Gene transcript accumulation and enzyme activity of β-amylases suggest involvement in the starch depletion during the ripening of cherry tomatoes

• The expression of several plastidial bAmy genes was elevated later during fruit development.
• Multiple bAmy genes were expressed during tomato fruit development.
• bAmy activity peaked at the breaker stage.
• The starch levels declined during the fruit development.

The flavor of tomato fruits is mostly influenced by the accumulation of sugars and organic acids. During fruit ripening a conversion of starch to sugars occurs, which modulates significantly the taste and consequently the quality of the ripe tomato fruits. β-Amylases, a group of major starch hydrolytic enzymes involved in starch degradation were examined in developing cherry tomatoes. Our results suggest that the enzyme activity and the gene transcript accumulation of plastidial β-amylase isoenzymes were elevated during the late stages of fruit development indicating a participation of the enzyme in starch depletion and in the increase of total soluble sugar levels in ripe tomatoes.