DNA barcoding reveals a new record of Potamogeton distinctus (Potamogetonaceae) and its natural hybrids, Potamogeton distinctus × Potamogeton nodosus and Potamogeton distinctus × Potamogeton wrightii (Potamogeton ×malainoides) from Myanmar

Indo-China floristic region is among the 34 richest floristic regions of the world, and its plant diversity is still under investigation. Here we report a new record of an aquatic plant, Potamogetondistinctus, from Myanmar, a part of the region, that is detected by means of DNA barcoding method. The molecular method further identified the other specimens as hybrids of Potamogeton: one is Potamogeton×malainoides (Potamogetondistinctus × Potamogetonwrightii), and the other is Potamogetondistinctus × Potamogetonnodosus. The first of these was thus far genetically confirmed in China, but the parental combination of the hybrid in Myanmar was reciprocal to those reported from China. The second hybrid was also recorded from China, but the maternal lineage was revealed for the first time, in this case it was Potamogetondistinctus. The present study showed that 1) nrITS is useful to distinguish closely related Potamogeton species as well as hybrids among them and 2) atpB-rbcL has higher utility than other frequently used plastid DNA markers. We thus propose nrITS and atpB-rbcL as DNA barcoding markers for future Potamogeton studies.