In vitro cultivation of arbuscular mycorrhizal fungi (AMF) is challenging due to their biotrophic symbiosis. The principal aim of this study was to demonstrate the effect of establishing in vitro dual cultures of arbuscular mycorrhizal fungi (AMF) inoculated on Swietenia macrophylla (mahogany) roots on plant growth. Furthermore, it was sought to demonstrate that plant colonization by Glomeromycota can be achieved with a replicable protocol. This study established monoxenic cultures of carrot (Daucus carota) Ri T-DNA ROC inoculated with Glomus sp. on two-compartment plates. At 75 days, hyphal growth reached 223.93 mm in the root compartment and 103.71 mm in the hyphal compartment. Spores produced in vitro measured 26.14 ± 1.70 µm, smaller than ex vitro spores (101.2 ± 4.22 µm). Rhodotorula mucilaginosa was isolated from cultures and appeared to stimulate hyphal growth and root–fungal contact. From these cultures, a dual culture of mahogany inoculated with Glomus sp. was established. No significant differences were observed between inoculated and non-inoculated plants in stem length, root length, root number, or leaf number at 30 days. Spore production ranged from 10,166 to 27,696 per plate, averaging 14,795 ± 3301, with hyphal lengths of 3655.46 ± 308.75 mm. Hyphal development included running and branching patterns, with solitary and clustered spores. Spore diameter averaged 27.68 ± 3.85 µm. Arbuscular colonization reached 41.49% at 30 days and 52.13% at 75 days, exceeding rates reported for other culture systems. Monoxenic cultures are a reliable, aseptic source of high-quality inoculum, supporting biofertilizer production and biotechnological applications. These methods provide valuable tools for studies involving AMF, such as those demonstrated with mahogany.

Arbuscular mycorrhizal fungi (AMF) provide benefits to host plants by enhancing nutrition and overall fitness. In this study, AMF species were isolated from the soil rhizosphere of Jatropha curcas and were identified and evaluated for their potential in fostering the development of Jatropha seedlings within a controlled greenhouse environment. The first experiment assessed the interplay between hydric stress and AMF inoculation on mycorrhizal colonization. The next experiment examined the impact of quercetin on mycorrhizal colonization. Out of 204 glomerospores corresponding to 28 species spanning 10 genera, Acaulospora (14) and Scutellospora (5) were the most abundant taxa. Six new records of AMF for Costa Rica are reported. Mycorrhizal colonization was observed in 43.2% of Jatropha plants (34.7% by AMF typical hyphae; arbuscules 8.9%; coils 5.6%; and vesicles 5.4%). Significant survival effects due to AMF inoculation under hydric stress were observed. On day 85, non-mycorrhizal plants subjected to hydric stress showed a mere 30% survival rate, whereas their mycorrhizal counterparts under hydric stress exhibited survival rates of 80% and 100% with and without irrigation, respectively. Furthermore, plants with irrigation and mycorrhizas showed greater hydric stress tolerance and superior growth. The inoculated plants, irrespective of irrigation, demonstrated mycorrhizal colonization rates of 63% and 72%, respectively. Quercetin did not affect Jatropha’s growth, but there were differences in AMF root colonization. In summary, these findings accentuate the viability of a native consortium in augmenting Jatropha survival, warranting consideration as a potent biofertilizer within greenhouse settings. The AMF described can be used for Jatropha propagation programs.