Rapid analysis for the identification of the seagrass Halophila ovalis (Hydrocharitaceae)

Seagrasses are considered as one of the most important species as they play key ecological roles in various types of ecosystems and also provide a food source for endangered animal species. There are two main  characteristics of seagrasses that hinder efforts to correctly identify species based on conventional identification keys alone: i) the variability of  morphological characteristics and ii) lack of needed morphological  characters especially flowers. A taxonomically unresolved complex such as Halophila spp. is reported. Plant DNA barcoding regions (rbcL and trnH-psbA) were used to confirm species of collected seagrasses from the southern coast of Thailand. Small and big-leaved samples of Halophila spp. were analysed in this study. The big-leaved samples were identified on the field as Halophila ovalis whilst it was uncertain whether the small-leaved samples belonged to H. ovalis. DNA analysis revealed that the small-leaved samples could be H. ovalis. We also coupled PCR with high resolution melt (HRM) to more cost-effectively identify individuals of H. ovilis than using barcoding alone. Using HRM to resolve differences in the sequence of two genes showed that the two unknown seagrasses belonged to the same species as H. ovalis.  In conclusion, using HRM proved to pose great potential in seagrass identification. Key words: DNA barcoding, Halophila ovalis, rbcL, trnH-psbA, species identification

Poisonous or non-poisonous plants? DNA-based tools and applications for accurate identification

Plant exposures are among the most frequently reported cases to poison control centres worldwide. This is a growing condition due to recent societal trends oriented towards the consumption of wild plants as food, cosmetics, or medicine. At least three general causes of plant poisoning can be identified: plant misidentification, introduction of new plant-based supplements and medicines with no controls about their safety, and the lack of regulation for the trading of herbal and phytochemical products. Moreover, an efficient screening for the occurrence of plants poisonous to humans is also desirable at the different stages of the food supply chain: from the raw material to the final transformed product. A rapid diagnosis of intoxication cases is necessary in order to provide the most reliable treatment. However, a precise taxonomic characterization of the ingested species is often challenging. In this review, we provide an overview of the emerging DNA-based tools and technologies to address the issue of poisonous plant identification. Specifically, classic DNA barcoding and its applications using High Resolution Melting (Bar-HRM) ensure high universality and rapid response respectively, whereas High Throughput Sequencing techniques (HTS) provide a complete characterization of plant residues in complex matrices. The pros and cons of each approach have been evaluated with the final aim of proposing a general user\u2019s guide to molecular identification directed to different stakeholder categories interested in the diagnostics of poisonous plants