The entire chloroplast genome sequence of Asparagus setaceus (Kunth) Jessop: Genome structure, gene composition, and phylogenetic analysis in Asparagaceae.

Abstract

Asparagus setaceus (Kunth) Jessop is a horticultural plant of the genus Asparagus. Herein, the whole chloroplast (cp) genome of A. setaceus was sequenced with PacBio and Illumina sequencing systems. The cp genome shows a characteristic quadripartite structure with 158,076 bp. In total, 135 genes were annotated, containing 89 protein-coding, 38 tRNA, and 8 rRNA genes. Contrast with the previous cp genome of A. setaceus registered in NCBI, we identified 7 single-nucleotide polymorphisms and 15 indels, mostly situated in noncoding areas. Meanwhile, 36 repeat structures and 260 simple sequence repeats were marked out. A bias for A/T-ending codons was shown in this cp genome. Furthermore, we predicted 78 RNA-editing sites in 29 genes, which were all for C-to-U transitions. And it was also proven that positive selection was exerted on the rpoC1 gene of A. setaceus with the K a/K s data. Meanwhile, a conservative gene order and highly similar sequences of protein-coding genes were revealed within Asparagus species. Phylogenetic tree analysis indicated that A. setaceus was a sister to Asparagus cochinchinensis. Taken together, our released genome provided valuable information for the gene composition, genetics comparison, and the phylogeny studies of A. setaceus.