Gene loss, pseudogenization, and independent genome reduction in non-photosynthetic species of Cryptomonas (Cryptophyceae) revealed by comparative nucleomorph genomics

Jong Im Kim, Goro Tanifuji, Minseok Jeong, Woongghi Shin, John M. Archibald

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

Background: Cryptophytes are ecologically important algae of interest to evolutionary cell biologists because of the convoluted history of their plastids and nucleomorphs, which are derived from red algal secondary endosymbionts. To better understand the evolution of the cryptophyte nucleomorph, we sequenced nucleomorph genomes from two photosynthetic and two non-photosynthetic species in the genus Cryptomonas. We performed a comparative analysis of these four genomes and the previously published genome of the non-photosynthetic species Cryptomonas paramecium CCAP977/2a. Results: All five nucleomorph genomes are similar in terms of their general architecture, gene content, and gene order and, in the non-photosynthetic strains, loss of photosynthesis-related genes. Interestingly, in terms of size and coding capacity, the nucleomorph genome of the non-photosynthetic species Cryptomonas sp. CCAC1634B is much more similar to that of the photosynthetic C. curvata species than to the non-photosynthetic species C. paramecium. Conclusions: Our results reveal fine-scale nucleomorph genome variation between distantly related congeneric taxa containing photosynthetic and non-photosynthetic species, including recent pseudogene formation, and provide a first glimpse into the possible impacts of the loss of photosynthesis on nucleomorph genome coding capacity and structure in independently evolved colorless strains.

Original languageEnglish
Article number227
JournalBMC Biology
Volume20
Issue number1
DOIs
Publication statusPublished - Dec 2022

Bibliographical note

Funding Information:
This work was supported by the following operating grants: the National Research Foundation (NRF) of Korea (NRF-2018R1D1A1B07050727, 2021R1C1C2012996) to JIK; the Japanese Society for Promotion of Sciences (JSPS; numbers 26840123, 17H03723, and 21H02554) awarded to GT; the National Research Foundation (NRF) of Korea (2019R1I1A2A01063159) awarded to WS; and a Discovery Grant awarded to JMA from the Natural Sciences and Engineering Research Council of Canada (RGPIN-2019-05058).

Publisher Copyright:
© 2022, The Author(s).

ASJC Scopus Subject Areas

  • Biotechnology
  • Structural Biology
  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • General Biochemistry,Genetics and Molecular Biology
  • General Agricultural and Biological Sciences
  • Plant Science
  • Developmental Biology
  • Cell Biology

PubMed: MeSH publication types

  • Journal Article
  • Research Support, Non-U.S. Gov't

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