抗植物细菌病害基因工程的研究进展

综述了利用基因工程技术提高植物抵抗细菌病害能力的研究进展。植物抗细菌病害基因工程的方法包括：阻断病原细菌的致病途径,强化植物抗病反应及其信号转导途径,导入植物防御基因,导入非植物源抗菌蛋白的编码基因,利用细胞调亡反应控制病害的发生。随着基因组学和功能基因组学的发展,和对植物与病原细菌之间相互作用更深入的了解,植物抗细菌病害基因工程所面临的问题会逐步得到解决,因此利用植物基因工程技术培育抗病品种将具有广阔的应用前景。     

植物抗细菌病害基因工程的研究进展及应用前景

植物抗细菌病害基因工程的主要方法包括 :抑制细菌致病和毒性因子 ,激活植物本身抗病机制 ,导入植物防御基因 ,导入非植物抗菌蛋白的编码基因 ,利用细胞调亡反应控制病害的发生。本文综述了这方面的研究进展及应用前景。     

植物基因工程进展

一、转基因植物和转化方法二、抗病毒的转基因植物(一)利用基因工程达到抗病毒的几种策略(二)利用病毒外壳蛋白的基因(三)病毒非结构蛋白基因介导的抗性三、抗虫转基因植物(一)预计可能的商品化时间表(二)关于修饰B。tCryIA,CryIA基因密码(三)多途径应用Bt杀虫蛋白基因(四)抗同翅目害虫转基因植物的突破。四。抗真菌性病害的转基因植物(一)抑制核糖体蛋白(二)几丁酶和葡聚糖酶五。抗细菌的转基因植物(一)利用病原细菌天然解毒能力(二)利用天然抗菌肽和溶菌酶六、结束语--简介植物基因工程在培育雄性不育株系,改良植物品质及植物生物反应器方面的应用,以及回顾和展望。     

抗冻蛋白及其在植物抗冻基因工程的应用

从应用的角度系统综述了抗冻蛋白（ＡＦＰs)的特性、活性、用途、生化特征、在细菌中的表达,在植物抗冻生理中的作用及其基因工程,简洁地讨论了抗冻蛋白的研究现状和最新进展。     

抗病毒植物基因工程的研究进展

病毒病害一直是农业生产的一大问题,分子生物学的发展,特别是基因工程的发展为防治病毒病带来了希望。就目前的情况看,有效的抗基因主要来源于病毒本身,如外壳蛋白基因、卫星RNA基因、正义RNA序列,反义RNA序列等。除此之外,一些其它的策略也被采用,如核酶(Ribozyme)策略等。人们也正在试图从植物本身分离抗病毒基因和探索新的抗病毒策略,这一切都有助于推动抗病毒植物基因工程的发展。本     

植物抗真菌和细菌病害基因工程的策略及其进展

本文从（1）在植物与病原物相互识别水平上调控而激活其保卫反应机制;（2）导入植物保卫反应相关基因;（）导人降解或抑制病原菌致病因子基因等方面讨论了植物抗真菌和细菌病害基因工程的策略,介绍了目前的主要进展,并对有关策略作了简要的评价。     

植物抗细菌病害基因工程研究进展和展望

综述了利用基因工程提高植物对细菌病害抗性的各种方法,包括利用非植物抗菌蛋白,抑制细菌的致病或毒性因子,增强植物本身的抗病能力和人工诱导侵染点细胞程序化坏死。这些方法的成功都与抗菌化合物的作用机制及植物和病原细菌之间的相互作用的分子生物学的研究密切相关,还展望了这些方法的应用前景。     

植物抗病基因工程的研究进展

植物病原真菌、细菌、病毒常年危害农作物,给农业生产带来巨大损失,而防治病害的最有效措施是抗病育种。生物技术的发展给抗病育种开辟了新途径。本文简述了国内外抗病毒病害,抗细菌病害,抗真菌病害基因工程的研究现状及其发展趋势。同时指出在发展生物技术的同时,须基因工程与基础研究并重,要基因工程技术与常规农业技术有机结合以及加强基因工程与环境生态平衡的研究。     

