ORGANIZATION AND POLYMORPHISM OF THE CHLOROPLAST GENOME REGION psbA-trnH IN REPRESENTATIVES OF THE GONIOLIMON BOISS.

Abstract

Four out of twenty-two species of the genus Goniolimon are common in Ukraine: G. besserianum, G. graminifoli-um, G. rubellum and G. tataricum. Two of them, G. graminifolium and G. rubellum, are listed as vulnerable species in the Red Data Book of Ukraine. Some populations of both species are sometimes reported under different species names, manly as G. desertorum (Trautv.) Klokov. and G. rubellum (S.G. Gmel.) Klokov. To clarify these taxonomic questions, the application of molecular phylogenetic methods is necessary. Recently, the fragment between the psbA and trnH genes has been particularly actively used for similar purposes. In this work, we tested the use of the psbA-trnH chloroplast genomic region for phylogenetic analysis and DNA barcoding of representatives of the genus Goni-olimon. We amplified and sequenced the psbA-trnH sequences for samples of all four species of this genus distributed in Ukraine and compared them with the psbA-trnH sequences available in the GenBank database for species of Goni-olimon and related genera. The comparison of the available sequences showed that the representatives of the genus Goniolimon differ in twelve variable nucleotide positions, seven of which are parsimony-informative. They also differ in one oligonucleotide indel and a sequence inversion corresponding to the stem-loop region in the 3΄ UTR region of psbA mRNA. The difference between the psbA-trnH regions of Goniolimon species and representatives of related gene-ra was much higher. In addition to numerous SNPs, they also differ by a polynucleotide indel. Such significant differ-ences indicate a higher rate of evolution of the psbA-trnH region during the divergence of the genus Goniolimon compared to other regions of the chloroplast genome. On the phylogenetic dendrogram based on the comparison of psbA-trnH sequences, the Goniolimon species from Central Asia form a distinct group, which is probably due to chlo-roplast genome transfer as a result of hybridization in a common distribution area. In general, the high variability of the psbA-trnH regions in representatives of the genus Goniolimon found in our study allows us to use this region to clarify the position of controversial taxa in the group.