Phylogenetic relationships and molecular evolution of woody forest tree family Aceraceae based on plastid phylogenomics and nuclear gene variations.

The forest tree family Aceraceae is widespread in the northern hemisphere and it has ecological and economic importance. However, the phylogenetic relationships and classifications within the family are still controversial due to transitional intraspecific morphological characteristics and introgression hybridization among species. In this study, we determined the evolutionary relationships and molecular evolution of Aceraceae based on plastid phylogenomics and two nuclear gene variations. Phylogenetic analysis based on the plastid genomes suggested that Aceraceae species can be divided into two larger sub-clades corresponding to the two genera Acer and Dipteronia. Conjoint analysis of the plastid and nuclear gene sequences supported the classification with two genera in the family. Molecular dating showed that the two genera diverged 60.2 million years ago, which is generally consistently with previously reported results. Divergence hotspots and positively selected genes identified in the plastid genomes could be useful genetic resources in Aceraceae.

Complete chloroplast genome of a Chinese endemic species Corydalis trisecta Franch. (Papaveraceae).

Corydalis trisecta Franch. is an endemic plant found in China. In this study, we presented the first complete chloroplast genome of C. trisecta, which was assembled and characterized based on Illumina pair-end sequencing data. The complete chloroplast genome was 161,410 bp in length, with a GC content of 41.4% in total. Its structure contained a large single copy (LSC) region of 89,127 bp and a small single copy (SSC) region of 16,993 bp, which were separated by a pair of extremely inverted repeats (IRs) of 27,645 bp each, with GC content 39.8, 87.2, and 45.2%, respectively. The phylogenetic analysis indicated that C. triscta was sister to Lamprocapons spectabilis in Papaveraceae.