Complete Chloroplast Genome Sequence of Triosteum sinuatum, Insights into Comparative Chloroplast Genomics, Divergence Time Estimation and Phylogenetic Relationships among Dipsacales.

Triosteum himalayanum, Triosteum pinnatifidum (Triosteum L., Caprifoliaceae, Dipsacales) are widely distributed in China while Triosteum sinuatum mainly occurrs in northeast China. Few reports have been determined on the genus Triosteum. In the present research, we sequenced 2 chloroplast genomes of Triosteum and analyzed 18 chloroplast genomes, trying to explore the sequence variations and phylogeny of genus Triosteum in the order Dipsacales. The chloroplast genomes of the genus Triosteum ranged from 154,579 bp to 157,178 bp, consisting of 132 genes (86 protein-coding genes, 38 transfer RNA genes, and 8 ribosomal RNA genes). Comparative analyses and phylogenetic analysis supported the division of Dipsacales into two clades, Adoxaceae and six other families. Among the six families, a clade of Valerianaceae+Dipsacaceae was recovered as a sister to a clade of Morinaceae+Linnaeaceae. A closer relationship of T. himalayanum and T. pinnatifidum among three species was revealed. Our research supported that Loniceraferdinandi and Triosteum was closely related. Zabelia had a closer relationship with Linnaea borealis and Dipelta than Morinaceae. The divergence between T. sinuatum and two other species in Triosteum was dated to 13.4 mya.

The complete chloroplast genome of Triosteum himalayanum (Caprifoliaceae), a perennial alpine herb.

Triosteum himalayanum is a perennial herb which is distributed in the eastern Himalayas, Hengduan Mountains, and central China. The complete chloroplast genome of T. himalayanum is studied for the first time, which is 154,579 bp in length and is divided into four regions: two inverted repeat (IRA and IRB) regions of 23,370 bp, a small single copy (SSC) region of 18,682 bp and a large single copy (LSC) region of 89,157 bp. The plastid genome contains 133 genes, including 86 protein-coding genes, 39 tRNA genes, and 8 rRNA genes. The overall CG content in the chloroplast genome of T. himalayanum is 38.38%. The phylogenetic analysis on the complete plastome sequence of T. himalayanum will help to show the intergeneric diversity of Caprifoliaceae.

Characterization of the complete chloroplast genome of Linnaea borealis, a rare, clonal self-incompatible plant.

Linnaea borealis L. is a creeping shrub which grows about 5-10 cm high and is a rare clonal plant. Linnaea is a monotypic genus. Here, we release and detail the complete chloroplast genome sequences of L. borealis, whose size is 161,576 bp, containing a large single copy region (LSC) of 85,609 bp and a single copy region (SSC) of 46,694 bp which typically separates by a pair of inverted repeats (IRs) of 29,210 bp. The amount of the overall genes is 136, which includes 37 tRNA genes, eight rRNA genes, and 91 protein-coding genes. The content of the G/C in whole plastome is 61.74% while the G/C content of the LSC, SSC, and IR region are 36.58%, 38.86%, and 42.25%, respectively. The complete cp genome sequences of L. borealis will be a useful resource to the phylogenetics study in family Caprifoliaceae.