Self-incompatibility in plants.
Sexual reproduction in many flowering plants involves self-incompatibility (SI), which is one of the most important systems to prevent inbreeding. In many species, the self-/nonself-recognition of SI is controlled by a single polymorphic locus, the S-locus. Molecular dissection of the S-locus revealed that SI represents not one system, but a collection of divergent mechanisms. Here, we discuss recent advances in the understanding of three distinct SI mechanisms, each controlled by two separate determinant genes at the S-locus. In the Brassicaceae, the determinant genes encode a pollen ligand and its stigmatic receptor kinase; their interaction induces incompatible signaling(s) within the stigma papilla cells. In the Solanaceae-type SI, the determinants are a ribonuclease and an F-box protein, suggesting the involvement of RNA and protein degradation in the system. In the Papaveraceae, the only identified female determinant induces a Ca2+-dependent signaling network that ultimately results in the death of incompatible pollen.
Takayama
Seiji
S
Laboratory of Intercellular Communications, Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0101, Japan. takayama@bs.naist.jp
Isogai
Akira
A
D019607:Brassicaceae / Q000201:enzymology / Q000378:metabolism / Q000502:physiology*; D020013:Calcium Signaling; D028101:Papaveraceae / Q000201:enzymology / Q000378:metabolism / Q000502:physiology*; D010940:Plant Proteins / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction; D019657:Solanaceae / Q000201:enzymology / Q000378:metabolism / Q000502:physiology*
D010940:Plant Proteins