烟草叶片光合和呼吸作用对烟草野火病菌侵染的响应

发布时间：2018-05-30 19:17

本文选题：光照 + 烟草　；参考：《东北林业大学》2016年博士论文

【摘要】：烟草野火病是由烟草野火病菌(Pseudomonas syringae pv. tabaci, Pst)引起的流行性细菌病害,对烟叶产量和品质均有显著负影响。近年来,野火病菌侵染及植物防御机制成为相关研究的热点问题。植物的光合作用和呼吸作用是植物物质和能量的来源,在植物抗病响应过程中具有重要作用,因此是许多病原微生物的主要攻击目标。然而野火病菌对烟草叶片光合和呼吸作用的影响及其机理尚不清楚。本研究在光照(200μmol m-2s-1)或黑暗条件下,人工注射野火病菌悬液(106)对烟草叶片接种,通过叶绿素荧光快速诱导动力学曲线分析、膜蛋白Western blot分析等方法,探讨野火病菌侵染后对烟草叶片光系统Ⅱ (Photosystem Ⅱ, PSII)和光系统I(Photosystem Ⅰ, PSI)产生的影响,阐明光照条件下野火病菌对烟草叶片光合机构产生较轻伤害的机理。同时为了排除叶绿体和菌本身呼吸的影响,采用没有功能性叶绿体的烟草BY-2悬浮细胞系和含有野火粗毒素的野火病菌代谢产物(Pst ext)来探讨野火病菌对烟草呼吸途径的影响。研究野火病菌对烟草光系统和呼吸电子传递链的影响不仅有助于阐明烟草-野火病菌相互作用的机制,还可以从生理角度加深人们对野火病害的理解,为烟草抗性育种和基因改良提供理论依据。实验结果显示：(1)野火病菌侵染3d后,叶片内叶绿素含量显著下降,叶片注射区域出现萎黄病变,呈现野火病特征,在黑暗条件下病变更严重；(2)野火病菌侵染3d后,K点和J点的相对可变荧光Wk和VJ逐渐增大,叶片最大光化学效率(Fv/Fm)和单位面积有活性反应中心的数目(RC/CSm)均显著下降,放氧复合体(Oxygen evolving complex, OEC)的核心组分PsaO、PSII反应中心核心蛋白D1以及PSI核心组分PsaA均发生明显的降解,PSI活性显著下降,在黑暗条件下变化幅度更大；(3)野火病菌侵染3d后,烟草叶片内病原菌数量显著增加,黑暗下叶片内野火病菌的数目是光照下的17倍,烟草叶片H2O2含量明显升高,光照条件下升高比例更大;(4)在黑暗条件下,侵染之前用H2O2预处理,3d后烟草叶片萎黄病变减轻,叶片内病原菌数目降低；在光照条件下,侵染之前用甲基紫精(Methyl viologen, MV)预处理,3d后烟草叶片萎黄病变减轻,叶片内病原菌数目降低；侵染之前用敌草隆(3-(3,4-dichloropheny1)-1,1-dimethylurea, DCMU)预处理,3d后烟草叶片萎黄病变加重,同时叶片内病原菌数目增加；(5)野火病菌代谢物处理后,烟草BY-2细胞内出现非光合电子传递链介导的活性氧(Reactive oxygen species, ROS)积累、细胞总呼吸降低、交替氧化酶呼吸途径(Alternative respiration pathtway, AOX)在总呼吸中所占比例增加,胞内ATP含量降低。综上所述,本研究结果表明野火病菌侵染后,在光照和黑暗条件下光合电子传递链QA到QB电子传递受到限制,OEC受到伤害,烟草叶片PSII供体侧、受体侧、反应中心的数目和活性均受到伤害,烟草叶片PSI和PSII发生光抑制或光抑制类似的伤害,且在黑暗条件下对光系统的伤害更为严重；烟草叶片的萎黄病变症状以及叶片内部野火病菌的数目均与H202积累负相关,光可以通过H202的积累来抑制野火病菌侵染后烟草叶片内病原菌的数目,这可能是光照条件下野火病菌导致烟草光系统出现较轻伤害的原因之一。
[Abstract]:Tobacco wildfire is a popular bacterial disease caused by Pseudomonas syringae pv. tabaci (Pst) and has a significant negative effect on the yield and quality of tobacco leaves. In recent years, the infection of wildfire pathogen and plant defense mechanism have become a hot issue in the related research. Plant photosynthesis and respiration are plant material and energy. The source, which plays an important role in the process of plant disease resistance and response, is the main target for many pathogenic microorganisms. However, the effect and mechanism of wildfire pathogen on Photosynthesis and respiration of tobacco leaves are not clear. In this study, under the light (200 mu m-2s-1) or dark strips, the artificial injection of wildfire pathogen suspension (106) to tobacco The effects of wild fire pathogen on the production of light system II (Photosystem II, PSII) and I (Photosystem I, PSI) of tobacco leaves after the infection of wildfire pathogens were investigated by the method of chlorophyll fluorescence rapid induction kinetic curve analysis and membrane protein Western blot analysis. The photosynthetic mechanism of tobacco leaves under light conditions was elucidated. At the same time, in order to eliminate the effects of the chloroplast and the respiration of the bacteria itself, the effect of wildfire pathogen on the respiration pathway of tobacco was explored by using the BY-2 suspension cell line without functional chloroplasts and the metabolite of wildfire pathogen containing wildfire crude toxin (Pst ext). The effect of the transfer chain not only helps to elucidate the mechanism of the interaction between tobacco and wildfire pathogens, but also can deepen people's understanding of Wildfire Disease from the physiological point of view, and provide theoretical