Abstract:

In order to explore the effect of exogenous putrescine (Put) on anthocyanin accumulation in apple skin, putrescine (50 mg·L-1) was applied to ‘Red Fuji’apple fruits immediately after bags were removed from fruit. Anthocyanin accumulation was determined by spectrophotometer and high-performance liquid chromatography, and transcriptional levels of several anthocyanin synthesis-related genes including MYB1 and genes encoding UDP-glycose: flavonoid 3-O-glycosyltransferase (UFGT), chalcone isomerase (CHI), anthocyanidin reductase (ANR), leucoanthocyanidin dioxygenase (LDOX) and dihydroflavonol 4-reductase (DFR), were determined by real-time fluorescence quantitative PCR. Anthocyanin content was significantly promoted with Put treatment, to about 1.9-fold that with control treatment. Put treatment revealed cyanidin 3-arabinoside content, although low, which was not revealed with control treatment. The transcriptional level of MYB1 was increased 1.6-fold with 1-day Put treatment and two-fold with 3-day treatment. The changed transcriptional level of UFGT gene was similar to that of MYB1; transcriptional levels of CHI, ANR and LDOX were increased as well. The transcriptional level of LDOX was 10.2- and 3.8-fold after 1- and 3-day Put treatment, respectively. Among six genes investigated in our study DFR was the only gene of which transcriptional level was inhibited with Put treatment. The strong effect of inhibition was revealed with 3-day treatment that the transcriptional level of DFR with control treatment was 2.3-fold of that with Put treatment.