Complete Chloroplast Genome of the Wollemi Pine (Wollemia nobilis): Structure and Evolution

PLoS One. 2015 Jun 10;10(6):e0128126. doi: 10.1371/journal.pone.0128126. eCollection 2015.

Abstract

The Wollemi pine (Wollemia nobilis) is a rare Southern conifer with striking morphological similarity to fossil pines. A small population of W. nobilis was discovered in 1994 in a remote canyon system in the Wollemi National Park (near Sydney, Australia). This population contains fewer than 100 individuals and is critically endangered. Previous genetic studies of the Wollemi pine have investigated its evolutionary relationship with other pines in the family Araucariaceae, and have suggested that the Wollemi pine genome contains little or no variation. However, these studies were performed prior to the widespread use of genome sequencing, and their conclusions were based on a limited fraction of the Wollemi pine genome. In this study, we address this problem by determining the entire sequence of the W. nobilis chloroplast genome. A detailed analysis of the structure of the genome is presented, and the evolution of the genome is inferred by comparison with the chloroplast sequences of other members of the Araucariaceae and the related family Podocarpaceae. Pairwise alignments of whole genome sequences, and the presence of unique pseudogenes, gene duplications and insertions in W. nobilis and Araucariaceae, indicate that the W. nobilis chloroplast genome is most similar to that of its sister taxon Agathis. However, the W. nobilis genome contains an unusually high number of repetitive sequences, and these could be used in future studies to investigate and conserve any remnant genetic diversity in the Wollemi pine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Australia
  • Biological Evolution
  • Genetic Variation
  • Genome, Chloroplast*
  • Sequence Analysis, DNA
  • Tracheophyta / genetics*

Grants and funding

Funding for this work was provided by a grant from Bioplatforms Australia (www.bioplatforms.com.au) to AW and SKD, the Ramaciotti Centre for Genomics (University of New South Wales)(www.ramaciotti.unsw.edu.au), the Royal Botanic Gardens and Domain Trust (Sydney) (www.rbgsyd.nsw.gov.au) and an Early Career Research Grant from the Faculty of Science, University of New South Wales to SKD. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.