Mutational approaches to the study of self-incompatibility: Revisiting thepollen-part mutants

We present a review of literature on the genetics of pollen-part mutations created in plants with a gametophytic self-incompatibility system. Plants c arrying a pollen-part mutation produce pollen with an altered self-incompat ibility response but have styles that display a normal response. Pollen-par t mutants in the Fabaceae and Onagraceae have a simple loss-of-function mut ation at the S locus and this is also believed to be true of pollen-part mu tants from the Rosaceae. In the Solanaceae, pollen-part mutations are more complex and are frequently associated with a duplicated S allele. This sugg ests that pollen-part mutations, at least in the Solanaceae, can also resul t from gain-of-function mutations. Some solanaceous plants with a pollen-pa rt mutation apparently lack duplicated S alleles suggesting that the mutant phenotypes arise from lesions at the S locus. These studies are discussed in the context of current self-incompatibility models. (C) 2000 Annals of B otany Company.