The complete chloroplast genome sequence of Ulmus szechuanica (Ulmaceae) and its phylogenetic analysis

Ulmus szechuanica is a species of Sect.Ulmus and Ser.Nitentes in Ulmaceae, and it is an endangered wild plant in China. The complete chloroplast genome (cp) of U. szechuanica was reported in this study. The result showed that the cp genome was 159,703 bp in length including a large single-copy (LSC) 88,039 bp and a small single-copy (SSC) 19,072 bp, which were separated by two inverted repeats (IRs) of 26,296 bp with the typical quadripartite structure, respectively. The genome encoded 131 genes, including 86 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The GC content was 35.53%. Chloroplast sequences were used for constructing phylogenetic tree to determine the evolutionary status of U. szechuanica. The maximum-likelihood phylogenetic analysis showed that U. szechuanica displayed a closer kinship to five other Ulmus species. This study provides important information for identification and conservation of species, germplasm resources utilization, and genetic engineering of Ulmus. The cp will provide a reference for future studies on species evolution of Ulmus.