Quality Effect Analysis Of Subunits 5~t+10.5~t Of Aegilops Tauschii In The Yellow River Basin Introduced Into Common Wheat

As an important gene resource for wheat genetic improvement,Aegilops tauschii Coss.（2n = 2x = 14,DD）is considered to be the donor species of the D genome of common hexaploid wheat,which contains many valuable properties,including disease resistance,insect resistance,stress resistance and rich HMW-GS types.With the improvement of people’s living standards,wheat quality improvement is one of the main goals of wheat breeding in recent years.In this study,we choose the population derived from the two crossings between the bread wheat cultivar and Ae.tauschii accession（Zhoumai l8 × T093 and Zhoumai l8 × T015）with the HMW-GS combination of 5^t+10.5^t as the materials,and the lines containing the subunits 5^t+10.5^t were screened by HMW-GS composition analysis using SDS-PAGE.Then,the genetic effect of subunit 5^t+10.5^t introduced into wheat was determined using SSR marker,HMW-GS cloning and quality identification,which will provide theoretical basis for the innovation of wheat germplasm resources and quality improvement.The main results are as follows:（1）We analyzed the HMW-GS composition of 251 BC₃F₈-T093-Zhou18 lines and 301 BC1F8-T015-Zhou18 lines by using SDS-PAGE.The results showed that only the subunit 2+12 of the offspring line 18108 was replaced by the subunit 5^t+10.5^t in BC₃F₈-T093-Zhou18 lines,and a total of 40 lines of subunit 2+12 were replaced by the 5^t+10.5^t subunit in BC1F8-T015-Zhou18 lines.（2）141 pairs of SSR molecular markers were used to analyze the genetic diversity of 27 wheat strains from Jiangsu,Shandong,Hebei,Henan province and 6 randomly selected lines（18108,18458,18497,18526,18532,18668）and parent Zhoumai 18.As a result,a total of 26 pairs of polymorphic primers were determined.The phylogenetic relationships displayed that Zhoumai 18 was clustered with the progeny lines of 6 substitution lines,indicating that these 6 progeny lines derive from Zhoumai 18.（3）According to the high conservation of both ends of the HMW-GS gene,the primers P1 and P2 were designed to perform PCR amplification on T093 and the progeny line 18108.Then,the gene sequences of subunit Dx5 t and Dy10.5^t in T093 and 18108 lines were obtained by directional deletion subcloning.The HMW-GS gene in T093 was tentatively named T093-Dx5 t,T093-Dy10.5^t,and the HMW-GS gene in 18108 was tentatively named 18108-Dx5 t,18108-Dy10.5^t.The full length of T093-Dx5 t and T093-Dy10.5^t gene sequences were 2514 bp and 1968 bp,which were the same as the 18108-Dx5 t and 18108-Dy10.5^t gene sequences of their descendant line 18108.Through sequence alignment,it was found that these genes have the typical structure of HMW-GS gene.In addition,the Dx5 t and Dy10.5^t of T093 have very small changes in offspring 18108,with only individual nucleotide differences.By phylogenetic tree construction of these genes with the HMW-GS gene on the genomes of common wheat and the D genome of Aegilops,it was found that the Dx5 t and Dy10.5^t genes of 18108 were all combined with the HMW-GS of the D genome of Aegilops together,indicating Dx5 t and Dy10.5^t subunit gene of T093 was transferred into the progeny line 18108.（4）In order to explore the genetic effect of subunit 5^t+10.5^t on the quality of the progeny lines,the main quality parameters of the two lines were measured by far infrared instrument.The result showed that the average value of protein content,wet gluten content,sedimentation value and flour extensibility of the lines containing 5^t+10.5^t subunit were higher than the corresponding average value of the lines containing 2+12 subunit.