Cold-induced modulation of CbICE53 gene activates endogenous genes to enhance acclimation in transgenic tobacco

Abstract

Inducers of C-repeat binding factor (CBF) expression [inducer of CBF expression 1 (ICE1)-like], being MYC-type transcription factors, play an important role in plant tolerance to low temperatures and other abiotic environmental stresses. These ICEs are the key activators binding to C-repeat/dehydration-responsive elements, triggering the response of CBF signaling and other cold-related genes under cold stress. Our previous report documented a novel ICE transcription factor from Capsella bursa-pastoris, named CbICE53 (GenBank accession no. AY506804), which is responsive to cold, salt stress, and exogenous IAA, GA3, ABA, MeJA, and SA. In the present study, subcellular localization analyses reveal that CbICE53 is specifically localized to the nucleus. Similarly to AtICE1, CbICE53 exhibited slightly increased transcript level under cold induction. Compared with wild-type plants, transformants overexpressing CbICE53 showed increased tolerance to both chilling and freezing temperature according to the index of electrolyte leakage, relative water content and glucose content, and survival rate assay. The expressions of endogenous cold-responsive genes in transgenic tobacco (NtDREB1, NtDREB3, NtERD10a, and NtERD10b) were obviously upregulated only in cold condition. These results suggest that CbICE53 increases plant tolerance to low temperature via activating downstream cold-responsive pathways, which can be considered as a potential candidate for transgenic engineering in plant breeding for cold-tolerant crops.