Effect of tea seed oil treatment on browning of litchi fruit in relation to energy status and metabolism

'Dadingxiang' litchi fruit were treated with 0.1% tea seed oil (TSO) and then stored at 25 degrees C for up to 8 days to investigate the effects of TSO and possible mechanisms on pericarp browning. The results showed that TSO effectively delayed the development of pericarp browning and the loss of red color in litchi fruit. TSO treatment markedly maintained membrane integrity as indicated by a lower relative electrical conductivity, which might contribute to delayed fruit senescence. In addition, TSO treatment enhanced the ATP level, energy charge and activities of H+-ATPase and Ca2+-ATPase and regulated the expression of four genes related to energy metabolism, including LcAtpB, LcAAC1, LaAOX1 and LcSnRK2. These results indicate that the process of browning and senescence in litchi fruit may be closely associated with energy status via the regulation of energy metabolism related enzymes and genes. We suggest that TSO treatment is a convenient and safe approach for reducing browning of harvested litchi fruit.