Expression analysis of genes downstream of MtCBF4 in Arabidopsis. Abiotic stress-responsive genes in MtCBF4 transgenic and wild-type plants were analyzed by qRT-PCR. Total RNA was extracted from three-week-old seedlings grown under normal conditions. The graphs indicate the induction levels of AtCOR15A, AtCOR15B, AtKIN1, AtRD29A, AtRD29B and AtRD17 in the transgenic lines L17 and L24 compared with those of wild-type plants (WT). AtACTIN and Atβ-TUBULIN were amplified as controls. Data represent means and SE of three replications. Primers used are listed in Additional file 3 (Table S2).