ABSTRACT
Phosphate is a key constituent of crucial molecules allowing living cells to function, and it represents one of the main limiting factors for plant growth and fitness. Whereas its high levels in the sea often represent an ecological risk, hampering biodiversity and triggering algal blooming and eutrophication, in the soil it is rarely accessible to plants. This growth limit has translated into a strong selective pressure for plant growth and development, driving its adaptation at the level of the root developmental system. The archetype case, also described as the “mother of root endosymbioses”, is the arbuscular mycorrhizal symbiosis where soil fungi belonging to the Mycoromicotina family provide the majority of needed phosphate to the plant. In this ecologically and physiologically pivotal interaction, phosphate acts both as the main currency exchanged by the fungus and as the main regulator of the transcriptomic, metabolic, and morphological changes happening within plant root cells. In this chapter, we discuss the up-to-date knowledge regarding the molecular mechanisms regulating plant-microbe interaction influenced by plant phosphate homeostasis, with a special focus on arbuscular mycorrhizal symbiosis and plant-bacterial interactions. Finally, we present the biotechnological approaches that have been used to improve plant phosphate nutrition in crops.
