Effect of high-molecular-weight glutenin subunit deletion on soft wheat quality properties and sugar-snap cookie quality estimated through near-isogenic lines

High-molecular-weight glutenin subunits (HMW-GSs) play a critical role in determining the viscoelastic properties of wheat dough. The HMW-GSs are encoded by Glu-A1, Glu-B1, and Glu-D1 loci on the long arms of chromosomes 1A, 1B, and 1D, respectively. In the present study, four near-isogenic lines with different HMW-GS deletions and compositions at the Glu-A1 and Glu-D1 loci in Yangmai 18 background were used for quality analysis. Deletion in Glu-D1 showed much weaker gluten quality and dough strength than null Glu-A1 genotype and wild genotype (WT), based on the measurements of sodium dodecyl sulfate (SDS)-sedimentation, lactic acid solvent retention capacity (SRC), gluten index, development time, stability time, and alveograph P and L values. The deletion of Glu-D1 did not significantly affect grain hardness, grain protein content, water SRC, sodium carbonate SRC, and sucrose SRC. Double null genotype in Glu-A1 and Glu-D1 and single null genotype in Glu-D1 showed significantly higher cookie diameter, crispness, and lower cookie height compared with single null genotype in Glu-A1 and WT. These indicate that the null Glu-D1 genotype is useful for improvement of biscuit quality, and use of this germplasm would be a viable strategy to develop new wheat varieties for biscuit processing.     

Effect of high-molecular-weight glutenin subunit Dy10 on wheat dough properties and end-use quality

High-molecular-weight glutenin subunits (HMW-GSs) are the most critical grain storage proteins that determine the unique processing qualities of wheat. Although it is a part of the superior HMW-GS pair (Dx5+Dy10), the contribution of the Dy10 subunit to wheat processing quality remains unclear. In this study, we elucidated the effect of Dy10 on wheat processing quality by generating and analyzing a deletion mutant (with the Dy10-null allele), and by elucidating the changes to wheat flour following the incorporation of purified Dy10. The Dy10-null allele was transcribed normally, but the Dy10 subunit was lacking. These findings implied that the Dy10-null allele reduced the glutenin:gliadin ratio and negatively affected dough strength (i.e., Zeleny sedimentation value, gluten index, and dough development and stability times) and the bread-making quality; however, it positively affected the biscuit-making quality. The incorporation of various amounts of purified Dy10 into wheat flour had a detrimental effect on biscuit-making quality. The results of this study demonstrate that the Dy10 subunit is essential for maintaining wheat dough strength. Furthermore, the Dy10-null allele may be exploited by soft wheat breeding programs.     

六倍体普通小麦高分子量谷蛋白亚基Glu-A1和Glu-B1共同缺失材料研究初报

利用SDS-PAGE方法对源于CIMMYT的六倍体普通小麦材料SYN351进行了高分子量谷蛋白亚基(HMW-GS)分析,结果表明SYN351Glu-A1和Glu-B1位点编码的HMW-GS同时全部缺失,唯有Glu-D1位点编码的HMW-GS(5 10)存在(N,N,5 10),是六倍体普通小麦中一种高分子量谷蛋白亚基缺失的新类型。     

小麦高分子量谷蛋白14亚基基因的PCR体系及原核表达研究

    小麦高分子量谷蛋白14亚基(HMW-GS 1Bx14)被认为可能对面团加工品质有很大贡献的亚基.为了验证其功能,本研究欲通过PCR方法扩增14亚基基因,并使其在大肠杆菌中大量表达,为下一步用掺粉实验验证其功能奠定基础.但是由于HMW-GS 1Bx14基因由2388 bp个碱基组成,GC含量较高,并且在基因中包含约1.6 kb的重复区,所有这些都使常规PCR难以成功扩增出HMW-GS 1Bx14 基因.本研究采取以下三种措施:①设计一对高Tm值的特异引物;②采用二段法PCR反应程序;③改良PCR反应的缓冲体系、添加有机溶剂(DMSO,甜菜碱等)和Taq酶保护剂(BSA等);最后成功地扩增出目的片段.此外由于不同生物间对密码子使用存在很大差异,因此HMW-GS 1Bx14基因很难在大肠杆菌中得到有效大量的表达.本研究选用万能菌株Rosetta(DE3)plysS作为表达用菌,从而克服了不同生物间密码子使用偏爱性的问题,成功的使HMW-GS 1Bx14得到表达,为下一步研究HMW-GS 1Bx14的基因功能奠定了基础.     

