of wheat protoplasts and Nicotiana benthamiana cells. TaYS1A was significantly up-regulated in wheat leaves after being infected with the avirulent Pst isolate CYR23 and after treatment with salicylic acid (SA). Silencing of TaYS1A by the virus-induced gene silencing method enhanced the susceptibility of wheat to Pst accompanied by reducing the accumulation of SA and H2O2 and down-regulating the transcriptions of TaPR1 and TaPR2. In addition, TaYS1A was found to interact with TaNH2, a homolog of OsNH2, by yeast-two-hybrid assay, and silencing of TaYS1A diminished the expression of TaNH2. Our findings suggested the existence of positive regulation of TaYS1A in providing resistance against Pst by modulating SA-induced signaling and offered new insight into the biological role of YSL in wheat against pathogens.

Central role of 70-kDa heat shock protein in adaptation of plants to drought stress

The 70-kDa heat shock proteins (HSP70s) are a conserved class of chaperones that play critical roles during the normal life cycle of plants. HSP70s are particularly involved in the regulation of biotic and abiotic stress responses. In this paper, the potential roles of this protein were investigated. A reverse genetic approach was employed for transient silencing of hsp70 gene in tomato (Solanum lycopersicum L.) to evaluate different growth and physiological parameters under normal conditions and during the response to drought stress. A combined ANOVA (analysis of variance) and HCA (hierarchical clustering analysis) showed that hsp70 silencing led to severe growth retardation and mortality, significant membrane damage and leakage, decline in relative water content, low rate of pigment accumulation, and reduced antioxidant enzyme activity under normal and drought stress conditions. Among the different parameters, proline was the only trait that was unaffected by gene silencing and accumulated by similar amounts to that of nonsilent plants. In conclusion, HSP70 played critical roles in maintaining the cellular homeostasis of plants during adaptation to drought and under normal plant life conditions. It was speculated that proline was, to some extent, involved in improving the loss of protein folding or function resulting from HSP70 deficiency, and played a crucial role in the adaptation of plants on exposure to stress.

Cloning and Expression Analysis of the BocMBF1c Gene Involved in Heat Tolerance in Chinese Kale

Chinese kale (Brassica oleracea var. chinensis Lei) is an important vegetable crop in South China, valued for its nutritional content and taste. Nonetheless, the thermal tolerance of Chinese kale still needs improvement. Molecular characterization of Chinese kale's heat stress response could provide a timely solution for developing a thermally tolerant Chinese kale variety. Here, we report the cloning of multi-protein bridging factor (MBF) 1c from Chinese kale (BocMBF1c), an ortholog to the key heat stress responsive gene MBF1c. Phylogenetic analysis showed that BocMBF1c is highly similar to the stress-response transcriptional coactivator MBF1c from Arabidopsis thaliana (AtMBF1c), and the BocMBF1c coding region conserves MBF1 and helix-turn-helix (HTH) domains. Moreover, the promoter region of BocMBF1c contains three heat shock elements (HSEs) and, thus, is highly responsive to heat treatment. This was verified in Nicotiana benthamiana leaf tissue using a green fluorescent protein (GFP) reporter. In addition, the expression of BocMBF1c can be induced by various abiotic stresses in Chinese kale which indicates the involvement of stress responses. The BocMBF1c-eGFP (enhanced green fluorescent protein) chimeric protein quickly translocated into the nucleus under high temperature treatment in Nicotiana benthamiana leaf tissue. Overexpression of BocMBF1c in Arabidopsis thaliana results in a larger size and enhanced thermal tolerance compared with the wild type. Our results provide valuable insight for the role of BocMBF1c during heat stress in Chinese kale.

