Fig. 7

A 60 kb inversion mediated by a pair of short inverted repeats generated isomeric plastomes. (a) Diagram of the 60 kb inversion. Isomers 1 and 2 represent preinversion and postinversion plastomes, respectively. In the case of Pereskia aculeata, a pair of 679 bp repeats mediated genome inversion. We designed two pairs of primers on both sides of the repeats for F1 + R1 and F2 + R2 to perform PCR expansion experiments. (b) Graphic assembly of plastid genomes using GetOrganelle (v1.7.3). In addition to the classic IR region, a pair of short repeat sequences was detected during assembly, which may have mediated a 60 kb inversion of the plastome. (c) The two isomers were verified by PCR. We conducted experiments according to the primer pairs designed as shown in Fig. 7a and verified the alternative configuration of the plastome by exchanging primer pairs