Indentification Each Chromosome Of Solanumphureja (DM) And Comparing Analyses With Its Wild Relatives Using Fluorescence In Situ Hybridization

The potato is the third world's important non-grain crops.The completion of sequencing of DM,which was developed from Solanum phureja(2n = 24)greatly promoted the research of potato genome.On account of the limitations of the second generation sequencing and assembly technologies,there are much unknown information about the position,distribution and abundance of tandem repeats in DM and its wild relatives.In addition,using the new techniques in modern cell biology,identification each chromosome in plant has been widely achieved in many species.However,this technique has not been established in potato.In this thesis,using twelve BACs,which were known their linkage groups from S.tuberosum,combined with rDNA repeats(45 S rDNA,5S rDNA),centromeric tandem repeats(St18,St49,St57 and St3-294)and subtelomeric repeats(CL14,CL34)as probes a two-step successive fluorescence in situ hybridization(FISH)were applied on the DM somatic metaphase chromosomes.The positions,distributions and abundances of all these repetitive sequences were physical located on chromosomes of DM,and the relationships between the cytogenetic map and the genetic linkage map were revealed by BAC-FISH.According to the distribution characteristics of repetitive sequence on the chromosomes,we selected the centromeric repeats St3-238,two rDNA repeats(45S rDNA,5S rDNA),as well as the two subtelomeric repeats(CL 14,CL34)as probes and developed a two-step successive hybridization upon the same somatic metaphase chromosomes of DM.Every chromosome was shown its own distinctive signal pattern,which made the precise distinguishs each chromosome of this species possible.Finally,we extended the tool kit about karyotypes of DM to its wild relatives and found that the centromeric repeat St49 has signals in most wild species,suggesting that it is a conservative repeat sequence.The signals of CL14 and CL34 changed a lot among different species,indicating that the deficiency and restructuring had happened in evolution in these wild species.Taking together,this study has significant to improve our knowledge about the genome structure of DM and its wild relatives.This new developed technique will become an important research tool for the chromosomal engineering,polyploid evolution and cytogenetic studies in potato.