Phylogeny of the non-photosynthetic green micro-algal genus Prototheca (Trebouxiophyceae, Chlorophyta) and related taxa inferred from SSU and LSU ribosomal DNA partial sequence data

Abstract

All five species in the heterotrophic micro-algal genus Prototheca and their relatives were compared for the extent of nucleotide divergence in the nuclear small-subunit (SSU) and in the 5' end of large-subunit (LSU) ribosomal RNA genes (rDNAs). Phylogenetic analysis based on combined SSU and LSU rDNA sequence alignment was implemented with the neighbor-joining, the maximum-parsimony, and the maximum-likelihood methods. The relationships among the species of Prototheca based on this data set were largely concordant with those inferred from SSU or LSU rDNA sequences alone. The obtained phylogenetic trees indicated that P. stagnora and P. ulmea should be regarded as different species and that both of the species as well as P. moriformis were placed in a cluster represented by P. zopfii, whereas P. wickerhamii was not directly grouped together with the other members of Prototheca and was more closely related to the autotrophic alga Auxenochlorella protothecoides. Therefore, the genus Prototheca is paraphyletic in its present circumscription; and these conclusions lead us to propose the transfer of P. wickerhamii to Auxenochlorella or to a new genus. On the basis of nucleotide sequence similarities, unlike SSU rDNA, the LSU rDNA region examined in this study appeared to be variable in recognizing a heterogeneity within a single species P. zopfii, which had been shown earlier in a chemotaxonomic study.

Distribution of norspermidine as a cellular polyamine within micro green algae including non-photosynthetic achlorophyllous Polytoma, Polytomella, Prototheca and Helicosporidium

“…Hegewald and Kneifel (1982) reported that differences in the pattern of the polyamines within the genus Chlorella led to separation of two groups: those characterized by the near absence of norspermidine and those by high concentration of norspermidine. However, it has been shown that phylogenetically heterogeneous Chlorella species distribute in different clusters in the Trebouxiophyceae and Chlorophyceae (Ali et al, 2001;NCBI home page, 2004;Ueno et al, 2003). In the present study, C. vulgaris, C. kessleri and C. sorokiniana belonging to authentic genera Chlorella as well as "C. saccharophila" and "C. ellipsoidea" located in another cluster of Trebouxiophyceae were almost entirely lacking in norspermidine.…”

“…are known to be pathogenic to vertebrates (Galan et al, 1997;Mohabeer et al, 1997). Another non-photosynthetic unicellular green algal group consisting of the Polytoma and Polytomella species belongs to Chlorophyceae (Nedelcu, 2001;Tartar et al, 2003;Ueno et al, 2003). They have degenerate chloroplasts and grow heterotrophically in the dark whereas other green algae ordinarily grow phototrophically in the light.…”

“…Although norspermidine was also detected in another achlorophyllous pathogenic species of Helicosporidium, the cellular level of norspermidine relative to spermidine level was very low. A novel photosynthetic alga, Auxenochlorella protothecoides ATCC 30407 (formerly deposited as a strain of "Chlorella protothecoides") belonging to the clade consisting Prototheca and Helicosporidium species (NCBI home page, 2004;Ueno et al, 2003) contained spermidine and spermine. Polyamine profiles of the three genera in this clade were different.…”

Phylogeny and Molecular Evolution of the Green Algae

“…The non-photosynthetic, parasitic Prototheca and Helicosporidium are also included in the Chlorellales based on nuclear and chloroplast gene data (Huss & Sogin, 1990;Tartar et al, 2003;Ueno et al, 2003;de Koning et al, 2005;Ueno et al, 2005). Although plastids are not apparent in Helicosporidium cells, molecular evidence indicates that it maintains a functional plastid genome (Tartar et al, 2003;de Koning & Keeling, 2004;Tartar & Boucias, 2004;de Koning & Keeling, 2006).…”

Detection and Identification of Genotypes of <i>Prototheca zopfii</i> in Clinical Samples by Quantitative PCR Analysis

“…Specific oligonucleotides: The P. zopfii-specific primers 18PZF1 and 18PZR1 were generated on the basis of the alignment of the small subunit ribosomal DNA (SSU rDNA) base sequences of the genera Chlorella and Prototheca obtained from DDBJ/EMBL/ GenBank (25,26,45). The TaqMan } MGB probe PZP1 (nucleotides 378-395 of the SSU rDNA sequence, DDBJ/EMBL/GenBank accession no.…”