The isolation and characterization of fruit specific promoters are critical for the manipulation of nutritional value and agronomic quality of fruits by genetic engineering and also opened a new era in edible vaccine technology. Expansins are proteins that induce loosening of individual plant cells by disrupting the non-covalent interactions between cellulose and hemicellulose microfibrils and hence have role in growth programs including fruit ripening. We report the identification of an expansin gene (CsExp) from Cucumis sativus that exhibits high levels of mRNA abundance and is specifically expressed in ripened fruit. The promoter region of CsExp also contains elements responsible for its fruit specific expression. Transient expression studies of the CsExp promoter were conducted with particle bombardment, followed by GUS histochemical assay and real time PCR. CaMV35S promoter was used as the positive control in all these experiments. Clear fruit specificity was observed for CsExp promoter in all the experiments. Thus CsExp promoter from Cucumber is a good candidate to target expression of the foreign genes to engineer fruit specific traits.

No abstract