Ouahmane L. auteur aut IRD Revel J. C. auteur aut IRD Hafidi M. auteur aut IRD Thioulouse J. auteur aut IRD Prin Y. auteur aut IRD Galiana A. auteur aut IRD Dreyfus Bernard auteur aut IRD Duponnois Robin auteur aut IRD text journalArticle eng text/pdf born digital access We examined the effects of an ectomycorrhizal (EM) fungus, Pisolithus sp., on of the growth of Pinus halepensis (Allepo pine) seedlings, soil microbial functions and rock phosphate solubilization in a un-disinfected soil amended or not with a Moroccan rock phosphate. Allepo pine seedlings were inoculated with an EM fungus (Pisolithus sp. strain PH4) isolated from a P. halepensis plantation and selected for its high ability to mobilize P from an inorganic form of phosphate. After 4 month's culture in a disinfected substrate, plants were transferred in 10 l-containers filled with a natural forest soil and amended or not with rock phosphate powder. After 12 month's culturing, the growth, needle nutrient concentrations of P. halepensis plants were measured. Soil microbial catabolic diversity was assessed by measuring CO2 production of substrate induced respiration responses. Fluorescent pseudomonads were isolated from each soil treatment and tested in axenic conditions for their ability to solubilize a source of inorganic phosphate. The results clearly showed that (i) P. halepensis growth was greatly promoted by the presence of the ectomycorrhizal fungus Pisolithus strain PH4 in a disinfected soil/vermiculite mixture and in a non disinfected soil, (ii) ectomycorrhizal inoculation induced significant changes in the functions of soil microbial communities and selected microorganisms potentially beneficial to the plant growth (i.e. phosphate-solubilizing fluorescent pseudomonad) and (iii) rock phosphate solubilisation was mainly dependent on EM inoculation and mycorrhizosphere microorganisms. These results were in accordance with previous studies where it was demonstrated that EM symbiosis has a beneficial effect on plant growth through a direct effect on the host plant but also an indirect effect via a selective pressure on soil microbiota that favours microorganisms potentially beneficial to plant growth. specialized Bacteria Ectomycorrhizosphere effect Fluorescent pseudomonads Pinus halepensis Pisolithus sp. Rock phosphate Soil functional abilities Morocco 084 320 1-2 169-179 2009 0032-079X https://www.documentation.ird.fr/hor/fdi:010046143 10.1007/s11104-008-9882-z 0032-079X [F B010046143] https://www.documentation.ird.fr/hor/fdi:010046143 https://www.documentation.ird.fr/intranet/publi/2009/06/010046143.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2009-07-08 2017-08-23 fdi:010046143 fre