Differential gene expression in two grapevine cultivars recovered from "flavescence dorée"

The biological bases of recovery of two grapevine cultivars, Nebbiolo and Barbera, showing different susceptibility and recovery ability to "flavescence dorée" (FD) phytoplasma infection were investigated. The expression over one vegetative season, in FD-recovered and healthy grapevines, of 18 genes involved in defence, hydrogen peroxide and hormone production was verified at two time points. Difference (Δ) between the relative expressions of August and July were calculated for each target gene of both cultivars. The significance of differences among groups assessed by univariate and multivariate statistical methods, and sPLS-DA analyses of the Δ gene expression values, showed that control and recovered grapevines of both cultivars were clearly separated. The Barbera-specific deregulation of defence genes supports a stronger response of this variety, within a general frame of interactions among H₂O₂, jasmonate and ethylene metabolisms, common to both varieties. This may strengthen the hypothesis that FD-recovered Barbera grapevines modulate transcription of their genes to cope with potential damages associated to the alteration of their oxidative status. Nebbiolo variety would fit into this picture, although with a less intense response, in line with its lower degree of susceptibility and recovery incidence to FD, compared to Barbera. The results evidenced a scenario where plant response to phytoplasma infection is highly affected by climatic and edaphic conditions. Nevertheless, even after several years from the original FD infection, it was still possible to distinguish, at molecular level, control and recovered grapevines of both cultivars by analyzing their overall-season response, rather than that of a single time point.

Hydrogen Peroxide Response in Leaves of Poplar (Populus simonii × Populus nigra) Revealed from Physiological and Proteomic Analyses

Hydrogen peroxide (H₂O₂) is one of the most abundant reactive oxygen species (ROS), which plays dual roles as a toxic byproduct of cell metabolism and a regulatory signal molecule in plant development and stress response. Populus simonii × Populus nigra is an important cultivated forest species with resistance to cold, drought, insect and disease, and also a key model plant for forest genetic engineering. In this study, H₂O₂ response in P. simonii × P. nigra leaves was investigated using physiological and proteomics approaches. The seedlings of 50-day-old P. simonii × P. nigra under H₂O₂ stress exhibited stressful phenotypes, such as increase of in vivo H₂O₂ content, decrease of photosynthetic rate, elevated osmolytes, antioxidant accumulation, as well as increased activities of several ROS scavenging enzymes. Besides, 81 H₂O₂-responsive proteins were identified in the poplar leaves. The diverse abundant patterns of these proteins highlight the H₂O₂-responsive pathways in leaves, including 14-3-3 protein and nucleoside diphosphate kinase (NDPK)-mediated signaling, modulation of thylakoid membrane structure, enhancement of various ROS scavenging pathways, decrease of photosynthesis, dynamics of proteins conformation, and changes in carbohydrate and other metabolisms. This study provides valuable information for understanding H₂O₂-responsive mechanisms in leaves of P. simonii × P. nigra.

A furoviral replicase recruits host HSP70 to membranes for viral RNA replication

Many host factors have been identified to be involved in viral infection. However, although furoviruses cause important diseases of cereals worldwide, no host factors have yet been identified that interact with furoviral genes or participate in the viral infection cycle. In this study, both TaHSP70 and NbHSP70 were up-regulated in Chinese wheat mosaic furovirus (CWMV)-infected plants. Their overexpression and inhibition were correlated with the accumulation of viral genomic RNAs, suggesting that the HSP70 genes could be necessary for CWMV infection. The subcellular distributions of TaHSP70 and NbHSP70 were significantly affected by CWMV infection or by infiltration of RNA1 alone. Further assays showed that the viral replicase encoded by CWMV RNA1 interacts with both TaHSP70 and NbHSP70 in vivo and vitro and that its region aa167-333 was responsible for the interaction. Subcellular assays showed that the viral replicase could recruit both TaHSP70 and NbHSP70 from the cytoplasm or nucleus to the granular aggregations or inclusion-like structures on the intracellular membrane system, suggesting that both HSP70s may be recruited into the viral replication complex (VRC) to promote furoviral replication. This is the first host factor identified to be involved in furoviral infection, which extends the list and functional scope of HSP70 chaperones.

Molecular cloning and functional analysis of the drought tolerance gene MsHSP70 from alfalfa (Medicago sativa L.)

