A C-Repeat Binding Factor Transcriptional Activator (CBF/DREB1) from European Bilberry (Vaccinium myrtillus) Induces Freezing Tolerance When Expressed in Arabidopsis thaliana

Abstract

Freezing stress affects all plants from temperate zones to the poles. Global climate change means such freezing events are becoming less predictable. This in turn reduces the ability of plants to predict the approaching low temperatures and cold acclimate. This has consequences for crop yields and distribution of wild plant species. C-repeat binding factors (CBFs) are transcription factors previously shown to play a vital role in the acclimation process of Arabidopsis thaliana, controlling the expression of hundreds of genes whose products are necessary for freezing tolerance. Work in other plant species cements CBFs as key determinants in the trait of freezing tolerance in higher plants. To test the function of CBFs from highly freezing tolerant plants species we cloned and sequenced CBF transcription factors from three Vaccinium species (Vaccinium myrtillus, Vaccinium uliginosum and Vaccinium vitis-idaea) which we collected in the Arctic. We tested the activity of CBF transcription factors from the three Vaccinium species by producing transgenic Arabidopsis lines overexpressing them. Only the Vaccinium myrtillus CBF was able to substantially activate COR (CBF-target) gene expression in the absence of cold. Correspondingly, only the lines expressing the Vaccinium myrtillus CBF were constitutively freezing tolerant. The basis for the differences in potency of the three Vaccinium CBFs was tested by observing cellular localisation and protein levels. All three CBFs were correctly targeted to the nucleus, but Vaccinium uliginosum CBF appeared to be relatively unstable. The reasons for lack of potency for Vaccinium vitis-idaea CBF were not due to stability or targeting, and we speculate that this was due to altered transcription factor function.

Isolation and characterization of a C-repeat binding factor (CBF)-like gene in cassava (Manihot esculenta Crantz)

“…The amino acid change is also found in CBF4 from A. thaliana, HbCBF1 from H. brasiliensis, CBFs from Vaccinium myrtillus. It has been previously demonstrated that the change in V. myrtillus CBFs do not inhibit the binding of CBF to the DRE/CRT DNA motif (Polashock et al 2010;Walworth et al 2012;Oakenfull et al 2013). Therefore, the change in cassava MeCBF1 may not inhibit its function.…”

“…The deduced amino acid sequence of MeCBF1 is 231 amino acids, and contains motifs of PKK(P/R)AGRxKFxETRHP and DSxWR (Fig. 1), which are commonly conserved in C-repeat binding factor transcriptional activator genes (Canella et al 2010;He et al 2012;Oakenfull et al 2013;Peng et al 2013). The molecular weight (MW) and theoretical isoelectric point (PI) were 25.572 kDa and 5.36, respectively, which were calculated by the online Computer PI/Mw Tool (http://cn.expasy.org/tool).…”

“…On the contrary, plants, from tropical and subtropical regions, are sensitive to chilling temperature, and would be easily injured when the temperatures are lower than 12°C. Transcription factors play critical roles in plant stress signaling pathways through modulating expression of cold-related genes during cold acclimation (Qin et al 2011;Zhou et al 2011;Oakenfull et al 2013). A gene family, CBF/DREB1 coding genes, has been isolated from many cold resistant plant species, such as A. thaliana (Thomashow et al 2001;Gilmour et al 2004;Novillo et al 2007), Brassica napus (Gao et al 2002), Triticum aestivum (Badawi et al 2007), Malus pumila (Yang et al 2011), Vitis amurensis (Xiao et al 2006;Dong et al 2013), Vaccinium corymbosum (Walworth et al 2012), and Populus spp (Benedict et al 2006).…”

The Omics of Cold Stress Responses in Plants

“…Overexpression of OsDREB1A (Dubouzet et al 2003 ), maize DREB1 (Qin et al 2004 ), a modifi ed AP2/ERF transcription factor from Brassica napus (Xiong et al 2013 ), Vaccinium myrtillus CBF/DREB1 (Oakenfull et al 2013 ) in transgenic Arabidopsis plants resulted in enhanced freezing tolerance. Transgenic barley lines overexpressing TaCBF14 and TaCBF15 exhibited enhanced freezing tolerance (Soltesz et al 2013 ).…”

Molecular cloning and characterization of a novel freezing-inducible DREB1/CBF transcription factor gene in boreal plant Iceland poppy (Papaver nudicaule)

“…Cold-inducible DREB1/CBF genes have been isolated from numerous dicotyledonous plant species, such as oilseed rape, Vaccinium myrtillus (Oakenfull et al , 2013), Caragana korshinskii (Wang et al , 2011), Capsicum annuum (Hong and Kim, 2005), grape (Xiao et al , 2006), and chrysanthemum (Tong et al. , 2009), as well as monocotylous plant species, such as wheat ( Triticum aestivum ), rye ( Secale cereale ) (Jaglo et al , 2001), rice (Dubouzet et al , 2003), maize (Qin et al , 2004), etc.…”