Abstract: The present study employed gas chromatography-mass spectrometry (GC-MS) and RNA-Seq to probe the changes in volatile constituents and the expression of genes involved in terpenoid biosynthesis in ponkan fruit peel during peel puffing. The results obtained were as follows. A total of 53 volatile components were identified in normal and puffing fruits, with terpenoids accounting for up to 96% of the total amount. Normal and puffing fruits did not differ with respect to volatile composition except for the contents of 32 volatile components. The contents of total volatile compounds and terpenoids in puffing fruits decreased to 82% and 81.4% as compared with the normal fruits, respectively. A total of 12 key genes involved in terpenoid biosynthesis were identified, most of which were down-regulated significantly during peel puffing. This study revealed for the first time the pattern of change in volatile constituents in ponkan fruit peel during peel puffing, and that this dynamic pattern was closely related with the down-regulation of gene expression involved in terpenoid biosynthesis.

Key words: peel puffing, volatile constituents, ponkan fruits, gas chromatography-mass spectrometry (GC-MS), RNA-Seq