Genomic cloning and sequencing of betaine aldehyde dehydrogenase gene in spinach

Abstract

A genornic library derived from leaves of spinach was constructed with the λGeml1-BamHI Arms as the vector. The library was screened using thc BADH cDNA of mountiain spinach as a probe and six positive clones were obtained through three rounds of screening. One of the positive clones named D, which was hybridized with the 5’600 bp fragment of mountain spinach BADH cDNA, was sclcctrd and further analyzed. The size of the insert in clone D was about 12 kb. 8 856 nucleotides of the insert were sequenced which contained 2 459 nucleotides of 5′ noncoding region, 6 111 nucleotides of the complete sequence of the BADH gene, and 286 nuclrotides of a 3′ noncoding rcgion. The result of sequence analysis indicated that the BADH gene contained 14 introns and the junction scquenccs at splicing sites followed the GT-AG rule basically.