Phylogenetic analysis of the polymorphic 4× species complex Lonicera caerulea(Caprifoliaceae) using RAPD markers and noncoding chloroplast DNA sequences

The blue-berried honeysuckle (Lonicera caeruleaL.) is one of the most representative species of the genus LoniceraL. in horticulture. This article presents the results of research on the taxonomy of blue-fruited honeysuckles, which is quite complicated due to the phenotypic plasticity, ability to hybridize and distribution across different ecological zones. We used the random amplified polymorphic DNA (RAPD) markers and sequencing of seven chloroplast DNA (cpDNA) regions (trnH-psbA, rpS12-rpL20, trnL-trnF, trnS-trnG, trnG, rpS16and trnS-psbZ) to assess the phylogenetic relationships among the taxa within the polymorphic 4 × species complex L. caeruleaand to determine the position of Lonicera boczkarnikowaePlekh. and Lonicera venulosaMaxim. within this complex. Lonicera chrysanthaTurcz. ex Ledeb., L. orientalisLam. and L. xylosteumL. were used as the outgroup species. The RAPD and cpDNA analyses both indicated that all of the studied taxa of the blue-fruited honeysuckle form a single cluster consisting of two subclusters. A second cluster includes the outgroup species. According to the cpDNA analysis, L. boczkarnikowaeand L. venulosabelong to the subcluster that includes the taxa of the polymorphic tetraploid complex L. caerulea. A separate subcluster within the cluster of blue-fruited honeysuckles contains L. altaicaand L. edulis.