Molecular and biochemical mechanisms of phosphorus uptake into plants

Abstract

Phosphorus (P) acquisition is often a limiting factor in plant growth. To understand the molecular and biochemical processes involved in P uptake, our group is characterizing P transport systems from two distinct families, named Pht1 and Pht2. Pht1 transporters are root transporters which can be divided into two subfamilies, namely those which are expressed in both the root and the shoot, and those which are specifically expressed in roots during P deprivation. Genetic and biochemical studies performed with the tomato transporter LePT1 suggest a major role for this protein and presumably all Pht1 transporters in P acquisition from the soil solution into the root. The Pht2 family consists of transporters which are different from the Pht1 family members. Pht2;1 from Arabidopsis thaliana is the first family member and is predominantly expressed in the shoot. Biochemical analysis of transport activity and tissue localization studies indicate that Pht2;1 is involved in loading of above ground organs, especially leaves, with P.