Biomonitoring for traditional herbal medicinal products using DNA metabarcoding and single molecule, real-time sequencing

Global concerns have been paid to the potential hazard of traditional herbal medicinal products (THMPs). Substandard and counterfeit THMPs, including traditional Chinese patent medicine, health foods, dietary supplements, etc. are potential threats to public health. Recent marketplace studies using DNA barcoding have determined that the current quality control methods are not sufficient for ensuring the presence of authentic herbal ingredients and detection of contaminants/adulterants. An efficient biomonitoring method for THMPs is of great needed. Herein, metabarcoding and single-molecule, real-time (SMRT) sequencing were used to detect the multiple ingredients in Jiuwei Qianghuo Wan (JWQHW), a classical herbal prescription widely used in China for the last 800 years. Reference experimental mixtures and commercial JWQHW products from the marketplace were used to confirm the method. Successful SMRT sequencing results recovered 5416 and 4342 circular-consensus sequencing (CCS) reads belonging to the ITS2 and regions. The results suggest that with the combination of metabarcoding and SMRT sequencing, it is repeatable, reliable, and sensitive enough to detect species in the THMPs, and the error in SMRT sequencing did not affect the ability to identify multiple prescribed species and several adulterants/contaminants. It has the potential for becoming a valuable tool for the biomonitoring of multi-ingredient THMPs.

Testing plant barcoding in a sister species complex of pantropical Acacia (Mimosoideae, Fabaceae).

Acacia species are quite difficult to differentiate using morphological characters. Routine identification of Acacia samples is important in order to distinguish invasive species from rare species or those of economic importance, particularly in the forest industry. The genus Acacia is quite abundant and diverse comprising approximately 1355 species, which is currently divided into three subgenera: subg. Acacia (c. 161 species), subg. Aculiferum (c. 235 species), and subg. Phyllodineae (c. 960 species). It would be prudent to utilize DNA barcoding in the accurate and efficient identification of acacias. The objective of this research is to test barcoding in discriminating multiple populations among a sister-species complex in pantropical Acacia subg. Acacia, across three continents. Based on previous research, we chose three cpDNA regions (rbcL, trnH-psbA and matK). Our results show that all three regions (rbcL, matK and trnH-psbA) can distinguish and support the newly proposed genera of Vachellia Wight & Arn. from Acacia Mill., discriminate sister species within either genera and differentiate biogeographical patterns among populations from India, Africa and Australia. A morphometric analysis confirmed the cryptic nature of these sister species and the limitations of a classification based on phenetic data. These results support the claim that DNA barcoding is a powerful tool for taxonomy and biogeography with utility for identifying cryptic species, biogeograhic patterns and resolving classifications at the rank of genera and species.