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题名: 群体感应在丁香假单胞菌烟草致病变种与烟草互作中的调控作用
作者: 程菲菲1
学位类别: 博士
答辩日期: 2017-05
授予单位: 中国科学院生态环境研究中心
授予地点: 北京
导师: 庄国强
关键词: 群体感应,N-酰基高丝氨酸内酯,转基因烟草,丁香假单胞菌烟草致病变种,病原菌与植物互作 ; Quorum Sensing, N-acylhomoserine lactone, transgenic tobacco plants, P.syringae pv. tabaci 11528, pathogen-plant interactions
其他题名: Quorum sensing regulation on the interactions betweenP. syringae pv. tabaci 11528 and tobacco plants
学位专业: 环境科学
中文摘要: 植物病害是当今农业面临的一个巨大挑战。目前,植物病害的防治大多是施用农药。然而,农药的过量使用不仅严重影响了经济和农业生态,还极大程度地威胁动物甚至人类的健康。因此,稳定且环境友好型的生物防治越来越受到关注。近年来,通过植物遗传转化技术,在模式植物烟草导入多种功能酶基因已成功提高了植物的抗病性。 群体感应(Quorum Sensing,QS)作为一种微生物细胞间交流方式,能调控细菌多种生理行为。目前,利用 QS信号分子干扰植物病原菌生理行为,提高植 物抗病害的能力成为生物防治领域的研究热点。虽然 QS信号分子 N-酰基高丝氨 酸内酯(AHL)转基因植物在植物抗病性上表现出了很好的效果,但 QS在植物 病原菌中的调控功能及在植物保护中的应用机制还没有完全被阐明。为了回答这 两个科学问题,本研究以植物病原菌丁香假单胞菌烟草致病变种(Pseudomonas syringae pv. tabaci 11528,Pta11528)与产 QS信号分子转基因烟草(Nicotiana tabacum L.)为模式研究对象,研究 QS在病原菌与植物互作中的调控作用,包 括以下两方面的工作: 1.丁香假单胞菌烟草致病变种(P. syringae pv. tabaci 11528)的 QS调控作用 AHL介导的 QS调控主要发生在对数期至稳定期的过渡期。QS系统是病原 菌 Pta11528基因表达的重要调节子,调控基因组中的 18.5%蛋白编码基因表达, 其中负调控病原菌 Pta11528的毒性及移动性。3OC6-HSL是病原菌 Pta11528的 主要 QS信号分子,在 QS调控中起到关键的作用。此外,在病原菌 Pta11528与宿主烟草相互作中,AHL介导的 QS调控早期的病原菌 Pta11528定殖和后期的烟草感染等不同阶段。 2.产 QS信号分子 AHL转基因烟草提高抗病性的分子机制产 QS信号分子 AHL转基因烟草提高了对病原菌 Pta11528的抗性。在病原菌 Pta11528与烟草互作的早期,转基因植物产 AHL不影响 Pta11528在烟草叶 片上的定殖方式和定殖位点,但抑制其生长。转基因烟草产生的群体感应信号分子 AHL与病原菌 Pta11528产的 AHL种类相同,转基因烟草产 AHL干扰病原菌 Pta11528的基因表达模式,提高其鞭毛合成相关基因的表达量。接种病原菌后烟草防卫基因才被诱导表达,且接种后转基因烟草产 AHL可激活广泛的植物防卫 反应。 通过以上研究,我们发现:AHL介导的 QS系统负调控病原菌 Pta11528与 植物互作的致病性;此外,转基因植物产 AHL不仅抑制病原菌在植物上的附生 生长,还干扰了病原菌的早期基因表达,提高了鞭毛的合成,从而提前诱导了植 物免疫力。这些研究结果进一步促进我们对 QS在病原菌与植物互相作用过程中 的调控认识,为 QS调控在植物病害的生物防治的应用提供了理论指导和分子基 础。
英文摘要: Plant diseases is one of the greatest challenges for contemporary agriculture. Current strategies for the control of plant diseases are largely based on synthetic pesticides. However, the excessive use of chemical pesticides has not only seriously affected agricultural ecology, but also greatly threatens animal and human health. Thus, there is growing focus on steady and environmentally friendly biological control. In recent years, enhanced disease resistance against phytopathogens has been successfully engineered in the model plant tobacco by the introduction of genes encoding various functional enzymes using plant genetic transformation. Quorum Sensing (QS), a cell-cell communication, regulates bacterial diverse physiological processes. Currently, to enhance plant disease resistance against pathogens, interference with physiological behaviors of plant pathogens by using QS signal molecule has become one of the research hotspots in the field of biological control. Although transgenic plants producing QS signal molecule N-acylhomoserine lactone (AHL) have showed good results in plant disease resistance, both the regulation function of QS system in phytopathogens and the application mechanism of QS system in plant protection are not elucidated. To answer these two questions above, in this study, we worked on two model research objects: Pseudomonas syringae pv. tabaci 11528 (Pta11528) and transgenic tobacco plants (Nicotiana tabacum L.) producing QS signal molecule, and carried out the QS regulation on pathogen-plant interactions, including the following two aspects of work. 1. Quorum sensing regulation in P. syringae pv. tabaci 11528. AHL-dependent QS regulation mainly occurred in the transition from exponential to stationary phase. QS system was a significant important regulator for gene expression, as it regulated ~18.5% of coding sequences in Pta11528 genome, including down- regulated virulence factors and motility. N-3-oxohexanoyl-homoserine lactone (3OC6- HSL), a major QS signal molecule, had a critical contribution to the QS-dependent regulation on gene expression in pathogen Pta11528. Moreover, AHL-mediated QS system played important roles in distinct stages of interactions between pathogen Pta11528 and tobacco plants, including early pathogen colonization and late plant infection. 2. Molecular mechanism for enhanced disease resistance in transgenic tobacco plants producing QS signal molecule AHL. Transgenic tobacco plants producing QS signal molecule AHL enhanced disease resistance against pathogen Pta11528. Transgenic tobacco plants-produced AHL didn’t affect distribution formation and colonization sites but limited the growth of Pta11528 during the early stage of Pta11528-tobacco plants interactions. The type of AHL produced in transgenic tobacco plants was common to AHL synthesized by Pta11528.The production of AHL in transgenic tobacco plants effected the gene expression pattern of pathogen Pta11528 on plants, resulting in enhanced expression of flagella during early tobacco plants infection. Plant defense responses were not activated in plants until the inoculation with pathogens and the production of AHL in transgenic tobacco plants enhanced a wide spectrum of plants defense responses following inoculation. Based on the above studies, we find that AHL-mediated QS system negatively regulates the pathogenicity of pathogen Pta11528 during plant-pathogen interactions. Moreover, AHL produced form transgenic tobacco plants not only limits pathogen growth on plants, but also disturbs its early gene expression and enhances its production of flagella, resulting in the premature induction of plant immunity. These findings will extend our understanding of QS regulation on pathogen-plant interactions, and provide theoretical guidance and molecular basis for QS regulation in biological control of plant diseases
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/38607
Appears in Collections:中科院环境生物技术重点实验室_学位论文

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作者单位: 1.中国科学院生态环境研究中心

Recommended Citation:
程菲菲. 群体感应在丁香假单胞菌烟草致病变种与烟草互作中的调控作用[D]. 北京. 中国科学院生态环境研究中心. 2017.
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