三种鲆鲽鱼养殖群体的遗传多样性及特异性AFLP标记研究

应用AFLP技术对条斑星鲽、星斑川鲽及漠斑牙鲆的养殖群体进行遗传分析。8对EcoRI／MseI 引物在条斑星鲽、星斑川鲽、漠斑牙鲆养殖群体中分别得到196、207、187条扩增带。其群体的多态位点比例分别为26.02％、25.12％、39.57％,Nei遗传多样性指数和Shannon遗传多样性指数分别为0.1101和0.1587,0.1008和0.1465,0.1566和0.2238。结果表明,条斑星鲽和星斑川鲽养殖群体的遗传变异水平相对较低,而漠斑牙鲆的遗传变异水平相对较高。同时还筛选获得了这3种鲆鲽鱼的共享标记19个,种的特有标记依次为44、45、34个。并根据两两间的遗传距离构建了UMPGA聚类关系图,从分子生物学角度衡量了其亲缘关系。     

栉孔扇贝不同地理群体的遗传多样性分析

应用AFLP技术对栉孔扇贝的中国长岛群体和韩国东部、西部群体进行了遗传多样性分析。实验表明，中国长岛群体的群体内遗传相似度最高，为0．6754，韩国东部群体次之，为0．6714，韩国西部群体最低，为0．6309；中国长岛群体与韩国东部、西部群体间的遗传距离分别为0．1703和0．1786，韩国两群体间的遗传距离只有0．057。这一结果说明，长岛群体与韩国群体遗传差异较大，韩国两个群体遗传相似度较高，应视为同一个群体。本研究共获得6个韩国两群体的共享特征标记，4个长岛群体的特异性标记，1个韩国西部群体所特有的标记，这些标记可以用于鉴定和区分这三个群体。为提高我国栉孔扇贝群体遗传多样性，以引进韩国西部群体为好。     

利用AFLP技术分析中国明对虾的韩国南海种群和养殖群体的遗传差异

利用AFLP技术对新发现的中国明对虾的一个地理种群——韩国南海种群（SP）和中国明对虾的养殖群体（CP）进行了遗传分析。每个群体随机取样30个,5对AFLP引物获得326个位点。其中SP多态位点比例（P0.99）46.93％,Shannon多样性指数（Ⅰ）0．1884,Nei（1978）基因多样性指数（h）0．1197,群体差异性位点9个,占检测位点总数的2．7％。CP多态位点比例（R9q）51．84％,Shannon多样性指数（Ⅰ）0．1954,Nei（1978）基因多样性指数（h）0．1229,群体差异性位点19个,占检测位点总数的5．8％。SP种群各项遗传参数都低干CP种群。两个群体的非偏差遗传相似度和遗传距离分别为0．9899和0．0102。利用中国明对虾的韩国南海种群和养殖群体杂交可以获得新的种质资源,这将为获得最大变异数量性状表型和基因多样性的产生提供可能。     

黑龙江省土壤中大豆疫霉菌（Phytophthora sojae）的多样性

为探究不同类型土壤中大豆疫霉菌（Phytophthora sojae）的多样性,以分离自5种不同类型土壤的176株P.sojae为研究对象,利用基因推导法和AFLP分子标记技术进行多样性分析。结果表明,不同类型土壤中P.sojae无毒基因型、无毒基因种类、无毒基因组合和群体致病力均表现出差异性,其中黑土、白浆土和草甸土中的P.sojae无毒基因型、无毒基因种类和无毒基因组合多样性相对丰富,群体致病力中等偏弱;盐碱土中的P.sojae无毒基因型、无毒基因种类和无毒基因组合多样性丰富度较低,群体致病力相对较强;风沙土中没有分离到P.sojae。聚类分析表明,以0.76为阈值时,可将176株P.sojae划分为6个组,其中黑土和白浆土中的P.sojae呈现丰富的遗传多样性;草甸土和盐碱土中的P.sojae遗传多样性丰富度较低。综合分析表明,黑龙江省P.sojae群体无毒基因和遗传多样性丰富,并与土壤类型存在一定的相关性。     

Advances in molecular diagnosis of toxigenic Fusarium species: A review

The development of advanced molecular diagnosis for the critical toxigenic Fusarium species is considered in this review. The specific topics discussed are (1) isolation of mating type genes of Gibberella complex, (2) molecular detection of Fusarium-producing fumonisins, (3) molecular detection of Fusarium-producing trichothecenes and enniatins. Particular attention is given to the development of PCR assays for genes involved in the toxin biosynthesis that would permit the early detection of Fusarium species-producing toxins and potentially even reveal which particular toxin may be present within a food or feed product. Most of these data have been obtained within the 'De-Tox Fungi' project supported by the European Commission (QLK1-CT-1998-01380).     

