Phosphate transporters of Medicago truncatula and arbuscular mycorrhizal fungi

Most vascular plants acquire phosphate from their environment either directly, via the roots, or indirectly, via a symbiotic interaction with arbuscular mycorrhizal (AM) fungi. The symbiosis develops in the plant roots where the fungi colonize the cortex of the root to obtain carbon from the plant host, while assisting the plant with acquisition of phosphate and other mineral nutrients from the soil solution. As a first step toward understanding the molecular basis of the symbiosis and phosphate utilization, we have cloned and characterized phosphate transporter genes from the AM fungi Glomus versiforme and Glomus intraradices, and from the roots of a host plant, Medicago truncatula. Expression analyses and localization studies indicate that each of these transporters has a role in phosphate uptake from the soil solution.