Phylotranscriptomic and Evolutionary Analyses of Oedogoniales (Chlorophyceae, Chlorophyta)

Abstract

This study determined the transcriptomes of eight Oedogoniales species, including six species from Oedogonium and two species from Oedocladium to conduct phylotranscriptomic and evolutionary analyses. 155,952 gene families and 192 single-copy orthogroups were detected. Phylotranscriptomic analyses based on single-copy orthogroups were conducted using supermatrix and coalescent-based approaches. The phylotranscriptomic analysis results revealed that Oedogonium is polyphyletic, and Oedocladium clustered with Oedogonium. Together with the transcriptomes of the OCC clade in the public database, the phylogenetic relationship of the three orders (Oedogoniales, Chaetophorales, Chaetopeltidales) is discussed. The non-synonymous (dN) to synonymous substitution (dS) ratios of single-copy orthogroups of the terrestrial Oedogoniales species using a branch model of phylogenetic analysis by maximum likelihood were estimated, which showed that 92 single-copy orthogroups were putative rapidly evolving genes. Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses results revealed that some of the rapidly evolving genes were associated with photosynthesis, implying that terrestrial Oedogoniales species experienced rapid evolution to adapt to terrestrial habitats. The phylogenetic results combined with evolutionary analyses suggest that the terrestrialization process of Oedogoniales may have occured more than once.

Phylotranscriptomic and Evolutionary Analyses of the Green Algal Order Chaetophorales (Chlorophyceae, Chlorophyta)

“…Due to its distinct benefits, phylotranscriptomics is increasingly being used for phylogenetic and evolutionary investigations on green algae. It has been demonstrated that acquiring high-density transcriptomic data in conjunction with the development of numerous sophisticated analytical techniques is an effective strategy for clarifying ambiguous evolutionary relationships between distinct species [ 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. However, no transcriptomic data had been published on members of the Chaetophorales and little was known about the phylotranscriptomics of this order.…”