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 Rhizophagusirregularis 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.

The cultivation of coriander (Coriandrum sativum L.) destined for essential oils production was recently presented as an innovative and economically viable alternative for the phytomanagement of trace elements (TE)-polluted soils. However, Cd accumulation in shoots has proven to be an obstacle in the valorization of the distillation residues and the development of these phytotechnologies. The present study aimed to evaluate the effect of arbuscular mycorrhizal fungus (Funneliformis mosseae) inoculation and organic amendment application on the soil TE bioavailability and plant uptake, as well as on the soil quality and health improvement. The application of compost and sewage sludge improved the growth of coriander and Cd and Zn immobilization in soil, resulting in reduced Cd plant uptake. A synergistic effect of arbuscular mycorrhizal fungi (AMF) inoculation and organic amendments was observed in the decrease in the extractable soil Cd and Zn concentrations, but not in the Cd plant uptake. Despite a significant decrease in Cd accumulation in shoots, coriander retained its accumulative phenotype, with a metal bioconcentration factor close to 1. Furthermore, both the vegetation and the organic amendments improved the soil quality and health by increasing its microbial biomass, as estimated by phospholipid fatty acids, soil enzyme activities (dehydrogenase, phosphatase, β-glucosidase, and cellubiosidase), and the bacterial metabolic function and diversity. The findings demonstrate the potential of C. sativum, particularly in combination with organic amendments and AMF inoculation, for the phytomanagement of TE-polluted soils and soil quality and health improvement.

The cultivation of aromatic plants for the extraction of essential oils has been presented as an innovative and economically viable alternative for the remediation of areas polluted with trace elements (TE). Therefore, this study focuses on the contribution of the cultivation of coriander and the use of arbuscular mycorrhizal fungi (AMF) in combination with mineral amendments (steel slag) on the bacterial function of the rhizosphere, an aspect that is currently poorly understood and studied. The introduction of soil amendments, such as steel slag or mycorrhizal inoculum, had no significant effect on coriander growth. However, steel slag changed the structure of the bacterial community in the rhizosphere without affecting microbial function. In fact, Actinobacteria were significantly less abundant under slag-amended conditions, while the relative proportion of Gemmatimonadota increased. On the other hand, the planting of coriander affects the bacterial community structure and significantly increased the bacterial functional richness of the amended soil. Overall, these results show that planting coriander most affected the structure and functioning of bacterial communities in the TE-polluted soils and reversed the effects of mineral amendments on rhizosphere bacterial communities and their activities. This study highlights the potential of coriander, especially in combination with steel slag, for phytomanagement of TE-polluted soils, by improving soil quality and health.

Plant biostimulants are increasingly recognized as natural solutions that enhance plant growth and support sustainable agriculture. However, their effects on soil microbial communities remain poorly understood. This study evaluated three biostimulants: Plantiful™ (fermented marine algae with beneficial bacteria), CelexT07™ (fermented medicinal plants with beneficial bacteria), and Phylgreen™ (seaweed extract), compared with water and conventional NPK fertilization. Rhizospheric microbial biomass, community structure, and metabolic potential were assessed using metabarcoding, phospholipid fatty acid (PLFA) profiling, and Biolog EcoPlates™ assays. Total microbial biomass did not differ significantly from the untreated control. Similarly, bacterial biomass (7.4–9.8 µg/g soil) remained stable across treatments. Saprotrophic fungal biomass was 2–4-fold lower under Phylgreen^TM and CelexT07^TM than NPK, but comparable to the control. Bacterial and fungal communities were dominated by Actinobacteriota, Pseudomonadota, Acidobacteriota, Chloroflexota, and Ascomycota, with similar richness and diversity across treatments in wheat rhizosphere soil after 9 weeks of growth. Functional analyses revealed only modest shifts, with AWCD being significantly reduced by 43.5% under Phylgreen™ (64.11) compared with NPK (113.44), while remaining comparable to the untreated control (94.74). The network analysis results were also consistent with the previous results, indicating that biostimulant treatments maintained microbial richness. Overall, these findings support the use of the tested biostimulants as sustainable crop management tools that preserve rhizosphere microbial communities.