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

The blue-berried honeysuckle ( Lonicera caerulea L.) is one of the most representative species of the genus Lonicera L. 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, rpS16 and trnS-psbZ ) to assess the phylogenetic relationships among the taxa within the polymorphic 4 × species complex L. caerulea and to determine the position of Lonicera boczkarnikowae Plekh. and Lonicera venulosa Maxim. within this complex. Lonicera chrysantha Turcz. ex Ledeb., L. orientalis Lam. and L. xylosteum L. 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. boczkarnikowae and L. venulosa belong 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. altaica and L. edulis .