The role of energy transport system in pericarp browning of harvested longan fruit

Energy transport system plays a pivotal role in maintaining cellular energy status. The adenine nucleotide translocator (ANT) family includes ATP/ADP carrier (AAC) and ATP/AMP translocator (ADNT). This research aims to illuminate the role of energy transport in pericarp browning process of postharvest longans. The results elucidated that the ATP content decreased with longan pericarp browning, and was positively correlated with expression levels of DlAAC1 and DlAAC5. Besides, the bongkrekic acid (BKA) treatment, which has a strong energy transport inhibitory property, could down-regulate the expressions of DlANTs, maintain lower energy level and activities of Ca2+-ATPase, Mg2+-ATPase and H+-ATPase in membranes of plasmas, mitochondria and vacuoles, and hasten the browning development of postharvest longan. While the ATP treatment kept higher expression levels of DlANTs, higher energy level and ATPase activities, and reduced the occurrence of longan pericarp browning. These findings suggested that the expression of DlANTs was regulated by energy status, and the inhibition of energy transport could lead to the reduction of energy level, the decreased ATPase activities, the down-regulated expressions of DlANTs, which might cause energy deficiency and thus accelerated pericarp browning of harvested longan fruit.