小麦产量构成因素的基因效应和杂种优势分析

为提高对小麦产量构成因素的选择效率,以7个半冬性小麦品种及按7×7双列杂交设计的21个F1杂交组合在2个地点的试验资料,研究了小麦2个产量构成因素—每穗粒数和千粒质量的基因效应和杂种优势。结果表明,每穗粒数和千粒质量的遗传符合加性-显性模型,基因显性效应的作用远大于其加性效应,显性程度为超显性。增效基因为显性,减效基因为隐性。每穗粒数和千粒质量在2个试点的平均狭义遗传力分别为54.00%和63.17%。每穗粒数和千粒质量表现正向的平均杂种优势和超亲优势,变异幅度较大,并在基因型、地点及基因型与地点互作间存在极显著差异。     

小麦植酸酶基因TaPHY1的克隆、分子特征和表达特性研究

利用小麦植酸酶基因PAPhya1进行同源查找,获得1个与该基因高度同源、尚未开展分子特征和生物学功能研究的小麦新型植酸酶基因TaPHY1.TaPHY1的全长cDNA序列为1771 bp,编码548个氨基酸残基,TaPHY1含有紫色酸性磷酸酶(PAP)类植酸酶通常含有的保守域Metallophos、Purple acid...     

A genetic linkage map with 178 SSR and 1901 SNP markers constructed using a RIL population in wheat (Triticum aestivum L.)

The construction of high density genetic linkage map provides a powerful tool to detect and map quantitative trait loci(QTLs) controlling agronomically important traits. In this study, simple sequence repeat(SSR) markers and Illumina 9K i Select single nucleotide polymorphism(SNP) genechip were employed to construct one genetic linkage map of common wheat(Triticum aestivum L.) using 191 recombinant inbred lines(RILs) derived from cross Yu 8679×Jing 411. This map included 1 901 SNP loci and 178 SSR loci, covering 1 659.9 c M and 1 000 marker bins, with an average interval distance of 1.66 c M. A, B and D genomes covered 719.1, 703.5 and 237.3 c M, with an average interval distance of 1.66, 1.45 and 2.9 c M, respectively. Notably, the genetic linkage map covered 20 chromosomes, with the exception of chromosome 5D. Bioinformatics analysis revealed that 1 754(92.27%) of 1 901 mapped SNP loci could be aligned to 1 215 distinct wheat unigenes, among which 1 184(97.4%) were located on o ne single chromosome, and the rest 31(2.6%) were located on 2 to 3 chromosomes. By performing in silico comparison, 214 chromosome deletion bin-mapped expressed sequence tags(ESTs), 1 043 Brachypodium genes and 1 033 rice genes were further added onto the genetic linkage map. This map not only integrated genetic and physical maps, SSR and SNP loci, respectively, but also provided the information of Brachypodium and rice genes corresponding to 1 754 SNP loci. Therefore, it will be a useful tool for comparative genomics analysis, fine mapping of QTL/gene controlling agronomically important traits and marker-assisted selection breeding in wheat.     

Effect of grazing time and intensity on growth and yield of spring wheat(Triticum aestivum L.)

