小麦Glu-B1位点1Bx14+1By18新亚基对材料的创制及其对加工质量的影响分析

以小偃54为轮回亲本，以引进品种Prinqual为1Bx17+1By18的供体，培育高分子量麦谷蛋白亚基（HMW-GS）近等基因系，以期客观评价1Bx14、1By15、1Bx17和1By18等亚基（对）对小麦加工品质的贡献。近等基因系回交至BC₄代时发现一个1Bx17亚基不表达的重组体，该重组体经自交分离纯合后获得了携带新亚基对1Bx14+1By18且可稳定遗传的品系012912。采用SDS-聚丙烯酰胺凝胶电泳（SDS-PAGE）、酸性聚丙烯酰胺凝胶电泳（A-PAGE）、小麦SDS微量沉降值和面粉揉面仪等方法。对小偃54和012912的谷蛋白及醇溶蛋白组成、总蛋白质含量、沉降值和揉面特性等指标进行了比较，结果表明，012912（1Ax1, 1Bx14+1By18, 1Dx2+1Dy12）与其轮回亲本小偃54（1Ax1, 1Bx14+1By15, 1Dx2+1Dy12）在谷蛋白成分上的唯一差别是以1By18替换了小偃54的1By15亚基，且1By18基因的表达量比小偃54的1By15表达量提高29%；012912品系的沉降值比小偃54高2.5 mL，揉面特性比小偃54好，说明1By18基因比1By15对面团加工品质的正向效应大。

A Novel Line with HMW-GS 1Bx14+1By18 with Positive Effect on Processing Quality

High molecular weight glutenin subunits(HMW-GS) are wheat endosperm storage proteins,which play an important role in the viscoelastic properties of dough.They are encoded by genes(Glu-1) located on the long arms of the group 1 chromosomes of hexaploid wheat(Triticum aestivum L.).Each locus consists of two tightly linked genes,an x-type and a y-type,which encode the high Mr x-type and the low Mr y-type subunit,respectively.Although 1Ax1,1Ax2,1Bx7 1By8,1Bx7OE 1By8,1Bx14 1By15,1Bx17 1By18,1Bx13 1By16,and 1Dx5 1Dy10 are recognized correlating with good bread-making quality,the x-type and y-type subunit genes at the same locus are very difficult to be separated in breeding.Therefore,it is very difficult to confer a score value for a single subunit.In breeding near-isogenic-lines(NILs) for HMW-GS of Xiaoyan 54(1Ax1,1Bx14 1By15,1Dx2 1Dy12),an introduced variety,Prinqual was used as the donor of 1Bx17 1By18.A novel recombinant line 012912 with 1Bx14 1By18 was obtained.The recombinant(1Bx14 1By18) can stably inherit from generation to generation.Except the substitution of 1By15 by 1By18,all of the glutenin subunits and gliadin components of 012912 are consistent with those of Xiaoyan 54.The expression level of 1By18 was more than that of 1By15 by 29%,but the total protein content of the line 012912 was more than that of Xiaoyan 54 only by 0.29%.The SDS sedimentation of line 012912 was more than that of Xiaoyan 54 by 2.5 mL,and the mixing time and mixing tolerance were better than Xiaoyan 54.The results indicate that 1By18 has stronger positive effect than 1By15 on processing quality.