Pre-harvest application of hexanal formulation enhances shelf life and quality of 'Fantasia' nectarines by regulating membrane and cell wall catabolism-associated genes

Post-harvest technologies play a key role in enhancing shelf life and maintaining quality characteristics of tender fruits such as nectarines (Prunus persica [L.] Batsch var. nectarina). This research investigated the effects of an 'Enhanced Freshness Formulation' (EFF) with hexanal as the key ingredient in enhancing shelf life of field grown nectarines. Pre-harvest sprays of EFF on 'Fantasia' nectarines, conducted at two commercial orchards in the Niagara region, ON, showed improvement in shelf life. Application of hexanal formulation delayed the incidence of chilling injury symptoms (internal browning and mealiness/woolliness) by one week. As well, treated fruits maintained significantly higher firmness until 38d post-harvest. There were no differences in total soluble solids, titratable acidity and color values between treated and control fruits. qRT-PCR was conducted to evaluate the expression levels of 22 genes potentially involved in ripening, to understand the regulatory effects of the hexanal formulation. EFF application induced a highly significant reduction in transcript levels of three Phospholipase D genes, five N-glycoprotein group genes, and other genes involved in ripening and softening processes. These findings indicate that, a delay in the ripening process caused by hexanal formulation, may be associated with the modulation of the expression of key ripening related genes, enhancing shelf life and quality of nectarines.