Unveiling native mycorrhizal fungi diversity: insights into growth performance, nutrient uptake, and root system robustness in caper-bush (Capparis spinosa L.) seedlings

This study investigates the role of native arbuscular mycorrhizal fungi (AMF) in enhancing the growth performance, nutrient uptake, and root system robustness of caper bushes ( Capparis spinosa L.), a key species for rehabilitating marginal lands in the Mediterranean region. The primary aim is to identify AMF communities in the rhizosphere soils of caper bushes and evaluate their effects on seedling growth and nutrition. Greenhouse experiments were conducted over two years in Morocco's Safi region, using two seedling groups: one inoculated with a newly identified native AMF complex, and another uninoculated (control) group. Numerous AMF morphotypes were discovered in the rhizospheric soils under mature caper-bush plants, predominantly from the Glomus genus. Soil analysis revealed a sandy loam texture and high alkalinity. Results showed that AMF inoculation significantly enhanced plant biomass (∼135 %), root length (∼58 %), and the number of secondary roots (∼141 %) compared to controls. Mycorrhizal dependency was approximately 58 %. Furthermore, inoculated plants showed substantial improvements in mineral nutrient levels: potassium (K + ), calcium (Ca 2+ ), phosphorus (P), magnesium (Mg 2+ ), iron (Fe 2+ ), and zinc (Zn 2+ ), with increases ranging from ∼1.5 to ∼3 times that of non-inoculated plants. The fresh and dry weights of mycorrhizal plants also increased by ∼87 % and ∼135 %, respectively. Additionally, the specific absorption rates for these nutrients were enhanced, with increases ranging from ∼7 % to ∼170 %. These results highlight pre-transplant AMF inoculation as a promising strategy to enhance caper-bush growth and nutrition in challenging environments. Future research should focus on optimizing AMF inoculation for caper-bush cultivation and exploring its potential for land restoration. • First-ever identification of native AMF spores in the rhizosphere of Capparis spinosa in a key Mediterranean habitat known for caper intensification and production. • Extensive investigation into the role of AMF in enhancing growth and nutrient uptake of Capparis spinosa L., with a focus on the caper-bush plants in Morocco's Safi region. • Significant presence of AMF communities, predominantly from the Glomus genus, found in soils with sandy loam texture and high alkalinity. • AMF inoculation greatly improved plant growth, root development, and nutrient levels. • Pre-transplant AMF inoculation offers a promising eco-engineering strategy to cultivate caper bushes in marginal soils.