Plastome variations reveal the distinct evolutionary scenarios of plastomes in the subfamily Cereoideae (Cactaceae)

Background The cactus family (Cactaceae) has been reported to have evolved a minimal photosynthetic plastome size, with the loss of inverted-repeat (IR) regions and NDH gene suites. However, there are very limited genomic data on the family, especially Cereoideae, the largest subfamily of cacti. Results In the present study, we assembled and annotated 35 plastomes, 33 of which were representatives of Cereoideae, alongside 2 previously published plastomes. We analyzed the organelle genomes of 35 genera in the subfamily. These plastomes have variations rarely observed in those of other angiosperms, including size differences (with similar to 30 kb between the shortest and longest), dramatic dynamic changes in IR boundaries, frequent plastome inversions, and rearrangements. These results suggested that cacti have the most complex plastome evolution among angiosperms. Conclusion These results provide unique insight into the dynamic evolutionary history of Cereoideae plastomes and refine current knowledge of the relationships within the subfamily.

Automated summary

This study assembled and annotated 35 plastomes of the Cereoideae subfamily, revealing their high diversity and complexity, and providing insights into their evolutionary history and relationships.