Structure and features of the complete chloroplast genome of Salix triandroides (Salicaceae)

Abstract

Salix triandroides W. P. Fang, an indigenous small willow with high potential for heavy-metal soil remediation and levee protection, has been used for wetland ecological restoration for decades. However, studies on the evolution and genetic breeding of S. triandoides have been hindered by the lack of its genetic information. Here, we present the complete chloroplast genome of S. triandroides, which was assembled from Illumina sequencing data. The chloroplast genome of this species is circular, 155,683 bp in length and includes two inverted repeat regions (IRs) (27,490 bp) separated by a large single-copy (LSC) region (84,463 bp) and a small single-copy (SSC) region (16,240 bp). A total of 126 unique genes were identified, including 81 protein-coding genes, 37 tRNA genes and eight rRNA genes. Comparative analysis identified some hypervariable regions, with potential to be used as specific DNA barcodes or candidate markers for phylogenetic studies. Based on the sequences of the protein-coding genes, the phylogenetic analysis assigned 32 Salix species into two major clades and revealed that S. triandoides was a sister taxon to S. triandra. Our results provide a foundation for further molecular breeding of S. triandroides and insights into the evolution of Salix. Supplemental data for this article is available online at https://doi.org/10.1080/13102818.2021.2023326 .