Extensive losses of photosynthesis genes in the plastome of a mycoheterotrophic orchid, Cyrtosia septentrionalis (Vanilloideae: Orchidaceae)

Young Kee Kim, Sangjin Jo, Se Hwan Cheon, Min Jung Joo, Ja Ram Hong, Myoung Hai Kwak, Ki Joong Kim

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


Cyrtosia septentrionalis is an achlorophyllous mycoheterotrophic orchid in the subfamily Vanilloideae (Orchidaceae). This article reports C. septentrionalis's complete plastome sequence and compare it with other orchid plastomes with a same mycoheterotrophic nutritional mode. The C. septentrionalis plastome has decreased to 96,859 bp in length, but it still maintains a quadripartite structure. The C. septentrionalis plastome contains 38 protein-coding genes, 25 tRNA genes, and four ribosomal RNA genes. Most genes related to photosynthesis have been lost, whereas the majority of housekeeping genes remain; this pattern corresponds to the end of stage 3 gene degradation. The inverted repeat regions of the C. septentrionalis plastome have decreased to 10,414 bp and mainly contain the gene ycf2. A block consisting of four rrn genes and rps7 and rps12 has shifted to a small single-copy region. As a result, the small single-copy region was found to be expanded, despite the loss of all ndh genes in the region. Three inversion mutations are required to explain the C. septentrionalis plastome's current gene order. The species is endangered, and these results have implications for its conservation.

Original languageEnglish
Pages (from-to)565-571
Number of pages7
JournalGenome Biology and Evolution
Issue number2
Publication statusPublished - 2019 Feb 1

Bibliographical note

Funding Information:
We thank the Saemangeum Regional Environmental Office of Korea for the Cyrtosia septentrionalis collection permit. This work was supported by the National Research Foundation of Korea (NRF) under Grant No. NRF-2015M3A9B8030588 and by the National Institute of Biological Resources (NIBR) under the genetic diversity research program (2016) for endangered species to K.J.K. We thank the two anonymous reviewers for their helpful suggestions, which improved the manuscript.

Publisher Copyright:
© The Author(s) 2019.


  • Cyrtosia septentrionalis
  • Gene loss
  • Gene relocation
  • Inverted repeat contraction
  • Mycoheterotrophy
  • Plastome

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics


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