食品基碳量子点的制备、生物活性及其在食品包装中的应用研究进展

碳量子点是一种尺寸小于10nm的新型碳纳米材料,因其优异的光学特性受到国内外学者的广泛关注。目前用于合成碳量子点的食品主要来自果蔬及其制品、乳及乳制品、肉及肉制品和水产品及其制品等。一步水热合成法是制备食品基碳量子点最常用的方法。因此,食品基碳量子点相比于化学材料合成的碳量子点具有易于合成、价格低廉、绿色无毒、生物相容性好等优势。并且食品基碳量子点表面通常带有丰富的官能团与杂元素,赋予了碳量子点更优异的抗癌、抗氧化和抗菌等功能活性。目前在生物医学、功能性材料、食品检测等领域广泛应用。近年来,由于食品基碳量子点优异的抗氧化、抗菌和光学活性已被添加到食品包装系统中,增强食品包装紫外屏蔽、抗氧化和抗菌等性能。本文综述了以食品为原料的碳量子点制备方法和原料来源,探讨了食品基碳量子点的优势及其生物活性,以及添加食品基碳量子点的活性包装在果蔬等食品保鲜中的应用,为食品碳量子点的绿色制备及其在活性包装中的应用提供参考和理论依据。

5株生防真菌对孢囊线虫的杀线活性测定

为了丰富防治线虫的真菌资源,测定了实验室分离保存的5株生防真菌粉红粘帚霉JGZ、淡紫紫孢菌Y2和BL2、哈茨木霉菌L4和球孢白僵菌BJ对甜菜孢囊线虫、大豆孢囊线虫和禾谷孢囊线虫的杀线虫活性。结果表明,淡紫紫孢菌Y2和哈茨木霉菌L4的孢囊寄生率为100%,随着作用时间增长,孢囊壁消解破裂。5株真菌发酵液随着稀释倍数的增加,线虫的校正死亡率降低。哈茨木霉菌L4的5倍发酵稀释液对甜菜孢囊线虫、大豆孢囊线虫和禾谷孢囊线虫的校正死亡率分别为96.75%、95.95%和96.35%;淡紫紫孢菌Y2的5倍发酵稀释液对甜菜孢囊线虫、大豆孢囊线虫和禾谷孢囊线虫的校正死亡率分别为97.37%、95.74%和97.77%,两者差异不显著。盆栽试验结果表明,哈茨木霉菌L4和淡紫紫孢菌Y2发酵液作用大豆孢囊线虫30 d,孢囊减退率分别为43.67%和41.87%,根长和茎粗显著高于其他处理,哈茨木霉菌L4处理地上鲜重和地下鲜重显著高于其他处理。结合孢囊寄生率、发酵液杀线活性、孢囊减退率和促生作用综合评价,哈茨木霉菌L4生防效果最好。

基于厌氧环境的低盐雪菜挥发性风味物质分析

为研究厌氧环境对低盐雪菜挥发性风味物质的影响,运用顶空固相微萃取-气-质联用(SPME-GC-MS)分别对低盐、高盐和CO_2、N_2低盐厌氧环境处理的雪菜中挥发性物质进行了分析。结果表明,4组不同的腌制雪菜中共分析出46、40、46和44种挥发性化合物,相对含量分别为91.12%、79.29%、84.17%和88.09%,主要包括酯类、醛醇类、酸类、烷烃及其杂环类物质,一起共同构成了雪菜的整体风味。异硫氰酸酯类化合物为低盐、高盐和低盐CO_2厌氧处理3组雪菜中最主要的挥发性物质,分别占雪菜中酯类物质的72.75%、81.50%和43.29%。低盐量N_2处理组中并未检出异硫氰酸酯类化合物,且醛醇类化合物比其他3组的含量高。雪菜挥发性化合物种类主成分分析(PCA)表明,雪菜挥发性物质中,酯类、醇类、酸类和醛类化合物与不同盐量与保存方式相关。