Molecular characterization and fumonisin production by Fusarium verticillioides isolated from corn grains of different geographic origins in Brazil

Gibberella moniliformis is most commonly associated with maize worldwide and produces high levels of fumonisins, some of the most agriculturally important mycotoxins. Studies demonstrate that molecular methods can be helpful for a rapid identification of Fusarium species and their levels of toxin production. The purpose of this research was to apply molecular methods (AFLP, TEF-1α partial gene sequencing and PCR based on MAT alleles) for the identification of Fusarium species isolated from Brazilian corn and to verify if real time RT-PCR technique based on FUM1 and FUM19 genes is appropriated to estimate fumonisins B₁ and B₂ production levels. Among the isolated strains, 96 were identified as Fusarium verticillioides, and four as other Fusarium species. Concordant phylogenies were obtained by AFLP and TEF-1α sequencing, permitting the classification of the different species into distinct clades. Concerning MAT alleles, 70% of the F. verticillioides isolates carried the MAT-1 and 30% MAT-2. A significant correlation was observed between the expression of the genes and toxin production r = 0.95 and r = 0.79 (correlation of FUM1 with FB₁ and FB₂, respectively, P < 0.0001); r = 0.93 and r = 0.78 (correlation of FUM19 with FB₁ and FB₂, respectively, P < 0.0001). Molecular methods used in this study were found to be useful for the rapid identification of Fusarium species. The high and significant correlation between FUM1 and FUM19 expression and fumonisins production suggests that real time RT-PCR is suitable for studies considering the influence of abiotic and biotic factors on expression of these genes. This is the first report concerning the expression of fumonisin biosynthetic genes in Fusarium strains isolated from Brazilian agricultural commodity.     

Comparison of two AFLP methods and PFGE using strains of Listeria monocytogenes isolated from environmental and food samples obtained from Piedmont, Italy

Listeria monocytogenes ranks among the most frequent causes of death due to foodborne illness (20-30% case fatality rate).Discriminative subtyping methods are important to detect the relatedness of isolates and verify epidemiologic associations. AFLP analysis is a DNA fingerprinting technique based on the selective amplification of genomic restriction fragments. In this study, two AFLP methods and PFGE were compared in regard to discriminatory power, typeability and concordance.A total of 103 unrelated L. monocytogenes strains isolated from different environmental and food sources were analyzed. Strains were isolated from samples obtained from food-production plants, supermarkets and small food markets in Piedmont, Italy.All methods clustered L. monocytogenes strains into two genetic lineages, Lineage I and II. The three methods were compared using the 82 isolates which were typeable with all techniques. The calculated pair-wise Pearson's correlation coefficients (r) showed close agreement between all three methods.Our findings suggest that the AFLP II method can be successfully used to subtype L. monocytogenes strains isolated from foods and food processing facilities.     

A rapid identification of barley varieties using DNA‐AFLP

Barley (Hordeum vulgare L.) is one of the most ancient crops in the world, and is mainly used in feed, as a grain and as industrial material for beer, medicine and health protection. Its purity can affect beer taste and quality, thus it is important to set up rapid and accurate identification methods for the malting industry. In this study, 27 domestic and imported malt barley varieties were studied. Three pair primers of EcoR I + 3/Mse I + 3 were selected from 64 different primer combinations for DNA–AFLP (amplified fragment length polymorphisms) and an AFLP fingerprinting map of the 27 domestic and imported malt barley varieties was constructed, with the primer combination of E‐AGG/M‐CAA amplification after polyacrylamide gel electrophoresis. With this fingerprinting map, it was possible to distinguish all of the 27 malt barley varieties with 10 specific loci. This could be useful for the identification of malt barley varieties in the beer industry. Copyright © 2015 The Institute of Brewing & Distilling     

制作云南乳扇用酸乳清中乳杆菌的多样性分析

针对制作云南乳扇用酸乳清中的乳杆菌的来源及种属,对其多态性进行研究。采用AFLP技术和NTSYS-pc2.1软件对从云南大理白族地区牧民家庭制作乳扇用的的酸乳清中分离出的70株乳杆菌进行多样性分析。结果表明,AFLP扩增出的条带清晰,重复性好,多态性高。聚类分析表明,在0.89的水平上,70株乳杆菌共分为4个大群:高加索乳杆菌群Ⅰ、发酵乳杆菌群Ⅱ,瑞士乳杆菌群Ⅲ和植物乳杆菌群IV。其中,瑞士乳杆菌群Ⅲ中的乳杆菌占供试乳杆菌的65.7%,为优势菌群。进一步对优势菌群聚类,进行种内分型,以0.90为界,群Ⅲ被分为8个基因型。     

Development of DNA markers for discrimination between domestic and imported beef

In the meat industry, correct breed information in food labeling is required to assure meat quality. Genetic markers provide corroborating evidence to identify breed. This paper describes the development of DNA markers to discriminate between Japanese and Australian beef. Two Bos indicus-specific markers and MC1R marker were used as possible candidate markers. Amplified fragment length polymorphism method was employed to develop additional candidate markers. The 1564 primer combinations provided three markers that were converted into single nucleotide polymorphisms markers for high-throughput genotyping. In these markers, the allele frequencies in cattle from both countries were investigated for discrimination ability using PCR-RFLP. The probability of identifying Australian beef was 0.933 and probability of misjudgment was 0.017 using six selected markers. These markers could be useful for discriminating between Japanese and Australian beef and would contribute to the prevention of falsified breed labeling of meat.