The Structure and Gene Repertoire of an Ancient Red Algal Plastid Genome (original) (raw)

Abstract.

Photosynthetic eukaryotes can, according to features of their chloroplasts, be divided into two major groups: the red and the green lineage of plastid evolution. To extend the knowledge about the evolution of the red lineage we have sequenced and analyzed the chloroplast genome (cp-genome) of Cyanidium caldarium RK1, a unicellular red alga (AF022186). The analysis revealed that this genome shows several unusual structural features, such as a hypothetical hairpin structure in a gene-free region and absence of large repeat units. We provide evidence that this structural organization of the cp-genome of C. caldarium may be that of the most ancient cp-genome so far described. We also compared the cp-genome of C. caldarium to the other known cp-genomes of the red lineage. The cp-genome of C. caldarium cannot be readily aligned with that of Porphyra purpurea, a multicellular red alga, or Guillardia theta due to a displacement of a region of the cp-genome. The phylogenetic tree reveals that the secondary endosymbiosis, through which G. theta evolved, took place after the separation of the ancestors of C. caldarium and P. purpurea.

We found several genes unique to the cp-genome of C. caldarium. Five of them seem to be involved in the building of bacterial cell envelopes and may be responsible for the thermotolerance of the chloroplast of this alga. Two additional genes may play a role in stabilizing the photosynthetic machinery against salt stress and detoxification of the chloroplast. Thus, these genes may be unique to the cp-genome of C. caldarium and may be required for the endurance of the extreme living conditions of this alga.

Access this article

Log in via an institution

Subscribe and save

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

Author information

Authors and Affiliations

  1. IMB Jena, Dept. of Genome Analysis, Beutenbergstr. 11, 07745 Jena Germany, , , , , , DE
    Gernot Glöckner & André Rosenthal
  2. Institut für Pflanzenphysiologie, Justus-Liebig-Universität Gießen, Heinrich Buff Ring 34-36, Gießen, Germany, , , , , , DE
    Klaus Valentin

Authors

  1. Gernot Glöckner
    You can also search for this author inPubMed Google Scholar
  2. André Rosenthal
    You can also search for this author inPubMed Google Scholar
  3. Klaus Valentin
    You can also search for this author inPubMed Google Scholar

Additional information

Received: 3 June 2000 / Accepted: 18 July 2000

Rights and permissions

About this article

Cite this article

Glöckner, G., Rosenthal, A. & Valentin, K. The Structure and Gene Repertoire of an Ancient Red Algal Plastid Genome.J Mol Evol 51, 382–390 (2000). https://doi.org/10.1007/s002390010101

Download citation