SCCB published an online article entitled “Melatonin attenuates postharvest physiological deterioration of cassava storage roots” in the Journal of Pineal Research on March 17, 2016. This work firstly revealed the function of melatonin in delaying the post-harvest physiological deterioration (PPD) of cassava storage roots as either reactive oxygen species (ROS) scavenger or signal.

Cassava (ManihotesculentaCrantz) is an important food crop in tropics and the major raw materials for modified starches and non-grain based biofuels in China. The rapid postharvest physiological deterioration (PPD) of its storage roots after 2-3 days harvest reduces their marketability and limits further applications.

Graduate student Qiuxiang Ma found that exogenous melatonin could delay the occurrence of postharvest physiological deterioration in cassava storage roots. Further analysis showed that melatonin significantly decreased the ROS accumulation and the damage of cell membrane.Melatonin could maintain ROS homeostasis by regulating the gene expression related with ROS turnover and scavenging and theactivities of antioxidant enzymes. Further experiment showed that the expression of melatonin biosynthetic genes, together with melatonin content, was significantlyincreased during the PPD process.This study demonstrates that melatonin acts as an effective free radical scavenger to maintain ROS homeostasis to attenuate PPD symptoms; Or ROS burst triggers de novo biosynthesis of endogenous melatonin which acts as a signal modulator for many genes and factors to regulate PPD occurrence in cassava roots. Therefore, this study provides a novel approach in controlling PPD. This work was joint efforts between SCCB and Prof. Zhen-Yu Wang from Hainan University.