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.

Variability in Chemical Composition and Biochemical Activities of Mentha x piperita L. Essential Oil, in Response to Mycorrhizal Symbiosis and Heavy Metal Stress

“…Regardless of the Pb and Cd stress, mycorrhization with G. intraradices enhanced the essential oil yield in M. x piperita , in which mycorrhizal plants showed higher yield than non‐mycorrhizal plants (Figure 1). In agreement with our results, several previous studies [1,4,46,54–71] reported that mycorhization with arbuscular mycorrhizal fungi significantly improved the essential oil yield of medicinal and aromatic plants, such as Anethum graveolens, Trachyspermum ammi, Coriandrum sativum, Mentha arvensis, Mentha piperita, Ocimum basilicum, Mentha viridis, Mentha crispa , Thymus satureioides, Thymus pallidus , Lavandula dentata, Corianderum sativum , Atractylodes lancea , Inula ensifolia , Artemisia umbelliformis , Plectranthus amboinicus , Satureja macrostema , Salvia officinalis , Origanum vulgare, Origanum onites , Thymus daenensis , Thymus vulgaris and Foeniculum vulgare .…”

“…Similar to our results, there are several reports in which mycorrhization resulted in improved concentration of essential oil components; e. g ., limonene and carvone in Anethum graveolens , thymol in Trachyspermum ammi , anethol in Foeniculum vulgare , geraniol and linalool in Coriandrum sativum , [1–3] menthol in Mentha arvensis , [56] forskolin in Coleus forskohlii , [4] α‐terpineol in Ocimum basilicum , [57] artemisinin in Artemisia annua , [5,6] carvacrol in Origanum vulgare , [76] bornyl acetate, 1,8‐cineole, α‐ thujones and β ‐thujones in Salvia officinalis , [77] limonene, 1,8 cineole, carvone, eugenol and (E) ‐methyl cinnamate in Mentha viridis , [62] carvacrol, linalool, thymol, β ‐caryophyllene, carvacrol methyl ether, terpinene‐4‐ol and borneol in Thymus satureioides , β ‐caryophyllene, α‐ terpinene, (+)‐4‐carene, γ ‐terpinene, camphene, verbenene and terpinen‐4‐ol in Thymus pallidus , tricyclene, D‐limonene, germacrene D, L‐fenchone, β ‐eudesmol, bornyl acetate, carveol and camphor in Lavandula dentata [71] …”

“…Similar to our results, there are several reports in which mycorrhization resulted in improved concentration of essential oil components; e. g., limonene and carvone in Anethum graveolens, thymol in Trachyspermum ammi, anethol in Foeniculum vulgare, geraniol and linalool in Coriandrum sativum, [1][2][3] menthol in Mentha arvensis, [56] forskolin in Coleus forskohlii, [4] α-terpineol in Ocimum basilicum, [57] artemisinin in Artemisia annua, [5,6] carvacrol in Origanum vulgare, [76] bornyl acetate, 1,8-cineole, αthujones and β-thujones in Salvia officinalis, [77] limonene, 1,8 cineole, carvone, eugenol and (E)-methyl cinnamate in Mentha viridis, [62] carvacrol, linalool, thymol, β-caryophyllene, carvacrol methyl ether, terpinene-4-ol and borneol in Thymus satureioides, β-caryophyllene, α-terpinene, (+)-4-carene, γ-terpinene, camphene, verbenene and terpinen-4-ol in Thymus pallidus, tricyclene, D-limonene, germacrene D, L-fenchone, β-eudesmol, bornyl acetate, carveol and camphor in Lavandula dentata. [71] Regarding globally the essential oil composition, Mucciarelli et al [55] observed that mycorrhizal colonization by a nonmycorrhizal fungus change the essential oil composition of Mentha piperita, and similarly, Copetta et al [57] reported that the essential oil composition of Ocimum basilicum change under mycorrhizal colonization condition. In contrast, Khaosaad et al [78] found that mycorrhizal colonization of Origanum vulgare plants by Glomus mosseae does not affect significantly the essential oil composition.…”

Features of growth and development of Lavandula angustifolia when grown under drip irrigation conditions in the Southern Steppe zone of Ukraine

“…AMF-S and AMF-C showed the best results (Popescu & Popescu, 2022). Similar results have been obtained in other studies ( Binet et al, 2020, Pirsarandib et al, 2022, in particular, a positive effect on the composition of essential oils during AMF treatment was found (Akachoud et al, 2022). This indicates the feasibility of conducting research in this area to increase the efficiency of lavender cultivation in the Southern Steppe of Ukraine and reduce the impact of drought on plant growth and development and the quality content of essential oils.…”

Arbuscular Mycorrhizal Fungi as Biostimulant and Biocontrol Agents: A Review

“…Anthocyanins, carotenoids and other phenolic compounds are increased in lettuce in response to Rhizophagus fasciculatus, R. irregularis and Funneliformis mosseae inoculations [103]. AMF can also boost essential oil yields in medicinal and aromatic plants and improve their composition in terpenoids and flavonoids [104][105][106]. For all these reasons, mycorrhizal inoculation is becoming an agronomic tool among biofertilizers and plant biostimulants [107][108][109][110].…”