title: Identification of the pollen determinant of S-RNase-mediated self-incompatibility.
abstract: Many flowering plants have adopted self-incompatibility mechanisms to prevent inbreeding and promote out-crosses. In the Solanaceae, Rosaceae and Scrophulariaceae, two separate genes at the highly polymorphic S-locus control self-incompatibility interactions: the S-RNase gene encodes the pistil determinant and the previously unidentified S-gene encodes the pollen determinant. S-RNases interact with pollen S-allele products to inhibit the growth of self-pollen tubes in the style. Pollen-expressed F-box genes showing allelic sequence polymorphism have recently been identified near to the S-RNase gene in members of the Rosaceae and Scrophulariaceae; but until now have not been directly shown to encode the pollen determinant. Here we report the identification and characterization of PiSLF, an S-locus F-box gene of Petunia inflata (Solanaceae). We show that transformation of S1S1, S1S2 and S2S3 plants with the S2-allele of PiSLF causes breakdown of their pollen function in self-incompatibility. This breakdown of pollen function is consistent with 'competitive interaction', in which pollen carrying two different pollen S-alleles fails to function in self-incompatibility. We conclude that PiSLF encodes the pollen self-incompatibility determinant.
authors.affiliation: Integrative Biosciences Graduate Degree Program, The Pennsylvania State University, 403 Althouse Laboratory, University Park, Pennsylvania 16802, USA.
authors.forename: Paja
authors.initials: P
authors.lastname: Sijacic
authors.forename: Xi
authors.initials: X
authors.lastname: Wang
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Skirpan
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Peter E
authors.initials: PE
authors.lastname: Dowd
authors.forename: Andrew G
authors.initials: AG
authors.lastname: McCubbin
authors.forename: Shihshieh
authors.initials: S
authors.lastname: Huang
authors.forename: Teh-Hui
authors.initials: TH
authors.lastname: Kao
mesh_terms: D000483:Alleles; D044783:F-Box Proteins / Q000235:genetics / Q000378:metabolism*; D005306:Fertilization / Q000235:genetics / Q000502:physiology; D035264:Flowers / Q000235:genetics / Q000502:physiology; D005638:Fruit; D017343:Genes, Plant / Q000235:genetics*; D005838:Genotype; D018525:Germination; D032306:Petunia / Q000201:enzymology / Q000235:genetics* / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011058:Pollen / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012260:Ribonucleases / Q000235:genetics / Q000378:metabolism*; D013045:Species Specificity; D014170:Transformation, Genetic; D019076:Transgenes / Q000235:genetics
chemical_list: D044783:F-Box Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D012260:Ribonucleases; C092227:S1-RNase