Differential and coordinated expression of Cbf and Cor/Lea genes during long-term cold acclimation in two wheat cultivars showing distinct levels of freezing tolerance

Abstract

The cold acclimation process in plants is primarily regulated through the signal transduction pathways that lead to the induction and enhancement of expression of different sets of Cor / Lea genes. Winter wheat 'Mironovskaya 808' (M808) exhibited a much higher level of freezing tolerance than spring wheat 'Chinese Spring' (CS), and the difference became clearer after the long-term cold acclimation. To understand the molecular basis of this cultivar difference, we isolated two CBF/DREB1 homologs, Wcbf2 , which are the candidate gene for a transcription factor of the Cor / Lea genes. Expression of the Wcbf2 gene was induced rapidly by low temperature (LT) and drought but not by abscisic acid (ABA). The gene expression was temporal and at least twice up-regulated by LT. The first up-regulation occurred within 1-4 h, which might correspond to the rapid response to LT, while the second up-regulation occurred during 2-3 weeks of cold acclimation. After the second up-regulation, the amount of Wcbf2 transcript greatly decreased in CS, while it increased again in M808 after 4 weeks until 9 weeks (end of the test period). The maintenance of this high level of the Wcbf2 transcript might represent the long-term effect of cold acclimation. The activation of Cor/Lea genes followed the accumulation of Wcbf2 transcript suggested direct involvement of the Wcbf2 gene in the induction and enhancement of the Cor/Lea gene expression. The cultivar difference in freezing tolerance developed during different stages of cold acclimation can be at least partly explained by the differential and coordinated regulation of the predicted Cor/Lea gene signal transduction pathway that is mediated by the CBF/DREB1 transcription factors in common wheat.

Enhanced in vitro drought tolerance of Solanum tuberosum and Solanum commersonii plants overexpressing the ScCBF1 gene

“…Similar to previous studies reporting that CBF/ DREB gene expression is associated with the expression of P5CS and DNH-like genes under abiotic stress (Gilmour et al, 2000;Kobayashi et al, 2005;Kume et al, 2005), in both potato species, the constitutive overexpression of the ScCBF1 gene was also associated with P5CS and DNH10 transcript accumulation under in vitro drought stress (Figure 3). …”

“…However, the precise function of these proteins remains unknown. In wheat, early Dehydrin expression has been associated with drought tolerant genotypes and CBF gene expression Kume et al, 2005). In Solanum species, such as tobacco and potato, DHN-like genes have been associated with cold tolerance and CBF gene expression (Pino et al, 2008).…”

Characterization of the TaAIDFa gene encoding a CRT/DRE-binding factor responsive to drought, high-salt, and cold stress in wheat

“…6b). Kume et al (2005) found that the DBF1-type gene, TaWCBF2, displayed diVerential expression during long-term cold acclimation in two wheat cultivars in a manner similar to TaDREB1, a DBF2-type gene (Shen et al 2003). Genetic variation may result from diVerences in the regulatory motifs present in promoters in diVerent cultivars (TaAIDFa was isolated from winter wheat cv.…”

C-Repeat Binding Factor and Dehydrin Genes are Induced Co-Ordinately in Drought Tolerance Response of Wheat Cultivars

“…Parallel expression of DHN and Cbf genes has been found in cold stress (e.g. Kume et al, 2005). Cbf and other cold responsive genes were found activated by ABA independent and ABA dependent pathways as well (Knight et al, 2004).…”