AP2 DNA-binding Domain Research Articles

Functional Characterization of Tea Plant (Camellia sinensis L.) CsCBF2 Gene Involved in Multiple Abiotic Stress Response in Tobacco (Nicotiana tabacum L.)

C-repeat binding factors/dehydration responsive element binding factors 1 (CBFs/DREB1s) are a small family of transcription factors that play important roles in plant resistance to various external stresses. However, functional characterization of tea plant (Camellia sinensis L.) CBF gene (CsCBF) was still seldom reported. Here, functional study of the cold-responsive CBF gene (CsCBF2) was done. Results showed that CsCBF2 had conserved AP2 DNA-binding domain and the typical PKK/RPAGRxKFxETRHP and DSAWR signature sequences of CBF/DREB1. Yeast one-hybrid and transcription activation assays revealed that the activation domain of CsCBF2 could activate the reporter gene expression, and the N terminal of CsCBF2 displayed an inhibitory effect. Although CsCBF2 was conserved to bind the C-repeat/dehydration-responsive element (CRT/DRE), intact CsCBF2 protein preferred the CRT cis element. Under normal growth conditions, CsCBF2-overexpressing tobacco plants (CsCBF2-OX) exhibited lighter green leaf color, growth retardation, and dwarfism. Smaller leaf of CsCBF2-OX was only seen in eight weeks after been sown in soil. Under cold, salinity, or drought stress, CsCBF2-OX displayed better growing with longer roots, heavier fresh weight, higher germination rate, and accumulated more proline and sugar contents, but lower electrolyte leakage. The results demonstrated that CsCBF2 enhanced plant tolerance to multiple abiotic stresses.

Genome-wide identification and expression analysis of the CBF/DREB1 gene family in lettuce

The C-repeat binding factor (CBF)/dehydration-responsive element binding (DREB1) proteins play a prominent role in freezing tolerance and are highly conserved in higher plants. Here we performed a genome-wide search of the CBF/DREB1 gene family in lettuce (Lactuca sativa L.) and identified 14 members of the family with one member gene containing a non-sense mutation within the AP2 DNA-binding domain. A comprehensive phylogenetic analysis of the CBF/DREB1 family members in 20 plant species from the Asterid or Rosid clade provided evidence that tandem duplication played an important role in the expansion of the CBF/DREB1 family. Expression analysis showed that twelve of the lettuce CBF genes were responsive to low temperature (4 °C), and that three and six of them could also be responsive to salt and heat stresses, respectively. Unlike Arabidopsis thaliana whose members of the CBF/DREB1 family respond only to a particular stress, lettuce CBFs provide wider protection from combinations of abiotic stresses. A global transcriptome analysis revealed distinctive temporal expression patterns among the cold-regulated genes in lettuce plants exposed to low temperature. Genes induced throughout the cold treatment are enriched in functions associated with protection from UV and high-light intensity and the genes suppressed after 7 days of cold exposure are enriched in photosynthesis-associated functions. These results provide insight into the molecular evolutionary properties of the CBF/DREB1 gene family in lettuce and a reference for genetic improvement of the lettuce response to cold acclimation.

Isolation and characterization of a c-repeat binding factor gene from <i> Tevang-1</i> maize cultivar

C-repeat binding factor (CBF) proteins are transcription factors involved in plant response to abiotic stresses, especially low-temperature condition. In this research, a CBF3-coding gene was isolated from a cold-acclimation maize variety, Zea mays var. Tevang-1 and denoted as ZmCBF3tv. The isolated gene shared 96.49% homology with the B73-reference gene and had no intron in the coding sequence. By using bioinformatic tools, a number of variations in the nucleotide and amino acid sequences were identified. An alignment between ZmCBF3tv and other CBF/DREB1 proteins from various species revealed functional regions and typical features, such as nuclear localization signal (NLS), the AP2 DNA-binding domain, and acidic-amino-acid-rich segments. Additionally, a phylogenetic analysis based on the AP2 domain showed that the maize CBF3 transcription factor had the highest similarity with that from rice and closely related to other DREB1/CBF protein of monocots. The function of the ZmCBF3tv product is suggested to be a CBF/DREB1 transcription factor.

