大豆低植酸突变体籽粒的抗氧化性分析

植酸具有较强的抗氧化能力,对作物籽粒的耐储性和活力均具有重要作用,但其作用机制尚不明确。为揭示大豆低植酸突变体和野生型亲本中抗氧化代谢产物的差异,本研究以低植酸突变体Gm-lpa-ZC-2、Gm-lpa-TW-1、Gm-lpa-TW-1-M,以及野生型亲本浙春3号、台湾75为材料,分析大豆籽粒发育过程中植酸含量对抗氧化能力的影响。结果表明,大豆籽粒发育过程中的总抗氧化能力受过氧化物酶和过氧化氢酶活力的影响较大,而非酶类氧化剂谷胱甘肽对总抗氧化能力影响较小。随着籽粒的成熟,脂质氧化物、丙二醛与蛋白羰基化产物的含量逐渐增加。低植酸突变体Gm-lpa-ZC-2、Gm-lpa-TW-1-M和亲本浙春3号、台湾75的总抗氧化能力较强,且籽粒活力也较高;而低植酸突变体Gm-lpa-TW-1的总抗氧化能力最弱,且籽粒活力也最弱,说明大豆籽粒抗氧化水平与籽粒活力呈正相关,但与植酸含量无相关关系。由此推测植酸并非影响大豆籽粒抗氧化能力和活力的直接因素。本研究结果为进一步探索低植酸作物的籽粒活力下降机制,培育高籽粒活力低植酸大豆品种提供了参考。     

低植酸作物遗传改良途径与磷资源高效利用

[目的]磷是作物生长发育所必需的营养元素.在植物体内,磷多以植酸形式储存在成熟籽粒中.非反刍动物,包括人类,无法消化植酸来获取磷及植酸螯合的有益元素,籽粒中收获的大量磷素进入人及动物排泄物,不仅造成磷资源浪费,也加大了环境风险.因此,培育籽粒低植酸品种是改善作物营养品质、降低磷素环境风险的重要途径.本文综述作物籽粒磷的...     

玉米中植酸代谢及其育种

植酸及其代谢中间体具有重要的生物学功能.禾谷科和油料作物的种子中积累了丰富的植酸.植酸既是一种抗营养因子,也是一种重要的健康因子.然而自植酸被发现至今,人们对于其在植物中的合成过程仍然知之甚少,对其生物学功能更是缺乏全面的了解.近年来,有关于植酸代谢及其功能分析的研究逐渐引起了人们的关注.在玉米(Zea mays)、水稻(Oryza sativa)、大豆(Glycine max)中,人们发展、分离了一系列的低植酸突变体,以期降低种子中的植酸含量,从而获得可用于生产的、能够增强动物磷和矿质营养利用效率并能降低环境污染的新品种.早期的研究发现,植物中植酸的合成途径有两条:依赖于磷脂酰的合成途径和不依赖于磷脂酰的合成途径.有证据表明,作物种子中植酸的积累主要是不依赖于磷脂酰途径的贡献.玉米是中国主要的粮食和饲料作物,关注玉米中植酸代谢和育种的相关研究将有利于动物营养强化以及人类和环境健康.本文综述了植酸的生物学功能以及植酸代谢研究现状,分析并总结了植酸的代谢通路,评述了植酸在玉米中代谢的研究成果,为今后植酸代谢相关的研究提供参考.     

玉米自交系低植酸突变体的生物学与光合特性研究

利用玉米自交系低植酸突变体及其野生型,通过田间试验与营养液培养试验研究了玉米低植酸突变体的主要生物学特性及光合速率。结果表明,与对应的野生型相比,突变体的播种-抽雄与播种-吐丝时间均有延长,叶面积变小,地上部与地下部生物量减少,根冠比提高,叶绿素计读数值SPAD降低,但净光合速率增加。同时,本文还针对玉米低植酸突变体的生物学特性,提出了低植酸玉米育种改良与利用的对策建议。     