Heat shock proteins (HSPs) are a ubiquitously expressed class of protective proteins that play a key role in plant response to stressful conditions. This study aimed to characterize and investigate the function of an HSP gene in alfalfa (Medicago sativa). MsHSP70, which contains a 2028-bp open reading frame, was identified through homology cloning. MsHSP70 shares high sequence identity (94.47%) with HSP70 from Medicago truncatula. Expression analysis of MsHSP70 in alfalfa organs revealed a relatively higher expression level in aerial organs such as flowers, stems and leaves than in roots. MsHSP70 was induced by heat shock, abscisic acid (ABA) and hydrogen peroxide. Transgenic Arabidopsis seedlings overexpressing MsHSP70 were hyposensitive to polyethylene glycol (PEG) and ABA treatments, suggesting that exogenous expression of MsHSP70 enhanced Arabidopsis tolerance to these stresses. Examination of physiological indexes related to drought and ABA stress demonstrated that in comparison with non-transgenic plants, T3 transgenic Arabidopsis plants had an increased proline content, higher superoxide dismutase (SOD) activity, and decreased malondialdehyde (MDA) content. Furthermore, higher relative water content (RWC) was detected in transgenic plants compared with non-transgenic plants under drought stress. These findings clearly indicate that molecular manipulation of MsHSP70 in plants can have substantial effects on stress tolerance.

TaDIR1-2, a Wheat Ortholog of Lipid Transfer Protein AtDIR1 Contributes to Negative Regulation of Wheat Resistance against Puccinia striiformis f. sp. tritici

Very few LTPs have been shown to act through plasma membrane receptors or to be involved in the hypersensitive response (HR). DIR1, a new type of plant LTP interacts with lipids in vitro, moves to distant tissues during systemic acquired resistance (SAR) and therefore is thought to be involved in long-distance signaling during SAR. However, the exact functions of DIR1 orthologs in cereal species under biotic and abiotic stresses have not been thoroughly defined. In this study, a novel wheat ortholog of the DIR1 gene, TaDIR1-2, was isolated from Suwon11, a Chinese cultivar of wheat and functionally characterized. Phylogenetic analysis indicated that TaDIR1-2 is clustered within the nsLTP-Type II group and shows a closer relationship with DIR1 orthologs from monocots than from eudicots. TaDIR1-2 was localized in the cytoplasm and the cell membrane of wheat mesophyll protoplast. Transcription of TaDIR1-2 was detected in wheat roots, stems and leaves. TaDIR1-2 transcript was significantly induced during the compatible interaction of wheat with the stripe rust pathogen, Puccinia striiformis f. sp. tritici (Pst). Treatments with salicylic acid (SA) and low temperature significantly up-regulated the expression of TaDIR1-2. Transient overexpression of TaDIR1-2 did not induce cell death or suppress Bax-induced cell death in tobacco leaves. Knocking down the expression of TaDIR1-2 through virus-induced gene silencing increased wheat resistance to Pst accompanied by HR, increased accumulation of H₂O₂ and SA, increased expression of TaPR1, TaPR2, TaPAL, and TaNOX, and decreased expression of two reactive oxygen species (ROS) scavenging genes TaCAT and TaSOD. Our results suggest that TaDIR1-2 acts as a negative regulator in wheat resistance to Pst by modulating ROS and/or SA-induced signaling.

The host-pathogen interaction between wheat and yellow rust induces temporally coordinated waves of gene expression

Background

Understanding how plants and pathogens modulate gene expression during the host-pathogen interaction is key to uncovering the molecular mechanisms that regulate disease progression. Recent advances in sequencing technologies have provided new opportunities to decode the complexity of such interactions. In this study, we used an RNA-based sequencing approach (RNA-seq) to assess the global expression profiles of the wheat yellow rust pathogen Puccinia striiformis f. sp. tritici (PST) and its host during infection.

Results

We performed a detailed RNA-seq time-course for a susceptible and a resistant wheat host infected with PST. This study (i) defined the global gene expression profiles for PST and its wheat host, (ii) substantially improved the gene models for PST, (iii) evaluated the utility of several programmes for quantification of global gene expression for PST and wheat, and (iv) identified clusters of differentially expressed genes in the host and pathogen. By focusing on components of the defence response in susceptible and resistant hosts, we were able to visualise the effect of PST infection on the expression of various defence components and host immune receptors.

Conclusions

Our data showed sequential, temporally coordinated activation and suppression of expression of a suite of immune-response regulators that varied between compatible and incompatible interactions. These findings provide the framework for a better understanding of how PST causes disease and support the idea that PST can suppress the expression of defence components in wheat to successfully colonize a susceptible host.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-2684-4) contains supplementary material, which is available to authorized users.

