Molecular Identification Of Ry Subunit Variation In Synthetic Hexaploid Triticale

Wide hybridization and allopolyploidization can produce a large number of genetic variations,which is an important driving force for new species formation and species evolution.At the same time,genetic variation can rapidly broaden genetic diversity,which is of great significance for crop genetic improvement.Wheat-rye wide hybridization is an important way for wheat genetic improvement.It can not only integrate and transfer the excellent genes of rye,but also create new mutations,generate new traits.It is of great significance to study its molecular mechanism for the innovation and utilization of wheat germplasm resources.In the preliminary work,the synthetic hexaploid triticale was obtained by crossing the common wheat Shinchunaga(Triticum aestivum L.cv.Shinchunaga,2n = 42,AABBDD)with the Qinling rye(Secale cereale L.cv.Qinling,2n = 14,RR).Use SDS-PAGE technique analysis,the high-molecular-weight glutenin subunit(HMW-GS)Ry disappeared and was stably inherited.In this study,gene cloning and molecular markers revealed that the disappearance of Ry may be related to the deletion of the sequence of the coding gene;transcriptome analysis of the endosperm filling stage of the seed found that the material of Ry disappearing has no Glu-Ry transcription product.We further suggested the deletion mutations was occurred in Glu-Ry coding region.Comparative genomic and molecular cloning analysis suggested that the material of Ry lost has sequence variation in the 5'-UTR region of Glu-Ry,and the mutation breakpoint is located about-4000 bp upstream of the start codon;the mutation sequence was amplificated by Genome Walking.A 1485 bp(-5080~-3595 bp)sequence was obtained and the sequence variation was aligned with the corresponding sequence of the reference sequence,and there are 13 single base variations,and two insertions,T and TAC,respectively.In summary,this study preliminarily revealed that the disappearing Ry subunit may be related to the sequence variation of the-4000 bp position in the 5'-UTR region of Glu-Ry.The results lay a foundation for further exploring the molecular mechanism of Ry disappearance.