Chemotypic Diversity and Metabolic Strategies in Drought-Resistant Myrtle (Myrtus communis L.)

Myrtus communis L. (common myrtle) is an economically valuable Mediterranean shrub with diverse applications in food, pharmaceutical, and ornamental sectors. However, the biochemical diversity of drought- and salt-resistant genotypes remains insufficiently characterized, particularly regarding the relationship between primary and secondary metabolism and stress adaptation. This study investigated the biochemical and aroma profiles of six drought-resistant myrtle genotypes from natural populations in Antalya, Turkey, to identify chemotypic diversity and elucidate metabolic strategies underlying abiotic stress tolerance. Volatile compounds were analyzed using HS-SPME/GC-MS, while sugars and organic acids were quantified by HPLC. Multivariate statistical analyses (PCA, hierarchical clustering) were employed to evaluate metabolic relationships and genotype classification. Three chemotypes were identified: (i) Eucalyptol-type (G34, G36) with 35-40% 1,8-cineole; (ii) α-Pinene-type (G15, G37) with elevated terpenes (15.7-20.5%) and high sugar content (11.9-12.4 g/100 ml); and (iii) Ester-aldehyde type (G9) characterized by dominant esters (30.4%) and negligible eucalyptol. Significant genotypic variation was observed across metabolite classes (p 0.90). Hierarchical clustering revealed three metabolic strategies: volatile-focused antioxidant defense (Cluster 1), osmotic adjustment with chemical defense (Cluster 2), and specialized stress signaling (Cluster 3). These findings highlight substantial metabolic plasticity and provide a basis for targeted breeding and diverse industrial applications.