Isolation and characterization of a c-repeat binding factor gene from <i> Tevang-1</i> maize cultivar

C-repeat binding factor (CBF) proteins are transcription factors involved in plant response to abiotic stresses, especially low-temperature condition. In this research, a CBF3-coding gene was isolated from a cold-acclimation maize variety, Zea mays var. Tevang-1 and denoted as ZmCBF3tv. The isolated gene shared 96.49% homology with the B73-reference gene and had no intron in the coding sequence. By using bioinformatic tools, a number of variations in the nucleotide and amino acid sequences were identified. An alignment between ZmCBF3tv and other CBF/DREB1 proteins from various species revealed functional regions and typical features, such as nuclear localization signal (NLS), the AP2 DNA-binding domain, and acidic-amino-acid-rich segments. Additionally, a phylogenetic analysis based on the AP2 domain showed that the maize CBF3 transcription factor had the highest similarity with that from rice and closely related to other DREB1/CBF protein of monocots. The function of the ZmCBF3tv product is suggested to be a CBF/DREB1 transcription factor.

An ApiAP2 member regulates expression of clonally variant genes of the human malaria parasite Plasmodium falciparum

Variegated surface antigen expression is key to chronic infection and pathogenesis of the human malaria parasite Plasmodium falciparum. This protozoan parasite expresses distinct surface molecules that are encoded by clonally variant gene families such as var, rif and stevor. The molecular mechanisms governing activation of individual members remain ill-defined. To investigate the molecular events of the initial transcriptional activation process we focused on a member of the apicomplexan ApiAP2 transcription factor family predicted to bind to the 5′ upstream regions of the var gene family, AP2-exp (PF3D7_1466400). Viable AP2-exp mutant parasites rely on expressing no less than a short truncated protein including the N-terminal AP2 DNA-binding domain. RNA-seq analysis in mutant parasites revealed transcriptional changes in a subset of exported proteins encoded by clonally variant gene families. Upregulation of RIFINs and STEVORs was validated at the protein levels. In addition, morphological alterations were observed on the surface of the host cells infected by the mutants. This work points to a complex regulatory network of clonally variant gene families in which transcription of a subset of members is regulated by the same transcription factor. In addition, we highlight the importance of the non-DNA binding AP2 domain in functional gene regulation.

Cytokinin Response Factor 5 has transcriptional activity governed by its C-terminal domain

ABSTRACTCytokinin Response Factors (CRFs) are AP2/ERF transcription factors involved in cytokinin signal transduction. CRF proteins consist of a N-terminal dimerization domain (CRF domain), an AP2 DNA-binding domain, and a clade-specific C-terminal region of unknown function. Using a series of sequential deletions in yeast-2-hybrid assays, we provide evidence that the C-terminal region of Arabidopsis CRF5 can confer transactivation activity. Although comparative analyses identified evolutionarily conserved protein sequence within the C-terminal region, deletion experiments suggest that this transactivation domain has a partially redundant modular structure required for activation of target gene transcription.

Expression and regulation of a cold-responsive gene,CsCBFinCitrus sinensis(L.) Osbeck under low temperature, high salinity and abscisic acid

