Rice DREB1B promoter shows distinct stress-specific responses, and the overexpression of cDNA in tobacco confers improved abiotic and biotic stress tolerance

Abstract

CBF/DREB (C-repeat binding factor/dehydration responsive element binding factor) family of transcription factors in plants is reported to be associated with regulation of gene expression under stress conditions. Here, we report the functional characterization of a DREB transcription factor, DREB1B gene from rice (Oryza sativa ssp. indica). The OsDREB1B gene was differentially regulated at the transcriptional level by osmotic stress, oxidative stress, salicylic acid, ABA, and cold. A 745 bp promoter region of OsDREB1B cDNA was fused to the beta-glucuronidase (GUS) gene and introduced via Agrobacterium tumifaciens into the genome of Arabidopsis. Histochemical analysis of GUS expression in T(2) transgenic Arabidopsis plants indicated that OsDREB1B shows stress-specific induction pattern in response to a variety of stresses like mannitol, NaCl, PEG, methyl viologen, cold, ABA, and salicylic acid. Leaf-order-dependent induction pattern of the promoter was observed in response to both cold and ABA stresses. Further, OsDREB1B cDNA was introduced into tobacco plants under the control of CaMV35S promoter to investigate the role of DREB1B product in plant stress response. Transgenic tobacco plants have shown improved seed germination, root growth, membrane stability, and 2, 2-diphenyl-1-pycrilhydrazil hydrate (DPPH) free radical scavenging activity under inhibitory concentrations of mannitol. Importantly, transgenic plants accumulated higher fresh weight under long-term osmotic stress, and also have shown retention of more water than the wild type during drought stress. Overexpression of OsDREB1B in tobacco also improved the oxidative and freezing stress tolerance of transgenic plants. In addition, tobacco plants constitutively expressing OsDREB1B have shown decreased sensitivity to tobacco streak virus infection. Constitutive expression of OsDREB1B in tobacco also induced the expression of PR genes in transgenic plants. The data obtained provide strong in vivo evidence that OsDREB1B is involved in both abiotic and biotic stress responses, and confers broad-spectrum stress tolerance to transgenic plants.

The Submergence Tolerance Regulator Sub1A Mediates Stress-Responsive Expression of AP2/ERF Transcription Factors

“…Arabidopsis TF DREB1 in IIIc controls the expression of many stress-inducible genes. OsDREB1A and OsDREB1B, DREB1 orthologs in rice, are induced by cold stress, and the overexpression of OsDREB1 increased tolerance to highsalt and freezing stresses (Ito et al, 2006;Gutha and Reddy, 2008). These rice transgenic plants also showed growth retardation under normal conditions, implicating rice AP2/ERF TFs in group IIIc function as repressors of GA biosynthesis, although we cannot ignore the possibility that group IIIc regulates BR biosynthesis or response (Ito et al, 2006).…”

Advances in physiological and molecular aspects of plant cold tolerance

“…Chinnusamy et al (2003) reported that ICE1, which is a nuclear gene encoding a MYC-like bHLH protein, has a crucial role in regulating some CBF genes. The role of ICE1-CBF/DREB1 singling pathway in increasing cold tolerance has been investigated in different plant species such as A. thaliana (Welling & Palva 2008;Chen et al 2009;Fursova et al 2009;Yang et al 2011), Cucumis sativa , Triticum aestivum (Miller et al 2006;Morran et al 2011), Hordeum vulgare L. (Stockinger et al 2007;Campoli et al 2009), Solanum tuberosum (Behnam et al 2007), eucalyptus (Navarro et al 2009), Nicotiana plumbaginfolia (Gutha & Reddy 2008), apple (Artlip et al 2014), etc. Badawi et al (2008 reported that there are two ICE1 homologs, TaICE141 and TaICE187, in wheat and they up-regulate the expression of CBF group IV genes in wheat.…”

Transcription factors as tools to engineer enhanced drought stress tolerance in plants

“…Many key genes have been identified that are involved in the regulatory networks under abiotic stress (Seki et al, 2007). Probably the best studied group of TFs involved in abiotic stress particularly, in drought and cold tolerance are the DREB1 genes (Gutha and Reddy, 2008;Oh et al, 2007;Qin et al, 2007;Sakuma et al, 2006). Many osmotic stress inducible genes contain a conserved drought responsive element (DRE) in their promoters (Shinozaki and Yamaguchi-Shinozaki, 2000;Thomashow, 1999).…”