The complete plastome of Sorbaria kirilowii: genome structure, comparative analysis, and phylogenetic implications.

Sorbaria kirilowii is a deciduous perennial admired for its showy white blossoms. Though of importance for horticultural purposes, the plastomic study concerning this species is still lacking. Here, the plastome of S. kirilowii was de novo assembled using the high-throughput sequencing data. The complete plastome assembly of S. kirilowii was 160,810 bp in length, with a GC content of 36.03%. It featured a typical quadripartite structure, containing a pair of inverted repeats (IRs; 26,338 bp) separated by a large single-copy (LSC; 88,762 bp) and a small single-copy (SSC, 19,372 bp). In total, 132 genes were annotated in the plastome, including 87 protein-coding genes, 8 rRNA genes, and 37 tRNA genes. Furthermore, 63 SSRs, most of which were AT-rich, were identified in the cp genome of S. kirilowii. 71.7% of the cpSSRs were shown to be located in the intergenic regions. In addition, 49 repeats of varying sizes and types were also identified in the plastome. Through comparison, eight divergence hotspots were identified between the plastome of S. kirilowii and S. sorbifolia var. stellipila. These variable regions could potentially be developed into molecular markers for species delimitation or phylogenetics in future studies. We re-investigated the relationship among 17 Rosaceae species using the plastomic sequences, and S. kirilowii was shown to be a sister to S. sorbifolia var. stellipila. Overall, this study provides plastomic resources which could facilitate marker development and phylogenomics of Rosaceae.