A simulated grazing field experiment was conducted to determine the effect of timing and intensity of grazing on the growth and yield of a mid-late maturing spring wheat(cv. Flanker) under different watering regimes, at Wagga Wagga in southeastern Australia. The experiment was a factorial design of watering regime and pasture "grazing" as factors, with three replications. The two watering regimes were rainfed(R) and supplemental irrigation(I). There were four simulated grazing treatments: no grazing, "crash" grazing by mowing to 5 cm height on 13 June(Cut1-5), "crash" grazing by mowing to 5 cm on 15 July(Cut2-5) and "clip" grazing by mowing to 15 cm height on 15 July(Cut2-15). The lowest dry matter(simulated grazing) was obtained from RCut1-5(0.13 t ha~(–1)) and the highest(0.86 t ha~(–1)) was from ICut2-5. There was no significant difference(P0.05) among the grain yields of the grazing treatments in the respective watering regimes. However, there was significant difference(P0.05) between the grain yields of the rainfed(3.60 t ha~(–1)) and irrigated(6.0 t ha~(–1)) treatments. Under both watering regimes, the highest grain yield was obtained from the late "clip" grazings: 3.79 t ha~(–1)(RCut2-15) for rainfed and 6.47 t ha~(–1)(ICut2-15) for irrigated treatments. The lowest grain yield for the rainfed treatment was 3.26 t ha~(–1)(RCut1-5) and for the irrigated treatments, the lowest grain yield was 5.50 t ha~(–1)(ICut2-5). Harvest index(HI) was not significantly affected(P0.05) by either the watering regime or grazing. Seed weight was significantly(P0.05) affected both by the watering regime and grazing with the lowest value for 1 000-seed weight of 30.05 g(RCut2-5) and the highest value of 38.00 g(ICut2-15). Water use efficiency was significantly(P0.05) affected both by the watering regime and grazing with the lowest value of 9.94 kg ha~(–1) mm~(–1)(ICut2-5) and the highest value 13.43 kg ha~(–1) mm~(–1)(RCut2-5). By "crash" grazing late(just before stem elongation stage) to a height of 5 cm, a significantly higher(P0.05) above ground dry matter can be grazed without significantly affecting the yield both in seasons with low amount of rainfall and high amount of rainfall(irrigated in this study) although in a wet season a slightly lower(15% lower) grain yield is obtained relative to "clip grazing" to 15 cm height. Grazing of mid-late maturing wheat cultivars has the potential to fill the feed gap without significantly affecting grain yield.     

小麦磷转运蛋白基因TaPT4的克隆和表达分析

在富集低磷响应基因的小麦根系cDNA差减杂交文库中,测序后获得1个与大麦磷转运蛋白基因HvPT4高度同源的表达序列标签TaPT4-EST。经BLAST分析获得该EST对应的全长cDNA,将其命名为TaPT4。TaPT4的cDNA全长为1 927bp,编码537个氨基酸残基,编码蛋白含有12个跨膜保守域。系统进化分析表明,TaPT4除与HvPT4具有较高的相似性外,还与呈高亲和特征的黑麦磷转运蛋白基因PT和小麦磷转运蛋白基因PT1高度同源。TaPT4在叶中的表达为组成型,在根中的表达受到低磷诱导;此外,无论在低磷处理还是正常供磷条件下,TaPT4在根中的表达均表现明显的昼夜节律特征,表现为随照光时间延长而表达增高,进入暗期后表达减弱。上述结果表明TaPT4可能是归属于高亲和特征的小麦磷转运蛋白,在增强小麦在低磷逆境下的磷素吸收中发挥着重要作用。     

Genetic analysis and QTL mapping of a novel reduced height gene in common wheat(Triticum aestivum L.)

