EPSP Synthase Gene - 5-enolpyruvyl shikimate-3-phosphate synthase (EPSPS) is an enzyme involved in aromatic amino acid biosynthetic pathway and is the target of glyphosate based herbicides. In petunia, enzyme is synthesized in flowers at a high level and is hardly found in leaves, although in tomato it is synthesized both in flowers and leaves.

Transgenic tobacco plants carrying CAT gene or GUS gene fused with deletion mutant forms of EPSPS gene were analysed and it was concluded that sequences between -1800 to -800 of petunia EPSPS gene were responsible for tissue specific expression of this gene.