Efficient DNA barcode regions for classifying Piper species (Piperaceae)

Piper species are used for spices, in traditional and processed forms of medicines, in cosmetic compounds, in cultural activities and insecticides. Here barcode analysis was performed for identification of plant parts, young plants and modified forms of plants. Thirty-six Piper species were collected and the three barcode regions, matK, rbcL and psbA-trnH spacer, were amplified, sequenced and aligned to determine their genetic distances. For intraspecific genetic distances, the most effective values for the species identification ranged from no difference to very low distance values. However, P. betle had the highest values at 0.386 for the matK region. This finding may be due to P. betle being an economic and cultivated species, and thus is supported with growth factors, which may have affected its genetic distance. The interspecific genetic distances that were most effective for identification of different species were from the matK region and ranged from a low of 0.002 in 27 paired species to a high of 0.486. Eight species pairs, P. kraense and P. dominantinervium, P. magnibaccum and P. kraense, P. phuwuaense and P. dominantinervium, P. phuwuaense and P. kraense, P. pilobracteatum and P. dominantinervium, P. pilobracteatum and P. kraense, P. pilobracteatum and P. phuwuaense and P. sylvestre and P. polysyphonum, that presented a genetic distance of 0.000 and were identified by independently using each of the other two regions. Concisely, these three barcode regions are powerful for further efficient identification of the 36 Piper species.