Low stature in wheat is closely associated with lodging resistance, and this impacts harvest index and grain yield. The discovery of novel dwarfing or semi-dwarfing genes can have great significance for dwarf wheat breeding. In this study, we identified an EMS-induced dwarf wheat mutant JE0124 from the elite cultivar Jing411. JE0124 possesses increased stem strength and a 33% reduction in plant height compared with wild type. Gibberellic acid(GA) treatment analysis suggested that JE0124 was GA-sensitive. Analysis of the frequency distribution of plant height in four F2 populations derived from crosses between JE0124 and the relatively taller varieties Nongda 5181 and WT indicated that the dwarfism phenotype was quantitatively inherited. We used two F2 populations and 312 individuals from the reciprocal cross of Nongda 5181 and JE0124 to map the quantitative trait locus(QTL) for reduced height to a 0.85-cM interval on chromosome 2 DL. The mapping was done by using a combination of 660 K SNP array-based bulked segregant analysis(BSA) and genetic linkage analysis, with logarithm of odds(LOD) scores of 5.34 and 5.78, respectively. Additionally, this QTL accounted for 8.27–8.52% of the variation in the phenotype. The dwarf mutant JE0124 and the newly discovered dwarfing gene on chromosome 2 DL in this study will enrich genetic resources for dwarf wheat breeding.     

土壤高砷污染对冬小麦和油菜生长影响的比较研究

采用盆栽试验研究了土壤高浓度砷污染对冬小麦和油菜生长、生物量、产量的影响及磷、砷在此2种作物各个部位的累积规律。结果表明,200 mg·kg-1土壤砷污染显著抑制了冬小麦的生长,收获时冬小麦株高较对照降低17%;冬小麦地上部分、根系的生物量和产量较对照分别降低了52.2%,60.6%和46.8%。但土壤砷污染对油菜株高、生物量影响均不显著,产量较对照降低了15.4%。砷在冬小麦、油菜各部位的含量为根系>茎叶>颖壳(角果皮)>种子。相同砷污染条件下,小麦根系砷浓度(74.86 mg·kg-1)显著高于油菜根系砷浓度(57.76 mg·kg-1),但地上部分砷含量差异不大,冬小麦籽粒中砷的含量高于油菜籽粒,但均未超过0.7 mg·kg-1。土壤砷污染对冬小麦、油菜根系、茎叶中磷含量影响不大,但显著降低了颖壳(角果皮)中磷的含量。油菜较冬小麦对砷有更高的耐性,砷污染土壤中种植越冬作物时,更适合种植油菜。     

不同小麦品种苗期的耐盐性鉴定及其相关生理参数研究

以15个河北平原区推广的小麦品种(Triticum aestivum L.)为材料,采用水培方法研究了供试品种苗期的耐盐能力差异及其相关生理参数。结果表明:不同供试小麦品种的耐盐能力具有较大差异,依据NaCl处理(200 mmol/L)9 d时的单株干物重较对照下降幅度,可将供试品种划分为耐盐能力强、较强和敏感3种类型。对盐分处理3、6和9 d后的幼苗形态学性状(株高)和生理参数(可溶性蛋白含量、超氧化物歧化酶活性和丙二醛)含量的研究发现,盐分处理后株高与幼苗的耐盐能力具有较高程度一致性,表现为随着小麦耐盐能力的增强,盐分胁迫下株高呈不断增加趋势。盐分胁迫下,供试小麦品种的耐盐能力强弱与可溶性蛋白含量和SOD活性不呈明显的相关,但MDA含量在盐分处理后期表现为随着小麦耐盐能力增强而降低。因此,可分别用株高和MDA含量作为评价小麦苗期耐盐能力强弱的形态学和生理指标。     

