Biosynthesis of Camphane Volatile Terpenes in Lour: Involved Genes and Enzymes.

() Lour., a medicinal species of the family, is used for medical purposes. Bornyl acetate, camphor, and borneol are the main bioactive ingredients in fruit, and the amount of bornyl acetate is regarded as a measure of the fruit's quality. In order to explore the major effective genes regulating the biosynthesis of camphane volatile terpenes in some DEGs involved in camphane volatile terpene biosynthesis and transcription factors were analyzed and summarized in this study. The result showed that the content of bornyl acetate was altered in the different growth stages. In particular, the significant change occurred from 7 to 30 DAP (days after pollination). The content of bornyl acetate at 30 DAP was 169.3% more than that at 7 DAP. In total, 4782 up-regulated and 5284 down-regulated unigenes were found in G2 vs. G1, as well as 3324 up-regulated and 5036 down-regulated unigenes in G3 vs. G1, and 3332 up-regulated and 4490 down-regulated unigenes in G3 vs. G2. A total of 323 up-regulated and 820 down-regulated unigenes were shared in three growth stage comparisons. We screened the genes that encode the enzymes most likely to inhibit bornyl diphosphate synthase, borneol dehydrogenase, and BAHD acyltransferases. Interestingly, we found that borneol dehydrogenase and bornyl diphosphate synthase displayed bi-substrate features, suggesting that a substrate of catalyzation is promiscuity in the biosynthesis downstream pathway, and the unknown bornyl pyrophosphate hydrolase may not be the specific enzyme for borneol formation. Additionally, the DXR, HDS, and IDS found in the PPI network would assist in the understanding of molecular regulation. The results of this study constructed DGE libraries and identified key genes related to camphane volatile terpenes, which laid a foundation for a deep investigation of the mechanism of volatile terpene biosynthesis, and provided a reference for mining other key genes in fruits.