Brachypodium distachyon T-DNA insertion lines: a model pathosystem to study nonhost resistance to wheat stripe rust

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (PST), is one of the most destructive diseases and can cause severe yield losses in many regions of the world. Because of the large size and complexity of wheat genome, it is difficult to study the molecular mechanism of interaction between wheat and PST. Brachypodium distachyon has become a model system for temperate grasses' functional genomics research. The phenotypic evaluation showed that the response of Brachypodium distachyon to PST was nonhost resistance (NHR), which allowed us to present this plant-pathogen system as a model to explore the immune response and the molecular mechanism underlying wheat and PST. Here we reported the generation of about 7,000 T-DNA insertion lines based on a highly efficient Agrobacterium-mediated transformation system. Hundreds of mutants either more susceptible or more resistant to PST than that of the wild type Bd21 were obtained. The three putative target genes, Bradi5g17540, BdMYB102 and Bradi5g11590, of three T-DNA insertion mutants could be involved in NHR of Brachypodium distachyon to wheat stripe rust. The systemic pathologic study of this T-DNA mutants would broaden our knowledge of NHR, and assist in breeding wheat cultivars with durable resistance.

Overexpression of Rosa rugosa anthocyanidin reductase enhances tobacco tolerance to abiotic stress through increased ROS scavenging and modulation of ABA signaling

Anthocyanidin reductase (ANR) is a key enzyme involved in the biosynthesis of proanthocyanidins (PAs) and plays a role in the plant stress response. However, the mechanism by which ANR confers stress tolerance in plants is not understood. Here, we report the isolation of RrANR, the homologous gene from rose, and NtABF, an ABA-response related transcription factor gene from tobacco. These genes were characterized regarding their functions in stress responses through the use of transgenic, transcriptomic and physiological analyses. Over-expression of RrANR in tobacco resulted in an increased accumulation of both PAs and abscisic acid (ABA), and also enhanced stress tolerance. Transcriptomic analysis of these transgenic tobacco lines indicated that RrANR overexpression induced global transcriptomic changes, including these involved in oxidation/reduction, hormone response and secondary metabolism. Genes related to ABA biosynthesis and reactive oxygen species (ROS)-scavenging were up-regulated in RrANR transgenic lines, and these effects were phenocopied by the direct treatment of tobacco plants with PAs and ABA. Transcriptomic data from each of these treatments identified the upregulation of a putative NtABF. Furthermore, the up-regulation of NtABF in RrANR transformants or in PAs- and ABA-treated tobacco plants was associated with enhanced stress tolerance. Overexpression of NtABF in transgenic tobacco mimicked the effects of RrANR-transgenic plants with regard to the up-regulation of ROS-scavenging genes and an increase in oxidative tolerance. Taken together, our findings indicate that overexpression of RrANR results in an increase in plant tolerance to oxidative stress via increased scavenging of ROS and modulation of the ABA signaling pathway.

Overexpression of MuHSP70 gene from Macrotyloma uniflorum confers multiple abiotic stress tolerance in transgenic Arabidopsis thaliana

A 70-KD heat shock protein (HSP70) is one of the most conserved chaperones. It is involved in de novo protein folding and prevents the aggregation of unfolded proteins under lethal environmental factors. The purpose of this study is to characterise a MuHSP70 from horsegram (Macrotyloma uniflorum) and elucidating its role in stress tolerance of plants. A MuHSP70 was cloned and characterised from a natural drought stress tolerant HPK4 variety of horsegram (M. uniflorum). For functional characterization, MuHSP70 was overexpressed in transgenic Arabidopsis. Overexpression of MuHSP70 was found to provide tolerance to the transgenic Arabidopsis against various stresses such as heat, cold, drought, salinity and oxidative stress. MuHSP70 transgenics were observed to maintain the shoot biomass, root length, relative water content, and chlorophyll content during exposure to multi-stresses relative to non-transgenic control. Transgenic lines have further shown the reduced levels of MDA, H2O2, and proteolytic activity. Together, these findings suggest that overexpression of MuHSP70 plays an important role in improving abiotic stress tolerance and could be a crucial candidate gene for exploration in crop improvement program.

