Analysis Of Chromosome And Localization Of The S-receptor Kinase(SRK) Gene Sequence In Brassic.Oleracea By FISH

Brassica species have a typical sporophytic self incompatibility system controlled by multiple alleles or haplotypes at a single S-locus. Several S and S-related genes have been isolated and characterized genetically and biochemically. The S-locus glycoprotein (SLG) and S receptorkinase (SRK) genes linked to the S-locus are directly involved in self incompatibility. Self-incompatibility (SI) response in Brassica is initiated by haplotype-specific interactions between the pollen-borne ligand S locus protein 11/SCR and its stigmatic S receptor kinase, SRK. This binding induces autophosphorylation of SRK, which is then thought to trigger a signaling cascade that leads to self-pollen rejection. A recessive mutation of the modifier (m) gene eliminates the SI response in stigma. Positional cloning of M has revealed that it encodes a membrane-anchored cytoplasmic serine/threonine protein kinase, designated M locus protein kinase (MLPK). Transient expression of MLPK restores the ability of papilla cells to reject self-pollen, suggesting that MLPK is a positive mediator of Brassica SI signaling.But it is still unknown to us that for B.oleracea the S-locus gene is on which chromosomes or on which part of the chromosome.The genus Brassica is a major crop taxon of worldwide importance and is characterized by three basic diploid cytodemes (A, B, and C; n = 10, 8,and 9, respectively) and amphidiploid tetraploid species. The species Brassica oleracea (CC, 2n = 18) includes the vegetable crops cauliflower, Cabbage, calabrese, and Brussels sprouts.The location of S-locus gene on chromosome of Brassica oleracea will contribute to a wide range of research. It can provide information complementary to that from physical molecular maps currently being developed, as well as the location of genes in relation to features of chromosomal organization.In this paper we demonstrate the use of imaging methods in combination with fluorescence in situ hybridization to localize, the single copy S-receptor kinase(SRK) gene involved in B. oleracea.var.capitata. At the same time we observed chromosome behavior in meiosis, we found the abnormal chromosome behaviors and discussed the possible reason and its influences on low fruit-bearing percentage.1. Detailed observations on chromosome behavior in meiosis of more than five hundreds microsporocytes at all stages for self-incompatible homogenous diploids Brassica oleracea var.capitata were conducted. Two abnormal circumstances were observed: There exists a high frequent occurrence of tetravalent at diplotene diakinesis and metaphase I stage; Some bivalents separate early and some laggards were observed at metaphase I and anaphase I stage. These...