SELF COMPATIBILITY IN A LYCOPERSICON-PERUVIANUM VARIANT (LA2157) IS ASSOCIATED WITH A LACK OF STYLE S-RNASE ACTIVITY

A series of crosses between a naturally-occurring self-compatible accession of Lycopersicon peruvianum and a closely-related self-incompatible accession were used to demonstrate that the mutation to self-compatibility is located at the S-locus. Progeny of the crosses contain abundant style proteins of about 30 kDa that segregate with the S-6- and S-7-alleles from the SI parent and the S-c allele from the SC parent. The S-6- and S-7-associated proteins have ribonuclease activity whereas the S-c-associated protein is not an active ribonuclease. This finding indicates that S-RNases are determinants of self-incompatibility in the style and that the ribonuclease activity is essential for their function.