The exceptionally large chloroplast genome of the green alga Floydiella terrestris illuminates the evolutionary history of the Chlorophyceae.

摘要: The Chlorophyceae, an advanced class of chlorophyte green algae, comprises five lineages that form two major clades (Chlamydomonadales + Sphaeropleales and Oedogoniales Chaetopeltidales Chaetophorales). four complete chloroplast DNA (cpDNA) sequences currently available for chlorophyceans uncovered extraordinarily fluid genome architecture as well many structural features distinguishing this group from other algae. We report here the 521,168-bp cpDNA sequence a member (Floydiella terrestris), sole chlorophycean lineage not previously sampled analysis. This genome, which contains 97 conserved genes 26 introns (19 I 7 II introns), is largest ever sequenced. Intergenic regions account 77.8% size are populated by short repeats. Numerous genomic shared with chaetophoralean Stigeoclonium helveticum, notably absence large inverted repeat presence unique gene clusters trans-spliced introns. Although only one Floydiella encodes homing endonuclease gene, our finding free-standing reading frames having similarity such suggests endowed mobility were once more abundant in lineage. Parsimony analysis phylogenetic data unambiguously resolved sister to Chaetophorales. An evolutionary scenario molecular events shaped Chlorophyceae presented.