Promoter sequences of two homologous pectin esterase genes from Chinese cabbage (Brassica campestris L. ssp. pekinensis) and pollen-specific expression of the GUS gene driven by a promoter in tobacco plants

Abstract

The promoter regions of two genomic clones, GBAN215-6 and GBAN215-12 from Chinese cabbage (Brassica campestris L. ssp. pekinensis), were sequenced. The nucleotide sequences of their promoter regions were compared with that of the Bp19 pollen-specific gene of Brassca napus. High nucleotide sequence homologies were observed among these three genes in the region between 210 bp upstream and the putative transcription start site. A sequence motif TGTGGTG, which is similar to that of the PB core motif (TGTGGTT) of two tomato pollen-specific genes, LAT52 and LAT56, was present in these two cloned genes. To determine regulatory sequences responsible for the anther-specific expression of the gene BAN215-6, two recombinant plasmids, pBPE3 (-274- + 109) and pBPE4 (-816- + 109) containing different lengths of the promoter fused with the GUS gene, were constructed and introduced into tobacco plants by Agrobacterium-mediated transformation. The result showed that the 383 bp (-274- + 109) of the BAN215-6 promoter region was sufficient for the anther-specific expression of the GUS gene. The GUS expression in a tobacco plants transformed with these constructs was first detected in uninucleate microspores and persisted at in vitro germinated pollen tubes. The expression level was increased during anther development, reaching the highest level in mature pollens.