A three-marker DNA barcoding approach for ecological studies of xerothermic plants and herbivorous insects from central Europe

The DNA barcoding technique developed for species identification has recently been adapted for ecological studies (e.g. host plant identification). Comprehensive barcode databases, covering most species inhabiting areas, habitats or communities of interest are essential for reliable and efficient identification of plants. Here we present a three-barcode (plastid rbcL and matK genes and the trnL intron) database for xerothermic plant species from central Europe. About 85% of the xerothermic plant species (126 out of c. 150) known to be associated with xerothermic habitats were collected and barcoded. The database contains barcodes for 117 (rbcL and trnL) and 96 (matK) species. Interspecific nucleotide distances were in the ranges 0-17.9% (0-3.2% within genera) for rbcL, 0-44.4% (0-3.1%) for trnL and 0-52.5% (0-10.9%) for matK. Blast-searching of each sequence in the database against the entire database showed that species-level identification is possible for 89.6% (rbcL), 98.4% (trnL) and 96.4% (matK) of examined plant species. The utility of the presented database for identification of host plants was demonstrated using two insect species associated with xerothermic habitats: the oligophagous leaf-beetle Cheilotoma musciformis (for which two host plants in Fabaceae were identified) and the polyphagous weevil Polydrusus inustus (which was found to feed on 14 host plants, mostly Rosaceae, Asteraceae and Fabaceae). The developed database will be useful in various applications, including biodiversity, phylogeography, conservation and ecology. (C) 2015 The Linnean Society of London.