烟草TILLING技术体系的建立及NtPhyB基因的筛选

定向诱导基因组局部突变技术（Targeting Induced Local Lesions In Genomes,TILLING）是一种新近发展起来的高通量检测点突变的反向遗传学方法。本研究首次将TILLING技术用于EMS处理的烟草突变体筛选中,通过对正反向荧光引物使用量的摸索,确定了10 μL PCR体系中IRDye-700标记的正向引物（1 μM）适用量为0.32～0.64 μL,IRDye-800标记的反向引物（1 μM）适用量1.12～1.6 μL;对异源双链CEL Ⅰ酶切体系实验表明,10 μL PCR产物中加入0.6 μL CEL I酶,1.5 μL 10× Buffer酶切效果最好。从而建立并优化了适用于普通烟草基因组研究的TILLING技术体系。在此基础上,以NtPhyB为目标基因,在1000份0.6% EMS诱变的M2突变体中进行筛选,共得到13个突变体,该基因突变频率约为1/94 kb。本试验建立的TILLING筛选体系能够快速、高效地筛选任意已知序列基因的突变体,对烟草功能基因组研究具有重要意义。     

Fusarium oxysporum f. sp. niveum Molecular Diagnostics Past,Present and Future

Watermelon is an important commercial crop in the Southeastern United States and around the world. However, production is significantly limited by biotic factors including fusarium wilt caused by the hemibiotrophic fungus Fusarium oxysporum forma specialis niveum (Fon). Unfortunately, this disease has increased significantly in its presence over the last several decades as races have emerged which can overcome the available commercial resistance. Management strategies include rotation, improved crop resistance, and chemical control, but early and accurate diagnostics are required for appropriate management. Accurate diagnostics require molecular and genomic strategies due to the near identical genomic sequences of the various races. Bioassays exist for evaluating both the pathogenicity and virulence of an isolate but are limited by the time and resources required. Molecular strategies are still imperfect but greatly reduce the time to complete the diagnosis. This article presents the current state of the research surrounding races, both how races have been detected and diagnosed in the past and future prospects for improving the system of differentiation. Additionally, the available Fon genomes were analyzed using a strategy previously described in separate formae speciales avirulence gene association studies in Fusarium oxysporum races.     

ARTP诱变钝顶螺旋藻突变体比较组学研究

微藻作为地球上重要的生物资源,为水圈提供了大量的初级代谢产物,是合成生物学和生物制造研究和应用的重要底盘微生物。其中,钝顶螺旋藻(Spirulina platensis)具有多糖含量高、营养价值高、培养工艺成熟、应用范围广等特点,其诱变育种及比较组学研究可为微藻细胞工厂系统改造技术发展提供重要依据。本课题组前期通过常压室温等离子体(atmospheric and room temperature plasmas,ARTP)诱变方法获得了三株钝顶螺旋藻突变体。本研究在连续光照培养条件下,对三株突变体的重要生理特征进行了表征,发现突变株具有高絮凝表型,且重要化合物含量也与野生型具有一定的差异。进一步,本研究通过对其主要代谢产物的代谢组学分析和全基因组测序,对突变表型产生的机理进行了初步解析。     

Insights into the Host Specificity of a New Oomycete Root Pathogen,Pythium brassicum P1: Whole Genome Sequencing and Comparative Analysis Reveals Contracted Regulation of Metabolism,Protein Families,and Distinct Pathogenicity Repertoire

Pythium brassicum P1 Stanghellini, Mohammadi, Förster, and Adaskaveg is an oomycete root pathogen that has recently been characterized. It only attacks plant species belonging to Brassicaceae family, causing root necrosis, stunting, and yield loss. Since P. brassicum P1 is limited in its host range, this prompted us to sequence its whole genome and compare it to those of broad host range Pythium spp. such as P. aphanidermatum and P. ultimum var. ultimum. A genomic DNA library was constructed with a total of 374 million reads. The sequencing data were assembled using SOAPdenovo2, yielding a total genome size of 50.3 Mb contained in 5434 scaffolds, N50 of 30.2 Kb, 61.2% G+C content, and 13,232 putative protein-coding genes. Pythium brassicum P1 had 175 species-specific gene families, which is slightly below the normal average. Like P. ultimum, P. brassicum P1 genome did not encode any classical RxLR effectors or cutinases, suggesting a significant difference in virulence mechanisms compared to other oomycetes. Pythium brassicum P1 had a much smaller proportions of the YxSL sequence motif in both secreted and non-secreted proteins, relative to other Pythium species. Similarly, P. brassicum P1 had the fewest Crinkler (CRN) effectors of all the Pythium species. There were 633 proteins predicted to be secreted in the P. brassicum P1 genome, which is, again, slightly below average among Pythium genomes. Pythium brassicum P1 had only one cadherin gene with calcium ion-binding LDRE and DxND motifs, compared to Pythium ultimum having four copies. Pythium brassicum P1 had a reduced number of proteins falling under carbohydrate binding module and hydrolytic enzymes. Pythium brassicum P1 had a reduced complement of cellulase and pectinase genes in contrast to P. ultimum and was deficient in xylan degrading enzymes. The contraction in ABC transporter families in P. brassicum P1 is suggested to be the result of a lack of diversity in nutrient uptake and therefore host range.     

Genetic basis of improving the palatability of beef cattle: current insights

Beef palatability is a complex concept and could be described through an array of features such as tenderness, juiciness and flavor traits. Improving the eating experience when consuming beef and the ability to accurately inform the consumers of the expected eating quality when the product is purchased are critical challenges. In this review, we discuss the current knowledge of quantitative and molecular genetic aspects of palatability and discuss implications of genetic manipulation for the cattle industry.     

And what would you like for lunch Dr Frankenstein? The food supply chain: past history and future visions

A model of the key drivers influencing the food supply chain is tested by considering the historical and current examples of technologies and used to speculate on the probabilities of success of new technologies. The successful technologies are likely to be those that offer benefits to each element of the supply chain. © 2000 Society of Chemical Industry     

普通烟草Dof转录因子家族的全基因组鉴定及分析

Dof(DNA binding with one finger)蛋白是植物特有的一类转录因子,在植物的多种生命进程中发挥着重要作用。为解析烟草中Dof家族成员在生长发育过程中的潜在作用,本研究利用比较基因组学、进化分析、共线性分析等方法解析烟草中的Dof家族成员的潜在生物学功能。结果表明,在烟草基因组中共鉴定到69个Dof转录因子,其Dof功能域在进化上十分保守,根据系统进化分析结果将其划分为9个亚家族。共线性分析表明,烟草中的16个Dof基因与拟南芥17个Dof基因有27个共线性基因对,同时,25个Nt Dof基因被检测到存在17个全基因组复制对,表明复制事件在烟草Dof基因家族的扩张中起关键作用。此外,表达模式分析表明Nt Dof基因的表达存在明显的组织特异性,其中NtDof05和NtDof28基因可能与根系生长发育有关。本研究对烟草基因组中的Dof转录因子进行了系统的鉴定和分析,为烟草Dof转录因子家族成员的功能研究奠定了基础。