Noodles are an important food in Asia. Wheat starch is the most important component in Chinese noodles. Loss of the waxy genes leads to lower activity of starch synthesis enzymes and decreased amylose content that further affects starch properties and noodle quality. To study the effects of different waxy (Wx) protein subunits on starch biosynthesis and processing quality, the high-yielding wheat cultivar Jimai 22 was treated with the mutagen ethyl methane sulfonate (EMS) to produce a population of Wx lines and chosen 7 Wx protein combinations. The amylose content increased but swelling power decreased as the number of Wx proteins increased. Both GBSS activity and gene expression were the lowest for the waxy mutant, followed by the mutants with 1 Wx protein. The combinations of these mutant alleles lead to reductions in both RNA expression and protein levels. Noodles made from materials with 2 Wx protein subunits had the highest score, which agreed with peak viscosity. The influence of the Wx-B1 protein on amylose synthesis and noodle quality was the highest, whereas the influence of Wx-A1 protein was the lowest. Mutants with lower amylose content caused by the absence of 1 subunit, especially the Wx-B1 subunit, had superior noodle quality. Additionally, the identified mutant lines can be used as intermediate materials to improve wheat quality.

济麦55是山东省农业科学院作物研究所选育的优质高产节水抗逆小麦新品种,于2009年以泰农18为母本、济麦22为父本配置杂交组合,经系谱法单株选择育成.2018年1月获植物新品种权证书(CNA20161721.4),2021年通过黄淮北片水地组国家审定(国审麦20210053).

为了更好地利用与改良品质较差小麦面粉的加工品质,将面包、面条加工品质较优与较劣的面粉按不同比例进行配粉,分析不同配粉比例对面粉理化特性和面包、面条品质的影响.结果表明,配粉能够显著改善品质较劣面粉的理化特性及其加工面包、面条的品质,优质面粉添加比例为30％时就可以明显改善面粉的理化特性,添加比例为50％时面包、面条品质提升效果最明显.配粉后,面粉蛋白质、沉淀值、干面筋含量、面筋指数以及面团形成时间、稳定时间、粉质质量指数、吸水率、稀懈值与面包、面条评分呈极显著正相关关系.

小麦是我国重要的口粮作物,面条、面包优质兼用小麦更适合我国国情,淀粉理化特性改良是当前选育优质兼用小麦品种的关键.本文综述了选育优质兼用小麦的重要性、可行性以及淀粉理化特性对面条、面包品质的影响及其调控,以期为小麦品质遗传改良提供参考.兼用优质小麦蛋白和面团特性接近优质面包小麦,淀粉理化特性明显优于优质面包小麦,与优质面条小麦相近,具体表现为直链淀粉含量较低,支链淀粉短链比例较高,中链比例较低,小淀粉粒比例较高,中型淀粉粒比例较低,淀粉糊化和膨胀特性好.淀粉理化特性主要源于品种差异,受一系列淀粉合成酶的调控,并受环境因素的巨大影响,因此应进一步加强遗传育种和栽培研究.

面包、面条加工品质对我国小麦生产和消费非常重要,我们前期筛选出面包优质和劣质、面条优质和劣质、二者兼优和均劣6类品质差异显著的小麦品种,研究发现其蛋白和淀粉理化特性、面包和面条加工品质存在显著差异.本研究选取花后7、17、27 d的籽粒,利用RNA-Seq技术构建了籽粒灌浆动态转录组文库.通过转录组测序,以面包优质小麦为对照,花后7 d共找到4529个差异表达基因,花后17 d共找到3198个差异表达基因,花后27 d共找到2955个差异表达基因.进一步针对蔗糖与淀粉代谢通路研究,结果表明,不同品质类型小麦籽粒中蔗糖代谢形成淀粉合成前体的相关酶类(蔗糖磷酸合酶SPS、蔗糖转化酶INV、蔗糖合成酶SuS)以及淀粉代谢相关酶类(淀粉去分支酶DBE、α-淀粉酶与β-淀粉酶)存在差异,可能是总淀粉含量及其组分差异的重要原因.同面包优质小麦相比,其他5类小麦品种中DBE与α-淀粉酶基因均上调,可能是面包优质小麦总淀粉含量较低、支链淀粉含量较高的原因.由此推测,调控籽粒蔗糖代谢通路以及淀粉水解通路可以作为调控小麦加工品质的新思路.

为了解叶片衰老抑制基因PSAG12-IPT在小麦遗传改良中的作用,利用共表达PSAG12和IPT的转基因小麦材料(TIPT-XN1376)与推广小麦品种陕麦159、周麦18、远丰175、西农979和郑麦9023杂交,并对其后代进行分子标记辅助选择和叶绿素含量测定,研究PS4G12-IPT基因在小麦中的遗传特点及其与衰老和叶片叶绿素含量的关系.结果表明,150个转基因株系中,携带PSAG12-IPT植株与不携带PSAG12-IPT植株的分离比为110 ∶ 40,x2检验表明,符合3:1的分离特点,说明PSAG12-IPT基因以单基因形式在子代中稳定遗传.携带PSAG12-IPT的F2株系平均叶绿素含量(55.4 mg·g-1)比不携带PSAG12-IPT的F2株系(51.7 mg·g-1)提高7％,说明PS412-IPT基因能够降低植株叶片叶绿素的降解速率,使叶片维持较长持绿时间,延缓叶片衰老.