A PCR diagnostic assay for rapid detection of plant pathogenic pseudomonads

Molecular detection of phytopathogens is increasingly being applied to identify regulated organisms at the border in many parts of the world. However, even with molecular tests, complete phenotyping and identification of a strain is often time consuming and sometimes inconclusive. In this study, a leaf-based pathogenicity test was used to separate pseudomonads into two groups, Group A containing pathogens, and Group B containing saprotrophs. Comparative genomics of 56 pseudomonad genomes from different plant hosts (including 29 strains from kiwifruit) agreed with kiwifruit pathogenicity test results, placing pathogens into Group A and saprotrophs into Group B. Sixteen loci were found unique to Group A. A PCR assay was developed for amplification of one of these loci, the trehalose phosphatase gene. The generation of this 655 bp amplicon was associated with production of water-soaked lesions on inoculated kiwifruit leaves by pseudomonads in Group A. This test was validated for further strains from all seven pathogenic Pseudomonas phylogroups, non-pathogenic pseudomonads, and other bacterial genera. The sensitivity of the PCR was comparable to the limit of recovery of pseudomonads by culturing. This simple PCR assay could be used as part of a testing pipeline at the border and for general surveillance for screening plants with and without symptoms, offering the potential to detect uncharacterized pseudomonads that may pose a biosecurity risk. The method was shown to be able to rapidly identify pathogens cultured from plant material with symptoms, or, more importantly, to detect pathogens directly from plant tissue.     

产肠毒素大肠杆菌感染的分子致病机制

产肠毒素大肠杆菌（enterotoxigenic Escherichia coli,ETEC）是发展中国家人群腹泻的主要原因,一直是西方国家旅行者腹泻的最常见病因,也是引起动物（尤其是幼龄动物）腹泻的主要病原菌。根据ETEC产生热敏和（或）热稳定肠毒素特性可以将其分类成不同致病型。针对这类重要病原体的疫苗研发目前仍然面临着艰难的挑战。本文综述了病原体-宿主相互作用的分子机制,从基因组学和蛋白质组学两方面介绍致病菌的多种毒力因子以及作为靶标研发疫苗的潜力,分析了病原与不同宿主易感性的差异,为针对ETEC新型疫苗的研发和有效预防ETEC感染提供理论依据。     

耐辐射球菌DNA修复机制研究新进展

耐辐射球菌是迄今为止发现的最耐辐射的原核生物,是研究DNA损伤与修复的模式生物.根据国内外实验室和本实验在耐辐射球菌研究上取得的最新研究成果,本文从该细菌的结构特征、分子防御机制、重要修复基因、基因组学和蛋白质组学等方面综述了耐辐射球菌在DNA修复机制方面取得的进展,探讨了未来揭示该细菌独特高效的DNA修复分子机理可能采取的途径.     

严重急性呼吸道综合征(SARS)病毒基因组比较分析与进化研究

“严重急性呼吸道综合征”(SARS)由于危害严重，引起人们的高度重视，在各国科研人员努力下，目前已完成了十几个毒株的分离与全基因组测序工作。本研究对世界各地分离的SARS毒株的基因组全序列进行比较，发现不同毒株的同源性在99．8％以上，SARS病毒的遗传稳定性较高；将SARS病毒与其它冠状病毒基因组以及编码蛋白质序列进行比较分析，证实SARS病毒是一种新的冠状病毒，可能进化起源较早，并发现SARS病毒和牛冠状病毒同源程度最高。SARS病毒orflab、orfla、S、M、N编码区氨基酸序列和牛冠状病毒同源程度最高，鼠肝炎病毒次之。     

Functional genomic approach to the study of biodiversitywithin Trichoderma

Trichoderma is a fungal genus of great and demonstrable biotechnological value, but its genome is poorly surveyed compared with other model microorganisms. Due to their ubiquity and rapid substrate colonization, Trichoderma species have been widely used as biocontrol organisms for agriculture, and their enzyme systems are widely used in industry. Therefore, there is a clear interest to explore beyond the phenotype to exploit the underlying genetic systems using functional genomics tools. Th…     

TILLING技术的原理、特点及其在点突变筛选中的应用

TILLING(TargetingInducedLocalLesionsINGenomes),是一种全新的反向遗传学研究方法,它提供了一种高通量、低成本规模化高效筛选化学诱变剂EMS诱发产生点突变的技术。本文简要介绍了TILLING的原理和技术优势,并对其在植物功能基因组学、突变分子育种和预测突变频率中的应用作了初步探讨。     

Research on ways to improve crop productivity through the regulation of rhizosphere environments

ABSTRACT

In this mini review, the importance of rhizosphere is focused. As the rhizosphere is underneath the soil, the analytical approach is still required from the viewpoints of understanding the interaction among root, soil and its interface. For this purpose, multi omics approach has been carried out with the effort to visualize the active rhizosphere area.     

单细胞微生物基因组学研究

本文介绍了单细胞微生物基因组测序 ,全基因组序列的注释 ,以及基因组进一步研究的主要内容     

Faba bean breeding for resistance against biotic stresses: Towards application of marker technology

Summary Faba beans are adversely affected by numerous fungal diseases leading to a steady reduction in the cultivated area in many countries. Major diseases such as Ascochyta blight (Ascochyta fabae), rust (Uromyces viciae-fabae), chocolate spot (Botrytis fabae), downy mildew (Peornospora viciae) and foot rots (Fusarium spp.) are considered to be the major constraints to the crop. Importantly, broomrape (Orobanche crenata), a very aggressive parasitic angiosperm, is the most damaging and widespread enemy along the Mediterranean basin and Northern Africa. Recent mapping studies have allowed the identification of genes and QTLs controlling resistance to some of these diseases. In case of broomrape, 3 QTLs explained more than 70% of the phenotypic variance of the trait. Concerning Ascochyta, two QTLs located in chromosomes 2 and 3 explained 45% of variation. A second population sharing the susceptible parental line also revealed two QTLs, one of them likely sharing chromosomal location and jointly contributing with a similar percentage of the total phenotypic variance. Finally, several RAPD markers linked to a gene determining hypersensitive resistance to race 1 of the rust fungus U. viciae-fabae have also been reported. The aim of this paper is to review the state of the art of gene technology for genetic improvement of faba bean against several important biotic stresses. Special emphasis is given on the application of marker technology, and Quantitative Trait Loci (QTL) analysis for Marker-Assisted Selection (MAS) in the species. Finally, the potential use of genomic tools to facilitate breeding in the species is discussed. The combined approach should expedite the future development of lines and cultivars with multiple disease resistance, one of the top priorities in faba bean research programs.