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

Abstract

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.