70份国外小麦品种(系)的苗期和成株期抗叶锈病鉴定

小麦叶锈病是小麦生产中的重要病害之一,培育持久抗病品种是最经济、有效和环保的方法。本研究用19个不同毒力的叶锈菌小种苗期接种70份国外引进小麦品种(系)及36个已知抗叶锈病基因的载体品种进行抗性鉴定,同时在2016—2017年度分别于河北保定和河南周口对70份国外引进品种进行田间抗叶锈性鉴定。为进一步检测材料中所携带的苗期和成株抗叶锈病基因,利用12个与已知基因紧密连锁的分子标记进行检测,综合基因推导、系谱分析和分子标记检测的结果,在33份材料中鉴定出15个抗叶锈病基因,包括Lr1、Lr2a、Lr26、Lr3ka、Lr11、Lr17、Lr30、Lr10、Lr14a、Lr2b、Lr13、Lr15、Lr21、Lr44和Lr45,田间鉴定筛选出39份品种表现慢锈性。苗期和田间表现表明,国外品种中含有丰富的对我国叶锈菌小种有效的苗期和成株期抗叶锈病基因,可作为小麦抗叶锈病抗源在抗病育种中加以利用。

40份国内小麦品种抗叶锈性鉴定

为分析40份国内小麦材料所含有的抗叶锈病基因,本研究采用16个叶锈菌生理小种对其进行基因推导,推测待测材料抗叶锈病基因组成,并利用11个与己知抗病基因紧密连锁的特异性分子标记进行验证。进一步选取5个高毒力小种制成混合菌种,在保定试验田进行成株期接菌,筛选可能含有成株慢锈基因的小麦品种。综合系谱分析、基因推导、分子标记检测结果,在待测小麦品种中检测出6个已知抗叶锈病基因(Lr1、Lr11、Lr20、Lr26、Lr30、Lr37)。其中运黑14207等10个品种含有Lr1,禾美988和百农207含有Lr11,豫麦49和百农207含有Lr20,万丰269等23个品种含有Lr26,运黑14207和郑麦103含有Lr30,漯6073等4个品种含有Lr37,并且有的品种含有未知抗叶锈病基因。田间成株期抗性鉴定筛选出漯6073等7个品种具有慢锈性。本研究明确了部分品种的基因构成,发掘了优良抗源材料,可用于抗病育种及基因聚合。

基于转录组测序开发的一个小麦叶锈菌特异分子标记

小麦叶锈菌毒性变异频繁,新的毒性小种不断出现,往往导致小麦抗叶锈病品种在推广种植几年后的抗性丧失。因此,开发用于田间小麦叶锈病的诊断与预测预报的特异性分子标记具有重要意义。在前期已经完成小麦叶锈菌PHNT转录组测序的基础上,本研究拟在数据库中挑选候选效应蛋白,利用实时荧光定量PCR明确其在叶锈菌侵染小麦后不同时间点的表达模式,根据差异表达分析筛选出候选效应蛋白,再根据编码候选效应蛋白的基因序列设计引物,对小麦叶锈菌PHNT基因组DNA进行PCR扩增,旨在开发小麦叶锈菌特异性分子标记。结果在转录组数据库中筛选出24个候选效应蛋白,qPCR检测明确其中17个具有明显的表达差异。PCR扩增结果表明,基于候选效应蛋白基因PTTG-05290设计的引物在小麦叶锈菌PHNT中获得一条920 bp的条带,且在检测的25种叶锈菌生理小种中均稳定存在,而在小麦条锈菌、菜豆锈菌、枣树锈菌、柳树锈菌、苹果树锈菌及芦苇锈菌6种锈菌中不能获得有效扩增,表明该引物在小麦叶锈菌中具有特异性。qPCR结果表明,PTTG-05290在叶锈菌侵染小麦4 d时达到表达高峰,表达量为0 d的218倍,而0.5 d时便大量检测到该基因。因此,PTTG-05290可作为分子标记用于小麦叶锈菌的田间早期检测及预测预报,对小麦抗叶锈病品种在田间的合理布局具有重要意义。

