18S and ITS2 rDNA sequence-structure phylogeny of Prototheca (Chlorophyta, Trebouxiophyceae)

Abstract Protothecosis is an infectious disease caused by organisms currently classified within the green algal genus Prototheca . The can manifest as cutaneous lesions, olecranon bursitis or disseminated systemic infections in both immunocompetent and immunosuppressed patients. Concerning diagnostics, taxonomic validity important. , closely related to Chlorella species complex, known be polyphyletic, branching with Auxenochlorella Helicosporidium phylogeny of was discussed revisited several times last decade; new have been described. Phylogenetic analyses were performed using ribosomal DNA (rDNA) partial mitochondrial cytochrome b ( cytb ) sequence data. In this work we use Internal Transcribed Spacer 2 (ITS2) well 18S rDNA However, for first time, reconstruct phylogenetic relationships primary RNA secondary structure information simultaneously, a concept shown increase robustness accuracy tree estimation. Using encoded sequence-structure data, Neighbor-Joining, Maximum-Parsimony Maximum-Likelihood methods yielded well-supported trees agreement other calculated on rDNA; but differ aspects from marker. ITS2 structures sequences are well-known common core eukaryotes show unusual differences their helix lengths. An elongation fourth some seems occurred independently course evolution.