Proteomics Analysis and Identification of Proteins Related to Isoprenoid Biosynthesis in Cinnamomum camphora (L.) Presl

Cinnamomum camphora is an evergreen tree that contains essential oils and the leaf is the main organ used to extract essential oils. Isoprenoid is a key component contributing to the essential oils of C. camphora. Still, the molecular mechanisms and regulatory pathways underlying isoprenoid biosynthesis remain to be explored. In our study, we found that the content of linalool was higher in 65-day-old leaves than that in 15-day-old leaves of linalool-type C. camphora. The leaf proteome of these two materials was then analyzed based on data-independent acquisition, respectively, and 11,503 proteins were identified, of which 11,076 were annotated. Analysis of differentially expressed proteins revealed that the expression levels of MCT, MDS, and AACT increased significantly in 65-day-old leaves. Further analysis of the protein interaction network indicated that 15 differentially expressed proteins related to isoprenoid biosynthesis were co-expressed, and also suggested that the transcription factor families of BES1, C3H, MYB, NF-YC, Nin-like, WRKY, ZF-HD, and bHLH may act as candidate regulators of leaf development in C. camphora. Our study verified that the process of isoprenoid biosynthesis in C. camphora is regulated by a complicated network consisting of conserved synthetases, and provides proteomic information for further investigation of isoprenoid metabolic.