Mediates the transport of sporopollenin precursors (e.g. polyketides) across the tapetum plasma membrane into the anther locule for polymerization on developing microspore walls, thus being required for male fertility and pollen exine formation and patterning prior to tapetum programmed cell death. Homo- or heterodimer. Mostly expressed in flowers, especially in tapetum within anthers. In developing anthers, transiently localized to tapetum cells during early pollen wall formation, sporopollenin biosynthesis and sporopollenin deposition. Drastic decrease in seed production (PubMed:21223384, PubMed:20732973, PubMed:21205178, PubMed:21696844). Severely reduced fertility, with most siliques failing to produce seeds by self-fertilization and mature anthers failing to release pollen grains characterized by the absence of an exine wall on microspores, due to an impaired sporopollenin deposition (PubMed:20732973, PubMed:21205178, PubMed:21696844, PubMed:21223384, PubMed:25415974). Aberrant structures in tapetal cells such as accumulation of numerous vesicles and granules probably containing polyketides precursors in tapetal cells (PubMed:21223384, PubMed:25415974). Abnormal pollen grains germinating in the anther before anthesis (PubMed:21205178). Belongs to the ABC transporter superfamily. ABCG family. Eye pigment precursor importer (TC 3.A.1.204) subfamily.