Table 1.

Summary of Three Types of SI Mechanisms

Plant FamilyType of SIGenetic LocusFemale DeterminantMale DeterminantMechanism
Solanaceae, Rosaceae, ScrophulariaceaeGSIS-locusS-RNaseSLF/SFB?S-RNase–mediated degradation of pollen tube RNA
PapaveraceaeGSIS-locusS-geneUnknownS-protein–mediated signaling cascade in pollen
BrassicaceaeSSIS-locusSRKSCR/SP11Receptor-kinase–mediated signaling in stigma