rbcL plastid pseudogene as a tool for Orobanche (subsection Minores) identification

Among members of the Orobanchaceae, parasitism has led to a drastic reducti on in the morphological characters useful in identification. This is especi ally the case of species belonging to the subsection Minores (section Oroba nche), which is a real tangle for agronomists and botanists. In this study, more than 120 specimens collected in the west of France were studied for t heir morphological characters and molecular markers. Their rbcL plastid gen e was analyzed by RFLP and nucleotide sequencing. Because of several substi tutions, insertions and deletions in the coding sequence, leading to stop c odons and frameshift, this rbcL gene could be considered as a pseudogene. V ariations in both 5' upstream and coding regions allowed us to distinguish among specimens inside the Minores subsection. It was then possible to poin t out morphological characters, not used in floras, that fit with molecular analysis and confirm the existence of four taxa. Consequently, a new key t o species determination using molecular analysis or morphological character s or a combination of both is proposed for O. hederoe, O. amethystea, O. mi nor and O. loricata. Finally, the value of plastid pseudogenes in taxonomy is discussed.