A wound-repressible glycine-rich protein transcript is enriched in vascular bundles of tomato fruit and stem

The deduced protein sequence of a partial tomato cDNA clone is rich in the amino acid glycine and contains repeats of the amino acid sequence, (Gly)5Tyr(Gly)4-5Tyr(Gly)3ArgArgGlu. This protein sequence has significant similarity to a sorghum glycine-rich protein [S1, Cretin and Puigdomenech (1990) Plant Mol. Biol. 15: 783] and a maize embryo, abscisic acid-induced glycine-rich protein [Gomez et al. (1988) Nature 334: 262]. Tissue printing was used to localize the glycine-rich protein transcript in tomato fruit, stem and hypocotyl sections. The transcript is present throughout the tomato fruit pericarp but is enriched in the vascular bundles. In tomato hypocotyl tissue prints, the glycine-rich protein transcript as well as rRNA were localized within the vascular tissue. This shows that differential loading of RNA may occur when using the tissue printing technique on hypocotyl sections. Direct isolation and comparison of RNA from vascular-containing and non-vascular stem tissue confirmed, however, that the glycine-rich protein transcript is accumulated abundantly in the vascular tissue of tomato stem.