作物转Bt抗虫基因育种研究进展

本文概述了Bt抗虫基因的特性及其人工合成和转导技术 ,并根据转Bt基因作物种质的特点和遗传缺陷 ,总结了进行转Bt基因作物育种改良的策略 ,介绍了国内外转Bt基因植株鉴定、筛选技术和育出的优良品系及商业化生产状况 ,讨论了Bt抗虫基因在育种应用中存在的问题及其解决途径     

空间环境诱发作物突变的筛选技术及其应用

本文综述了作物经过空间诱变后的突变分析鉴定技术及其应用。分析鉴定技术主要包括:形态学鉴定技术、细胞学鉴定技术、物理学鉴定技术、同工酶鉴定技术、生理指标鉴定技术、分子标记鉴定技术以及其他一些鉴定技术,同时综述了各种鉴定技术在水稻、玉米、小麦、番茄、辣椒、油菜等作物上的应用情况。     

植物性食品原料中植酸降解代谢与调控

植酸广泛存在于生物界中,其在植物性食品原料中常以植酸盐形式存在。植酸及其降解产物在植物生长发育和调控细胞的生物学进程中起重要作用。本文综述了植酸在植物性食品原料中的存在形式、分布、降解代谢及其调控和植酸酶性质,并对植物中植酸降解代谢与调控进行展望,以期为植酸降解和提高植物性食品原料营养价值研究提供参考。     

大豆突变体Gm-lpa-TW-1中低植酸性状与种子发芽率和糖份含量的相关性分析

为明确低植酸突变体Gm-lpa-TW-1植酸性状突变与种子发芽率降低以及糖份含量变化的相关性,选用低植酸突变体Gm-lpa-TW-1与不同野生型亲本的杂交后代,低植酸纯合株系（LPA）和非低植酸纯合株系（HPA）为研究材料,分析不同株系在不同种植环境下收获种子的发芽率、总糖、蔗糖和低聚糖的含量。结果表明：无论是LPA株...     

外源DNA导入植物技术的发展及其在作物育种中的应用

本文综述了 2 0年多来外源DNA导入植物技术的研究进展 ,着重介绍了该技术在作物育种中的应用及其可靠性和可行性的实验验证。     

正常供磷及低磷胁迫下油菜种子植酸浓度与含量的全基因组关联分析

  【目的】  鉴定不同磷水平油菜种子植酸浓度 (PA_Conc)和含量 (PA_Cont) 显著关联的 SNP 位点,挖掘候选基因及其优异单倍型,为油菜低植酸品种的培育提供遗传基础和优异基因资源。  【方法】  采用田间试验,测定正常供磷(施磷,P₂O₅ 90 kg/hm2)及低磷(不施磷,P₂O₅ 0 kg/hm2)条件下403个甘蓝型油菜品种种子中的PA_Conc和PA_Cont,利用基于全基因组重测序技术获得的530多万个高质量SNP (single nucleotide polymorphism)标记,用 TASSEL 5.0 软件中的一般线性模型(general linear model,GLM)和混合线性模型(mixed linear model,MLM)进行全基因组关联分析(genome-wide association study, GWAS),鉴定种子植酸浓度和含量显著关联的SNP位点及其候选基因。采用Bcftools提取BnaA07.MRP13基因的SNP,利用Haploview 4.2软件进行单倍型分析。  【结果】  关联群体正常供磷处理PA_Conc变异范围为17.52～81.32 mg/g,PA_Cont变异范围为0.30～0.99 mg/5粒种子;低磷处理PA_Conc变异范围为17.47～49.05 mg/g,PA_Cont变异范围为0.33～0.85 mg/5粒种子。与正常供磷相比,关联群体低磷胁迫下的PA_Conc和PA_Cont均值分别降低13.5%和10.8%。GLM模型检测到56个与油菜种子植酸浓度和含量显著关联的SNP位点,分布在除A08和C03外的17条染色体上,它们对表型变异的解释率为7.33%～14.28%。其中A03染色体上含有最多的SNP (9个)。MLM模型共检测到23个与油菜种子植酸浓度和含量显著关联的SNP位点,分布在A03、A05、A06、A07、A09、C01、C02、C04、C05、C06和C07等11条染色体上,它们对表型变异的解释率为9.6%～14.28%。其中A03染色体上含有8个SNP。对显著SNP位点上下游300 kb范围内的基因进行分析,挖掘出可能与种子中植酸合成相关的14个候选基因,其中包括拟南芥植酸合成通路中的MRP、PLC、PIP5K和SULTR4等同源基因。对BnaA07.MRP13进行候选基因关联及单倍型分析,鉴定出高植酸单倍型“BnaA07.MRP13ContHap1”(TTTA)和低植酸单倍型“BnaA07.MRP13ContHap2”(CCCT)。自然群体中18%的品种(72/403)为低植酸单倍型,种子平均植酸含量为 0.56 mg/5粒种子,极显著低于高植酸单倍型 (平均植酸含量为0.62 mg/5粒种子)。  【结论】  正常供磷和低磷胁迫下,油菜种子植酸浓度和含量均具有广泛的遗传变异。GLM模型和MLM模型分别检测到56和23个与油菜种子植酸浓度和含量显著关联的SNP位点,预测的与油菜种子植酸含量相关的候选基因有14个,发现的BnaA07.MRP13的高和低植酸单倍型为后续油菜种子植酸含量的遗传改良奠定了基础。     

