Molecular And Cytological Identification Of Wheat-Dasypyrum Villosum Alien Substitution Line And Radiation Mutagenesis Translocation Lines

Dasypyrum villosum is one of the wild relatives of wheat,its growing environment is complex and diverse,and a large number of beneficial genes are preserved during the evolution process.These preserved beneficial genes provide abundant gene resources for the improvement of wheat varieties with disease resistance and stress resistance.Previous studies showed that the frequency of chromosome pairing between 6V#2 and 6V#4 of D.villosum from different sources was low,and there were diversities in chromosome karyotypes,molecular markers and some disease resistance phenotypes.Using big data to compare the DNA level differences between 6V#2 and6V#4 chromosomes and wheat 6A and 6D chromosomes can provide the basis for the precise design and breeding of wheat-D.villosum targeted translocation.In addition,compared with wheat background parents,the translocation lines of 6V#2S.6AL and 6V#4S.6DL were not only highly resistant or immune to powdery mildew,but also showed significant increase in plant height and grain weight.In order to explore the physical distance between the genes regulating plant height and grain weight on the arm of alien chromosome and the powdery mildew resistance genes,it is necessary to identify and screen materials with different degrees of deletion or translocation of small fragments of alien chromosomes.In this study,wheat-D.villosum alien substitution lines and translocation lines carrying the 6V#2 and 6V#4 chromosomes respectively,were used as materials to carry out the following research:(1)The previously selected two new types of substitutions were verified by the 6V specific molecular markers and GISH,55 K SNP microarray was used to analyze the new substitution lines and their parents.At the same time,the two accessions of Dasypyrum villosum were analyzed and screened for the 6V specific SNP by 660 K chip.(2)According to the specific molecular markers on the 6V genetic linkage map,the progeny plants derived from 6V#4S.6DL translocation line treated with radiation were identified,and the materials with alien chromosomal deletion or small fragment translocation mutation were screened,and then the cytological identification and wheat SNP microarray analysis were performed on these targeted materials.(3)Based on the different mutant materials screened in(2),some of the reported 6V specific molecular markers were located in different regions of 6VS,and the agronomic traits of different mutant materials were investigated.The following results has been obtained:(1)Two new type substitution lines were confirmed.The results of wheat 55 K microarray showed thatthe detection efficiency of the corresponding chromosome probes was significantly reduced due to the deletion of wheat chromosome and the replacement of alien chromosomes in the alien substitution lines,and the proportion of NA typing was greatly increased,and most of the NA typing showed polymorphism between two different exogenous chromosomes.The detection efficiency of the same probe for the two exogenous chromosomes was different.Wheat 6A probe could detect 6V#2 better while wheat 6D probe could detect 6V#4 better.Thirty-seven SNP markers specific for 6V were obtained from the congruent genotyping of 6V chromosome between Dasypyrum villosum and wheat alien substitution line.(2)Two powdery mildew resistant mutant materials were screened out(20FL88-1 and 20GL107-3),and both of them were missing five molecular markers.The results of cytology showed that the exogenous chromosome fragments were partially truncated.In addition,FISH analysis on the two materials 20FL562 and 20FL300-4,which were previously screened out by our research team,showed that a new wheat chromosome involved in the alien translocation chromosome was derived from A or B genomes.The results of the identification of the panicle mutant 20FL656 a showed that there was no significant variation in 6V#4S.6DL,but there were quantitative and structural variations in 5B and 5A chromosomes.(3)Five markers were located between 6VS-09 and the telomere using the above-mentioned exogenous chromosomal deletion materials or small fragment translocation materials;Three molecular markers were located between 6VS-09 and 6VS-10;Eight markers were located between MBH1 and 6VS-10,and four markers were located between 6VS-10 and the base of the centromere.