Arabidopsis CBF3/DREB1A and ABF3 in Transgenic Rice Increased Tolerance to Abiotic Stress without Stunting Growth  

Abstract

Rice (Oryza sativa), a monocotyledonous plant that does not cold acclimate, has evolved differently from Arabidopsis (Arabidopsis thaliana), which cold acclimates. To understand the stress response of rice in comparison with that of Arabidopsis, we developed transgenic rice plants that constitutively expressed CBF3/DREB1A (CBF3) and ABF3, Arabidopsis genes that function in abscisic acid-independent and abscisic acid-dependent stress-response pathways, respectively. CBF3 in transgenic rice elevated tolerance to drought and high salinity, and produced relatively low levels of tolerance to low-temperature exposure. These data were in direct contrast to CBF3 in Arabidopsis, which is known to function primarily to enhance freezing tolerance. ABF3 in transgenic rice increased tolerance to drought stress alone. By using the 60 K Rice Whole Genome Microarray and RNA gel-blot analyses, we identified 12 and 7 target genes that were activated in transgenic rice plants by CBF3 and ABF3, respectively, which appear to render the corresponding plants acclimated for stress conditions. The target genes together with 13 and 27 additional genes are induced further upon exposure to drought stress, consequently making the transgenic plants more tolerant to stress conditions. Interestingly, our transgenic plants exhibited neither growth inhibition nor visible phenotypic alterations despite constitutive expression of the CBF3 or ABF3, unlike the results previously obtained from Arabidopsis where transgenic plants were stunted.

Molecular, anatomical and physiological properties of a genetically modified soybean line transformed with rd29A:AtDREB1A for the improvement of drought tolerance

“…Both groups possess a conserved DNAbinding domain also found in ethylene-responsive element binding factor (ERF) and AP2 proteins, which was first identified in APETALA2 (Okamuro et al, 1997;Shinozaki and Yamaguchi-Shinozaki, 2000). DREB1A overexpression delays death following withdrawal of irrigation in transgenic wheat (Pellegrineschi et al, 2004), whereas improvements in tolerance to drought, salinity and low-temperature stresses have been reported in Arabidopsis (Kasuga et al, 1999), potato (Behnam et al, 2007, tobacco (Kasuga et al, 2004, rice (Oh et al, 2005) and wheat (Pellegrineschi et al, 2002).…”

A Drought-Inducible Transcription Factor Delays Reproductive Timing in Rice

“…The DNA binding region preferentially interacts with ABA-responsive elements (ABREs), which are predominantly located in the promoter regions of ABAinducible genes (Jakoby et al, 2002;Nijhawan et al, 2008). A great deal of genetic evidence shows that these ABRE-associated bZIP TFs are involved in drought tolerance response (Kang et al, 2002;Oh et al, 2005;Xiang et al, 2008;Lu et al, 2009;Hossain et al, 2010aHossain et al, , 2010bTang et al, 2012). Until now, none had been shown to regulate rice floral transition in response to drought stress.…”

Toward Understanding Molecular Mechanisms of Abiotic Stress Responses in Rice

“…The expression patterns of these genes are similar to their homologs in Arabidopsis, that is, OsDREB1A and OsDREB1B are induced by cold and OsDREB2A is induced by salt and drought [31]. Overexpression of these genes also enhanced the tolerance of Arabidopsis and rice to abiotic stress [31,70,123]. There are, however, some differences between OsDREBs and their orthologs in Arabidopsis.…”