Roles of Hsp70s in Stress Responses of Microorganisms, Plants, and Animals

Hsp70s (heat shock protein 70s) are a class of molecular chaperones that are highly conserved and ubiquitous in organisms ranging from microorganisms to plants and humans. Most research on Hsp70s has focused on the mechanisms of their functions as molecular chaperones, but recently, studies on stress responses are coming to the forefront. Hsp70s play key roles in cellular development and protecting living organisms from environmental stresses such as heat, drought, salinity, acidity, and cold. Moreover, functions of human Hsp70s are related to diseases including neurological disorders, cancer, and virus infection. In this review, we provide an overview of the specific roles of Hsp70s in response to stress, particularly abiotic stress, in all living organisms.

Cloning and expression analysis of HSP70 gene from mangrove plant Kandelia obovata under cold stress

Heat shock protein 70 (HSP70), the primary member of the HSPs that play various stress-protective roles in plants. In this study, a hsp70 gene of Kandelia obovata (KoHsp70) was cloned by rapid amplification of cDNA ends (RACE). The full-length of KoHsp70 was 2255 bp, consisting of a 5'-terminal untranslated region (UTR) of 118 bp, a 3'-terminal UTR of 178 bp, and an open reading frame (ORF) of 1959 bp. The ORF (KoHSP70) was predicted to encode a polypeptide of 652 amino acids with a theoretical molecular weight (MW) of 71.40 kDa and a pI of 5.16. The amino acid sequence analysis revealed that the KoHSP70 contained three conserved regions of HSP70 family, a bipartite nuclear localization signal sequences (NLS), an ATP/GTP-binding site motif and a cytoplasmic characteristic motif (EEVD). Homology analysis indicated that KoHSP70 shared 96.0 % identity with the known HSP70 (Gossypium hirsutum). Bioinformatics analysis indicated that the KoHSP70 was hydrophilic and had no signal peptide or transmembrane region. The mRNA expression of KoHsp70 kept relatively stable at first and then increased significantly after 48 h cold stress, and reached the highest level at 168 h after cold treatment. The results indicated that the KoHsp70 was a stress-inducible gene that might play a role in cold stress-protective response and in coping with environmental and biological stresses for K. obovata. This study provided a basis to further study the mechanism of anti-adverseness and expression characteristics under stress conditions of K. obovata.

Integrated Proteome Analysis of the Wheat Embryo and Endosperm Reveals Central Metabolic Changes Involved in the Water Deficit Response during Grain Development

The embryo and endosperm of wheat have different physiological functions and large differences in protein level. In this study, we performed the first integrated proteome analysis of wheat embryo and endosperm in response to the water deficit during grain development. In total, 155 and 130 differentially expressed protein (DEP) spots in the embryo and endosperm, respectively, were identified by nonlinear two-dimensional electrophoresis and tandem mass spectrometry. These DEPs in the embryo were mainly involved in stress/defense responses such as heat shock-related proteins (HSP) and peroxidase, whereas those in endosperm were mainly related to starch and storage protein synthesis such as α-amylase inhibitor and the globulin-1 S allele. In particular, some storage proteins such as avenin-like proteins and high-molecular weight glutenin subunit Dy12 displayed higher expression levels in the mature endosperm under a water deficit, which might contribute to the improvement in the quality of breadmaking.

Identification and characterization of a heat-inducible Hsp70 gene from Sorghum bicolor which confers tolerance to thermal stress

This study describes the first detailed molecular characterization of the heat shock protein 70 (Hsp70) gene from Sorghum bicolor, MN1618 designated as SbHsp70-1. The full-length cDNA of SbHsp70-1 consists of 2524 bp with a 1950 bp open reading frame, which encodes a protein of 649 amino acids. SbHsp70-1 is a cytoplasmic protein with high homology to other plant Hsp70s, especially grain crops. Recombinant SbHsp70-1 was able to bind and hydrolyse ATP in a dose-dependent manner, suggesting that SbHsp70-1 functions as an ATPase. Immunoblot assays showed that the expression of SbHsp70-1 is induced at temperatures of 37, 45, and 4 °C but reduced at 42 °C. In addition, the SbHsp70-1 mRNA transcript is constitutively expressed in both leaves and stem but is significantly increased upon heat shock at 42 °C. Upon cold shock at 4 °C, SbHsp70-1 mRNA transcript level increased in the leaf, but no significant change was observed in the stem. In addition, expression of the pET28a-SbHsp70-1 construct in Escherichia coli cells under heat stress resulted in their survival even at higher temperature (65 °C). Our results suggest that SbHsp70-1 is a heat-inducible protein that confer thermal tolerance to bacterial cells and can be claimed as a promising target to study stress tolerance in crops.

