- The polyketide synthase gene pks4 from Gibberella fujikuroi encodes a key enzyme in the biosynthesis of the red pigment bikaverin. Linnemannstöns, P., Schulte, J., del Mar Prado, M., Proctor, R.H., Avalos, J., Tudzynski, B. Fungal Genet. Biol. (2002)