DNA markers targeting three cellular genomes for the discrimination between Taxus baccata, T. cuspidata and their hybrid

The species identification in Taxus based on morphological differences has historically been difficult, and molecular markers are important tools to consistently identify Taxus species. The increasing availability of public DNA sequencing data supports efforts to develop such markers. In this study, a new molecular PCR-based marker for the differentiation of the three most abundantly occurring Taxus species in Europe, T. baccata, T. cuspidata, and their cultivated hybrid, T. x media, was identified in the ITS region in the nuclear genome, as well as markers for the identification of T. baccata and T. cuspidata that were identified in the psbB_psaI intergenic linker and chlN region of the chloroplast genome and in the cox1 region of the mitochondrial genome. Markers identified in public data were validated with 106 T. baccata, 12 T. x media and 10 T. cuspidata individuals with pre-existing phenotypical species declarations. The marker test results matched the identity of all but seven samples, and all deviating samples were identified by the markers as T. x media. In combination, these markers can also identify the crossing direction of T. x media samples. The results of the tests on T. x media samples in this study support a paternal inheritance of the mitochondrial genome in T. x media and revealed the crossing direction of multiple cultivars for which it was previously unknown. A minimal marker set was defined for rapid and cost-efficient identification of the analysed Taxus species and the crossing direction in T. x media.