Molecular Identification and Phylogenetic Placement of Rosa arabica Crép. (Rosaceae), a Critically Endangered Plant Species.

The Egyptian narrowly endemic and critically endangered plant species Rosa arabica Crép. was studied employing a taxonomic and molecular approach. Morphological investigations, distance analysis, and phylogenetic reconstruction revealed that R. arabica is a distinct species with great affinity to R. canina and differentiated from R. rubiginosa. Molecular identification based on the sequences of multiple markers single or in combination ITS, matK, rbcL, and trnL-F succeeded in identifying R. arabica at genus and species levels. We evaluated the potential of each marker and a combination of the nuclear ITS -Internal Transcribed Spacer- with one of the plastid markers, matK, rbcL, or trnL-F, to accurately identify Rosa species. All of them were successful in identifying R. arabica. Classification based on DNA sequences shows that R. arabica is placed within section Caninae in a clade comprising R. canina and R. rubiginosa. Moreover, R. arabica is closely related to other European Rosa species. In conclusion, our results indicate that the four DNA markers can provide species resolution in the context of the genus Rosa and relatives, aiming to characterize morphology and genetic diversity in the ecological and economically important genus Rosa.