A High Degree of Homology Exists between the Protein Encoded by SLG and the S Receptor Domain Encoded by SRK in Self-Inocompatible Brassica campestris L. : GENES STRUCTURE AND EXPRESSION : CELL-CELL INTERACTION

概要

論文の詳細を見る
The sporophyiic self-incompatibility system in Brassica campestris is controlled by multiple alleles of a single locus, S. We isolated and characterized cDNA clones that correspond to genes for S-glycoprotein (SLG) and S-receptor kinase (SRK) from an S^9-homozygous strain. An SRK^9 fragment was amplified by the polymerase chain reaction (PCR) by use of primers that corre-sponded to regions of the gene for the extracellular receptor domain (S-domain) and the kinase domain. The fragment was used as a probe to isolate an SRK^9 cDNA clone from the cDNA library of stigmas of an S^9-homozygote. An SLG^9 cDNA clone was also isolated from the library by use of SLG^8 cDNA as a probe. Restriction fragment length polymorphism (RFLP) Iinkage analysis of the F2 plants from an S^8S^9 hybrid demonstrated that the SRK and SLG genes were tightly linked to one another and were also linked to S-genotypes, as determined by pollination tests. The transcripts of SRK^9 and SLG^9 were detected in stigmas, but not in anthers or leaves. The cyioplasmic kinase domain encoded by SRK^9 contained amino acid sequences that are con-served in serine/threonine kinases. The nucleotide sequence encoding the S-domain of SRK^9 was 98.4~6 homologous to that of SLG^9 at the nucleotide level. This observation suggests the ex-istence of a mechanism for maintaining a high degree of similarity between SLG and the region that encodes the S-domain of SRK.
日本植物生理学会の論文