玫瑰黄链霉菌活性代谢产物诱导烟草灰霉病抗性机制研究

【目的】解析温室条件下玫瑰黄链霉菌Men-myco-93-63活性代谢产物Roflamycoin和Men-myco-A(简称R&M)诱导烟草灰霉病抗性的作用机制,为利用R&M绿色防控烟草灰霉病提供理论依据。【方法】通过80 mg/L R&M注射4~5叶期本生烟草叶片后过敏反应(HR)染色验证及100 mg/L R&M注射4~5叶期本生烟草叶片后抗病标志基因hsr203J的表达验证R&M的诱抗作用;采用相关试剂盒检测烟草处理(分别为80 mg/L R&M喷雾处理和清水处理)后非药剂接触烟叶内过氧化氢酶(CAT)和脂氧合酶(LOX)的活性变化,以及防御相关物质过氧化氢(H_(2)O_(2))的含量变化。采用实时荧光定量PCR(qRT-PCR)检测烟草处理(处理1,用80 mg/L R&M溶液灌根处理4~5叶期本生烟草2 d后,于上部第3片叶采用灰霉菌孢子悬浮液摩擦接种;处理2,清水灌根处理4~5叶期本生烟草2 d后,于上部第3片叶采用清水摩擦接种)后烟草叶片木质素合成基因PAL及病程相关蛋白(PR)基因PR1、PR5相对表达量的变化。【结果】80 mg/L R&M诱导处理后,烟叶中CAT活性2 d后逐步提高;LOX活性第3 d后显著提高(P<0.05,下同),第7 d达最高值;H_(2)O_(2)含量在第1 d迅速增加后降低;PAL基因相对表达量在24 h后显著上调,为清水对照的25.37倍;病程相关蛋白基因PR1、PR5相对表达量分别在24和72 h达最高值,分别为清水对照的11.23和11.17倍。【结论】R&M通过提高烟叶中相关防御酶活性、协调活性氧水平及增强抗病相关基因的表达等提高烟草植株的抗病性。玫瑰黄链霉菌Men-myco 93-63产生的活性代谢产物R&M具有作为植物病害诱抗剂的潜力,有望应用于植物灰霉病等重要病害的绿色防控。

Seedling and adult plant resistance to leaf rust in 46 Chinese bread wheat landraces and 39 wheat lines with known Lr genes

Wheat leaf rust,caused by Puccinia triticina(Pt),is an important foliar disease that has an important influence on wheat yield.The most economic,safe and effective way to control the disease is growing resistant cultivars.In the present study,a total of 46 wheat landraces and 34 wheat lines with known Lr(leaf rust resistance)genes were inoculated with 16Pt pathotypes for postulating seedling resistance gene(s)in the greenhouse.These cultivars and five wheat differential lines with adult plant resistance(APR)genes(Lr12,Lr22b,Lr34,Lr35 and Lr37)were also evaluated for identification of slow rusting resistance in the field trials in Baoding,Hebei Province of China in the 2014–2015 and 2015–2016 cropping seasons.Furthermore,10 functional molecular markers closely linked to 10 known Lr genes were used to detect all the wheat genotypes.Results showed that most of the landraces were susceptible to most of the Pt pathotypes at seedling stage.Nonetheless,Lr1 was detected only in Hongtangliangmai.The field experimental test of the two environments showed that 38 landraces showed slow rusting resistance.Seven cultivars possessed Lr34 but none of the landraces contained Lr37 and Lr46.Lr genes namely,Lr9,Lr19,Lr24,Lr28,Lr29,Lr47,Lr51 and Lr53 were effective at the whole plant stage.Lr18,Lr36 and Lr45 had lost resistance to part of pathotypes at the seedling stage but showed high resistance at the adult plant stage.Lr34 as a slowing rusting gene showed good resistance in the field.Four race-specific APR genes Lr12,Lr13,Lr35 and Lr37 conferred good resistance in the field experiments.Seven race-specific genes,Lr2b,Lr2c,Lr11,Lr16,Lr26,Lr33 and LrB had lost resistance.The 38 landraces showed slow rusting resistance to wheat leaf rust can be used as resistance resources for wheat resistance breeding in China.

外源诱导及共培养对植物乳杆菌J23合成细菌素Lac-B23的影响研究

目的 研究外源诱导物及共培养对植物乳杆菌J23合成细菌素Lac-B23的影响,提高细菌素产量。方法 利用双层琼脂牛津杯扩散法测定细菌素活性,通过单因素实验、自诱导和共培养验证实验探究外源诱导物及共培养对细菌素J23产量的影响。结果 当初始pH为7、37℃培养12 h,细菌素Lac-B23的产量达到最大值,为2560 AU/mL。甘油和丙酮酸基本不影响细菌素Lac-B23的合成;但酪氨酸、苯丙氨酸、精氨酸、谷氨酰胺和亮氨酸则能促进细菌素Lac-B23的产量。此外,自我诱导研究发现植物乳杆菌J23发酵培养基中含有可以诱导细菌素Lac-B23合成的信号分子。一定浓度范围内,植物乳杆菌J23与单增生李斯特菌或金黄色葡萄球菌共培养时可以提高细菌素Lac-B23的产量。然而,诱导菌的灭活菌体和无细胞上清液并不能提高细菌Lac-B23的产量。结论 环境诱导因素对细菌素的合成有较大影响。初始pH、发酵温度、培养时间、酪氨酸、苯丙氨酸、精氨酸、谷氨酰胺和亮氨酸可以作为诱导因子,提高细菌素Lac-B23的产量。此外,共培养诱导分子没有分泌到培养基中,可能需要活的诱导细菌来诱导细菌素Lac-B22的合成。

