Organization of Ripening and Ethylene Regulatory Regions in a Fruit-Specific Promoter from Tomato (Lycopersicon esculentum)

Abstract

Tomato (Lycopersicon esculentum) fruit ripening is initiated by an increase in ethylene hormone concentration. E8 gene transcription is fruit-specific and is activated at the onset of ripening and in unripe fruit treated with exogenous ethylene. To understand how E8 gene transcription is controlled during ripening, we analyzed the effect of deletions of flanking DNA sequences on E8 gene expression in transgenic tomato fruit. We found that a minimum of three 5' and one 3' regions influence E8 gene expression during fruit ripening. DNA sequences that confer responsiveness to exogenous ethylene in unripe fruit are distinct from DNA sequences that are sufficient for expression during fruit ripening.