Assessment of Genetic Diversity of Euphorbia hirta Linn in the Philippines using sequence-related amplified polymorphism (SRAP) markers

Euphorbia hirta Linn. is a medicinal plant found in the Philippines and known for its application for dengue management. E. hirta collected from different geographical locations have demonstrated variations in anti-thrombocytopenic activity in vivo. Hence, it is necessary to determine the intraspecific diversity of E. hirta to provide insights on the observed bioactivity. In this study, thirty-one (31) E. hirta plant specimens were collected from various geographic locations in the Philippines. Species identity was confirmed through DNA barcoding using rbcL and matK primers. Identification of intraspecies genetic variations were made through Sequence-Related Amplified Polymorphism (SRAP) analysis. Three (3) SRAP primer pairs produced 23 distinct and reproducible bands with average percent polymorphism of 84.63. The average values of the evaluation indices Nei’s genetic diversity (H) and Shannon’s diversity index (I), and the Polymorphic Information Content (PIC) of the primers were 0.332 ± 0.017, 0.484 ± 0.024, and 0.425, respectively. A moderate genetic differentiation (F _st = 0.172; P value = 0.001) were also found in the E. hirta accessions. UPGMA clustering based on the presence or absence of these bands grouped the plant samples into three clusters. Geographical distance did not play a role in the clustering. Two gene loci were also identified to have a potential use as markers for species identification. The study has shown the utility of SRAP markers to generate DNA fingerprints and identify E. hirta genetic variants. This may be adapted as a standard method in the molecular characterization of medicinally important plant samples.