Transcriptome Analysis of Aconitum carmichaelii and Exploration of the Salsolinol Biosynthetic Pathway
Abstract Background Aconitum carmichaelii has been used in traditional Chinese medicine for treating various diseases for several thousand years. The biosynthetic pathway of some alkaloids such as C19-diterpenoid alkaloids has been reported, but pathways in different varieties of A. carmichaelii remain unknown. Herein, we performed transcriptome analysis of varieties A. carmichaelii and characterized the biosynthetic pathway of salsolinol. The results expand our knowledge of alkaloids biosynthesis, and provide a theoretical basis for analysing differences in alkaloids biosynthesis patterns in different varieties. Results A total of 56 million raw reads (8.28 G) and 55 million clean reads (8.24 G) were obtained from two varieties (Z175 and R184) leaf transcriptomes, respectively, and 176,793 unigenes were annotated using six protein databases. This yielded 6,873 differentially expressed genes (DEGs) in the two varieties, of which 281 are involved in the salsolinol biosynthetic pathway, including 158 and 75 related to glycolysis and the shikimate pathway, respectively. Furthermore, 843 DEGs were found to be involved in the formation of C19-diterpenoid alkaloids, with 34 differed between the two varieties. These target genes were analysed to explore differences in C19-diterpenoid alkaloid biosynthesis in Z175 and R184. In addition, 322 DEGs encoding transcription factors potentially related to alkaloid accumulation were identified. Conclusions The biosynthesis pathway for C19-diterpenoid alkaloids and salsolinol included 34 and 24 DEGs in Z175 and R184, respectively. Thus, genes involved in alkaloid biosynthesis and accumulation differ between varieties. The mechanisms underlying the differences and their relevance require further exploration.