Abstract
Self-incompatibility (SI) is a genetic mechanism adopted by angiosperms to prevent inbreeding. In the Solanaceae, including Petunia, a ribonuclease, named S-RNase, was shown to be the stylar determinant and function as a cytotoxin specifically inhibits self-pollen tube growth. Recently, we proposed "collaborative non-self recognition" model, in which pollen determinant is comprised of multiple types of F-box proteins, named SLFs, each of which detoxifies a subset of non-self S-RNases. We showed that at least three types of divergent SLF proteins (type-1, -2 and -3 SLFs) function as the pollen determinant, but there remained some non-self S-RNases that were not recognized by these SLFs, suggesting that other types of SLFs should also comprise the pollen determinant. In this study, we explored other types of SLFs in Petunia and found that another type of SLF also functions as an element of pollen determinant. These results further support our "collaborative non-self recognition" model.
