The chloroplast genomes of Sanicula (Apiaceae): plastome structure, comparative analyses, and phylogenetic relationships

Sanicula (Apiaceae subfamily Saniculoideae) is a taxonomically difficult
genus of medicinal value. Its distribution center is in China, where there
are 18 species (11 of which are endemic). To provide plastid genome
resources, whole chloroplast genomes of five Sanicula species (S.
flavovirens, S. giraldii, S. lamelligera, S. odorata, and S.
rubriflora) were sequenced and compared to the previously
published S. orthacantha plastome. These genomes exhibit a
typical quadripartite structure. All contain 129 different genes,
including 84 protein-coding, 37 tRNA, and 8 rRNA genes. Loci
rpl2, matK, psbA, and ycf1 are the most
variable. Results of maximum likelihood analysis of 90 whole
plastome sequences from Apioideae and Saniculoideae and the outgroup
Hydrocotyle (Araliaceae) reveal sectional relationships in
Sanicula different from the traditional classification system,
support the monophyly of Apioideae and its sister group relationship to
Saniculoideae, and show concordant topologies to nrDNA ITS and
other plastome-based
phylogenies. Sanicula orthacantha and S.
chinensis form a clade sister group to S.
lamelligera and S. odorata, consecutively. These four species
comprise a clade sister group to the clade of S. rubriflora and
S. flavovirens, with this entire group sister to S. giraldii. The plastid
genome resources provided herein will be important for future systematic,
evolutionary, phylogenomic, and population-level studies of Sanicula.