The Amplification and Application of Ribosomal RNA (rDNA) Gene Sequences of Blidingia minima (Chlorophyta, Blidingia)

The sequence of the ribosomal RNA gene (rDNA) plays an important role in species identification and phylogenetic analysis. However, the only published full-length sequence of a ribosomal gene of green algae is that of Ulva mutabilis. In this study, we amplified the full-length sequence of each ribosomal gene unit of the ribosomal gene of Blidingia minima. The full-length sequence of the ribosomal gene in Blidingia minima is 8676 bp, including the 1759 bp 18S rDNA, 576 bp internal transcribed spacer (ITS) + 5.8S rDNA, 3282 bp 28S rDNA, and 3059 bp intergenic spacer (IGS) region. We then carried out a series of genetic analyses based on the ITS and IGS sequences, to verify whether IGS sequences are useful for studying the genetic diversity of green algae from different locations. We amplified the IGS sequences of Blidingia minima from 10 different locations in the Yellow Sea. Multiple alignments of the IGS sequences of samples from these 10 different sites revealed varying degrees of base differences, and comparative analysis of the ITS sequences revealed that our amplified species was classified as Blidingia minima and distinct from other green algae. In conclusion, our full-length amplified ribosomal gene provides useful information to enrich the data on green algae ribosomal genes and provides an effective molecular marker for the analysis of the interspecies and intraspecies relationships of Blidingia minima.