Figure 4.

Origin and evolution of C₄- and CAM-specific β-CA genes in Caryophyllales. A) Phylogenetic tree of β-CA genes from P. oleracea (Pol), P. amilis (Pam), H. undatus (Hun), A. hypochondriacus (Ahy), and B. vulgaris (Bvu) genomes in Caryophyllales. B) Gene expression of β-CA genes identified in P. oleracea under heat and drought treatments during the day and night. Magenta, blue, and orange ovals in the gene trees to the left represent γ, P-β, and Po-α WGD events, respectively; magenta dots represent TD events. CAM-specific β-CA genes were highlighted in magenta boxes. C) Synteny analysis of C₄- and CAM-specific β-CA genes (clade III in Fig. 4A) in the P. oleracea, P. amilis, H. undatus, A. hypochondriacus, and B. vulgaris genomes in Caryophyllales. CK, control group; D, drought group; H, heat group; DH, drought combined heat group.