Molecular polymorphism and volatile oil composition of the endemic Azorean species, Juniperus brevifolia

Fifty two Juniperus brevifolia (Seub.) Antoine individual twigs samples were collected on seven Azorean islands (Pico, Terceira and S. Jorge in 2004, Corvo and Flores in 2005 and Faial and S. Miguel in 2006).

DNA fingerprinting (RAPD's) was performed for each individual. An outgroup, J. chinensis was included in the analysis. Fifty one primers were tested, and thirty six were selected for molecular analysis based on the number of polymorphic bands and amplification fidelity. Volatiles from all the samples were extracted by distillation-extraction and analyzed by GC and GC-MS.

The cluster analysis of DNA data showed a low correlation (S_corr=0.45) in consequence of the high genetic polymorphism detected.

Eighty one components, representing 97–100% of the total oils, were identified. The oils consisted mainly of monoterpene hydrocarbons (84–96%), limonene (33–87%), γ-pinene (1–48%) and β-mircene (1–5%) being the main components, in accordance with previous studies [1]. The diterpene fraction (1–9%) was dominated by 13-epi-manool (1–6%) and trans-totarol (0.1–3%), while 1-octen-3-ol (trace-4%) was the major constituent of the non-terpenic fraction (trace-4%). In contrast to the molecular data, cluster analysis of the volatile oils components showed a high correlation among all samples (S_corr=0.84).

In our study, RAPDs were very useful for assessing genetic variation which was present among the J. brevifola plants tested. However, a good correlation between chemical and molecular analysis was not found and in the future different approaches have to be followed for that purpose.

Acknowledgements: Partially funded by FCT under research contract PTDC/AGR-AAM/70136/2006.

References: 1. Silva, J. et al. (2000) Flavour and Frag. J. 15: 31–39.