化感小麦植株及根际土壤水提液对看麦娘发根力的影响

以体积分数为0.2%、1.0%、5.0%的叶、根及根际土壤水提液水培看麦娘,测定了弱化感小麦抗10103、强化感小麦115/青海麦和92L89对看麦娘发根力的影响.结果表明,小麦叶、根及根际土壤水提液对看麦娘的发根力均具显著的抑制作用,抑制率随水提液体积分数提高而增大,不同小麦品种间存在显著差异,抑制效应大小:115/青海麦>92L89>抗10103,抑制效应115/青海麦最大,抗10103最小.不同体积分数的115/青海麦叶水提液对看麦娘根系根重、根数、根长、总根长抑制率分别为64.6%-78.2%、37.2%-42.7%、57.5%-77.4%、73.0%-85.6%,根水提液的抑制率为40.4%-67.8%、34.1%-36.0%、43.4%-50.0%、63.2%-68.2%,根际土壤水提液的抑制率分别为65.9%-69.6%、31.7%-37.2%、37.7%-48.1%、57.7%-69.1%;抗10103叶水提液处理的抑制率分别为54.0%-62.8%、29.3%-30.5%、57.5%-77.4%、63.2%-80.2%,根的抑制率分别为21.2%-49.2%、19.5%-26.8%、34.0%-47.2%、47.6%-61.2%,根际土壤的抑制率分别为10.6%-25.5%、4.3%-19.5%、30.2%-33.0%、33.6%-44.6%.强化感小麦对看麦娘的发根力具有较强的抑制效应.     

Growth traits and nitrogen assimilation-associated physiological parameters of wheat(Triticum aestivum L.) under low and high N conditions

In this study, 14 wheat cultivars with contrasting yield and N use efficiency(NUE) were used to investigate the agronomic and NUE-related traits, and the N assimilation-associated enzyme activities under low and high N conditions. Under deficient-N, the cultivars with high N uptake efficiency(UpE) and high N utilization efficiency(UtE) exhibited higher plant biomass, yields, and N contents than those with medium and low NUEs. The high Up E cultivars accumulated more N than other NUE type cultivars. Under sufficient-N, the tested cultivars showed similar patterns in biomass, yield, and N content to those under deficient-N, but the varietal variations in above traits were smaller. In addition, the high Up E cultivars displayed much more of root biomass and larger of root length, surface area, and volume than other NUE type cultivars, indicating that the root morphological traits under N deprivation are closely associated with the plant biomass through its improvement of the N acquisition. The high Ut E cultivars showed higher activities of nitrate reductase(NR), nitrite reductase(NIR), and glutamine synthetase(GS) at stages of seediling, heading and filling than other NUE type cultivars under both low and high N conditions. Moreover, the high Up E and Ut E cultivars also displayed higher photosynthetic rate under deficient-N than the medium and low NUE cultivars. Together, our results indicated that the tested wheat cultivars possess dramatically genetic variations in biomass, yield, and NUE. The root morphological traits and the N assimilation enzymatic acitivities play critical roles in regulating N accumulation and internal N translocation under the N-starvation stress, respectively. They can be used as morphological and biochemical references for evaluation of Up E and Ut E in wheat.     

Negative Effects of Oxytetracycline on Wheat （Triticum aestivum L.） Growth,Root Activity,Photosynthesis, and Chlorophyll Contents

A solution culture experiment was performed to investigate the effects of oxytetracycline (OTC) on wheat (Triticum aestivum L.) growth,chlorophyll contents,and photosynthesis at five levels of 0,10,20,40,and 80 mmol L-1 OTC.OTC is toxic to wheat.The wheat growth,especially wheat root was significantly decreased.Further OTC also significantly decreased root activity,chlorophyll contents,and photosynthetic parameters except for intercellular CO2 concentrations.The different responses of indicators such as root number,root activity and so on to OTC were also observed.The IC50 values for the tested indicators to OTC ranged from 7.1 to 113.4 mmol L-1 OTC.The order of indicator sensitivity to OTC was root number ＞ stomatal conductance ＞ chlorophyll a ＞ total chlorophyll ＞ photosynthetic rates ＞ total surface area ＞transpiration rate ＞ chlorophyll b ＞ fresh weight of root ＞ dry weight of root ＞ total length ＞ dry weight of shoot =fresh weight of shoot＞ total volume.The root number was more sensitive than other indicators with the ICs0 value of 7.1 mmol L-1 OTC,and could be taken as the sensitive indicator to predict the hazards of OTC to wheat.     

