Cloning and characterization of cDNA for the Oryza sativa phosphate transporter

A putative high-affinity phosphate (Pi) transporter gene in rice (Oryza sativa), OsLPT1, was isolated by RT-PCR from the leaves of the plants. The 1635-bp nucleotide sequence of OsLPT1 spans an open reading frame encoding a polypeptide of 535 amino acids with sequence similarity to phosphate transporters from other plant species. Southern blot analysis showed that the OsLPT1 gene might be present in three transcripts in the rice genome. RT-PCR analysis demonstrated the expression of OsLPT1 in both leaves and roots. The expression of OsLPT1 in the roots was enhanced by Pi deprivation. In situ hybridization revealed OsLPT1 expression in mesophyll cells, xylem parenchyma and phloem cells in the leaves, and in the epidermis, exodermis, and in the vasculature surrounding metaxylem vessels in the roots. The data suggests that the OsLPT1 protein may be involved in enhancing phosphate uptake under conditions of Pi starvation, and in the translocation of Pi among cells in shoots to increase the efficiency of internal Pi use.