A Pollen Factor Linking Inter- and Intraspecific Pollen Rejection in Tomato

摘要

Self-incompatibility (SI)-intraspecific pollen recognition systems that allow plants to avoid inbreeding-in the Solanaceae (the nightshade family) is controlled by a polymorphic S locus where "self" pollen is rejected on pistils with matching 5 alleles. In contrast, unilateral interspecific incompatibility (UI) prevents hybridization between related species, most commonly when the pollen donor is self-compatible (SO and the recipient is SI. We observed that in Solatium, a pollen-expressed Cullinl gene with high similarity to Petunia SI factors interacts genetically with a gene at or near the 5 locus to control Ul. Cultivated tomato and related red- or orange-fruited species (all SO exhibit the same loss-of-function mutation in this gene, whereas the green-fruited species (mostly SI) contain a functional allele; hence, similar biochemical mechanisms underlie the rejection of both "self" and interspecific pollen.