植物内生细菌在植物修复重金属污染土壤中的应用

土壤重金属污染是威胁人群健康和经济可持续发展的重要环境问题。植物修复具有经济、环保等特点,已成为治理重金属污染土壤的重要技术。如何提高植物对重金属的抗性、促进植物生长是影响植物修复效率的关键之一。内生菌群-植物共生关系在此方面具有独特优势。其中,植物内生细菌可改善植物营养、降低植物病菌感染、影响酶活性,以及分泌激素、含铁载体和有机配位体等,进而提高超积累植物对重金属的吸收作用。本文综述了近年来国内外关于抗重金属植物内生细菌筛选与应用的研究进展,分析了内生细菌促进植物生长、增强植物对重金属抗性、促进重金属向茎叶转移的机理,阐述了植物内生细菌在重金属污染土壤修复中的应用前景与研究重点。     

抗病原菌植物基因工程进展

植物病原菌给农林生产带来巨大的损失,植物基因工程在培育抗病原菌植物方面是传统育种技术的补充和发展,短短几年,在抗细菌和抗真菌植物基因工程方面出现了一些全新的成功策略,这些范例都是针对病原菌的生理结构、致病机理及与植物的相互关系。本文概括论述了这些策略的基本思路并对其局限性加以探讨。随着植物病理学、植物分子生物学和病原菌分子生物学的研究进展,新的抗性策略将会出现。     

Influence of plant developmental stage on microbial community structure and activity in the rhizosphere of three field crops

Seasonal shifts in rhizosphere microbial populations were investigated to follow the influence of plant developmental stage. A field study of indigenous microbial rhizosphere communities was undertaken on pea (Pisum satvium var. quincy), wheat (Triticum aestivum var. pena wawa) and sugar beet (Beta vulgaris var. amythyst). Rhizosphere community diversity and substrate utilization patterns were followed throughout a growing season, by culturing, rRNA gene density gradient gel electrophoresis and BIOLOG. Culturable bacterial and fungal rhizosphere community densities were stable in pea and wheat rhizospheres, with dynamic shifts observed in the sugar beet rhizosphere. Successional shifts in bacterial and fungal diversity as plants mature demonstrated that different plants select and define their own functional rhizosphere communities. Assessment of metabolic activity and resource utilization by bacterial community-level physiological profiling demonstrated greater similarities between different plant species rhizosphere communities at the same than at different developmental stages. Marked temporal shifts in diversity and relative activity were observed in rhizosphere bacterial communities with developmental stage for all plant species studied. Shifts in the diversity of fungal and bacterial communities were more pronounced in maturing pea and sugar beet plants. This detailed study demonstrates that plant species select for specialized microbial communities that change in response to plant growth and plant inputs.     

Intra- and Interspecific Variation in Plant Response to Inoculation with Deleterious Rhizosphere Pseudomonads

Accessions of wheat, spinach, lettuce and different Brassica species were tested in greenhouse experiments for reaction to inoculation with two isolates of growth-inhibitory rhizosphere bacteria. Seedlings grown in non-sterile soil were inoculated with bacterial suspension and shoot dry weight was measured after five weeks. Large differences were found between the plant species tested in their average sensitivity to each bacterial isolate, and in the majority of plant species, significant differences were also found between accessions in the response to one or both isolates. These findings suggest that, in addition to the variation between plant species, intraspecific variation in the reaction to deleterious bacteria is a common feature in plants. This supports the hypothesis that plant reaction to rhizosphere bacteria is under genetic control. The results further indicate specificity in the interactions between plants and bacterial isolates, both at the plant species level and at the accession level.     

植物群落和土壤理化性质对碧塔海湿地土壤细菌群落的影响

土壤微生物是湿地生态系统中土壤-植物系统生源要素迁移转化的引擎.探究湿地生态系统地上植物群落、土壤理化性质和空间结构与土壤细菌间的相互关系是维护湿地生态系统健康和稳定的关键.本研究运用双向指示种分析法(TWINSPAN)对碧塔海湿地采集的35个样方中的植物群落进行分类,并采用高通量测序技术对样方的表层土壤细菌进行测序,...     

