ISSR molecular characterization and leaf volatiles analysis of Pittosporum undulatum Vent. naturalized in the Azores archipelago (Portugal)

Pittosporum undulatum from the Azores archipelago was characterized by both molecular and volatiles analyses. Inter simple sequence repeat (ISSR) evaluation was performed based on a random sampling of 77 individuals from a total of 123 samples collected on all the Azorean islands. Molecular studies grouped the samples mainly according to the geographical collection site, with some exceptions. Leaf volatiles were isolated by distillation-extraction and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) from all the 123 samples. Cluster analysis based on the leaf volatiles chemical composition defined three main clusters, not related to sample site collection, and was based mainly on the relative amounts of limonene (3-89%), sabinene (0.1-64%) and terpinen-4-ol (traces-43%). Clusters obtained from both molecular studies and volatiles composition were not superimposable and no correlation between ISSR markers and volatile oils could be drawn. The results suggest that there is a high genetic variability among individuals of P. undulatum that can explain the invasive ability of this species in the Azores archipelago. The detailed characterization of this alien weed species may assist finding potential commercial uses as well as management strategies to help its eradication and/or control.