Isolation and Functional Analysis of a New DREB Transcription Factor ( BpDREB1 ) from Brassica pekinensis

Abstract

DREB1/CBF transcription factors play an important role in plant stress tolerance, and one of important significance to gain stress-tolerant crops by transgenic technologies. In this study, a DREB-like gene, named BpDREB1 (GenBank accession No. EF219470), was cloned from Chinese cabbage. The BpDREB1 cDNA was 647 bp in length, and encoded protein of 213 amino acids with an predicted molecular weight of 23 kD and a isoelectric point of 5.11, and shared 94% similarity with other DREB transcription factor from Chinese cabbage. On the basis of multiple sequence alignment and phylogenetic analysis, BpDREB1 was classified in A-1 group of the DREB family. The expression patterns analysis indicated that BpDREB1 was strongly up-regulated at low temperature, also responded to dehydration. However, the expression of BpDREB1 was not affected by high salinity. The expression pattern of BpDREB1 was the same as that of other DREB transcription factors in A-1 group. Overexpression of BpDREB1 greatly increased the contents of total soluable sugar and free proline in transgenic Arabidopsis plants, demonstrating that transgenic Arabidopsis induced the expression of soluable sugar and proline related genes to enhance the tolerance to stress. These results suggest that BpDREB1 from Chinese cabbage has the typical characteristic of DREB transcription factors, and functions under the stress conditions including low temperature and drought.