Postharvest ethanol vapor treatment of tomato fruit stimulates gene expression of ethylene biosynthetic enzymes and ripening related transcription factors, although it suppresses ripening

摘要

Postharvest ethanol vapor treatment suppresses tomato fruit ripening. The aim of this study was to clarify the mechanism of suppression at the molecular level. Tomato (Solanum lycopersicum cv. 'Micro Tom') fruit harvested at mature green and breaker stages was continuously treated with ethanol using an ethanol pad at 20 degrees C in the dark. Ethanol treatment stimulated ethylene production and increased gene expression of LeACS2 and LeACS4, which are related to ethylene-related ripening. The expression of genes encoding ripening-specific transcription factors acting upstream of ethylene was also induced, when the fruit was treated with ethanol. In the ethylene-dependent ripening process, ethanol inhibited the expression of RIN-dependent and ethylene-dependent ripening-related genes, suggesting that ethanol could inhibit some processes downstream of ethylene perception. In the ethylene-independent ripening process, expression of RIN-dependent and ethylene-independent ripening related genes was inhibited by ethanol, suggesting that ethanol could inhibit some processes downstream of RIN. Inhibition of each process by ethanol could be a mechanism by which ethanol inhibits ripening, although it stimulates ethylene production and factors upstream of the ripening process.