Effects of irradiated phytic acid on antioxidation and color stability in meat models

Lipid oxidation and color stability of meats treated with irradiated phytic acid were investigated during storage for 2 weeks at 4 degrees C. The phytic acid in deionized distilled water (DDW) was degraded by irradiation at 10 and 20 kGy, and the irradiated phytic acid showed a strong antiradical activity. For measuring the antioxidant effects of irradiated phytic acid in food models, beef and pork were prepared with DDW (control), irradiated (10 and 20 kGy) or non-irradiated phytic acid, and ascorbic acid as a model system. Irradiated phytic acid significantly inhibited the lipid oxidation in meats compared to the control and ascorbic acid treated samples during storage (P < 0.05). The redness of the meats treated with phytic acid had a higher value than did the control and ascorbic acid treated samples, but a significant difference was not observed in the samples treated with phytic acid regardless of irradiation treatment. Irradiated phytic acid was also effective in inhibiting the loss of heme iron and metmyoglobin formation during storage. Results indicated that irradiation might be helpful for improving the antioxidant activity of phytic acid in meats.     

Inhibition of iron uptake by phytic acid, tannic acid, and ZnCl2: studies using an in vitro digestion/Caco-2 cell model.

The objective of this study was to document the effects of phytic acid, tannic acid, and zinc on iron uptake in an in vitro digestion/Caco-2 cell culture model. The effects of phytic acid and tannic acid on iron uptake were measured at increasing molar ratios of FeCl3 to phytic acid or tannic acid. Maximal inhibition of iron uptake by phytic acid occurred at a 1:10 ratio of Fe to phytic acid. Dialyzable Fe decreased with a low Fe to phytic acid ratio but increased with Fe:phytic acid ratios greater than 1:3 indicating that more iron was soluble at higher phytic acid levels but less available. As in human studies, heme iron was less inhibited by phytic acid than nonheme iron. Tannic acid was a more potent inhibitor of nonheme iron uptake, as maximal inhibition (97.5%) of iron uptake occurred at a ratio of 1:1 or less. The addition of ZnCl2 to the digest at ratios of 1:0.5 and 1:1 decreased iron uptake by 57 and 80%, respectively. Overall, the results agree qualitatively with studies in humans and demonstrate the relative effects of these compounds on iron uptake in this model system. This study provides key information for determining iron availability under more complex meal conditions.     

Effects of phytic acid on peanut allergens and allergenic properties of extracts

Phytic acid would form soluble and insoluble complexes with proteins. Our objective was to determine if phytic acid forms insoluble complexes with major peanut allergens, and if such reaction results in a peanut extract with a lower level of soluble allergens and allergenic property. Extracts from raw and roasted peanuts were treated with and without phytic acid at various pH values and then analyzed by SDS-PAGE and a competitive inhibition ELISA (ciELISA). The ciELISA measured IgE binding using a pooled serum from peanut-allergic individuals. Results showed that phytic acid formed complexes with the major peanut allergens (Ara h 1 and Ara h 2), which were insoluble in acidic and neutral conditions. Succinylation of the allergens inhibited complex formation, indicating that lysine residues were involved. A 6-fold reduction in IgE binding or allergenic potency of the extract was observed after treatment with phytic acid. It was concluded that phytic acid formed insoluble complexes with the major peanut allergens, and resulted in a peanut extract with reduced allergenic potency. Application of phytic acid to a peanut butter slurry presented a similar result, indicating that phytic acid may find use in the development of hypoallergenic peanut-based products.     

