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2003 Fiscal Year Final Research Report Summary

Identification of the earliest land plant based on the complete structure of chloroplast genome and RNA editing

Research Project

Project/Area Number 14596003
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 生物多様性・分類
Research InstitutionFaculty of Science, Shizuoka University

Principal Investigator

YOSHINAGA Koichi  Shizuoka University, Faculty of Science, Professor, 理学部, 教授 (70021954)

Project Period (FY) 2002 – 2003
KeywordsChloroplast genome / RNA editing / hornwort / Plant evolution / Early land plants / Bryophytes / Charales / シャジクモ
Research Abstract

One of the most important problem remaining in the phylogeny of green plants is which is the earliest land plant. We have determined the complete structure of the chloroplast genome from hornwort which had been expected as the earliest land plant. ML tree, based on 10,854 amino acid sites from 51 protein genes which are commonly found in the known chloroplast genomes, revealed that bryophytes are monophyletic with high statistical confidence and form the earliest branch, which diverged from all the other main lineages of land plants. The tree shows that the hornwort is basal in bryophytes.
Another important problem, which is the direct ancestor of land plants, is in progress by analyzing the complete chloroplast structure from a charales which is expected as the direct ancestor of land plants.
Much more RNA editing sites have been found in the hornwort chloroplast than those in the other chloroplasts. They contained 436 sites of U to C conversion which is not observed any seed plants. These editing converts more than half the genes functional, and creates the anticodon of a tRNA and the sequence required for splicing. Almost all the RNA editing complementing the mutation in the genes would be required in early land plants, because RNA editing is not seen in the algae but seen in almost all land plants.
The sequence, named distant cis-recognition element (DGRE), complementary to the edited sequence has been observed within the same RNA. The premature transcript could form double stranded structure where there is a mismatch in base pairing. The mismatch could be recognized, and corrected by editing enzyme. This hypothetical mechanism for RNA editing will be proven in vitro.

  • Research Products

    (6 results)

All Other

All Publications (6 results)

  • [Publications] Masanori Kugita: "The complete nucleotide sequence of the hornwort (Anthoceros formosae) chloroplast genome : insight into the earliest land plants"Nucleic Acids Research. 31・2. 716-721 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Masanori Kugita: "RNA editing in hornwort chloroplasts makes more than half the genes functional"Nucleic Acids Research. 31・9. 2417-2423 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Koichi Yoshinaga: "Evolution of early land plants : insights from chloroplast genomic sequences and RNA editing in "Endosymbiosis and Eucaryotic Organelles""Masahiro Sugiura, Ralf Oelmueller and Junichi Obokata (in press). (2004)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Masanori Kugita: "The complete nucleotide sequence of the hornwort (Anthoceros formosae) chloroplast genome : insight into the earliest land plants."Nucleic Acids Research. 31-2. 716-721 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Masanori Kugita: "RNA editing in hornwort chloroplasts makes more than half the genes functional."Nucleic Acids Research. 31-9. 2417-2423 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] "Evolution of early land plants : insights from chloroplast genomic sequences and RNA editing"Endosymbiosis and Eucaryotic Organelles (Koichi Yoshinaga, Masahiro Sugiura, Ralf Oelmueller, Junichi Obokata edits). (in press). (2004)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2005-04-19  

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