Department of Plant Breeding, Institute for Sustainable Agriculture, Córdoba, Spain.
PLoS One. 2012;7(9):e45937. doi: 10.1371/journal.pone.0045937. Epub 2012 Sep 24.
In the present work the effects on dough quality by the down-regulation of γ-gliadins in different genetic backgrounds of bread wheat were investigated. RNAi-mediated silencing of γ-gliadins was introgressed by conventional crossing into three commercial bread wheat lines (namely 'Gazul', 'Podenco' and 'Arpain'), and along with the transgenic line A1152 (cv. Bobwhite) compared with their respective wild types. The protein fractions were quantified by RP-HPLC, whereas the technological and mixing properties were assessed by SDSS test and by the Mixograph instrument. Principal component analysis (PCA) was carried out for both the wild types and the transgenic lines, showing differences in the factors affecting the technological and mixing properties of the dough as a consequence of the reduction of the γ-gliadins. In transgenic lines, the α- and ω-gliadins, and total gliadins negatively affected the dough strength and tolerance to over-mixing, whereas the L/H ratio showed the opposite effect, positively influencing the dough quality. The increase of the SDSS volume in the transgenic lines of 'Gazul', 'Podenco' and 'Arpain' indicates increased gluten strength and quality respect to the wild types. SDSS volume was found to be positively influenced by the amount of glutenins, which were also increased in the transgenic lines. In addition, a positive effect was observed in the MT, PR1 and RBD in some of the transgenic lines of 'Podenco' and 'Arpain'. In conclusion, the down-regulation of γ-gliadins resulted in stronger doughs and a better tolerance to over-mixing in some transgenic lines. Although the reduction of γ-gliadins seems not to have a direct effect on the mixing and bread-making properties, the compensatory effect on the synthesis of the other prolamins may result in stronger doughs with improved over-mixing resistance.
本研究旨在探讨不同遗传背景下小麦醇溶蛋白 γ-亚基下调对面团品质的影响。通过常规杂交将 RNAi 介导的γ-醇溶蛋白沉默导入三个商业面包小麦品系（即“Gazul”、“Podenco”和“Arpain”），并与转基因品系 A1152（cv. Bobwhite）及其各自的野生型进行比较。采用反相高效液相色谱法（RP-HPLC）对蛋白质组分进行定量分析，采用 SDSS 测试和 Mixograph 仪器对面团的工艺和混合性能进行评估。对野生型和转基因系进行主成分分析（PCA），结果表明，由于 γ-醇溶蛋白的减少，影响面团工艺和混合性能的因素存在差异。在转基因系中，α-和 ω-醇溶蛋白以及总醇溶蛋白对面团强度和过度混合耐受性产生负面影响，而 L/H 比值则产生相反的影响，对面团质量产生积极影响。转基因系“Gazul”、“Podenco”和“Arpain”的 SDSS 体积增加表明与野生型相比，面筋强度和质量增加。发现 SDSS 体积与谷蛋白含量呈正相关，而转基因系中谷蛋白含量也增加。此外，在一些“Podenco”和“Arpain”的转基因系中观察到 MT、PR1 和 RBD 的正效应。总之，在一些转基因系中，下调 γ-醇溶蛋白可使面团更结实，对过度混合的耐受性更好。尽管 γ-醇溶蛋白的减少似乎对面团混合和面包制作特性没有直接影响，但对其他醇溶蛋白合成的补偿效应可能导致面团更结实，过度混合耐受性提高。