CBF (C-Repeat/Dehydration-Responsive Element Binding Factor) as a transcription factor plays important roles in stress responses and stress-related regulatory network in plants. CsCBF, a CBF encoding gene in sweet orange (Citrus sinensis (L.) Osbeck) was isolated and investigated in expression profiles under abiotic stresses. Semi-quantitative RT-PCR analysis indicated that CsCBF expression was altered obviously in response to low temperature (4°C), high salinity (250 mM NaCl) and abscisic acid (100 μM ABA). To learn more information about CsCBF gene, genomic DNA and upstream regulatory sequence were sequenced definitely and analyzed with a series of bioinformatic tools. The results showed that there were no introns in CsCBF genomic DNA, and CBF signature sequences and AP2 DNA binding domain were also highly conserved in CsCBF amino acid sequence. In addition, more than one CBF protein was encoded in sweet orange genome. Promoter prediction analysis suggested that several stress-related cis-acting elements were detected in CsCBF regulatory region, such as MYB, MYC, ABRE, Circadian, et al.. Importantly, two putative induction regions of CBF expression, ICEr1 and ICEr2, were also found in an 85-bp section of CsCBF promoter, which may contribute to understanding of CBF transcriptional activation under stress.

Genome-wide investigation and expression analysis of AP2-ERF gene family in salt tolerant common bean.

Apetala2-ethylene-responsive element binding factor (AP2-ERF) superfamily with common AP2-DNA binding domain have developmentally and physiologically important roles in plants. Since common bean genome project has been completed recently, it is possible to identify all of the AP2-ERF genes in the common bean genome. In this study, a comprehensive genome-wide in silico analysis identified 180 AP2-ERF superfamily genes in common bean (Phaseolus vulgaris). Based on the amino acid alignment and phylogenetic analyses, superfamily members were classified into four subfamilies: DREB (54), ERF (95), AP2 (27) and RAV (3), as well as one soloist. The physical and chemical characteristics of amino acids, interaction between AP2-ERF proteins, cis elements of promoter region of AP2-ERF genes and phylogenetic trees were predicted and analyzed. Additionally, expression levels of AP2-ERF genes were evaluated by in silico and qRT-PCR analyses. In silico micro-RNA target transcript analyses identified nearly all PvAP2-ERF genes as targets of by 44 different plant species' miRNAs were identified in this study. The most abundant target genes were PvAP2/ERF-20-25-62-78-113-173. miR156, miR172 and miR838 were the most important miRNAs found in targeting and BLAST analyses. Interactome analysis revealed that the transcription factor PvAP2-ERF78, an ortholog of Arabidopsis At2G28550, was potentially interacted with at least 15 proteins, indicating that it was very important in transcriptional regulation. Here we present the first study to identify and characterize the AP2-ERF transcription factors in common bean using whole-genome analysis, and the findings may serve as a references for future functional research on the transcription factors in common bean.

Genome-Wide Identification of the Target Genes of AP2-O, a Plasmodium AP2-Family Transcription Factor.

Stage-specific transcription is a fundamental biological process in the life cycle of the Plasmodium parasite. Proteins containing the AP2 DNA-binding domain are responsible for stage-specific transcriptional regulation and belong to the only known family of transcription factors in Plasmodium parasites. Comprehensive identification of their target genes will advance our understanding of the molecular basis of stage-specific transcriptional regulation and stage-specific parasite development. AP2-O is an AP2 family transcription factor that is expressed in the mosquito midgut-invading stage, called the ookinete, and is essential for normal morphogenesis of this stage. In this study, we identified the genome-wide target genes of AP2-O by chromatin immunoprecipitation-sequencing and elucidate how this AP2 family transcription factor contributes to the formation of this motile stage. The analysis revealed that AP2-O binds specifically to the upstream genomic regions of more than 500 genes, suggesting that approximately 10% of the parasite genome is directly regulated by AP2-O. These genes are involved in distinct biological processes such as morphogenesis, locomotion, midgut penetration, protection against mosquito immunity and preparation for subsequent oocyst development. This direct and global regulation by AP2-O provides a model for gene regulation in Plasmodium parasites and may explain how these parasites manage to control their complex life cycle using a small number of sequence-specific AP2 transcription factors.

