Evaluation of the taxonomic status of water dropwort (Oenanthe, Apiaceae) accessions from East Asia based on nuclear rDNA internal transcribed spacer sequences.

Oenanthe L. is a taxonomically complex genus, several species of which have long been used as vegetables and traditional medicines in East Asia. In order to clarify the taxonomic status of Oenanthe accessions and provide baseline data for the sustainable use of its genetic resources, we examined sequence variations in the internal transcribed spacer (ITS) region of Oenanthe accessions collected from a wide geographical area in China and its neighboring countries. For comparison, ITS sequences in GenBank for almost all currently reported species of Oenanthe were also included in our analyses. Both phylogenetic tree construction methods (Bayesian inference and maximum likelihood) revealed that the accessions tended to cluster into two groups, which were closely related to O. mildbraedii and O. sarmentosa. However, these two species have never been recorded in China or its neighboring countries. Therefore, it seems probable that in our sampled locations, Oenanthe accessions have been given an incorrect name, such as O. javanica. Future studies should carefully check the morphological characteristics of other Oenanthe species and sequence their ITS regions in order to clarify the taxonomic status of the genus.

Efficient isolation of high-quality RNA from lotus Nelumbo nucifera ssp nucifera tissues.

Nelumbo nucifera is widely used as food, as an ornamental, in medicine, and as packing material; it is also reported to have anti-HIV effects and antioxidant capacity. We sought an improved method for extracting high-quality total RNA from different tissues of N. nucifera. Four methods for RNA extraction were assessed for their ability to recover high-quality RNA applicable for evaluation of polyphenol oxidase (PPO) gene expression profiles. The recovery and quality of the RNA obtained from five different tissues by the best CTAB-LiCl method were evaluated through UV light absorbance. Both A(260)/A(280) and A(260)/A(230) absorbance ratios were more than 2.0; the yield ranged from 59.87 to 163.75 µg/g fresh weight. The brightness of the 28S band was approximately twice that of 18S; the latter was also considered as high-quality RNA. The PPO gene fragment (606 bp) was successfully amplified by RT-PCR, demonstrating the integrity of the isolated RNA. The relative expression levels of the PPO gene based on RT-PCR in five tissues of lotus were: rhizome buds (2.66), young leaves (2.42), fresh cut rhizome (2.02), petals (1.80), and petiole (1.65), using housekeeping gene ß-actin as an internal control. We concluded that the total RNA isolated by this protocol is of sufficient quality for molecular applications.