title: S-RNase complexes and pollen rejection.
abstract: Biochemical interactions between the pollen and the pistil allow plants fine control over fertilization. S-RNase-based pollen rejection is among the most widespread and best understood of these interactions. At least three plant families have S-RNase-based self-incompatibility (SI) systems, and S-RNases have also been implicated in interspecific pollen rejection. Although S-RNases determine the specificity of SI, other genes are required for the pollen rejection system to function. Progress is being made toward identifying these non-S-RNase factors. HT-protein, first identified as a non-S-RNase factor that was required for SI in Nicotiana alata, has now been implicated in other species as well. In addition, several pistil proteins bind to S-RNase in vitro. One hypothesis is that S-RNase forms a complex with these proteins in vivo that is the active form of S-RNase in pollen rejection.
authors.affiliation: Department of Biochemistry, Facultad de Química, National Autonomous University of México, Conjunto 'E' Paseo de la Investigacio'n Cientifica, Ciudad Universitaria, 04510 México DF, México.
authors.forename: Felipe
authors.initials: F
authors.lastname: Cruz-Garcia
authors.forename: C Nathan
authors.initials: CN
authors.lastname: Hancock
authors.forename: Bruce
authors.initials: B
authors.lastname: McClure
mesh_terms: D000595:Amino Acid Sequence; D005298:Fertility / Q000502:physiology; D035264:Flowers / Q000502:physiology; D006023:Glycoproteins / Q000378:metabolism; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011058:Pollen / Q000502:physiology*; D012260:Ribonucleases / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D006023:Glycoproteins; C400763:HT protein, Nicotiana alata; D010940:Plant Proteins; C076697:self-incompatibility glycoprotein, Nicotiana; D012260:Ribonucleases; C022542:ribonuclease S