Remarkably conserved plastid genomes of Quercus group Cerris in China: comparative and phylogenetic analyses

Quercus is one of the most important plant genera in terms of economic and ecological values, with approximately 500 species worldwide. Quercus group Cerris is endemic to Eurasia (with 11 species), and three species (Quercus acutissima, Quercus chenii and Quercus variabilis) are widely distributed in China. Here, we sequenced the complete plastid genomes of Q. acutissima and Q. chenii by Illumina pair-end sequencing and obtained an additional plastome of Q. variabilis from GenBank. In spite of geographically distant sampling, the three available plastomes of Cerris were remarkably conserved with regard to genome size, gene organization, GC content, and IR/SC boundary regions. A phylogenetic analysis showed that the Cerris group is nested within the Ilex group, forming a Cerris-Ilex clade. The current study provide plastid genomic-scale data for the less intensively studied Cerris group, which should be useful for studying speciation processes, geographical structure and phylogeny within the group in the future.