Mycorrhizal Inoculation Improves the Quality and Productivity of Essential Oil Distilled from Three Aromatic and Medicinal Plants: Thymus satureioides, Thymus pallidus, and Lavandula dentata

Abstract

In Morocco, extensive use, traditional practices, and climate change have seriously impacted the productivity of aromatic and medicinal plants (AMP). To mitigate these adverse effects, this study aims at evaluating the potential of the arbuscular mycorrhizal fungi (AMF), namely Rhizophagus irregularis and Funneliformis mosseae, in improving biomass, essential oils (EOs), and biomolecule production in Thymus satureioides, T. pallidus, and Lavandula dentata. Compared to non-inoculated-AMP, AMF induced significant increases in biomass production by 37.1, 52.4, and 43.6%, and in EOs yield by 21, 74, and 88% in T. satureioides, T. pallidus, and L. dentata, respectively. The EOs of inoculated-AMP exhibited increased proportions of major compounds such as thymol (23.7%), carvacrol (23.36%), and borneol (18.7%) in T. satureioides; α-terpinene (32.6%), thymol (28.79%), and δ-terpinene (8.1%) in T. pallidus; and camphor (58.44%), isoborneol (8.8%), and fenchol (4.1%) in L. dentata. Moreover, AMF significantly improved the anti-germinative and antifungal activities of the EOs. Indeed, IC50 values decreased by 1.8, 16.95, and 2.2 times against Blumerai graminis, Zymoseptoria tritici, and Fusarium culmorum, respectively, compared to non-inoculated-AMP. This study highlights the performance of the symbiosis between AMF and AMPs in terms of high quality of EOs production while respecting the environment. The associations F. mosseae-Thymus and R. irregularis-Lavandula are the most efficient.