To the Question of Rhododendron L. Genus Phylogeny Based on ITS1–ITS2 Spacers Sequence Studies
T. V. Baranova1, R. N. Kalendar2, V. N. Kalaev1
1Voronezh State University, Botanical Garden, Botanicheski sad, 1, Voronezh, 394068 Russian Federation
2University of Helsinki, Institute of Biotechnology, P.O. Box 65, Viikinkaari, 1, Helsinki, 00014 Finland
Keywords: phylogeny, phylogenetic community, nuclear ribosomal RNA, ITS sequence, nucleotide, Rhododendron, internal transcribed spacer (ITS) region, species-specific
Abstract
The first and second internal transcribed spacer (ITS1 and ITS2) regions of the ribosomal DNA and 5.8S rRNA gene from Rhododendron L. were analysed. This study reveals phylogenetic relationships and collation of data on the phylogeny of the genus Rhododendron L. according to the research of other authors using molecular and classical methods. Sequence analysis of ribosomal spacer showed low variability between species of the genus Rhododendron series of Dauricum. Rh. mucronulatum Turcz., Rh. dauricum L. and some other studied species had identical nucleotide ITS1–ITS2 sequence indicating the artificial division into separate species. Found species differing from each other by 1–2 or few nucleotides, which allows assuming their common phylogenetic affiliation or excluding one taxonomic unit. According to the analysis of ITS1–ITS2 sequences identified 16 groups of species with similar sequence ITS1–ITS2. When comparing the morphological descriptions of some species of the genus Rhododendron L. with a similar sequence of ITS1–ITS2 marked their small differences. Based on the results of molecular genetic analysis it has been assumed that Rhododendron dauricum L., Rh. ledebourii Pojark, Rh. sichotense Pojark and Rh. mucronulatum Turcz belong to the same species. The establishment phylogenetic relationships based on sequence ITS1–ITS2, applicable only in respect of highly isolated species Rhododendron L. To clarify the phylogenetic relationships of the genus Rhododendron L. necessary to expand the comparative analysis of the DNA sequences of universal genes or complex repeats elements (retrotransposons).
|
