The AS-PCR Markers Of HMW-GS1Bx14 And 1Dx5

Wheat gluten (glutenin) subunits include high molecular weight glutenin subunits (HMW-GS) and low molecular weight subunits (LMW-GS), and HMW-GS relate to the bread properties closely. The identification of HMW-GS and the HMW-GS composition analysis mainly depends on the differences between HMW-GS electrophoresis migration at present. But the migration is not always identical to the HMW-GS, so it is difficult for HMW-GS analysis and the same wheat material has often different analysis results. Moreover, this method is based on the seeds ruination, timewasting and painstaking, so this method is limited in screening and identification of lots of hybrid progenies, while AS (allelic specific) –PCR markers system can refrain from the restriction from its development in HMW-GS analysis and can ensure the accuracy of subunits identification. The high molecular weight glutenin subunits compositions of up to 50 wheat varieties (lines) were analyzed by using SDS-PAGE in this study, and the HMW-GS composition of several wheat varieties (lines) were determined. Then the AS–PCR markers were also determined based on the above results. The main results are summerized as follows:1. The high molecular weight glutenin subunits composition of about 50 wheat materials were analyzed by using SDS-PAGE in this study, and the HMW-GS composition of several wheat varieties (lines) were determined. The result showed that most of wheat varieties (lines) have good subunits such as 1, 14 + 15/ 17+18, or 5+10 respectively coded by Glu-A1, Glu-B1 and Glu-D1, and a few cultivars have the good subunits 1, 14+15/17+18, and 5+10 simultaneously. Several materials with14+15 and 5+10 subunits were definitely determined. 2. Ten pairs of specific primers for Glu-1Bx14 gene were designed to detect HMW-GS 1Bx14 according to its gene sequence from GENBANK. One good pair of primers was screened out. The results showed that AS-PCR product of 1256bp were amplified in 4 materials carrying the Glu-1Bx14 subunit when 7 cultivars with HMW-GS composition known were tested. The primers were used to detect 40 wheat materials of Shandong province also. It indicated that there were only 5 materials having the PCR product of 1256bp. And the probability of the 1Bx14 gene is only 12.5%. The subunit utilization is craved for being studied deeply.3. A pair of specific primers for subunit 1Dx5 gene (Glu-D1-2b) was designed on the basis of difference between the 1Dx5 gene and the 1Dx2 gene. The 11 wheat cultivars whose HMW-GS composition at Glu-Dx1 locus had been known were used to identify the specific fragments and to test the accuracy of the molecular markers. The results showed that 4 wheat cultivars which carried the 1Dx5 subunit exhibited a good PCR product of 450bp by using 1Dx5 AS-PCR markers, while others did not, and the high accuracy of the primers was identified. It is useful for the primers designed for the 1Dx5 to detect the 1Dx5 in wheat cultivars. 35 Shandong province wheat varieties/ lines were detected with PCR based on the primers above. The results showed that the 1Dx5 gene was found in 9 varieties/ lines, and the probability of the 1Dx5 gene is 25.7%,far lower than that in North American wheat lines.