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

Abstract

Reds Versus Greens Self-incompatibility (SI) allows plants to prevent inbreeding. Crosses with distant relatives (outbreeding) can also be problematic and is prevented by unilateral interspecific incompatability (UI). In the nightshade family, SI functions within green-fruited species, whereas crosses between green-fruited and red-fruited species (which includes tomato) results in UI. Li and Chetelat (p. 1827 ) found a gene, related to known SI genes within this family, that differs in transcript length and function between individuals that are red-fruited and those that are green-fruited. A survey of species shows that the green-fruited species have a functional allele of this gene, whereas the transcript of this gene in red-fruited species, which are self-compatible, produce a putatively nonfunctional protein. These findings suggest that cultivated tomato may have lost the ability to pollinate other species within the same family, owing to the loss of this protein.