Evolution of the TPBB gene families in the genomes of Oleaceae and outgroups. A, Identification of the TPBB gene families in the selected genomes. B, The expansion pattern of TPBB gene families in S. oblata. The color annotations of genes from the families (TPS, HMGR, DXS, GPPS, and PAL) are located at the bottom. The curves between gene pairs were color-coded according to their Ks. C, Phylogenetic tree of the TPS genes from selected genomes. TPS-a-O is a special type of TPS gene from Oleaceae that was reported in the previous study (Xu et al., 2022). D, Expression patterns of TPS-a genes in five tissues of S. oblata. The genes from TDGs were connected by red lines, while the genes from PGPs were marked using orange and crimson, respectively. The IF, BF, FF, and FF represent the initial flowering stage, bud stage, full flowering stage, and final flowering stage, respectively.