Genome-wide analysis and expression profiling under heat and drought treatments of HSP70 gene family in soybean (Glycine max L.)

Heat shock proteins (HSPs) perform a fundamental role in protecting plants against abiotic stresses. Previous studies have made great efforts in the functional analysis of individual family members, but there has not yet been an overall analysis or expression profiling of the HSP70 gene family in soybeans (Glycine max L.). In this study, an investigation of the soybean genome revealed 61 putative HSP70 genes, which were evaluated. These genes were classified into eight sub-families, denoted I-VIII, based on a phylogenetic analysis. In each sub-family, the constituent parts of the gene structure and motif were relatively conserved. These GmHSP70 genes were distributed unequally on 17 of the 20 chromosomes. The analysis of the expression profiles showed that 53 of the 61 GmHSP70 genes were differentially expressed across the 14 tissues. However, most of the GmHSP70s were differentially expressed in a tissue-specific expression pattern. Furthermore, the expression of some of the duplicate genes was partially redundant, while others showed functional diversity. The quantitative real-time PCR (qRT-PCR) analysis of the 61 soybean HSP70 genes confirmed their stress-inducible expression patterns under both drought and heat stress. These findings provide a thorough overview of the evolution and modification of the GmHSP70 gene family, which will help to determine the functional characteristics of the HSP70 genes in soybean growth and development.

Characterization of CaHsp70-1, a pepper heat-shock protein gene in response to heat stress and some regulation exogenous substances in Capsicum annuum L

Pepper (Capsicum annuum L.) is sensitive to heat stress (HS). Heat shock proteins 70 (Hsp70s) play a crucial role in protecting plant cells against HS and control varies characters in different plants. However, CaHsp70-1 gene was not well characterized in pepper. In this study, CaHsp70-1 was cloned from the pepper thermotolerant line R9, which encoded a protein of 652 amino acids, with a molecular weight of 71.54 kDa and an isoelectric point of 5.20. CaHsp70-1 belongs to the cytosolic Hsp70 subgroup, and best matched with tomato SlHsp70. CaHsp70-1 was highly induced in root, stem, leaf and flower in R9 with HS treatment (40 °C for 2 h). In both thermosensitive line B6 and thermotolerant line R9, CaHsp70-1 significantly increased after 0.5 h of HS (40 °C), and maintained in a higher level after 4 h HS. The expression of CaHsp70-1 induced by CaCl₂, H₂O₂ and putrescine (Put) under HS were difference between B6 and R9 lines. The different expression patterns may be related to the differences in promoters of CaHsp70-1 from the two lines. These results suggest that CaHsp70-1 as a member of cytosolic Hsp70 subgroup, may be involved in HS defense response via a signal transduction pathway contained Ca²⁺, H₂O₂ and Put.

Flowering as the most highly sensitive period of grapevine (Vitis vinifera L. cv Mourvèdre) to the Botryosphaeria dieback agents Neofusicoccum parvum and Diplodia seriata infection

Botryosphaeria dieback is a fungal grapevine trunk disease that currently represents a threat for viticulture worldwide because of the important economical losses due to reduced yield of affected plants and their premature death. Neofusicoccum parvum and Diplodia seriata are among the causal agents. Vine green stems were artificially infected with N. parvum or D. seriata at the onset of three different phenological stages (G stage (separated clusters), flowering and veraison). Highest mean lesion lengths were recorded at flowering. Major proteome changes associated to artificial infections during the three different phenological stages were also reported using two dimensional gel electrophoresis (2D)-based analysis. Twenty (G stage), 15 (flowering) and 13 (veraison) differentially expressed protein spots were subjected to nanoLC-MS/MS and a total of 247, 54 and 25 proteins were respectively identified. At flowering, a weaker response to the infection was likely activated as compared to the other stages, and some defense-related proteins were even down regulated (e.g., superoxide dismutase, major latex-like protein, and pathogenesis related protein 10). Globally, the flowering period seemed to represent the period of highest sensitivity of grapevine to Botryosphaeria dieback agent infection, possibly being related to the high metabolic activity in the inflorescences.

