RESUMO
Sugarcane stem is an ideal organ for producing foreign pharmaceutical proteins and chemicals by genetic engineering.A perfect promoter driving foreign gene to express strongly and specifically in sugarcane stem is necessary for this purpose.In order to isolate a Sugarcane stem-specific promoter,a fragment of 1968bp nucleotide sequence(Ppst2a)upstream 5' of sugarcane pst2a gene,which was demonstrated to express specifically in sugarcane stem previously was isolated by using chromosomal walking.Bioinformatical analysis of this sequence shows that the sequence contains some typical elements of a promoter.To identify the stem-specific of this promoter,a construct was derived from pCAMBIA1301,which original CaMV 35S promoter was replaced by the 1968bp nucleotide sequence,and named as pCAMBIA1900.Transformations of pCAMBIA1900 and pCAMBIA1301 to leaves and stem pieces of sugarcane were carried out by using particle bombardment.The transient expression of gus showed that the gus expressed specifically in sugarcane with a little higher level compared with CaMV 35S.It is the first report that pst2a promoter is a potential stem-specific promoter which can further be used in transgenes into sugarcane.