Left) Phylogenetic tree of diterpene cyclases and synthases from Salvia miltiorrhiza (Sm), Salvia splendens (Ss), Salvia fruticosa (Sf), Rosemarinus officinalis (Ro) and Arabidopsis thaliana (At), constructed using the neighbor-joining method with MEGA-X. Numbers at nodes indicate bootstrap values (percentage of 1000 replicates). The scale bar at bottom represents the genetic distance. Middle) Domain architecture (box coloring: white, plastid targeting sequence; orange, γ domain; green, β domain; blue, α domain). Right) Exon/intron structure of the indicated genes. Blue boxes indicate exons and black lines indicate introns