basis for tobacco resistance breeding and gene improvement. The experimental results show: (1) after the infection of 3D, the content of chlorophyll in leaves is significantly decreased and the injection area of leaves is injected. The region appeared yellow disease and showed the characteristics of wildfire, and the disease changed seriously under the dark condition. (2) after the infection of 3D, the relative variable fluorescence Wk and VJ of K point and J point increased gradually, and the maximum photochemical efficiency (Fv/Fm) and the number of active reaction centers (RC/CSm) in the unit area decreased significantly, and the oxygen complex (Oxygen evolving compl). The core components of ex, OEC, PsaO, the core protein D1 of the PSII reaction center and the PSI core component PsaA were degraded obviously, the activity of PSI decreased significantly, and the change amplitude was greater in the dark conditions. (3) the number of pathogens in tobacco leaves increased significantly, and the number of wildfire pathogens in the dark leaves was 17 times that of light under the darkness. The content of H2O2 in tobacco leaves increased significantly and increased significantly under light conditions. (4) under the dark conditions, H2O2 pretreatment was used before the infection. After 3D, the yellowish disease of tobacco leaves was reduced and the number of pathogenic bacteria in the leaves decreased. Under the light conditions, pre treatment was pretreated with methyl violet (Methyl viologen, MV), and the degeneration of tobacco leaves was reduced after 3D. The number of pathogenic bacteria in the leaves was reduced, and pretreated with diuron (3- (3,4-dichloropheny1) -1,1-dimethylurea, DCMU) before the infection, after 3D, the leaf yellow disease of tobacco leaves increased, and the number of pathogenic bacteria in the leaves increased. (5) after the metabolite of wildfire pathogen, the non photosynthetic electron transfer chain mediated reactive oxygen species (Reac) appeared in the BY-2 cells of the wild fire pathogen (Reac). Tive oxygen species, ROS) accumulated, total cell respiration decreased, and the proportion of alternate oxidase respiration pathway (Alternative respiration pathtway, AOX) increased in total respiration and decreased intracellular ATP content. In summary, the results of this study showed that after the infection of wildfire bacteria, the electron transfer chain of the photosynthetic electron transfer chain was carried out in light and dark conditions, and QA to QB electron transfer. Restricted, OEC was injured, the PSII donor side of tobacco leaves, the receptor side, the number and activity of the reaction center were injured, the tobacco leaves PSI and PSII had photoinhibition or photoinhibition similar damage, and the damage to the light system was more severe in the dark conditions; the yellow disease symptoms of tobacco leaves and the internal wildfire pathogens in leaf blades. The number of H202 accumulation was negatively correlated with the accumulation of H202, which could inhibit the number of pathogenic bacteria in tobacco leaves after the infection of wildfire pathogen, which may be one of the reasons for light damage caused by wildfire pathogen in light conditions.
【学位授予单位】：东北林业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S435.72

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