Effect of blue light on ethylene biosynthesis, signalling and fruit ripening in postharvest peaches

The involvement of ethylene gas in the ripening of peach fruit is a symbolic phenomenon that has a place in the history of research on plant hormones. It is well documented that fruit ripening is developmentally regulated and affected by environmental factors such as temperature and light. Blue light has been shown to induce pigment synthesis in postharvest fruit. However, information on its effect on fruit ripening is still limited. This study aimed to investigate the effect of light-emitting diode blue light treatment at 40 mu mol m(-2) s(-1) on fruit ripening, ethylene biosynthesis and signalling in postharvest peaches during storage at 10 degrees C. Blue light exposure induced fruit ripening as expressed by the enhanced decline of fruit firmness and increases in skin colour parameters, which was associated with the increase in ethylene production because of the up-regulated expression of PpLOXs and ethylene biosynthetic genes such as PpACO1 and PpACS3. Meanwhile, six genes in relation to ethylene perception and signalling were also investigated using real-time PCR. Among them, blue light treatment significantly inhibited expression of PpERS1 and enhanced transcript levels of PpEIN2, PpEIL1, PpEIL2 and PpERF2, which led to an induction ethylene signalling pathway and resulted in turn into the promotion of ethylene production and fruit softening in postharvest peaches. Compared to control fruit stored at darkness, higher expression level of ethylene biosynthetic and signalling genes in blue light exposed peaches could be beneficial for its ethylene production and consequently fruit ripening. (C) 2015 Elsevier B.V. All rights reserved.