植物根际的微生物互作及其在植物病害生物防治中的应用

介绍了在植物根际的微生物互作及其在生物防治中的应用现状.重点讨论了细菌生防因子与植物细菌和真菌病原物间的互作,真菌生防因子与原生动物、植物细菌和真菌病原物间的互作,以及根际微生物对植物生长的促进作用及多个生防因子的协同作用等.此外本文还简述了不同互作下的行为模式,如共生、抗生、竞争及寄生等.     

菌根真菌与植物根际微生物互作关系研究

菌根真菌是自然生态系统中最重要的功能群之一,深入研究和揭示它与植物根际微生物间的互作关系,对进一步利用和调控根围微生物的相互作用,促进植物生长,维持农林生态系统的稳定具有重要意义。菌根真菌与某些根际有益微生物(如MHB、PGPR)具有协同促生关系。这些有益微生物可通过改变根际土壤微环境、提高根系对菌根真菌侵染的感受性等为菌根菌在根部的定殖创造有利条件;而菌根真菌则可通过改变根际土壤pH值、根际营养等方面影响根际微生物的群落结构。菌根真菌与土壤微生物通过相互促进或抑制,对宿主植物产生影响。目前,国内外关于菌根真菌与根际微生物互作中二者相互识别、协同作用的机理研究还处于探索阶段。快速发展的分子生物学技术为研究菌根围微生态区系提供了新的途径,将有助于科学有效地研究菌根围微生物之间的互作机制。     

试论植物与微生物的互作

植物与其生长环境中的微生物有着密切的关系,两者共同组成一个生态区系根围。对植物与其根围中的微生物的互作关系进行了阐述。     

植物根际分泌物与土壤微生物互作关系的机制研究进展

近年来对土壤微生物和植物之间互作关系的研究越来越受到关注,植物的根际分泌物直接或间接的影响了根际微生物群落结构,同样,根际微生物也以各种不同方式影响着植物根际的土壤理化性质、根际分泌物释放、土壤物质循环等。本文从根际有益微生物对植物生长发育的促进作用以及植物根际分泌物对土壤微生物多样性的影响这两方面对土壤根际微生物与植物之间相互影响的途径与机制进行了综述。     

根系分泌物的收集及其介导的种间互作

根系分泌物是植物根系向根际分泌的自身代谢产物,是植物与根际环境对话的调控者,调控植物与植物、植物与微生物、微生物与微生物的相互关系。近年来,国内外学者摸索出多种收集根系分泌物的方法,并借此初步揭示根系分泌物在土壤种间互作中发挥的重要作用。通过阐述根系分泌物的概念和收集方法,分析不同方法的利弊;着重阐述根系分泌物在植物-植物、植物-土壤微生物种间互作中的重要作用,以及种间互作在生态农业中的应用;并提出今后研究的主要问题和发展方向。     

木霉菌及其效应蛋白在与植物互作机制中的作用研究进展

木霉菌是一类资源丰富的生防真菌，同时木霉菌可与植物形成良好的互作关系，促进植物生长，诱导植物抗病性。加大对木霉与植物互作及生防机制的研究，有利于推广生物防治，减少化学农药的使用。本文通过介绍木霉菌的生物学特性、木霉菌与植物互作机制，进一步综述了木霉菌分泌的效应蛋白在与植物相互作用过程中的作用。     

根系分泌物与根际微生物互作的研究进展

根系分泌物是植物与环境进行物质、能量和信息交流的重要载体,与根际微生物具有紧密的互作关系。重点概述了根系分泌物对根际微生物种群、数量、分布和生长发育的影响以及根际微生物对根系分泌物的影响与机制。深入研究根系分泌物和根际微生物是根际生态系统的重要组成部分,微生物非培养新技术的创新与突破将有助于揭示根际微生态规律,挖掘和利用根际功能微生物。     

香蕉枯萎病生防微生物产品的功效限制因子

由尖孢镰刀菌古巴专化型引起的香蕉枯萎病,是目前香蕉产业发展中的限制因子,采用生物防治的方法是目前非常有潜力的防控手段。生防微生物的效果主要与土壤水分、作为活菌制剂的微生物种类和性质、生防微生物在土壤中短期定殖影响因素、生防微生物长期定殖影响因素有关。采用茎叶滴注的方法进行香蕉内生芽胞杆菌接种或辅以适当的载体,和保水微生物一起混合接种到香蕉根围,可以有效防控香蕉枯萎病。     

