Biotech Updates

Functional Characterization of GlZEP Promoter in GE Tomato

February 10, 2012

Carotenoid production in plants is controlled by the spatiotemporal expression profiles of genes that code for enzymes in the carotenogenic pathway. Qingjie Yang of the Northeast Normal University in China and team cloned and characterized the Gentiana lutea zeaxanthin epoxidase (GlZEP) promoter to know its function in the regulation of carotenoid production, because the native gene is highly expressed in petals, which has large amounts of chromoplast. They transformed tomato plants with the gusA gene encoding the reporter enzyme β-glucuronidase (GUS) under the control of the GlZEP promoter, and analyzed the reporter expression profile at the mRNA and protein levels.

Their findings showed that there were high levels of gusA expression and GUS activity in chromoplast-containing flowers and fruits, but low expression in immature fruits with green chloroplasts. It was confirmed that GlZEP-gusA expression is exclusively related to fruit development and chromoplast differentiation. According to the authors, these findings suggest an evolutionarily-conserved link between ZEP and the differentiation of organelles that store carotenoid pigments.

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