Settlement of the diazotrophic,phytoeffective bacterial strain Pantoea agglomerans on and within winter wheat: An investigation using ELISA and transmission electron microscopy

The aim of this study was to investigate the ability of Pantoea agglomerans, a plant growth-promoting bacterium, to colonize various regions and tissues of the wheat plant (Triticum aestivum L.) by using different inoculation methods and inoculum concentrations. In addition, the enzyme-linked immunosorbent assay (ELISA) and transmission electron microscopy (TEM) were used to determine: (a) the ability of the bacterial cells to grow and survive both on the surface and within internal tissue of the plant and (b) the response of the plant to bacterial infection. After inoculation, cells of the diazotrophic bacterial strain P. agglomerans were found to be located in roots, stems and leaves. Colony development of bacterial cells was only detected within intercellular spaces of the root and on the root surface. However, single bacterial cells were observed in leaves and stems on the surface of the epidermis, in the vicinity to stomatal cells, within intercellular spaces of the mesophyll and within xylem vessels. Inoculated bacterial cells were found to be able to enter host tissues, to multiply in the plant and to maintain a delicate relationship between endophyte and host. The density of bacterial settlement in the plant in all experiments was about 10⁶ to 10⁷ cells per mL root or shoot sap. Establishment was confirmed by a low coefficient of variation of ELISA means at these concentrations.     

Bacterial secondary production on vascular plant detritus: relationships to detritus composition and degradation rate.

Bacterial production at the expense of vascular plant detritus was measured for three emergent plant species (Juncus effusus, Panicum hemitomon, and Typha latifolia) degrading in the littoral zone of a thermally impacted lake. Bacterial secondary production, measured as tritiated thymidine incorporation into DNA, ranged from 0.01 to 0.81 microgram of bacterial C mg of detritus-1 day-1. The three plant species differed with respect to the amount of bacterial productivity they supported per milligram of detritus, in accordance with the predicted biodegradability of the plant material based on initial nitrogen content, lignin content, and C/N ratio. Bacterial production also varied throughout the 22 weeks of in situ decomposition and was positively related to the nitrogen content and lignin content of the remaining detritus, as well as to the temperature of the lake water. Over time, production was negatively related to the C/N ratio and cellulose content of the degrading plant material. Bacterial production on degrading plant material was also calculated on the basis of plant surface area and ranged from 0.17 to 1.98 micrograms of bacterial C cm-2 day-1. Surface area-based calculations did not correlate well with either initial plant composition or changing composition of the remaining detritus during decomposition. The rate of bacterial detritus degradation, calculated from measured production of surface-attached bacteria, was much lower than the actual rate of weight loss of plant material. This discrepancy may be attributable to the importance of nonbacterial organisms in the degradation and loss of plant material from litterbags or to the microbially mediated solubilization of particulate material prior to bacterial utilization, or both.     

Crystal Structure of the First Plant Urease from Jack Bean: 83 Years of Journey from Its First Crystal to Molecular Structure

Urease, a nickel-dependent metalloenzyme, is synthesized by plants, some bacteria, and fungi. It catalyzes the hydrolysis of urea into ammonia and carbon dioxide. Although the amino acid sequences of plant and bacterial ureases are closely related, some biological activities differ significantly. Plant ureases but not bacterial ureases possess insecticidal properties independent of its ureolytic activity. To date, the structural information is available only for bacterial ureases although the jack bean urease (Canavalia ensiformis; JBU), the best-studied plant urease, was the first enzyme to be crystallized in 1926. To better understand the biological properties of plant ureases including the mechanism of insecticidal activity, we initiated the structural studies on some of them. Here, we report the crystal structure of JBU, the first plant urease structure, at 2.05 Å resolution. The active-site architecture of JBU is similar to that of bacterial ureases containing a bi-nickel center. JBU has a bound phosphate and covalently modified residue (Cys592) by β-mercaptoethanol at its active site, and the concomitant binding of multiple inhibitors (phosphate and β-mercaptoethanol) is not observed so far in bacterial ureases. By correlating the structural information of JBU with the available biophysical and biochemical data on insecticidal properties of plant ureases, we hypothesize that the amphipathic β-hairpin located in the entomotoxic peptide region of plant ureases might form a membrane insertion β-barrel as found in β-pore-forming toxins.