Evaluation of chloroplast genome annotation tools and application to analysis of the evolution of coffee species

PLoS One. 2019 Jun 12;14(6):e0216347. doi: 10.1371/journal.pone.0216347. eCollection 2019.

Abstract

Chloroplast sequences are widely used for phylogenetic analysis due to their high degree of conservation in plants. Whole chloroplast genomes can now be readily obtained for plant species using new sequencing methods, giving invaluable data for plant evolution However new annotation methods are required for the efficient analysis of this data to deliver high quality phylogenetic analyses. In this study, the two main tools for chloroplast genome annotation were compared. More consistent detection and annotation of genes were produced with GeSeq when compared to the currently used Dogma. This suggests that the annotation of most of the previously annotated chloroplast genomes should now be updated. GeSeq was applied to species related to coffee, including 16 species of the Coffea and Psilanthus genera to reconstruct the ancestral chloroplast genomes and to evaluate their phylogenetic relationships. Eight genes in the plant chloroplast pan genome (consisting of 92 genes) were always absent in the coffee species analyzed. Notably, the two main cultivated coffee species (i.e. Arabica and Robusta) did not group into the same clade and differ in their pattern of gene evolution. While Arabica coffee (Coffea arabica) belongs to the Coffea genus, Robusta coffee (Coffea canephora) is associated with the Psilanthus genus. A more extensive survey of related species is required to determine if this is a unique attribute of Robusta coffee or a more widespread feature of coffee tree species.

Publication types

  • Evaluation Study

MeSH terms

  • Coffee / genetics*
  • Evolution, Molecular
  • Genes, Plant
  • Genome, Chloroplast / genetics*
  • Molecular Sequence Annotation / methods*
  • Molecular Sequence Annotation / standards
  • Phylogeny*
  • Sequence Analysis, DNA

Substances

  • Coffee

Grants and funding

The authors received no specific funding for this work. Author Dominique Crouzillat is employed by Nestlé Centre Tours. Nestlé Centre Tours provided support in the form of salary for author DC, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific role of this author is articulated in the ‘author contributions’ section.