TaADF7, an actin-depolymerizing factor, contributes to wheat resistance against Puccinia striiformis f. sp. tritici

The actin cytoskeleton is involved in plant defense responses; however, the role of the actin-depolymerizing factor (ADF) family, which regulates actin cytoskeletal dynamics, in plant disease resistance, is largely unknown. Here, we characterized a wheat (Triticum aestivum) ADF gene, TaADF7, with three copies located on chromosomes 1A, 1B, and 1D, respectively. All three copies encoded the same protein, although there were variations in 19 nucleotide positions in the open reading frame. Transcriptional expression of the three TaADF7 copies were all sharply elevated in response to avirulent Puccinia striiformis f. sp. tritici (Pst) infection, with similar expression patterns. TaADF7 regulated the actin cytoskeletal dynamics by targeting the actin cytoskeleton to execute actin binding/severing activities. When the TaADF7 copies were all silenced by virus-induced gene silencing, the growth of Pst hypha increased and sporadic urediniospores were observed, as compared with control plants, upon inoculation with avirulent Pst. In addition, the accumulation of reactive oxygen species (ROS) and the hypersensitive response (HR) were greatly weakened, whereas cytochalasin B partially rescued the HR in TaADF7 knock-down plants. Together, these findings suggest that TaADF7 is likely to contribute to wheat resistance against Pst infection by modulating the actin cytoskeletal dynamics to influence ROS accumulation and the HR.

Novel aspects of grapevine response to phytoplasma infection investigated by a proteomic and phospho-proteomic approach with data integration into functional networks

BACKGROUND

Translational and post-translational protein modifications play a key role in the response of plants to pathogen infection. Among the latter, phosphorylation is critical in modulating protein structure, localization and interaction with other partners. In this work, we used a multiplex staining approach with 2D gels to study quantitative changes in the proteome and phosphoproteome of Flavescence dorée-affected and recovered 'Barbera' grapevines, compared to healthy plants.

RESULTS

We identified 48 proteins that differentially changed in abundance, phosphorylation, or both in response to Flavescence dorée phytoplasma infection. Most of them did not show any significant difference in recovered plants, which, by contrast, were characterized by changes in abundance, phosphorylation, or both for 17 proteins not detected in infected plants. Some enzymes involved in the antioxidant response that were up-regulated in infected plants, such as isocitrate dehydrogenase and glutathione S-transferase, returned to healthy-state levels in recovered plants. Others belonging to the same functional category were even down-regulated in recovered plants (oxidoreductase GLYR1 and ascorbate peroxidase). Our proteomic approach thus agreed with previously published biochemical and RT-qPCR data which reported down-regulation of scavenging enzymes and accumulation of H2O2 in recovered plants, possibly suggesting a role for this molecule in remission from infection. Fifteen differentially phosphorylated proteins (| ratio | > 2, p < 0.05) were identified in infected compared to healthy plants, including proteins involved in photosynthesis, response to stress and the antioxidant system. Many were not differentially phosphorylated in recovered compared to healthy plants, pointing to their specific role in responding to infection, followed by a return to a steady-state phosphorylation level after remission of symptoms. Gene ontology (GO) enrichment and statistical analysis showed that the general main category "response to stimulus" was over-represented in both infected and recovered plants but, in the latter, the specific child category "response to biotic stimulus" was no longer found, suggesting a return to steady-state levels for those proteins specifically required for defence against pathogens.

CONCLUSIONS

Proteomic data were integrated into biological networks and their interactions were represented through a hypothetical model, showing the effects of protein modulation on primary metabolic ways and related secondary pathways. By following a multiplex-staining approach, we obtained new data on grapevine proteome pathways that specifically change at the phosphorylation level during phytoplasma infection and following recovery, focusing for the first time on phosphoproteome changes during pathogen infection in this host.