2,4D、KT对小麦成熟胚愈伤组织形成、分化的影响

以小麦新品种川农 17、12成熟胚为外植体进行离体培养 ,结果表明 :2mg/L 2 ,4 D有利于胚性愈伤组织形成 ,5mg/LKT有利于植株再生 (两品种植株再生率分别为 73 6 3% ,89 4 7% )。高浓度 2 ,4 D(4～ 8mg/L)虽不影响成愈率 ,但抑制植株再生。这种抑制作用能被KT拮抗。而KT的这种拮抗作用在 2mg/L 2 ,4 D条件下不能体现。     

Genome-wide identification and transcriptome profiling reveal great expansion of SWEET gene family and their wide-spread responses to abiotic stress in wheat(Triticum aestivum L.)

The Sugars Will Eventually be Exported Transporter(SWEET) gene family, identified as sugar transporters, has been demonstrated to play key roles in phloem loading, grain filling, pollen nutrition, and plant-pathogen interactions. To date, the study of SWEET genes in response to abiotic stress is very limited. In this study, we performed a genome-wide identification of the SWEET gene family in wheat and examined their expression profiles under mutiple abiotic stresses. We identified a total of 105 wheat SWEET genes, and phylogenic analysis revealed that they fall into five clades, with clade V specific to wheat and its closely related species. Of the 105 wheat SWEET genes, 59% exhibited significant expression changes after stress treatments, including drought, heat, heat combined with drought, and salt stresses, and more up-regulated genes were found in response to drought and salt stresses. Further hierarchical clustering analysis revealed that SWEET genes exhibited differential expression patterns in response to different stress treatments or in different wheat cultivars. Moreover, different phylogenetic clades also showed distinct response to abiotic stress treatments. Finally, we found that homoeologous SWEET genes from different wheat subgenomes exhibited differential expression patterns in response to different abiotic stress treatments. The genome-wide analysis revealed the great expansion of SWEET gene family in wheat and their wide participation in abiotic stress response. The expression partitioning of SWEET homoeologs under abiotic stress conditions may confer greater flexibility for hexaploid wheat to adapt to ever changing environments.     

基因枪法导入Bar基因转化小麦幼胚的研究——抗性愈伤组织与再生植株的遗传转化

在前文研究基础上 ,轰击的 2 80 4个幼胚经 L - PPT筛选后共获得 2 5 9个抗性愈伤 ,对其中 2 0 0个抗性愈伤组织和再生的 32个植株 GU S gene的表达进行组织化学检测 ,以及再生植株的 PCR检测。研究结果表明 ,有 4 5个抗性愈伤组织呈 GUS阳性。32株再生植株中获得 4个抗性株系 ,经 X- Gluc染色 ,在花药中检测到 GU S基因表达 ,PCR检测也呈阳性 ,而在对照和其它再生植株中未发现 GU S和 BAR基因表达     

不同蛋白水平的螺旋藻饲料对锦鲤体色、生长及免疫的影响

试验以初始体重(5.85±0.19)g的红白锦鲤幼鱼为试验对象,研究螺旋藻添加量为12%时,饲料不同蛋白水平(25.65%、30.43%、35.56%、40.42%、45.90%)对锦鲤体色、生长及免疫的影响。每组设3个平行,每个平行饲养20尾,表观饱食投喂,试验期为60 d。结果表明,饲料蛋白水平为45.90%时,试验鱼体表红质a*值最高,与DL2、DL3组间无显著差异;蛋白水平为30.43%时,类胡萝卜素含量显著升高(P<0.05),最大值出现在DL5组(蛋白水平为45.90%),显著高于其他试验组(P<0.05);蛋白水平为35.56%时,试验鱼的BWG、PER显著高于DL2、DL5组(P<0.05);蛋白水平为45.90%时,试验鱼血清ALT显著高于DL1组(P<0.05),GLU浓度显著低于DL3组(P<0.05),肝胰脏CAT、SOD活力最高。研究结果说明,螺旋藻添加量为12%时,使锦鲤生长、着色达到最佳效果的适宜饲料蛋白水平为35.56%。