Complete chloroplast genomes of Impatiens cyanantha and Impatiens monticola: Insights into genome structures, mutational hotspots, comparative and phylogenetic analysis with its congeneric species

PLoS One. 2021 Apr 2;16(4):e0248182. doi: 10.1371/journal.pone.0248182. eCollection 2021.

Abstract

Impatiens L., the largest genus in the family Balsaminaceae with approximately 1000 species, is a controversial and complex genus that includes many economically important species well known for medicinal and ornamental values. However, there is limited knowledge of molecular phylogeny and chloroplast genomics, and uncertainties still exist at a taxonomic level. In this study, we have assembled four chloroplast genomics specimens of Impatiens cyanantha and Impatiens monticola, which are found at the different altitudes of Guizhou and Yunnan in China, and compared them with previously published three wild Balsaminaceae species (Impatiens piufanensis, Impatiens glandlifera, and Hydrocera triflora). The complete chloroplast genome sequences ranged from 152,236 bp (I. piufanensis) to 154,189 bp (H. triflora) and encoded 115 total distinct genes, of which 81 were protein-coding, 30 were distinct transfer RNA genes(tRNA), and 4 were ribosomal RNA genes (rRNA). A comparative analysis of I. cyanantha (Guizhou) vs. I. cyanantha (Yunnan) and I. monticola (Guizhou) vs. I. monticola (Yunnan) revealed minor changes in lengths; however, similar gene contents, gene orders, and GC contents existed among them. Interestingly, highly coding and non-coding genes, and regions matK, psbK, atpH-atpI, trnC-trnT, petN, psbM, atpE, rbcL, accD, psaL, rps3-rps19, ndhG-ndhA,rpl16, rpoB, ndhB, ndhF, ycf1, and ndhH were found, which could be suitable for identification of species and phylogenetic studies. During the comparison between I. cyanantha (Guizhou) and I. cyanantha (Yunnan), we observed that the rps4, ycf2, ndhF, ycf1, and rpoC2 genes underwent positive selection. Meanwhile, in the comparative study of I. monticola (Guizhou) vs. I. monticola (Yunnan), The accD and ycf1 genes were positively selected. Additionally, phylogenetic relationships based on maximum likelihood (ML) and Bayesian inference (BI) among whole chloroplast genomes showed that a sister relationship with I. monticola (Guizhou) and I. monticola (Yunnan) formed a clade with I.piufanensis proving their close connection. Besides, I.cyanantha (Guizhou) and I. cyanantha (Yunnan) formed a clade with I. glandlifera. Along with the findings and the results, the current study might provide valuable significant genomic resources for systematics and evolution of the genus impatiens in different altitudes of regions.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Balsaminaceae / genetics*
  • Chloroplasts / genetics
  • Genome, Chloroplast*
  • Mutation
  • Phylogeny
  • Plant Proteins / genetics
  • RNA, Ribosomal / genetics
  • RNA, Transfer / genetics

Substances

  • Plant Proteins
  • RNA, Ribosomal
  • RNA, Transfer

Grants and funding

This work was carried out with the support of the National Natural Science Foundation of China [32060364;32060366;31860230], Key Research and Development Plan Program of Yunnan Province [2018BB013], Young and Middle-aged Academic and Technical Leadership Training Project of Yunnan [2015HB046; 2018HB024], and Program for Innovative Research Team (in Science and Technology) in University of Yunnan Province.