Effects of Preharvest Aminoethoxyvinylglycine (AVG) Treatment on Fruit Ripening, Core Browning and Related Gene Expression in ‘Huangguan’ Pear (Pyrus bretschneideri Rehd.)

‘Huangguan’ pear (Pyrus bretschneideri Rehd. cv. Huangguan) is a widely planted cultivar in China. However, it susceptible to core browning after harvest. In this study, aminoethoxyvinylglycine (AVG) was applied at 200 mg L?1 one and two weeks prior harvest, its effects on fruit quality, ripening were investigated during storage ambient temperature (25 ± 1 °C). The results showed that there higher firmness, soluble solids content (SSC) titratable acid (TA) content, but lower ethylene production rate index AVG-treated than control (water). Compared with the fruit, AVG treatment decreased malondialdehyde (MDA) polyphenol oxidase (PPO) activity, delayed peak of chlorogenic (CGA) tissue, significantly inhibited expression genes such as ACC synthase (PbACS2, PbACS3a, PbACS5a PbASC5b), (PbACO1 PbACO2), receptors (PbETR2 PbERS1), response factor (PbERF1), phenylalanine ammonia lyase (PbPAL1), cinnamate 4-hydroxylase (PbC4H4), 4-hydroxycinnamoyl- CoA ligase (Pb4CL2), hydroxycinnamoyl- shikimate hydroxycinnamoyl transferase (PbHCT1 PbHCT3), (PbPPO1 PbPPO5), well phospholipase D (PbPLD) lipoxygenase (PbLOX1 PbLOX5). Thus, these suggested reduction by preharvest application might be due an inhibitory effect associated biosynthesis signaling pathways, CGA biosynthesis, PPO cell membrane degradation pear.