Taxonomy and phylogeny of the genus Cryptomonas (Cryptophyceae, Cryptophyta) from Korea
|
Bomi Choi1, Misun Son2, Jong Im Kim1 and Woongghi Shin1,*
|
1Department of Biology, Chungnam National University, Daejeon 305-764, Korea 2Yeongsan River Environment Research Center, Gwangju 500-480, Korea
|
|
|
|
| |
ABSTRACT |
The genus Cryptomonas is easily recognized by having two flagella, green brownish color, and a swaying behavior. They have relatively simple morphology, and limited diagnostic characters, which present a major difficulty in differentiating between species of the genus. To understand species delineation and phylogenetic relationships among Cryptomonas species, the nuclear-encoded internal transcribed spacer 2 (ITS2), partial large subunit (LSU) and small subunit ribosomal DNA (rDNA), and chloroplast-encoded psbA and LSU rDNA sequences were determined and used for phylogenetic analyses, using Bayesian and maximum likelihood methods. In addition, nuclear-encoded ITS2 sequences were predicted to secondary structures, and were used to determine nine species and four unidentified species from 47 strains. Sequences of helix ?, ??, and ???b in ITS2 secondary structure were very useful for the identification of Cryptomonas species. However, the helix ?V was the most variable region across species in alignment. The phylogenetic tree showed that fourteen species were monophyletic. However, some strains of C. obovata had chloroplasts with pyrenoid while others were without pyrenoid, which used as a key character in few species. Therefore, classification systems depending solely on morphological characters are inadequate, and require the use of molecular data.
|
Key words:
Cryptomonas; Cryptophyta; morphology; phylogeny; taxonomy |
|
|
|