Loss of a histidine residue at the active site of S-locus ribonuclease is associated with self-compatibility in Lycopersicon peruvianum

Abstract

Gametophytic self-incompatibility in the Solanaceae is controlled by a single, multiallelic locus, the S locus. We have recently described an allele of the S locus of Lycopersicon peruvianum that caused this normally self- incompatible plant to become self-compatible. We have now characterized two glycoproteins present in the styles of self-compatible and self-incompatible accessions of L. peruvianum: one is a ribonuclease that cosegregates with a functional self-incompatibility allele (S6 allele); the other cosegregates with the self-compatible allele (S(c) allele) but has no ribonuclease activity. The derived amino acid sequences of the cDNAs encoding the S6 and S(c) glycoproteins resemble..