The maritime pine (Pinus pinaster), distributed from Morrocan Atlantic coast to South of Europe, is the most planted forest species in France with about 1 million hectares located in the Landes region. Ectomycorrhizal fungi (ECM) and their associated mycorrhizosphere bacteria (MB) could play a major role in plant phosphorous (P) nutrition of maritime pine, particularly in the Landes forest ecosystem considering the low bioavailability of P in its sandy-acidic soils. In order to characterize the diversity and P-solubilizing ability of ECM-MB associations in different soil P conditions, three collection campaigns of ECM root tips were conducted from autumn 2005 to autumn 2006 across three forest stations. The ECM roots tips were systematically sampled from soil cores and separated into distinct morphotypes. Extracts of crushed ECM root tips were then transferred onto Trypcase medium for MB isolation. About 200 ECM-MB associations were successfully characterized based on sequencing of a fragment of mitochondrial large subunit rRNA gene and 16S rDNA respectively. From nine ECM genera identified overall (i.e.Lactarius, Russula, Suillus, Scleroderma, Thelephora, Tomentella, Xerocomus, Hygrophorus and Amanita from the most to the less abundant ones), five MB genera were isolated: Burkholderia (38%), Bacillus (28%), Pseudomonas (18%), Paenibacillus (11%) and Sphingobium (5%).Dramatic seasonal and annual changes were observed in the different MB-ECM associations especially in Burkholderia-Lactarius and BacillusRussula that were the most abundant ones. A factorial correspondence analysis showed significant and high affinities between two MB-ECM taxa associations in particular: Burkholderia-Lactarius and Bacillus-Russula. The less represented ECM taxa such as Thelephora, Suillus/Gomphidius and Scleroderma are also mainly associated to Burkholderia and Bacillus but in about equal proportions without any particular affinity. On the other hand, Pseudomonas, Paenibacillus and Sphi