Enhanced production of 3-methylthiopropionic ethyl ester in native Iranian Cucumis melo L. Group dudaim under regulated deficit irrigation

Abstract

Sulfur esters such as 3-methylthiopropionic ethyl ester (MTPE) significantly influence taste and fragrance of melons. Nutraceutical properties of MTPE have been demonstrated. GC–Mass analysis confirmed MTPE presence in two Cucumis melo L. Group dudaim cultivars of Iran, Birjand and Kerman. Considering potential effect of abiotic stresses on biosynthesis of esters, both cultivars were subjected to regulated deficit irrigation (RDI) at three levels of matric potentials [control (−50 kPa), moderate (−65 kPa), high (−75 kPa)]. MTPE production rose from 1.55 and 2.8 μg/kg of fresh pulp under control RDI to 7.65 and 9.1 under moderate and to 19.3 and 27.8 μg/kg under high RDI in Birjand and Kerman samples, respectively. MTPE higher production was accompanied by higher ethylene production and increased alcohol dehydrogenase activity. Ten-fold increase in MTPE production was assumingly owing to higher activities of the esterification enzymes which were supported by sulfur substrates coming from the accelerated methionine catabolism.

Keywords

• Melon
• Persia dudaim
• Sulfur esters
• Alcohol dehydrogenase
• Water-deficit stress