根际微生物组构建的影响因素研究进展

基于根际微生物调控作物生长发育已成为生态健康和农业发展研究的热点。综述了国内外关于植物根际微生物组构建影响因素的相关研究进展,探讨了根际周边微生物从土壤进入植物根系内部的定殖选择过程,重点关注植物本体、土壤类型、地理位置、生长环境等因素对植物根际微生物组的调控作用,揭示国内外研究中发现的影响根际微生物组构建的主控因素,阐明根际微生物组-宿主复杂的互作关系,以期为绿色农业、环境生态保护等研究提供新的思路。     

根际微生物群落与促生菌多样性及其筛选策略

根际是地球上最大的生态系统,在生物圈功能中发挥着非常显著的作用,微生物和植物在根际环境中形成的复杂网络式关系会直接或间接地影响植物生长,深入了解并利用这种互作关系对于提高农业产出投入比以及筛选获得更高效、广适的促生菌尤为必要.综述了根际微生物群落与促生菌多样性以及筛选策略,分析了研究中尚存在的一些问题,并对今后的研究进行了展望.     

药用植物根际微生物研究现状与展望

药用植物根际存在丰富的细菌、真菌及放线菌,药用植物根际微生物与药用植物的生长、繁殖及其代谢活动密不可分。近年来,对药用植物与根际微生物关系的研究越来越多。从研究对象、研究方法以及研究内容3方面对近年来药用植物根际微生物的研究进展进行了综述,并提出了今后药用植物根际微生物研究的重点,以期为今后药用植物的开发和利用提供参考。     

芽孢杆菌拮抗镰孢菌机制的研究进展

镰孢菌（Fusarium）分泌多种真菌毒素引起的枯萎病、赤霉病、根腐病和穗腐病等植物病害,造成重大的作物生产损失。化学防治是防治镰孢菌的重要手段,但其带来的镰孢菌抗性和生态环境污染等问题,严重制约了农业可持续发展。在病害管理中使用生物防治剂为控制镰孢菌引起的植物病害提供了一种安全、有效和可持续的手段,因此生物防治具有比化学防治更深远的优势。在生物防治剂中使用最广泛的生防微生物是芽孢杆菌属（Bacillus）的成员,其可通过多种机制为植物提供有效控制镰孢菌入侵的方案。芽孢杆菌作为一种优良的生物防治剂已被广泛研究,其可通过生态位竞争、产生抗菌物质、诱导植物系统抗性和塑造根际健康微生物组来拮抗镰孢菌侵染,本文从以上4个方面对芽孢杆菌拮抗镰孢菌的机制进行综述,为农业生产中芽孢杆菌防治镰孢菌病害的研究提供参考。     

适钙植物报春苣苔根际土壤微生物群落结构

为解析喀斯特适钙植物报春苣苔根际微生物群落结构的特点，采用高通量测序16S rRNA V4和ITS1区序列，比较分析了适钙植物报春苣苔根际/非根际土壤微生物群落结构差异，并利用CCA及斯皮尔曼相关系数分析了土壤可溶性钙含量和报春苣苔根际/非根际土壤微生物群落之间的关系。结果表明：报春苣苔根际土壤微生物群落包含41个细菌门及6个真菌门。细菌中优势菌门为变形菌门（Proteobacteria）、放线菌门（Actinobacteria）及酸杆菌门（Acidobacteria），占64%以上；真菌主要为子囊菌门（Ascomycota）、担子菌门（Basidiomycota）和接合菌门（Zygomycota），占99%以上。相比非根际土壤，在根际土壤中酸杆菌门菌群丰度显著上升，而变形菌门和芽单胞菌门丰度显著下降，生长受到抑制。报春苣苔的根际和非根际土壤微生物群落非常丰富，包含569个属的细菌及276个属的真菌。报春苣苔根际细菌的Shannon、Chao1和ACE等α-多样性指数显著高于非根际，表明报春苣苔根际细菌菌群种类数量高于非根际土壤；而报春苣苔根际真菌的PD_whole_tree指数显著低于非根际，表明报春苣苔根际真菌群落的群体进化低于非根际。土壤可溶性钙对于微生物群落结构的解释量仅为16.93%，且蒙特卡罗置换检验表明土壤可溶钙和物种分布显著不相关性；只有Hydrogenedentes门细菌与土壤可溶性钙显著正相关。报春苣苔根际/非根际土壤微生物群落之间差异显著，且两者与土壤可溶性钙的相关性有限；报春苣苔根际土壤微生物的物种组成丰富，且报春苣苔根系有利于根际土壤细菌群落多样性。     

