The mutualistic relationship between plants and arbuscular mycorrhizal fungi (AMF) is essential for optimal plant nutrition, enabling the plant to better withstand biotic and abiotic stressors and enhancing its chances of survival, reproduction, and colonization of new environments. Urban soil nutrient enrichment may reduce the benefits of AMF for plant nutrition, potentially reducing interaction with AMF in urban environments. Here, we test this prediction by studying how urbanization alter the plant-AMF interaction between the invasive herb Ruellia nudiflora (Acanthaceae) and AMF in Mérida city. We collected soil and plants from deep urban sites (DUS; e.g. sidewalks), open urban sites (OUS; parks), and rural sites (RS) to analyze the soil nutrient content, plant morphology, AMF-colonization rates, spore density, richness, and diversity. Unexpectedly, DUS showed the lowest soil nutrient concentrations except for phosphorus. Higher phosphorus levels in these sites reduced AMF colonization, supporting the prediction of reduced plant-AMF interactions in urban environments. We discovered that potassium affects the plant-AMF association, an understudied effect. Finally, urban plants produced smaller and more compact roots than rural plants, and no differences on AMF communities were found between urban and rural environments. To gain a better understanding of how AMF contributes to plant colonization in urban environments, further studies are required.