Phytate is considered a poorly available plant P source but proved to be useful for particular soil bacteria strains. In soil-free conditions, it has been shown that bacteria locked up the mineralized phosphorus from phytate whereas bacterial grazers like nematodes were able to deliver P to plants. Here, we aimed to determine if the interactions between phytate-mineralizing bacteria, bacterial grazer nematodes, and mycorrhizal fungi could increase plant P acquisition from phytate in high P-adsorbing soils. Pinus pinaster was grown in a Cambisol supplemented with phytate. Plants, whether associated or not associated with the ectomycorrhizal fungus Hebeloma cylindrosporum, were either inoculated or not inoculated with the phytase-releasing bacteria Bacillus subtilis and the bacterial-feeding nematode Rhabditis sp. After 100 days, the dual inoculation of bacteria and nematodes significantly increased net plant P accumulation. We observed that, on average, mycorrhizal plants accumulated more P in their shoots than non-mycorrhizal plants. However, the highest plant P acquisition efficiency was found when the three soil organisms were present in the P. pinaster rhizosphere. We conclude that, in a highly inorganic P-fixing soil, plant P acquisition from phytate strongly depends on the grazing of phytate-mineralizing bacteria. Our results confirm the importance of the soil microbial loop to improve plant P nutrition from phytate, which should be considered a route to improve the utilization of this source of poorly available P by plants.

植酸盐被认为是植物P的来源，但被证明对特定的土壤细菌菌株有用。在无土壤的条件下，已经证明细菌可以锁定植酸盐中的矿化磷，而像线虫这样的细菌放牧者能够将P传递到植物上。在这里，我们旨在确定植酸矿化细菌，细菌性掠食性线虫和菌根真菌之间的相互作用是否可以增加在高磷吸收性土壤中从植酸盐中获得植物磷。樟子松在含有肌醇六磷酸的坎比索尔生长。用释放植酸酶的细菌枯草芽孢杆菌（Bacillus subtilis）接种或不接种植物，无论其是否与外生菌根真菌Heliaoma cylindrosporum相关和以细菌为食的线虫横纹肌炎。100天后，细菌和线虫的双重接种显着增加了植物净磷的积累。我们观察到，平均而言，菌根植物的芽中比非菌根植物积累的磷更多。然而，当P. Pinaster根际存在三种土壤生物时，发现植物P的吸收效率最高。我们得出的结论是，在高度无机的固磷土壤中，从植酸中获取植物P很大程度上取决于植酸矿化细菌的放牧。我们的结果证实了土壤微生物环对于改善植酸中植物P营养的重要性，应将其视为改善植物对这种P来源缺乏的利用的途径。