บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

Gene expression of ascorbic acid-related enzymes during tomato fruit development and ripening.

Pateraki I., Kalamaki M.S., Alexandrou D., Giovannoni J.J., Kanellis A.K.

5th International Postharvest Symposium . Volume of Abstract . Verona, Italy 6-11 June 2004. page 13

2004

บทคัดย่อ

Gene expression of ascorbic acid-related enzymes during tomato fruit development and ripening.  Tomato fruit ripening has been described as an oxidative process during which production of reactive oxygen species (ROS) is balanced by their removal by antioxidant systems.Ascorbic acid (AA) in the apoplast is proposed to be involved in these oxidative processed and a change in AA redox to a more reduced state is observed as ripening progresses.

To further elucidate the role of AA in ripening, the expression profiles of GDP-mannose 3”5” epimerase and L-galactono-1,4-lactone dehydrogenase (GalLDH), enzymes that participate in ascorbate biosynthesis, and ascorbate oxidase (AO) and ascorbate peroxidase (APX), have been investigated in vegetative tissues and during tomato (Lycopersicon esculentum Mill. Cv. AilsaCraig) fruit development and ripening.GalLDH transcript was present in all green and floral tissues but it was not detected in seeds and roots.In fruit, GalLDH transcript accumulated early o­n and at the later stages of ripening. Furthermore, expression of GalLDH was induced 3 hours after exposure of mature green fruit to ethylene with levels dropping thereafter until 48 hours post-treatment.GDP-mannose 3”5” epimerase was highly expressed in all green tissues with lower levels detected in flowers, whereas transcript was present in al fruit developmental and ripening stage.AO transcript was detected o­nly in stems, petioles, apices and flowers.Thylacoid-bound APX mRNA was accumulated in all vegetative and fruit tissues.During ripening, PPX transcript abundance increased progressively to a peak at the pink stage and slightly decreased thereafter.

Our results indicate that genes participating in ascorbic acid metabolism are differentially expressedduring tomato fruit development and ripening suggesting a dynamic role of AA in this process.