A novel CBF that regulates abiotic stress response and the ripening process in oil palm (Elaeis guineensis) fruits

A new member of the C-repeat binding factor (CBF) encoding an AP2-domain protein was isolated from ripening oil palm (Elaeis guineensis var. Dura × Pisifera) fruit. Bioinformatics analysis revealed that EgCBF3 has an AP2 DNA binding domain containing 57 amino acids. According to the signature sequences found upstream and downstream of the AP2 domain, it was predicted that the deduced amino acid sequence belongs to the A-1 group of the CBF/DREB1 subfamily. EgCBF3 is differentially expressed in the fruit mesocarp tissue with the highest transcript accumulation in ripening fruit at 17 weeks after anthesis (w.a.a.). In the vegetative tissues, it showed higher expression levels in the roots compared to the leaves. In the mesocarp tissue, expression of EgCBF3 was upregulated after 2 h and peaked after 24 h of cold, ethylene and ABA treatments, while for drought and salt stresses, it exhibited the highest expression after 4 and 8 h, respectively. GFP fusion protein of EgCBF3 was localized to the nucleus of the onion’s epidermal cells. The in vitro and in vivo DNA-protein transactivation assay using electrophoretic mobility shift assay (EMSA) and yeast one-hybrid analysis revealed that EgCBF3 was able to bind to the DRE/CRT cis-element. Tomato was chosen as a model system for the climacteric oil palm fruits. Expression profile of the ethylene and abscisic acid biosynthesis-related genes and ripening-related genes were affected by transient overexpression of EgCBF3 in the tomato fruits at different developmental stages. These results suggest that EgCBF3 can mediate abiotic stress response in ripening fruits and may function as a regulator of ripening process-related genes.

Genome-wide analysis of the AP2/ERF family in Eucalyptus grandis: an intriguing over-representation of stress-responsive DREB1/CBF genes.

BackgroundThe AP2/ERF family includes a large number of developmentally and physiologically important transcription factors sharing an AP2 DNA-binding domain. Among them DREB1/CBF and DREB2 factors are known as master regulators respectively of cold and heat/osmotic stress responses.Experimental ApproachesThe manual annotation of AP2/ERF family from Eucalyptus grandis, Malus, Populus and Vitis genomes allowed a complete phylogenetic study for comparing the structure of this family in woody species and the model Arabidopsis thaliana. Expression profiles of the whole groups of EgrDREB1 and EgrDREB2 were investigated through RNAseq database survey and RT-qPCR analyses.ResultsThe structure and the size of the AP2/ERF family show a global conservation for the plant species under comparison. In addition to an expansion of the ERF subfamily, the tree genomes mainly differ with respect to the group representation within the subfamilies. With regard to the E. grandis DREB subfamily, an obvious feature is the presence of 17 DREB1/CBF genes, the maximum reported to date for dicotyledons. In contrast, only six DREB2 have been identified, which is similar to the other plants species under study, except for Malus. All the DREB1/CBF and DREB2 genes from E. grandis are expressed in at least one condition and all are heat-responsive. Regulation by cold and drought depends on the genes but is not specific of one group; DREB1/CBF group is more cold-inducible than DREB2 which is mainly drought responsive.ConclusionThese features suggest that the dramatic expansion of the DREB1/CBF group might be related to the adaptation of this evergreen tree to climate changes when it expanded in Australia.

Studies on Molecular Characterization of DREB Gene in Indica Rice (Oryza sativa L.)