水稻低植酸突变基因和外源铁蛋白基因的聚合

对所获得的2份低植酸突变系和2份铁蛋白(Fer)转基因富铁系稻米进行了无机磷、种子GUS、叶片PCR、稻米矿质元素含量检测和简单的遗传分析,表明这些材料作为低植酸突变种质和Fer富铁种质具有良好的实用价值。对所配杂种F1进行了花药培养,并对愈伤组织诱导、分化、生根和花培苗倍数性、成活率、结实性等性状进行考察,认为低植酸基因和铁蛋白外源基因对花培过程影响不明显。在大量的花培后代中筛选到31份低植酸基因和外源铁蛋白基因双重表达的花培纯系,经检测,该批材料富铁效果极为显著,是难得的低植酸富铁转基因优良新种质。     

Determination of phytic acid and inositol pentakisphosphates in foods by high-performance ion chromatography

A high-performance anion exchange chromatographic method was adapted for the quantitative determination of phytic acid and inositol pentakisphosphate isomers (excluding enantiomers) in foods. Because of the cost and limited availability of inositol phosphate standards, a phytic acid sodium salt standard was used for the calculation of an average relative response factor for the quantification of inositol pentakisphosphate isomers, and the purity of phytic acid sodium salt standard was also accurately established. The detection limits (S/N = 3) for phytic acid and inositol pentakisphosphates were in the range of 1.5-3.4 microM (0.1-0.2 microg/100 microL). This method has been successfully applied to the determination of phytic acid and inositol pentakisphosphates in a variety of beans and nuts after extraction with 0.5 M HCl and cleanup with solid phase extraction cartridges. The results demonstrated that there was a strong correlation between either the phytic acid content or the total content of phytic acid together with inositol pentakisphosphates and the total dietary fiber content in the group of all raw dry beans and in the group of raw dry black beans but not in the group of raw dry red kidney beans, which was probably due to the insufficient number of the raw dry red kidney bean samples.     

氮素和水分处理对稻米植酸含量和蛋白组分的影响

以直立密穗型粳稻品种秀水110和弯曲散穗型粳稻品种春江15为材料,对不同氮素水平处理和水分管理方式下稻米植酸含量和蛋白组分的影响及其互作效应进行了研究。结果表明,旱作栽培处理会导致水稻籽粒中植酸含量上升,而施氮处理对籽粒植酸含量的影响效应与水稻的水分管理方式有关,在常规水作条件下,高氮处理（N3）的籽粒植酸含量有所提高,但在旱作栽培方式下,中氮（N2）和低氮处理（N1,不施N）的籽粒植酸含量却略高于高氮处理（N3）,氮素水平与水分管理方式间的互作效应明显; 水稻籽粒植酸含量与粗蛋白总量、4种蛋白组分（清蛋白、球蛋白、醇溶蛋白和谷蛋白）及有关产量性状指标（有效穗数、每穗粒数、千粒重和结实率）在不同水肥处理间的相关性不显著,但氮肥用量过高不仅会导致水稻的产量水平下降,而且也不利于稻米营养品质的改良; 水肥处理对水稻籽粒植酸含量、蛋白总量和4种蛋白组分穗内粒位分布也存在一定影响,着生在稻穗下部的弱势粒,其稻米植酸含量高于稻穗上部或中部的强势粒,因此改善弱势粒灌浆的水肥管理措施将有利于稻米植酸含量的降低。     

Effect of processing conditions on phytic acid, calcium, iron, and zinc contents of lime-cooked maize

