Identification and characterization of the novel gene GhDBP2 encoding a DRE-binding protein from cotton (Gossypium hirsutum).
ABSTRACT A cDNA encoding one novel DRE-binding protein, GhDBP2, was isolated from cotton seedlings. It is classified into the A-6 group of DREB subfamily based on multiple sequence alignment and phylogenetic characterization. Using semi-quantitative RT-PCR, we found that the GhDBP2 transcripts were greatly induced by drought, NaCl, low temperature and ABA treatments in cotton cotyledons. The DNA-binding properties of GhDBP2 were analyzed by electrophoretic mobility shift assay (EMSA), showing that GhDBP2 successfully binds to the previously characterized DRE cis-element as well as the promoter region of the LEA D113 gene. Consistent with its role as a DNA-binding protein, GhDBP2 is preferentially localized to the nucleus of onion epidermal cells. In addition, when GhDBP2 is transiently expressed in tobacco cells, it activates reporter gene expression driven by the LEA D113 promoter. Taken together, our results indicate that GhDBP2 is a DRE-binding transcriptional activator involved in activation of down-stream genes such as LEA D113 expression through interaction with the DRE element, in response to environmental stresses as well as ABA treatment.
Article: Transcriptional profiling of Medicago truncatula under salt stress identified a novel CBF transcription factor MtCBF4 that plays an important role in abiotic stress responses.[show abstract] [hide abstract]
ABSTRACT: Salt stress hinders the growth of plants and reduces crop production worldwide. However, different plant species might possess different adaptive mechanisms to mitigate salt stress. We conducted a detailed pathway analysis of transcriptional dynamics in the roots of Medicago truncatula seedlings under salt stress and selected a transcription factor gene, MtCBF4, for experimental validation. A microarray experiment was conducted using root samples collected 6, 24, and 48 h after application of 180 mM NaCl. Analysis of 11 statistically significant expression profiles revealed different behaviors between primary and secondary metabolism pathways in response to external stress. Secondary metabolism that helps to maintain osmotic balance was induced. One of the highly induced transcription factor genes was successfully cloned, and was named MtCBF4. Phylogenetic analysis revealed that MtCBF4, which belongs to the AP2-EREBP transcription factor family, is a novel member of the CBF transcription factor in M. truncatula. MtCBF4 is shown to be a nuclear-localized protein. Expression of MtCBF4 in M. truncatula was induced by most of the abiotic stresses, including salt, drought, cold, and abscisic acid, suggesting crosstalk between these abiotic stresses. Transgenic Arabidopsis over-expressing MtCBF4 enhanced tolerance to drought and salt stress, and activated expression of downstream genes that contain DRE elements. Over-expression of MtCBF4 in M. truncatula also enhanced salt tolerance and induced expression level of corresponding downstream genes. Comprehensive transcriptomic analysis revealed complex mechanisms exist in plants in response to salt stress. The novel transcription factor gene MtCBF4 identified here played an important role in response to abiotic stresses, indicating that it might be a good candidate gene for genetic improvement to produce stress-tolerant plants.BMC Plant Biology 07/2011; 11:109. · 3.45 Impact Factor