Number of potential candidate genes (CGs) has been identified by transcriptome and transgenic approaches involved in the adaptive responses to drought in cereals. One of these genes conferring tolerance to drought is DREB gene family. The exploration of genetic/allelic variation within the DREB gene family is an important prerequisite towards a better understanding of stress tolerance. The present investigation aims to study allelic variation in nucleotide sequence within DREB gene of different rice cultivars need for crop improvement programme. Ten upland as well as lowland rice cultivars was used for molecular characterization and allele mining. The results showed that the DREB gene was found in all the tested germplasm and submitted to NCBI GenBank (accession numbers KF 545561 to KF 545569). Bioinformatics analysis showed that 100 percent identity with AP2 DNA binding domain of 59 amino acids which showed conserved three sheets with 14th valine and 19th glutamic acid conserved residues. AP2 domain of putative DREB protein were found rich in alanine (17.6%) and arginine (15.7%) amino acids with a predicted molecular mass of 5.89 kDa and iso-elecric point (pI) 10.38. It is observed that DREB gene nucleotide sequences were verified with DNA polymorphism analysis, out of which 196 invariable (monomorphic) and 8 variable (polymorphic) i.e. segregating sites were identified including 9 number of mutation and 5 haplotypes. The haplotypes (gene) diversity was 0.756; the variance and standard deviation diversity were 0.01678 and 0.130 respectively. The result showed that the variety ‘Khandagiri’ showed 97.5% similarity with all accessions DREB gene of rice and 0.036% evolutionary divergence with AK121956 accession present in the database. This might have enhanced the capability of DREB gene as a transcription factor and that lead to provide better adoption and tolerance capability of the cultivar during drought.

Characterization and expression analysis of three CBF/DREB1 transcriptional factor genes from mangrove Avicennia marina

Three CBF/DREB1 (C-repeat binding factor/dehydration responsive element-binding factor 1) homologues were isolated from mangrove Avicennia marina and designated AmCBF1, 2 and 3. Multiple sequence analysis showed that the three deduced proteins all contain an AP2 DNA-binding domain and two CBF signature sequences. According to the phylogenetic analysis, these proteins belong to the A-1 subgroup of the DREB subfamily. Expression analyses based on quantitative real-time PCR revealed that the AmCBF2 displayed relatively high expression under normal conditions, with the highest level in stems, while both AmCBF1 and 3 were weakly expressed without stress. The three genes also showed different responses to various environmental stimuli. The AmCBF2 was inducible by cold, drought, high salinity, heavy metals, as well as abscisic acid (ABA), and exhibited much stronger induction by cold, drought, Pb2+ or Zn2+ than by NaCl, ABA or Cd2+. In contrast, both AmCBF1 and AmCBF3 displayed insignificant changes under these stimuli. These results indicate that the three AmCBF genes play different roles in A. marina and the AmCBF2 might be involved in the signaling pathway of cold, drought and heavy metal stress response.

Isolation and characterization of an AP2/ERF-type drought stress inducible transcription factor encoding gene from rice

A genomic DNA fragment of 964 bp corresponding to AP2/ERF family transcription factor was isolated from drought tolerant Oryza sativa L. cv. ‘N-22’ (AP2/ERF-‘N-22’) and Oryza sativa L. cv. ‘Teipei 309’ (AP2/ERF-jap). The cDNA sequence of AP2/ERF-‘N-22’ (732 bp) was amplified using gene specific primers. The gene contains two exons and a single intron. The deduced protein of the AP2/ERF-‘N-22’ contains a potential nuclear localization signal, a possible regulation domain and an AP2 DNA binding domain of 60 amino acids. Northern and RT-PCR analysis showed that transcript of AP2/ERF-‘N-22’ accumulates in response to WDS and the Southern analysis indicated the presence of single copy of AP2/ERF-‘N-22’ gene in Oryza sativa genome. Phylogenetic analysis of AP2/ERF family revealed that AP2/ERF-‘N-22’ belongs to group Va along with SHN clade of AP2/ERF protein which activates wax biosynthesis. A higher epicuticular wax content was observed at decreased RWC and positively correlated with AP2/ERF-‘N-22’ expression.