Tortillas are made by cooking maize in a lime solution during variable times and temperatures, steeping the grain for up to 12 h, washing and grinding it to a fine dough, and cooking portions as flat cakes for up to 6 min. The effects of the main processing steps on the chemical composition, nutritive value, and functional and physicochemical characteristics have been areas of research. The present work evaluates the effect of lime concentration (0, 1.2, 2.4, and 3.6%) and cooking times (45, 60, and 75 min) on phytic acid retention of whole maize, its endosperm, and germ, as well as on the content of calcium, iron, and zinc on the same samples. The effects of steeping time and temperature and steeping medium on the phytic acid of lime-cooked maize were also studied. Finally, phytic acid changes from raw maize to tortilla were also measured. The results indicated that lime concentration and cooking time reduce phytic acid content in whole grain (17.4%), in endosperm (45.8%), and in germ (17.0%). Statistical analyses suggested higher phytic acid loss with 1.2% lime and 75 min of cooking. Cooking with the lime solution is more effective in reducing phytic acid than cooking with water. Steeping maize in lime solution at 50 degrees C during 8 h reduced phytic acid an additional 8%. The total loss of phytic acid from maize to tortilla was 22%. Calcium content increased in whole maize, endosperm, and germ with lime concentration and cooking and steeping times. The increase was higher in the germ than in the endosperm. The level, however, can be controlled if steeping of the cooked grain is conducted in water. Iron and zinc contents were not affected by nixtamalization processing variables but were affected in steeping.     

菜籽粕植酸提取和分离蛋白的制备

植酸和蛋白是菜籽粕中2种极具经济价值的成份。为提高菜籽粕的综合利用效果,该文以双低冷榨菜籽粕为原料,采用醋酸溶液提取植酸,在膜分离精制植酸粗提液过程中同时回收蛋白;再对植酸提取后的残余物进行蛋白分离,超滤纯化后获得高纯度的蛋白成品。响应面优化的植酸最适提取条件为：醋酸质量分数0.7%,提取温度48℃,液料比10 mL/g,提取时间1.6 h,该条件下植酸得率为1.865%。植酸粗提液中回收出的蛋白和损失植酸分别占菜籽粕的3.63%和0.395%。超滤精制的分离蛋白可达到70%～90%不同纯度的要求,蛋白中多酚含量显著减少,且植酸与硫苷未检出。     

60Co γ辐照与NO复合处理对杂交石斛类原球茎生长和生物碱合成的影响

摘要：以杂交石斛类原球茎为材料,硝普钠（sodium nitroprusside, SNP）为NO的供体,研究了60Co γ辐照和ＳＮＰ复合处理对石斛悬浮培养类原球茎的生长和生物碱合成的影响。结果表明,60Co　γ和ＳＮＰ单独或复合处理都能促进类原球茎生物碱的合成,且复合处理对石斛类原球茎生物碱的合成有一定的累加效应, 但类原球茎生长减缓。适宜的复合处理组合为01mmol/L SNP+10Gy60Co γ辐照,此时类原球茎生物碱含量高达00676%,与各因素单独处理差异显著,单位培养基生物碱产量为对照组的635倍。NO抑制剂L NAME和cPTIO均能抑制各处理组合对类原球茎生物碱合成的促进作用。复合处理影响类原球茎抗氧化酶POD、SOD、CAT活性,从而调控石斛类原球茎生长和生物碱合成。     

Quantitative analysis of phytate globoids isolated from wheat bran and characterization of their sequential dephosphorylation by wheat phytase

Wheat phytase was purified to investigate the action of the enzyme toward its pure substrate (phytic acid - myo-inositol hexakisphosphate) and its naturally occurring substrate (phytate globoids). Phytate globoids were purified to homogeneity from wheat bran, and their nutritionally relevant parameters were quantified by ICP-MS. The main components of the globoids were phytic acid (40% w/w), protein (46% w/w), and several minerals, in particular, K > Mg > Ca > Fe (in concentration order). Investigation of enzyme kinetics revealed that K(m) and V(max) decreased by 29 and 37%, respectively, when pure phytic acid was replaced with phytate globoids as substrate. Time course degradation of phytic acid or phytate globoids using purified wheat phytase was followed by HPIC identification of inositol phosphates appearing and disappearing as products. In both cases, enzymatic degradation initiated at both the 3- and 6-positions of phytic acid and end products were inositol and phosphate.