High level of intraspecific divergence and low frequency of RNA editing in the chloroplast genome sequence of Tagetes erecta

Abstract

Tagetes erecta L. is an important commercial and medicinal plant. In this study, we reported the complete chloroplast genome sequence of T. erecta. The genome has a circular structure of 152,076 bp containing a large single-copy region (LSC) of 83,914 bp, a small copy region (SSC) of 18,064 bp, and two inverted repeats (IR) of 25,049 bp by each. It harbors 111 unique genes, including 79 protein-coding genes, 4 ribosomal RNA genes, and 28 transfer RNA genes. A total of 41 microsatellite, 20 tandem, and 37 interspersed repeats were detected in the genome. The phylogenomic analysis shows that T. erecta is a single phylogenetic cluster. The complete chloroplast genome of T. erecta lays the foundation for the phylogenetic, evolutionary, and conservation studies of the genus Tagetes. Furthermore, the intergenic region of atpB-rbcL was variable among the species T. erecta. This suggests that this region might be a mutation hotspot and will be useful for phylogenetic study and the development of molecular markers. At last, we systematically identified the RNA editing sites in the chloroplast genome of T. erecta based on the transcriptome downloaded from the SRA database. This study identified the characteristics of the T. erecta chloroplast genome, SNPs, and RNA editing sites, which will facilitate species identification and phylogenetic analysis within T. erecta.

Keywords: RNA editing site; SNP; Tagetes erecta; chloroplast; phylogeny.