The EDLL motif: a potent plant transcriptional activation domain from AP2/ERF transcription factors

In plants, the ERF/EREBP family of transcriptional regulators plays a key role in adaptation to various biotic and abiotic stresses. These proteins contain a conserved AP2 DNA-binding domain and several uncharacterized motifs. Here, we describe a short motif, termed 'EDLL', that is present in AtERF98/TDR1 and other clade members from the same AP2 sub-family. We show that the EDLL motif, which has a unique arrangement of acidic amino acids and hydrophobic leucines, functions as a strong activation domain. The motif is transferable to other proteins, and is active at both proximal and distal positions of target promoters. As such, the EDLL motif is able to partly overcome the repression conferred by the AtHB2 transcription factor, which contains an ERF-associated amphiphilic repression (EAR) motif. We further examined the activation potential of EDLL by analysis of the regulation of flowering time by NF-Y (nuclear factor Y) proteins. Genetic evidence indicates that NF-Y protein complexes potentiate the action of CONSTANS in regulation of flowering in Arabidopsis; we show that the transcriptional activation function of CONSTANS can be substituted by direct fusion of the EDLL activation motif to NF-YB subunits. The EDLL motif represents a potent plant activation domain that can be used as a tool to confer transcriptional activation potential to heterologous DNA-binding proteins.

Isolation and characterisation of a gene for a DREB transcription factor from Phyllostachys edulis induced by drought

SummaryWe have cloned a novel drought-induced gene PeDREB2 from Phyllostachys edulis using the RACE method and demonstrated that the deduced protein sequence contained a conserved AP2 DNA-binding domain that belonged to the EREBP/AP2 family. PeDREB2 gene expression peaked at 12 h under conditions of drought stress, and transcripts accumulated rapidly by 6 h under salt stress, but expression was not affected by abscisic acid or cold stress treatments. In onion epidermal cells, the recombinant protein, PeDREB2-163GFP, was localised to the nucleus. In yeast, the PeDREB2 protein bound specifically to dehydration-response elements to activate transcription of the His3 and LacZ reporter genes. When fused to a sequence encoding the LexA DNA-binding domain, the PeDREB2 protein was an effective trans-activator in the yeast one-hybrid assay. Therefore, PeDREB2 represents a novel transcription factor and, like other EREBP/AP2 regulons, is activated in response to environmental stress factors in tropical plants such as Phyllostachys edulis (bamboo).

Discovery, phylogeny and expression patterns of AP2-like genes in maize

A transcription factor (TF) is a protein that binds to specific DNA sequences and thereby controls transcription. A large number of TFs are found in plants. The AP2/ERF family of TFs contain the AP2 DNA-binding domain, which play important roles in transcriptional regulation in plant life. To understand the AP2/ERF family TFs of maize, the discovery, phylogeny and expression pattern analysis of AP2-like genes from maize were described. A total of 167 AP2-like genes were identified by in silico cloning using the amino acid sequence of AP2/ERF family TFs from Arabidopsis thaliana as the probe. The maize AP2-like genes identified were orthologous to those TFs in Arabidopsis. The AP2/ERF TFs from maize were classified into four subfamilies (DREB, ERF, AP2 and RAV) and a Soloist. Using the EST information of maize as a source of expression data, those AP2-like genes from maize were detected in different plant tissues.

Complementary regulation of four Eucalyptus CBF genes under various cold conditions

CBF transcription factors play central roles in the control of freezing tolerance in plants. The isolation of two additional CBF genes, EguCBF1c and EguCBF1d, from E. gunnii, one of the cold-hardiest Eucalyptus species, is described. While the EguCBF1D protein sequence is very similar to the previously characterized EguCBF1A and EguCBF1B sequences, EguCBF1C is more distinctive, in particular in the AP2-DBD (AP2-DNA binding domain). The expression analysis of the four genes by RT-qPCR reveals that none of them is specific to one stress but they are all preferentially induced by cold, except for the EguCBF1c gene which is more responsive to salt. The calculation of the transcript copy number enables the quantification of constitutive CBF gene expression. This basal level, significant for the four genes, greatly influences the final EguCBF1 transcript level in the cold. A cold shock at 4 °C, as well as a progressive freezing which mimics a natural frost episode, trigger a fast and strong response of the EguCBF1 genes, while growth at acclimating temperatures results in a lower but more durable induction. The differential expression of the four EguCBF1 genes under these cold regimes suggests that there is a complementary regulation. The high accumulation of the CBF transcript, observed in response to the different types of cold conditions, might be a key for the winter survival of this evergreen broad-leaved tree.

