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Overexpression of AtCBF1 in Sinningia speciosa Enhances Chilling Stress Tolerance

Chun-Yan Zhan, Jia-Ning Xu, Da Li, Bin-Bin Liu, Yue-Guang Feng and Xiao-Yun Wang

Chilling is a common environmental stress strongly limits the survival and quality of plants. As tropical flower, Sinningia speciosa can hardly survive below 5ºC. Breeding new chilling-tolerant Sinningia speciosa varieties by transgenic approaches would expand its geographical distribution. As a transcriptional factor, C-Repeat Binding Factor 1 (CBF1) could increase chilling tolerance of many plants. In this study, Arabidopsis thaliana CBF1 (AtCBF1) gene was successfully transformed into Sinningia speciosa. Compared with wild-type plants (WT), the overexpressing plants (OE) exhibited low levels of hydrogen peroxide (H2O2) and superoxide radical (O2•−) under 4ºC chilling stress. Similarly, less malondialdehyde (MDA) content accumulated in OE than in WT plants. Consistent with the accumulation of reactive oxygen species, the activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POD), were apparently higher in OE than in WT plants. The changes of physiological indexes were consistent with the phenotype analysis under chilling stress. Overexpression of AtCBF1 could also increase the resistance of osmotic stress in detached leaves. This will be very helpful for expanding the planting of Sinningia speciosa in low-temperature areas.