Wheat TaRab7 GTPase is part of the signaling pathway in responses to stripe rust and abiotic stimuli

Small GTP-binding proteins function as regulators of specific intercellular fundamental biological processes. In this study, a small GTP-binding protein Rab7 gene, designated as TaRab7, was identified and characterized from a cDNA library of wheat leaves infected with Puccinia striiformis f. sp. tritici (Pst) the wheat stripe rust pathogen. The gene was predicted to encode a protein of 206 amino acids, with a molecular mass of 23.13 KDa and an isoeletric point (pI) of 5.13. Further analysis revealed the presence of a conserved signature that is characteristic of Rab7, and phylogenetic analysis demonstrated that TaRab7 has the highest similarity to a small GTP binding protein gene (BdRab7-like) from Brachypodium distachyon. Quantitative real-time PCR assays revealed that the expression of TaRab7 was higher in the early stage of the incompatible interactions between wheat and Pst than in the compatible interaction, and the transcription level of TaRab7 was also highly induced by environmental stress stimuli. Furthermore, knocking down TaRab7 expression by virus induced gene silencing enhanced the susceptibility of wheat cv. Suwon 11 to an avirulent race CYR23. These results imply that TaRab7 plays an important role in the early stage of wheat-stripe rust fungus interaction and in stress tolerance.

[Construction and analysis of the SSH library with the resistant wheat near-isogenic line and its susceptible parent infected by Puccinia striiformis Westend. f. sp. tritici]

To analyze the differentially expressed genes between resistant and susceptible wheat near-isogenic lines infected by Puccinia striiformis Westend. f. sp. tritici, a subtractive library containing about 1300 clones was constructed using suppression subtractive hybridization (SSH) in which the cDNA from resistant Yr4/6 × Taichung 29 seedlings inoculated with race CY26 was used as the tester, and the corresponding cDNA from susceptible Taichung 29 as the driver. Six hundred clones from the library were analyzed with reverse Northern blot. The positive clones were further tested by Northern blotting analysis. Twelve clones were verified and showed significant difference. By means of sequencing and BlastX analysis, six function-known differentially expressed sequences were detected, and their putative products were leucine-rich repeat protein, catalase, thioredoxin H-type, RNA binding protein, ascorbate peroxidase, and heat shock protein, respectively. Among them, leucine-rich repeat protein belongs to signal transduction protein, and others belong to defense response protein.

Cloning and characterization of a calcium binding EF-hand protein gene TaCab1 from wheat and its expression in response to Puccinia striiformis f. sp. tritici and abiotic stresses

Calcium is a ubiquitous and essential secondary messenger in eukaryotic signal transduction pathways. Calcium binding protein, as a component of pathways, plays various roles in response to biotic and abiotic stresses, as well as in developmental processes in plants. In this study, a calcium binding protein gene, designated as TaCab1 (Triticum aestivum calcium binding EF-hand protein 1), was isolated and characterized from wheat leaves (cv. Suwon 11) infected by Puccinia striiformis f. sp. tritici by in silico cloning and reverse transcription PCR (RT-PCR). TaCab1 did not have an intron and was predicted to encode a 216 amino acid protein which possesses an N-terminal region with a signal peptide, a transmembrane domain, an EF-hand motif and a caleosin domain. The results of transient assays with constructs of TaCab1 with green fluorescent protein (GFP) gene indicated that TaCab1 encodes a transmembrane protein. Quantitative real-time PCR (qRT-PCR) analyses revealed that TaCab1 was highly expressed in leaves than roots and stems. Although up-regulated expression profiles of TaCab1 were quite similar in both incompatible and compatible interactions, its transcript accumulation in the compatible interaction was much higher than in the incompatible interaction. The transcription of TaCab1 was also up-regulated at different degrees after treated by phytohormones [abscisic acid, benzyl adenine, ethylene, methyl jasmonate and salicylic acid (SA)] and stress stimuli [wounding, low temperature, polyethylene glycol and high salinity]. These results suggest that TaCab1 is involved in the plant-pathogen recognition, symptom development, and the basal tolerance to biotic and abiotic stresses through the SA signaling pathway.