Sequence variability and developmental expression of S-alleles in self-incompatible and pseudo-self-compatible Petunia

• Published in: The Plant cell Vol. 2; no. 8; pp. 815 - 826
• Main Authors: Clark, K.R. (Ohio State University, Columbus, OH), Okuley, J.J, Collins, P.D, Sims, T.L
• Format: Journal Article
• Language: English
• Published: United States American Society of Plant Physiologists 01-08-1990
• Subjects: ADN; Alleles; Amino Acid Sequence; Amino acids; ARN; AUTOCOMPATIBILIDAD; AUTOCOMPATIBILITE; AUTOESTERILIDAD; AUTOSTERILITE; Cloning, Molecular; Complementary DNA; DNA; EXPRESION GENICA; EXPRESSION DES GENES; FLORACION; FLORAISON; GENE; Gene Expression Regulation; GENES; Genes, Plant; GENETICA; GENETIQUE; Genomics; GINECEO; GYNECEE; Messenger RNA; Molecular Sequence Data; NUCLEOTIDE; NUCLEOTIDOS; Oligodeoxyribonucleotides - chemistry; PETUNIA; Plant Development; Plants - genetics; Pollen; Pollen tubes; Proteins; Reproduction; Restriction Mapping; RNA; RNA, Messenger - genetics; Sequence Alignment; TECHNIQUE ANALYTIQUE; TECHNIQUE DE PREVISION; TECNICAS ANALITICAS; TECNICAS DE PREDICCION; Tissue Distribution; VARIACION GENETICA; VARIATION GENETIQUE
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.2.8.815

We investigated the structure and expression of three S-alleles of Petunia hybrida in self-incompatible varieties and in a pseudo-self-compatible line in which the self-incompatibility response is defective. Comparison of derived amino acid sequences from different gametophytic S-alleles revealed a pattern of sequence conservation and variability that was highly nonrandom. In self-incompatible varieties, petunia S-locus mRNA accumulates preferentially in styles during the transition from bud self-compatibility to self-incompatibility. S-allele sequences homologous to the cloned S1 allele were present in a pseudo-self-compatible variety, and were expressed at levels indistinguishable from those observed in a self-incompatible line homozygous for the S1 allele. Taken together, our data indicate that (1) limited sequence differences may confer allelic specificity, (2) S-locus mRNAs accumulate in a precise organ-specific pattern during floral development, and (3) the ability to inhibit the growth of incompatible pollen tubes appears to require a threshold accumulation of the stylar gene product, along with the participation of as yet undefined pollen gene products