Identification of candidate CBF genes for the frost tolerance locus Fr-A m 2 in Triticum monococcum

A cluster of eleven CBF genes was recently mapped to the Frost resistance-2 (Fr-Am2) locus on chromosome 5 of diploid wheat (Triticum monococcum) using a cross between frost tolerant accession G3116 and frost sensitive DV92. The Fr-Am2 locus was mapped at the peak of two overlapping quantitative trait loci (QTL), one for frost survival and the other for differential expression of the cold regulated gene COR14b. Seven lines with recombination events within the CBF cluster were used to identify CBF candidate genes for these QTL. The lines carrying the critical recombination events were tested for whole plant frost survival and for differential transcript levels of cold induced COR14b and DHN5 genes. The strongest effect for these traits was associated to the linked TmCBF12, TmCBF14 and TmCBF15 genes, with the G3116 allele conferring improved frost tolerance and higher levels of COR14b and DHN5 transcript at mild cold temperatures (12-15 degrees C) than the DV92 allele. Comparison of CBF protein sequences revealed that the DV92 TmCBF12 protein contains a deletion of five amino acids in the AP2 DNA binding domain. Electrophoretic Mobility Shift Assays (EMSA) confirmed that the protein encoded by this allele cannot bind to the CRT/DRE (C-repeat/ dehydration-responsive element) motif present in the promoters of several cold induced genes. A smaller effect on frost tolerance was mapped to the distal group of CBF genes including TmCBF16. Transcript levels of TmCBF16, as well as those of TmCBF12 and TmCBF15 were up-regulated at mild cold temperatures in G3116 but not in DV92. Higher threshold induction temperatures can result in earlier initiation of the cold acclimation process and better resistance to subsequent freezing temperatures. The non-functional TmCBF12 allele in DV92 can also contribute to its lower frost tolerance.

Molecular cloning, bioinformatics, and expression profiling of a dehydration-responsive element-binding-2 (DREB2) homologue from Festuca arundinacea, FapDREB2, with high drought tolerance

SummaryImprovement of drought tolerance in plants depends upon understanding their molecular responses to dehydration stress. The drought resistance of 14 varieties of tall fescue (Festuca arundinacea Schreb.) was analysed by measuring various physiological traits under high temperature and drought conditions. A dehydration-responsive element-binding-2 (DREB2) homologue cDNA from the cultivar ‘Plantation’, with high drought tolerance, designated FapDREB2, was isolated and sequenced. The FapDREB2 cDNA was predicted to encode a protein of 262 amino acid residues, with a molecular mass of 41.3 kDa and a pI of 5.28. Its deduced protein sequence, with a conserved AP2 DNA-binding domain, shared characteristics with the DREB2 gene family based on sequence homology, structure and phylogenetic analysis. Expression of the FapDREB2 gene in different plant organs indicated that its transcripts were abundant in leaves and leaf sheaths, and scarce in roots. In addition, FapDREB2 gene expression under drought and high temperature conditions was stronger than without such treatments in the laboratory. FapDREB2 mRNA accumulated in response to various abiotic stresses, confirming that its expression was induced more prominently by drought or salt treatment than by cold stress, and did not respond to abscisic acid (ABA) treatment. FapDREB2 gene expression in seedlings grown in a study plot varied irregularly under drought and high temperature conditions, in contrast to seedlings grown with drought treatment in the laboratory. This suggests that expression of the DREB2 transcription factor would be complex during plant responses to different stresses. We concluded that the FapDREB2 gene is involved in plant responses to drought or salt stress through an ABA-independent pathway, which may lead to a better understanding of the regulatory mechanism of the DREB2 transcription factor in tall fescue.