玉米百粒重全基因组关联分析

以100份玉米自交系为材料,通过对2019-2020年山西榆次和太谷两地百粒重数据的测定,计算最佳线性无偏差预测值,结合均匀分布于玉米基因组的44 935个SNP标记,基于GLM模型和FarmCPU模型对百粒重进行全基因组关联分析(Genome-wide association study,GWAS)。关联分析结果表明,共鉴定到25个与百粒重显著关联的SNP(P<2.324e^-5),其中,关联位点1＿274302441、1＿298518163和9＿32699254位于已定位粒重QTL(Quantitative trait loci)的bin内。在显著SNP位点的连锁不平衡范围内共挖掘出28个候选基因,其中,GRMZM2G116640(乙酰氨基葡萄糖转移酶)、GRMZM2G048733(ABA受体蛋白)、GRMZM2G106424(14-3-3类蛋白)和GRMZM2G024104(谷氨酰胺合成酶)等是重要的百粒重候选基因。     

玉米大斑病抗性基因SNP基因芯片分析

利用SNP基因芯片(56 110个SNP)对3对玉米大斑病Ht3近等基因系进行检测分析。借助生物信息学和比较基因组学方法,确定了29个相关数量抗性候选基因,均分布于2、3、7、9号染色体;14个候选基因与各类酶活性、能源合成、金属离子、DNA合成修饰、抗逆等功能相关。其中,GRMZM2G058197位于7号染色体bin7.04区域166087520-166091392,与玉米大斑病质量抗性基因Ht3基因位置相吻合。     

碱胁迫下玉米microRNA827及其靶基因的表达响应

较高的pH影响植物根系对磷和氮的吸收,是盐碱土壤导致产量降低的主要原因之一。研究表明,植物在盐碱胁迫下microRNAs(miRNAs)通过调控靶基因的表达,提高植物对盐碱耐受性。通过实时定量RT-PCR分析表明,zma-miR827主要在冠根和花丝等组织中表达。碱胁迫处理玉米幼苗后,zma-miR827随着处理时间呈现先增加后降低趋势。通过玉米基因组数据库分析,预测zma-miR827-3p有4个靶基因,其中,GRMZM2G166976受碱胁迫后呈现先升高后持续下降的表达趋势;GRMZM2G077531则呈现先下降后升高;GRMZM2G127374呈现先下降后上升再下降后上升最后下降至最低值的趋势;GRMZM2G013176呈现持续升高的趋势。通过构建进化树分析表明,zma-miR827与水稻(Oryza sativa)中参与磷调控的osa-miR827高度同源。     

普通小麦（浙农林12×CASL7AS）DH系株高的分析

小麦株高与植株倒伏密切相关,影响小麦产量。为挖掘小麦株高QTL位点和候选基因,从遗传和分子水平上解释株高分子机理,本研究将野生二粒小麦染色体臂置换系CASL7AS为母本,课题组自选株系浙农林12（简称ZNL12）为父本,杂交F₁经过花培得到178个DH群体。通过4年2个种植点株高数据,利用55K SNP芯片构建高密度遗传图谱,对小麦株高性状进行QTL分析。该遗传连锁图谱包含3 655个SNP标记,长度为4 738.45 cM,标记间平均遗传距离为1.30 cM,覆盖了小麦21条染色体。其中,A、B、D染色体组分别含有标记1 466、1 492和697个。QTL分析共检测出53个QTL位点,分布于1A、3A、5A、7A、1B、3B、4B、5B、7B、2D、4D、6D和7D染色体上,可解释2.80%~38.50%表型变异。其中,稳定主效 QTL有2个,分别为QPh.zafu.4B-1和QPh.zafu.4D-1,其贡献率分别为25.18%~38.50%和20.67%。经细胞生物学分析,基因型为（0,2）矮秆植株胚芽鞘的表皮细胞长度显著短于基因型为（2,0）的高秆植株,基因型为（0,0）、（2,2）中间型的植株胚芽鞘表皮细胞长度无显著差异,由此推测小麦株高的变异由细胞长度因素决定。QPh.zafu.4B-1候选基因Rht-B1b基因编码区矮秆株系,第904核苷酸处发生碱基“C-T”的突变,形成终止密码子(CAG-TAG);而QPh.zafu.4D-1候选基因Rht-D1b基因编码区矮秆株系,第781核苷酸处碱基突变“G-T”,编码氨基酸中缬氨酸变为天冬氨酸。结果为小麦株高候选基因的筛选和QTL定位提供了优异的遗传位点和候选基因,未来可用于小麦抗倒伏相关的分子标记辅助育种。     

玉米子粒氮浓度全基因组关联分析

利用 253 份玉米自交系为关联群体，利用一般线性模型(GLM)、混合线性模型(MLM)、固定和随机模型交替概率统一(FarmCPU)和基因组相关预测集成工具(GAPIT)，分别对其子粒氮浓度进行全基因组关联分析。结果表明，共鉴定 25个与子粒氮浓度显著关联的 SNP(P<1.72E-05)。其中，GLM、FarmCPU和GAPIT方法分别检测到12、15和1个位点。S3_202120604、S1_2007087 47和S5_10258682在GLM和FarmCPU两种方法中均能检测到。Bin1.06、Bin3.07、Bin5.04、Bin1.07和Bin5.02可能是影响子粒氮浓度的重要区段。共挖掘30个相关候选基因，其中 Zm00001d031747、Zm00001d031749、Zm00001d031753、Zm00001d043502和Zm00001d01339等可能是影响玉米子粒氮浓度的关键候选基因。     

