The distribution of elongation factor-1 alpha (EF-1α), elongation factor-like (EFL), and a non-canonical genetic code in the ulvophyceae: Discrete genetic characters support a consistent phylogenetic framework

Gillian H. Gile, Philip M. Novis, David S. Cragg, Giuseppe C. Zuccarello, Patrick J. Keeling

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

The systematics of the green algal class Ulvophyceae have been difficult to resolve with ultrastructural and molecular phylogenetic analyses. Therefore, we investigated relationships among ulvophycean orders by determining the distribution of two discrete genetic characters previously identified only in the order Dasycladales. First, Acetabularia acetabulum uses the core translation GTPase Elongation Factor 1α (EF-1α) while most Chlorophyta instead possess the related GTPase Elongation Factor-Like (EFL). Second, the nuclear genomes of dasycladaleans A. acetabulum and Batophora oerstedii use a rare non-canonical genetic code in which the canonical termination codons TAA and TAG instead encode glutamine. Representatives of Ulvales and Ulotrichales were found to encode EFL, while Caulerpales, Dasycladales, Siphonocladales, and Ignatius tetrasporus were found to encode EF-1α, in congruence with the two major lineages previously proposed for the Ulvophyceae. The EF-1α of I. tetrasporus supports its relationship with Caulerpales\Dasycladales\ Siphonocladales, in agreement with ultrastructural evidence, but contrary to certain small subunit rRNA analyses that place it with Ulvales\Ulotrichales. The same non-canonical genetic code previously described in A. acetabulum was observed in EF-1α sequences from Parvocaulis pusillus (Dasycladales), Chaetomorpha coliformis, and Cladophora cf. crinalis (Siphonocladales), whereas Caulerpales use the universal code. This supports a sister relationship between Siphonocladales and Dasycladales and further refines our understanding of ulvophycean phylogeny.

Original languageEnglish (US)
Pages (from-to)367-372
Number of pages6
JournalJournal of Eukaryotic Microbiology
Volume56
Issue number4
DOIs
StatePublished - Jul 1 2009
Externally publishedYes

Keywords

  • Caulerpales
  • Chlorophyta
  • Dasycladales
  • Elongation factors
  • Green algae
  • Ignatius tetrasporus
  • Systematics
  • Taxonomy
  • Ulotrichales
  • Ulvales

ASJC Scopus subject areas

  • Microbiology

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