Abstract
Xylem sap contains macromolecules such as proteins and polysaccharides. We have analyzed the root specific gene expression of a lectin-like xylem sap protein (XSP30) in cucumber. The expression of XSP30 in roots oscillates in a diurnal pattern. The amplitude of the diurnal expression is regulated by leaf gibberellin. In this report, we histologically investigated gene expression and lectin activity of XSP30. The XSP30 promoter directed specific expression of a glucuronidase reporter gene in xylem parenchyma and pericycle cells in the central cylinder of mature transgenic hairy roots. The lectin activity of XSP30 was analyzed by lectin blot coupled with immunological detection of XSP30. The recognition site of XSP30 was N-acetylglucosamine of the glycoproteins. We also found that the glycoproteins having the recognition site of XSP30 was abundant in leaf parenchyma cells. From these result, we will discuss about the possible functions of XSP30.