全基因组关联分析定位水稻分蘖角度QTL

【目的】水稻分蘖角度是影响水稻产量的关键农艺性状,挖掘水稻分蘖角度QTL（基因）及其优势单倍型,有助于构建水稻理想株型。【方法】以333份来自水稻3K资源的核心种质为研究材料,于2020年和2022年分别在湖南农业大学耘园基地和春华基地种植,在抽穗期测量分蘖角度,结合基因型,利用TASSEL 5.2的MLM模型进行全基因组关联分析。【结果】共检测到6个分蘖角度QTL位点,分布在水稻2、5、6、9和12号染色体上,分别命名为qTA2、qTA5、qTA6.1、qTA6.2、qTA9和q TA12,这些QTL的表型贡献率为6.23%～16.22%。除了qTA9与分蘖角度主效QTLTAC1共定位外,其余5个QTL均为新的位点。进一步对5个QTL位点进行候选基因分析,初步筛选到qTA2和qTA6.1的候选基因别为Os02g0817900和Os06g0682800,候选基因Os02g0817900编码水稻细胞色素P450家族蛋白,候选基因Os06g0682800编码锌指结构域蛋白。【结论】本研究挖掘到新的水稻分蘖角度相关位点并对候选基因进行了分析,为分蘖角度新QTL（基因）的克隆以及分蘖角度的遗传...     

玉米抗虫分子标记研究进展

玉米螟是危害玉米的主要害虫之一,总结玉米对咀嚼式口器害虫的抗虫机制。玉米的抗虫性与丁布含量、蛋白质种类及含量、蛋白酶抑制剂、植物组织或器官硬化程度等多种因素相关。综述玉米对4种主要害虫抗虫数量性状位点QTL的研究进展,将这些QTL与目前已知的抗虫相关基因和经过全基因组关联分析(GWAS)获得的候选基因进行对比,并对重叠基因进行分析介绍。     

利用三倍体胚乳遗传模型定位爆裂玉米子粒蛋白含量QTL

在两种环境条件下种植以普通玉米自交系丹232和爆裂玉米自交系N04为亲本构建的259个F23∶家系群体,采用SSR标记构建了包含183个标记的爆裂玉米遗传连锁图谱,覆盖玉米基因组1762.2cM,标记间平均距离为9.6cM。利用三倍体胚乳遗传模型和区间作图方法对子粒蛋白含量进行了QTL定位和效应分析。在春、夏播条件下均检测到6个QTL,分别位于第1、3、4、6、7和第8染色体上,其中春、夏播条件下都检测到的QTL有3个,可解释的表型总变异分别为42.85%和53.19%,单个QTL可解释的表型变异为4.50%～17.70%。表现为加性、部分显性、显性和超显性的QTL数目分别为2、2、2和6。3个QTL的增效基因均来自丹232,其余QTL的增效基因均来自N04。     

应用候选基因定位水稻抗稻瘟病QTL

 应用经克隆了的已知功能或有潜在功能的DNA序列,即候选基因，作为分子标记，在中156/谷梅2号F8重组自交系群体中进行水稻抗稻瘟病QTL的分析。大部分候选基因在水稻染色体上成簇分布，并且位于已知抗病基因簇区域。应用复合区间法检测到1个调控病斑大小和1个调控病斑数量的QTL，前者位于第1染色体CG36a~RM212区间，贡献率为4.17%，抗性等位基因来自父本谷梅2号；后者定位于第2染色体CG18a~RM263区间，贡献率为6.25%，抗性等位基因来自母本中156。同时检测到2对控制病叶面积和1对控制病斑大小的基因互作。这些QTL和互作基因涉及抗性基因同源序列、离子通道调控子以及编码致病相关蛋白和几丁质酶的基因，表明候选基因的应用有助于揭示QTL的功能。玉米锈病抗性基因Rp1与稻瘟病抗性有关，提示了利用水稻这个模式作物来克隆较大基因组中有利基因的可能性。     

玉米种子耐储性的全基因组关联分析及候选基因预测

以197份玉米自交系为试材,人工加速老化后进行标准发芽试验,检测种子耐储性相关表型性状,结合平均分布于玉米基因组的SNP标记进行关联分析,挖掘关联SNP位点和候选基因。结果表明,共检测出8个与相对发芽势（RGE）、相对发芽指数（RGI）、相对活力指数（RVI）和相对简易活力指数（RSVI）等性状呈显著关联的SNP位点（P<0.000 1）,分布于染色体bin1.08、bin3.08、bin4.03、bin4.05和bin6.05区域;PZE-104063000、PZE-104064763和PZE-106085414这3个SNP位点均与2个性状关联。预测到7个候选基因,分别与纤维素合成酶活性、翻译起始因子、丝氨酸/苏氨酸蛋白激酶活性、磷酸二酯酶活性、类囊体膜组分、脂肪酸生物合成酰基转运活性和微管有关组分等相关。     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.     

Recent Modifications of Chitosan for Adsorption Applications: A Critical and Systematic Review

Chitosan is considered to be one of the most promising and applicable materials in adsorption applications. The existence of amino and hydroxyl groups in its molecules contributes to many possible adsorption interactions between chitosan and pollutants (dyes, metals, ions, phenols, pharmaceuticals/drugs, pesticides, herbicides, etc.). These functional groups can help in establishing positions for modification. Based on the learning from previously published works in literature, researchers have achieved a modification of chitosan with a number of different functional groups. This work summarizes the published works of the last three years (2012–2014) regarding the modification reactions of chitosans (grafting, cross-linking, etc.) and their application to adsorption of different environmental pollutants (in liquid-phase).     

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation,Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O₂^•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O₂^•− scavenging, (IC₅₀ = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC₂₅ = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC₅₀ = 863 µg/mL; elastase, IC₅₀ = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O₂^•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.