NTR1 ENCODES A HIGH-AFFINITY OLIGOPEPTIDE TRANSPORTER IN ARABIDOPSIS

Heterologous complementation of yeast mutants has enabled the isolatio n of genes encoding several families of amino acid transporters, Among them, NTR1 codes for a membrane protein with weak histidine transport activity, However at the sequence level, NTR1 is related to rather no n-specific oligopeptide tide transporters from a variety of species in cluding Arabidopsis and to the Arabidopsis nitrate transporter CHL1, A yeast mutant deficient in oligopeptide transport was constructed allo wing to show that NTR1 functions as a high affinity, low specificity p eptide transporter, In siliques NTR1-expression is restricted to the e mbryo, implicating a role in the nourishment of the developing seed.