Involved in the biosynthesis of hydroxylated tetraketide compounds that serve as sporopollenin precursors (the main constituents of exine). Is essential for pollen wall development. Acts on tetraketide alpha-pyrones and reduces the carbonyl function on the tetraketide alkyl chain to a secondary alcohol function. Interacts with 4CLL1/ACOS5, PKSA and PKSB. According to PubMed:21193572, TKPR1 is associated with the endoplasmic reticulum. Specifically expressed in anther tapetal cells during microspores development. Male sterility due to distorted pollen grains lacking reticulate exine pattern. Belongs to the NAD(P)-dependent epimerase/dehydratase family. Dihydroflavonol-4-reductase subfamily.