ABSTRACT: Polygala crotalarioides Buch.-Ham. ex DC. (Polygalaceae) is a perennial herbaceous plant widely distributed in southwest China. Its chloroplast genome sequence was obtained using Illumina NovaSeq sequencing technology, and then was assembled, annotated, and characterized. The total length of chloroplast genome is 164,269 bp and it contained a large (LCS, 82,697 bp) and a small (SSC, 8083 bp) single copy region, separated by a pair of inverted repeats (IRA/IRB, 36,744 bp). The overall GC content of genome was 36.8% and corresponding values of the LSC, SSC, and IR regions are 34.9%, 29.5%, and 39.7%, respectively. There are 135 genes that were predicted including 89 protein-coding, 38 tRNA, and 8 rRNA genes. The maximum-likelihood (ML) phylogenetic tree reconstructed by IQ-TREE indicated that P. crotalarioides had a strong genetic relationship with P. tenuifolia, P. sibirica, and P. japonica. In summary, the complete chloroplast genome of P. crotalarioides is reported for the first time, which is of great significance for future research on the evolutionary phylogeny and protection of Polygala.
