Functional characterization of Prunus SLFLs in transgenic Petunia
Many species in the Rosaceae, Solanaceae, and Plantaginaceae have S-RNase- based gametophytic self-incompatibility using S-RNase and F-box proteins as the pistil and pollen S determinants, respectively. It is generally accepted that pollen tube growth is arrested in the style by S-RNase cytotoxicity. In the Solanaceae, Plantaginaceae, and the subtribe Malinae in the Rosaceae, pollen S F-box proteins are assumed to target nonself S-RNases for degradation, to allow successful pollen tube growth in nonself pistils for fertilization. In contrast, SFB, the pollen S F-box protein in Prunus (Rosaceae), is thought to have a distinct function in the release of self S-RNase cytotoxicity. In contrast to the intrinsic function of the pollen S in the degradation of nonself S-RNase in plants other than Prunus, a hypothetical general inhibitor (GI) that is involved in detoxification of all S-RNases is proposed to be present in Prunus pollen tubes. Although the identity of the GI is unknown, phylogenetic and expression analyses have indicated that S locus F-box-like 1-3 (or S locus F-box with low allelic sequence polymorphism 1-3; SLFL1-3), which are encoded by regions flanking the Prunus S locus, are good GI candidates. In this study, we performed functional characterization of SLFLs by transforming self-incompatible petunia (Petunia × hybrida) to test the function of SLFLs. Although strong expression of Prunus SLFLs was observed in transgenic petunia pollen, no change in self-incompatibility phenotype was obtained. Furthermore, co-expression of Prunus Skp1-like (SSK1), which interacts with SLFLs to form the SCF complex, did not induce any self-incompatibility phenotypic change.
Morimoto, T. and Tao, R. (2019). Functional characterization of Prunus SLFLs in transgenic Petunia. Acta Hortic. 1231, 85-90
general inhibitor, self-incompatibility, S locus F-box like, S-RNase, sweet cherry