抗赤霉病小麦地方品种的贮藏蛋白分析

采用A-PAGE和SDS-PAGE方法,对来自不同地方的23个抗赤霉病小麦地方品种的醇溶蛋白和谷蛋白亚基进行了分析。结果表明,在A-PAGE电泳分析中,23个供试品种具有23种不同的醇溶蛋白带型,共分离出39条相对迁移率不同的谱带,其中31条具有多态性,占86.8％,每份材料可电泳出14～23条带,存在着广泛的等位基因变异。在SDS-PAGE电泳分析中,出现了9种不同的高分子量谷蛋白亚基及6种亚基组合类型,优质亚基及亚基组合所占的比例较少,品质评分较低,其变幅为5～9分,平均为6.8分。     

小麦籽粒谷蛋白大聚合体粒度分布特征及对氮素的响应

为了给小麦品质改良提供依据,以强筋小麦品种藁城8901和弱筋小麦品种山农1391为材料,设置不同氮素水平,研究了籽粒谷蛋白大聚合体(GMP)颗粒粒径分布特征及对氮素水平的响应.结果表明,小麦籽粒GMP颗粒粒径范围为0.375～200 μm.GMP颗粒体积分布总体上呈双峰曲线变化,＜12 μm的GMP颗粒体积百分比为11.2％～45％,＞12 μm的GMP颗粒体积百分比为55.0％～88.8％.与弱筋小麦山农1391相比,强筋小麦藁城8901有较高比例的＞12 μm颗粒.GMP颗粒数目分布表现为单峰分布,＜4 μm和＜12 μm的颗粒数目百分比分别为97.5％～98.0％和99.9％,表明小麦GMP颗粒中绝大多数为＜4 μm的小颗粒.在施氮0～240 kg·hm-2范围内,随着施氮量的增加,＜12 μm颗粒体积百分比显著降低,12～90 μm、＞90 μm颗粒体积百分比增加,说明适量施氮能够显著提高GMP大、中颗粒比例.过量氮素不利于小麦籽粒谷蛋白大聚合体的形成.     

Glu-B1位点亚基色谱鉴定及7OE对面团强度的影响

准准确鉴定高分子量谷蛋白亚基（HMW-GS）及探讨其对面团特性的影响是小麦品质研究的重要内容。用聚丙烯酰胺凝胶电泳（SDS-PAGE）和反相高效液相色谱（RP-HPLC）对62份品种（系）的HMW-GS组成进行鉴定。结果表明，结合SDS-PAGE和RP-HPLC两种方法可以对Glu-B1位点，尤其是Glu-B1（7+8）进行有效鉴定。选用13份姊妹系为材料，使用RP-HPLC和凝胶色谱（SE-HPLC）方法，研究了Glu-B1al（7^OE+8*）以及贮藏蛋白组分含量对面团强度的影响。结果表明，Glu-B1al（7^OE+8*）可显著提高HWM-GS总量和面团强度，7OE可作为优质亚基用于强筋小麦育种。相关性分析表明，谷蛋白总量、HWM-GS、LMW-GS以及x-HMW含量与最大抗阻力呈1%显著正相关，相关系数分别为0.76、0.76、0.77和0.72。SDS-不溶性谷蛋白大聚体（UPP）占谷蛋白聚合体总量的百分比与揉面仪峰值时间、粉质仪形成时间和稳定时间以及最大抗阻呈1%或0.1%显著正相关，相关系数分别为0.77、0.90、0.89和0.87。醇溶蛋白与谷蛋白含量的比值与揉面仪峰值时间呈1%显著负相关，相关系数为－0.69；与粉质仪稳定时间和最大抗阻呈5%显著负相关，相关系数分别为－0.58和－0.64。HPLC可有效分离和量化HWM-GS，并作为小麦品质育种有效的辅助手段。     

Polymerisation of gluten proteins in developing wheat grain as affected by desiccation

The breadmaking quality of wheat is affected by the composition of gluten proteins and the polymerisation of subunits that are synthesised and accumulated in developing wheat grain. The biological mechanisms and time course of these events during grain development are documented, but not widely confirmed. Therefore, the aim of this study was to monitor the accumulation of gluten protein subunits and the size distribution of protein aggregates during grain development. The effect of desiccation on the polymerisation of gluten proteins and the functional properties of gluten were also studied. The results showed that the size of glutenin polymers remained consistently low until yellow ripeness (YR), while it increased during grain desiccation after YR. Hence, this polymerisation process was presumed to be initiated by desiccation. A similar polymerisation event was also observed when premature grains were dried artificially. The composition of gluten proteins, the ratios of glutenin to gliadin and high molecular weight-glutenin subunits to low molecular weight-glutenin subunits, in premature grain after artificial desiccation showed close association with the size of glutenin polymers in artificially dried grain. Functional properties of gluten in these samples were also associated with polymer size after artificial desiccation.     

