Cereal phosphate transporters associated with the mycorrhizal pathway

A very large number of plant species are capable of forming symbiotic associations with arbuscular mycorrhizal (AM) fungi. The roots of these plants are potentially capable of absorbing P from the soil solution both directly through root epidermis and root hairs, and via the AM fungal pathway that delivers P to the root cortex. A large number of phosphate (P) transporters have been identified in plants; tissue expression patterns and kinetic information supports the roles of some of these in the direct root uptake pathways. Recent work has iden tified additional P transporters in several unrelated species that are strongly induced, sometimes specifically, in AM roots. The primary aim of the work described in this paper was to determine how mycorrhizal colonisation by dif ferent species of AM fungi influenced the expression of members of the Phtl gene families in the cereals Hordeum vulgare (barley), Triticum aestivum (wheat) and Zea mays (maize). RT-PCR and in-situ hybridisation, showed that