Studies on ribosomal DNA sequence analyses of Radix puerariae and its sibling species

OBJECTIVE To discuss the taxonomic status of Pueraria lobata and its sibling species DC.in China, and to provide DNA molecular markers for authenticating the Chinese crude drug Gegen.METHODS The internal transcribed spacers (ITS) including 5.8S rDNA,and partial 18S rDNA,26S rDNA of 3 sibling species of Pueraria DC.in China were determined by using direct sequencing of PCR product.RESULTS In DNA DIST analysis,the range of diversity between Pueraria lobata and P. thomsonii was 2.10% based on ITS1 and 2.09% based on ITS2.The range of diversity among the P.montana,P.lobata and P.thomsonii was above 8.14% based on ITS1 and 12.82% based on ITS2.Phylogram tree based on ITS and 5.8S sequence data indicated that P.lobata and P.thomsonii was closely related, while the genetic distance between P.montana and P.lobata was long.CONCLUSION Base on the molecular characters,P.thomsonii may be taken as variant of P.lobata, but P.montana is independent species.The ITS sequence is good molecular marker for identification of the Chinese medicine Gegen.