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Fruits are rich in phenolic compounds and exhibit high antioxidant activity.Recent studies have shown that wounding caused by cutting and some post-cutting treatments can increase the biosynthesis of phenolic compounds and improve the antioxidant activity of several fresh-cut fruits and vegetables.However,there is a need to better understand if these responses are tissue-dependent.In the present study,the effect of different degrees of wounding stress and a pre-cutting methyl jasmonate(MeJA)treatment on total phenolic content and antioxidant activity of fresh-cut pitaya fruits during 4 days of storage at 15℃ was investigated.For the wounding intensity study,pitaya fruits were cut into slice(1cm thickness),half-slice(1/2 section from a slice of 1cm thickness)and quarter-slice(1/4 section from a slice of 1cm thickness)to generate different wounding intensities,with the intact pitayas without any wounding as the control.For MeJA pretreatment study,intact pitaya fruits were first treated with 0,1,10 or 100 μmol/L of MeJA and then cut into quarter-slice.Total phenolic content(TPC),antioxidant activity(AA)and phenylalanine ammonia-lyase(PAL)activity in all fresh-cut produce increased significantly during storage compared with whole pitaya fruits.This enhancement in TPC,AA and PAL activity increased with wounding intensity.Increases in reactive oxygen species(ROS)production was also observed in all fresh-cut pitaya fruits.Pre-cutting treatment with 1001μmol/L of MeJA further promoted the increase in TPC,AA,PAL activity and ROS production in quartersliced pitaya fruits.These results demonstrated that increasing wounding intensity and pre-cutting MeJA treatment can enhance the biosynthesis of phenolics compounds and improve the antioxidant activity of fresh-cut pitaya fruits.ROS may play a key role as signaling molecules in wounding-induced biosynthesis of phenolic compounds in fresh-cut pitaya fruits.