SEQUENCE REQUIREMENTS OF THE 5-ENOLPYRUVYLSHIKIMATE-3-PHOSPHATE SYNTHASE 5'-UPSTREAM REGION FOR TISSUE-SPECIFIC EXPRESSION IN FLOWERS AND SEEDLINGS

We have analyzed expression from deletion derivatives of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) 5′-upstream region in transgenic petunia flowers and seedlings. In seedlings, expression was strongest in root cortex cells and in trichomes. High-level expression in petals and in seedling roots was conferred by large (>500 base-pair) stretches of sequence, but was lost when smaller fragments were analyzed individually. This apparent requirement for extensive sequence suggests that combinations of cis-elements that are widely separated control tissue-specific expression from the EPSPS promoter. We have also used the high-level, petal-specific expression of the EPSPS promoter to change petal color in two mutant petunia lines.