Influence of low soil nitrogen and phosphorus on gluten polymeric and monomeric protein distribution in two high quality spring wheat cultivars

The effect of low levels of nitrogen, phosphorus and a combination of the two on the distribution of polymeric and monomeric proteins in two high quality spring bread wheat cultivars was investigated for two consecutive seasons. Size exclusion-high performance liquid chromatography (SE-HPLC) was used to determine the quantity and relationships of monomeric and polymeric proteins, and their relationship with flour protein content (FPC) and SDS sedimentation volume (SDSS). The low nitrogen and combined low nitrogen and low phosphorus treatments had a much larger effect on the protein fractions than the low phosphorus treatment alone. The SDS-soluble large monomeric protein fraction and the percentage SDS-insoluble monomeric proteins, were significantly increased under low nitrogen and a combination of low nitrogen and low phosphorus treatments. The percentage SDS-insoluble large and total polymeric proteins was significantly reduced under low nitrogen and a combination of low nitrogen and phosphorus treatments. The SDS-soluble and -insoluble small polymeric proteins were significantly increased under both low nitrogen and a combination of low nitrogen and low phosphorus treatments. The low nitrogen treatment consistently caused the lowest FPC and SDSS values. Under low nitrogen conditions, there was a significant positive correlation between the SDS-soluble gliadins and SDSS, and FPC.     

Migration of gluten under shear flow as a novel mechanism for separating wheat flour into gluten and starch

This paper describes a novel principle for the separation of wheat flour into starch and gluten in a concentrated medium. The process is based on the use of simple shear flow in a cone-and-cone device. The separation takes place in two steps. Initially, local segregation of gluten and starch phases occurs, leading to formation of macroscopically visible gluten patches distributed throughout the dough. This local segregation can be understood by considering the dough as a visco-elastic matrix containing an inert filler (starch). Further shearing leads to aggregation of those patches and migration (large-scale separation) towards the apex of the cone. As a result, the wheat dough is separated into a protein-poor fraction, containing less than 4% protein, and a protein-rich fraction containing almost 50% protein on a dry weight basis. However, under the process conditions used, upon a very long shearing, a redistribution of the aggregated gluten structures in the starch phase was observed, demonstrating a processing limit for the separation performance. Compared to traditional processing, the separation process presented shows opportunities for producing high quality gluten accompanied with significant water savings. Considering the fact that simple shear flow in steady rate is less harmful to gluten quality, such a separation process could benefit gluten quality.     

粗山羊草高分子量谷蛋白亚基组成分析

为了发现能够用于小麦品质改良的优异高分子量谷蛋白亚基(HMW-GS),应用SDS-PAGE技术分析了47份粗山羊草Glu-Dt1位点的HMW-GS组成,分别检测到5种x-型亚基(1.1t、1t、1.5t、2t、3t)和4种y-型亚基(10.1t、11t、12t、12.4t).其中,1Dx1.1t是1种新的x-型亚基,它的迁移率比普通小麦的1Ax1亚基稍慢,这是目前在粗山羊草中发现的分子量最大的HMW-GS.供试粗山羊草中有8种HMW-GS组合类型:1.1t 11t、1t 11t、1.5t 12t、2t 10.1t、2t 11t、2t 12t、2t 12.4t和3t 11t.其中,1.1t 11t和2t 12.4t未见报道.     

硫素对不同基因型大豆球蛋白组成及含量的影响

为了探讨施硫量对不同基因型大豆7S和11S球蛋白亚基组成及含量的影响,寻找不同基因型大豆品种最佳施硫水平,以期提高大豆籽粒球蛋白的含量,改善期品质。选用在黑龙江省种植面积较大的‘黑农48’（高蛋白）、‘黑农37’（中间型）和‘黑农44’（高油）3种大豆作为试验材料。采用盆栽种植,每个品种设S1、S2、S3、S4 4个S处理（即每千克土壤分别施单质硫0、0.02、0.04、0.06 g）。采用SDS-PAGE凝胶电泳方法,对成熟大豆籽粒球蛋白亚基组成和含量2个指标进行研究。结果表明：在3个大豆品种中,7S球蛋白由α′、α、γ、β 4个亚基组成;11S球蛋白由酸性亚基和碱性亚基组成;各种亚基分子量在品种间的差异不显著。同一品种不同处理中均以S3水平下蛋白含量最高,对不同品种施用硫肥时,以高油品种提高球蛋白含量效果显著。施用硫肥对3个大豆品种的7S和11S球蛋白各种亚基组成都没有影响,对分子量的大小影响很小。施用硫肥对3个大豆品种中的7S和11S球蛋白和亚基含量有显著影响,适宜的施用硫肥有利于提高各品种球蛋白和亚基的含量。     

不同高分子量麦谷蛋白亚基小麦品种（系）的粒重增长特性分析

为给小麦高产优质育种提供参考,以黄淮麦区35个主栽小麦品种（系）为材料,利用SDSPAGE电泳技术对其进行了高分子量麦谷蛋白亚基鉴定,并对各参试品种的灌浆特性进行了分析。结果表明,35个黄淮麦区小麦品种（系）中 GluA1、GluB1和 GluD1位点分别只有2、5和4种亚基类型,分别以Null、7+9和2+12亚基为主,所占比例分别为71.4%、45.7%和62.7%。依据 GluB1和 GluD1位点的亚基特点,将参试品种（系）分为三类。对这三类品种（系）的灌浆期粒重增长特性分析发现,第I类（亚基组合：7+8/2+12）品种（系）灌浆速率较快,最终粒重较高;第II类（亚基组合：7+9/2+12）品种灌浆持续时间较长,但灌浆速率不及第I类,最终粒重较高;第III类（亚基组合：7/5+10或7+8/5+10）品种（系）灌浆持续时间较短,且灌浆速率较慢,最终粒重不高。三类品种（系）相比,粒重增长速率在灌浆前期基本相同,但35 d以后,第III类品种（系）粒重增长速率明显减慢,这可能是导致其最终粒重显著低于前两类品种（系）的主要原因。