Systemic acquired resistance, NPR1, and pathogenesis-related genes in wheat and barley

In Arabidopsis, systemic acquired resistance （SAR） is established beyond the initial infection by a pathogen or is directly induced by treatment with salicylic acid （SA） or its functional analogs, 2,6-dichloroisonicotinic acid （INA） and benzothiadiazole （BTH）. NPR1 protein is considered the master regulator of SAR in both SA signal sensing and transduction. In wheat （Triticum aesfivum） and barley （Hordeum vulgare）, both pathogen infection and BTH treatment can induce broad-spectrum resistance to various diseases, including powdery mildew, leaf rust, Fusarium head blight, etc. However, three different types of SAR-like responses including acquired resistance （AR）, systemic immunity （SI）, and BTH-induced resistance （BIR） seem to be achieved by activating different gene pathways. Recent research on wheat and barley NPR1 homologs in AR and SI has provided the initial clue for understanding the mechanism of SAR in these two plant species. In this review, the specific features ofAR, Si, and BIR in wheat and barley were summarized and compared with that of SAR in model plants of Arabidopsis and rice. Research updates on downstream genes of SAR, including pathogenesis-related （PR） and BTH-induced genes, were highlighted.

Mapping of QTL conferring leaf rust resistance in Chinese wheat lines W014204 and Fuyu 3 at adult plant stage

Wheat leaf rust is a destructive foliar disease of common wheat （Triticum aestivum L.） worldwide. The most effective, economical s to control the disease is growing resistant cultivars with adult plant resistance （APR）. The Chinese wheat tines W014204 and Fuyu 3 showed high leaf rust resistance in the field. To identify leaf rust APR genes in the two lines, two mapping populations with 215 and 163 F2：3 lines from the crosses W014204/Zhengzhou 5389 and Fuyu 3/Zhengzhou 5389, respectively, were phenotyped for leaf rust severities during the 2010-2011, 2011-2012 and 2012-2013 cropping seasons in the field at Baoding, Hebei Province, China. A total of 1 215 SSR markers were used to identify the quantitative trait loci （QTLs） for leaf rust APR in the two populations. In the W014204/Zhengzhou 5389 population, three QTLs were detected and designated as QLr.hbu-lBL.1, QLr.hbu-2BS.1 and QLr.hbu-7DS, and explained 2.9-8.4, 11.5-38.3 and 8.5-44.5% of the phenotypic variance, respectively; all the resistance alleles at these loci were derived from W014204. In the Fuyu 3/Zhengzhou 5389 population, three QTLs, QLr.hbu-lBL.2, QLr.hbu-2BS.2 and QLr.hbu-7BL, explained 12.0-19.2, 22.3-38.9 and 4.1-4.3% of the phenotypic variance, respectively, and all resistance alleles were contributed by Fuyu 3. Based on chromosome positions of closely linked markers, both QLr.hbu-lBL. 1 and QLr.hbu-lBL.2 are Lr46, and QLr.hbu-7DS is Lr34. QLr.hbu-7BL was mapped on chromosome 7BL near to Lr68 and they are likely the same gene. Based on chromosome positions, pedigree and field reactions, the two 2BS QTLs are different from all the known APR genes and are likely to be newAPR QTL for leaf rust. These QTLs and their closely linked markers are potentially useful for improving leaf rust resistance in wheat breeding.

