5'-Flanking region of rlpk2 gene was cloned by using PCR-based genomic DNA walking method (Fig.1), and designated P(rlpk2) (GenBank Accession Number: AY870314). Results of sequencing analysis showed that P(rlpk2) contains several putative cis-elements that respond to CTK, ABA, GA or IAA, as well as elements that respond to different environmental stresses, such as dehydration, coldness, wounding and etc. An expression vector containing the P(rlpk2)-GUS fusion gene was constructed (Fig.2) and transferred into soybean seedlings and Micro-Tom cotyledon explants by Agrobacterium-mediated method. A strong transient expression of GUS was observed in both soybean plumule and Micro-Tom cotyledon callus (Fig.3), thus confirming the promoter activity of P(rlpk2).