Occurrence of indigenous arbuscular mycorrhizal fungi associated with the rhizosphere of the naidi palm in Colombia

In the Colombian Pacific region, the naidi palm, Euterpe oleracea Mart. (Arecaceae) produces high-value fruit due to its high nutritional quality, representing an economic benefit to the families of the region. In this study, we evaluated the occurrence of arbuscular mycorrhizal fungi (AMF) in the rhizospheric soil of E. oleracea in Bajo Calima, Buenaventura. This is the first report of AMF of E. oleracea in Colombia. Surface soil samples (0 - 10 cm) were collected in two areas (L1 - under the influence of rice cropping and L2 - tropical rainforest). The chemical properties of the soil, the number of spores, and the mycorrhizal colonization in the root were established. We observed low mycorrhizal colonization (10 % in L1 and 4 % in L2), negatively correlated to the content of available phosphorus in the soil. However, significant differences between areas (p = 0.009) were recorded. Globose, subglobose, and ovoid spores were observed (660 and 791 spores/100 g soil in L1 and L2, respectively). Spores are represented in several morphotypes that can be classified as Claroideoglomeraceae, Glomeraceae, Diversisporaceae, Paraglomeraceae, and Ambisporaceae. High available P content (13.1 mg/kg in L1 and 20.5 mg/kg in L2), among other edaphic factors associated, could explain the low mycorrhizal colonization observed, especially when there are not enough studies linking ecological factors with AMF dynamics in tropical rainforests. On the other hand, spore abundances reported in the rhizospheric soil of E. oleracea suggest a high potential to explore indigenous AMF activity in the Colombian Pacific region to achieve sustainable production practices in this palm.