Molecular identification of Tiandong derived from Asparagus cochinchinensis (Lour.) Merrill by two typical deletions in cpDNA

The swollen and dried roots of Asparagus cochinchinensis (Lour.) Merrill is a crude drug called "Tiandong" (Japanese characters) in China and "Tenmondo" (Japanese characters) in Japan. It is difficult to identify the botanical origin by roots because the morphological characters are quite simple and some Asparagus species such as A. lycopodineus also have similar swollen roots. To develop an accurate and easy identification procedure of A. cochinchinensis, we evaluated previously reported regions of deletions in chloroplast DNA (cpDNA) of various Asparagus species by the method of PCR amplification. The result indicates that the only A. cochinchinensis has two large deletions. The PCR amplification using samples of A. cochinchinensis from various localities reveals that the deletions are well conserved. Moreover, amplification products were successfully obtained from all market samples and were used for the straightforward identification. From these results, the PCR amplification of the cpDNA regions for Tiandong allows the accurate identification of A. cochinchinensis.