Identification of leaf rust resistance genes in common wheat varieties from China and foreign countries

Wheat leaf rust,triggered by Puccinia triticina Eriks(Pt),is among the most important diseases of wheat worldwide.Deploying resistant varieties against leaf rust is the most effective,environmentally-friendly and economic way to control the disease.In the present study,66 wheat varieties form China and foreign countries were tested with 17 Pt races for gene postulation during the seedling stage in the greenhouse.All the varieties were also planted to identify slow rusting responses to leaf rust at the adult plant stage in Baoding and Zhoukou field trials during the 2016/2017 to 2017/2018 cropping seasons.Moreover,12 closely linked molecular markers to known leaf rust resistance(Lr)genes were used for assessing all the varieties.The results of both gene postulation and molecular marker identification showed that a total of eight Lr genes,Lr1,Lr10,Lr17,Lr20,Lr26,Lr34,Lr37 and Lr46,either singly or in combination were detected in 32 varieties.Known Lr genes were not identified in the remaining 34 varieties.Seventeen varieties were found to have slow rusting resistance.The resistance sources identified in this study can be used as resources for resistance against leaf rust in wheat breeding programs in China and the respective foreign countries.

Molecular mapping of leaf rust resistance genes in the wheat line Yu 356-9

The Chinese wheat line Yu 356-9 exhibits a high level of resistance to leaf rust. In order to decipher the genetic base of resistance in Yu 356-9, gene postulation, inheritance analyses, and chromosome linkage mapping were carried out. Gene postulation completed using 15 leaf rust pathotypes and 36 isogenic lines indicated that Yu 356-9 was resistant to all pathotypes tested. F1 and F2 plants from the cross Yu 356-9 （resistant）/Zhengzhou 5389 （susceptible） were tested with leaf rust pathotype ＂FHNQ＂ in the greenhouse. Results indicated a 3：1 segregation ratio, indicative of the presence of a single dominant leaf rust resistance gene in Yu 356-9 which was temporarily designated as LrYu. Bulk segregant analysis and molecular marker assays were used to map LrYu. Five simple sequence repeat （SSR） markers on chromosome 2BS were found closely linked to LrYu. Among these markers, Xwmc770 is the most closely linked, with a genetic distance of 5.7 cM.

Postulation of Leaf Rust Resistance Genes in Seven Chinese Spring Wheat Cultivars

To detect the leaf rust resistance genes in the 7 Chinese spring wheat clultivars Shenmian 99025, Shenmia 99042, Shenmian 85, Shenmian 91, Shenmian 96, Shenmian 1167 and Shenmian 962, Thatcher, Thatcher backgrounded near-isogenic lines and 15 pathotypes of P. triticina were used for gene postulate at the seedling stage, and 9 of the 15 pathotypes were used in the field tests. Molecular markers closely linked to, or co-segregated with resistance genes Lrl, Lr9, LrlO, Lrl9, Lr20, Lr21, Lr24, Lr26, Lr28, Lr29, Lr32, Lr34, Lr35, Lr37, Lr38, and Lr47 were screened to assist detection of the resistance genes. As results, 4 known resistance genes, including Lrl, Lr9, Lr26, and Lr34, and other unknown resistance genes were postulated singly or in combination in the tested cultivars. Shenmian 85, Shenmian 91, Shenmian 96, Shenmian 962, Shenmian 1167, and Shenmian 99042 are potentially useful for wheat production and breeding programs. The result suggested that combining gene postulation, molecular markers and pedigrees is effective and more accuracy method to know the resistance genes in cultivars.

Molecular Markers for Leaf Rust Resistance Gene Lr45 in Wheat Based on AFLP Analysis

Amplified fragment length polymorphism （AFLP） analysis was carried out in Thatcher, near isogenic lines （NILs） canting different genes conferring resistance against wheat leaf rust, and TcLr45 × Thatcher F2 progenies were used to develop markers for Lr45 gene. Sixty AFLP primer combinations were screened and most of them provided clear amplification products, 31 primer combinations displayed polymorphism of TcLr45 in 23 NILs. Two AFLP markers closely linked to the gene Lr45 were acquired： P-AGG/M-GAG261bp, which was found closely linked to the Lr45 locus at a distance of 0.6 cM on one side, and P-ACA/M-GGT105bp, which was found at a distance of 1.3 cM on the other side. The specific hands were cloned and subsequently sequenced. The 261-bp fragment produced by P-AGG/M-GAG showed 86% similarity with the sequence of Vulgate Hort I gene; the 105-bp fragment produced by P-ACA/M-GGT showed 96% similarity with the phosphatidylserine decarboxylase gene of the Triticum monococcum. Both included an open reading frame （ORF）.