Mediates folate monoglutamate transport involved in tetrahydrofolate biosynthesis. It also mediates transport of antifolates, such as methotrexate and aminopterin. Expressed in green as well as in non-green plastids. Constitutively expressed at low level. No visible phenotype. Belongs to the major facilitator superfamily. Folate-biopterin transporter (TC 2.A.71) family.