Immunological analysis of incompatibility (S) proteins and of cross-reacting material in a self-compatible mutant of Oenothera organensis

Abstract

Proteins of pollen of Oenothera organensis from heterozygous S₂S₃, S₂S₆, S₃S₆ and S₄S₆ and homozygous S₆S₆ genotypes produce characteristic precipitation lines in agar-gel plates against antisera prepared from the pollen. The maximum number of precipitation lines was three, and with some genotypes only one line was formed. The lines were characteristic of the different S alleles, but there was a strong cross-reaction between S₄ pollen and S₆ antiserum. The S protein diffused out from intact pollen grains as readily as from macerated pollen indicating that the normal site of action of the S protein, when the pollen tubes are growing down the style, is near the surface of the pollen tube. The self-compatible mutant S_6′S₆ in which the S_6′ allele has lost the ability to produce an active pollen S protein, has a protein which cross-reacts strongly with S₆ antiserum.