Fig. 4

Plastomic locally collinear blocks (LCBs). We identified the LCBs of the plastid genomes based on the progressiveMauve module of Mauve software (v2.3.1) with default parameters. The last IR region was removed before calculation. Each LCB was drawn on the right side of the phylogenetic tree with different colors. According to the arrangement order of LCBs, these plastid genomes are divided into five different types (type A - type E). For the expansion of the IR region and the 60 kb inversion observed in Opuntia microdasys and Ariocarpus retusus, we mark ‘IR expansion’ and ‘large inversion’ on the far right, respectively. These results show that the cactus plastomes have undergone extensive rearrangement