适钙植物报春苣苔根际土壤微生物群落结构

为解析喀斯特适钙植物报春苣苔根际微生物群落结构的特点,采用高通量测序16S rRNA V4和ITS1区序列,比较分析了适钙植物报春苣苔根际/非根际土壤微生物群落结构差异,并利用CCA及斯皮尔曼相关系数分析了土壤可溶性钙含量和报春苣苔根际/非根际土壤微生物群落之间的关系。结果表明：报春苣苔根际土壤微生物群落包含41个细菌门及6个真菌门。细菌中优势菌门为变形菌门（Proteobacteria）、放线菌门（Actinobacteria）及酸杆菌门（Acidobacteria）,占64%以上;真菌主要为子囊菌门（Ascomycota）、担子菌门（Basidiomycota）和接合菌门（Zygomycota）,占99%以上。相比非根际土壤,在根际土壤中酸杆菌门菌群丰度显著上升,而变形菌门和芽单胞菌门丰度显著下降,生长受到抑制。报春苣苔的根际和非根际土壤微生物群落非常丰富,包含569个属的细菌及276个属的真菌。报春苣苔根际细菌的Shannon、Chao1和ACE等α-多样性指数显著高于非根际,表明报春苣苔根际细菌菌群种类数量高于非根际土壤;而报春苣苔根际真菌的PD_whole_tree指数显著低于非根际,表明报春苣苔根际真菌群落的群体进化低于非根际。土壤可溶性钙对于微生物群落结构的解释量仅为16.93%,且蒙特卡罗置换检验表明土壤可溶钙和物种分布显著不相关性;只有Hydrogenedentes门细菌与土壤可溶性钙显著正相关。报春苣苔根际/非根际土壤微生物群落之间差异显著,且两者与土壤可溶性钙的相关性有限;报春苣苔根际土壤微生物的物种组成丰富,且报春苣苔根系有利于根际土壤细菌群落多样性。     

Changes in bulk soil affect the disease-suppressive rhizosphere microbiome against Fusarium wilt disease

Harnessing disease-suppressive microbiomes constitutes a promising strategy for optimizing plant growth. However, relatively little information is available about the relationship between bulk and rhizosphere soil microbiomes. Here, the assembly of banana bulk soil and rhizosphere microbiomes was investigated in a monoculture system consisting of bio-organic (BIO) and organic management practices. Applying BIO practice in newly reclaimed fields resulted in a high-efficiency biocontrol rate, thus providing a promising strategy for pre-control of Fusarium wilt disease. The soil microbiota was further characterized by MiSeq sequencing and quantitative PCR. The results indicate that disease suppression was mediated by the structure of a suppressive rhizosphere microbiome with respect to distinct community composition, diversity and abundance. Overall microbiome suppressiveness was primarily related to a particular set of enriched bacterial taxa affiliated with Pseudomonas, Terrimonas, Cupriavidus, Gp6, Ohtaekwangia and Duganella. Finally, structural equation modeling was used to show that the changes in bulk soil bacterial community determined its induced rhizosphere bacterial community, which serves as an important and direct factor in restraining the pathogen. Collectively, this study provides an integrative approach to disentangle the biological basis of disease-suppressive microbiomes in the context of agricultural practice and soil management.     

Rhizosphere immunity: targeting the underground for sustainable plant health management

Managing plant health is a great challenge for modern food production and is further complicated by the lack of common ground between the many disciplines involved in disease control. Here we present the concept of rhizosphere immunity, in which plant health is considered as an ecosystem level property emerging from networks of interactions between plants, microbiota and the surrounding soil matrix. These interactions can potentially extend the innate plant immune system to a point where the rhizosphere immunity can fulfil all four core functions of a full immune system: pathogen prevention, recognition, response and homeostasis. We suggest that considering plant health from a meta-organism perspective will help in developing multidisciplinary pathogen management strategies that focus on steering the whole plant-microbe-soil networks instead of individual components. This might be achieved by bringing together the latest discoveries in phytopathology, microbiome research, soil science and agronomy to pave the way toward more sustainable and productive agriculture.     

钩状木霉在辣椒根际定殖动态及其对辣椒疫病的生物防治

木霉菌（Trichoderma spp.）是自然界广泛分布的一类重要生防真菌资源。生防菌在宿主根际及其组织中定殖能力的强弱是评价其生防潜力的重要指标。选择钩状木霉（Trichoderma hamatum）真菌、辣椒及其重要土传病害菌辣椒疫霉（Phytophthora capsici）三者互作体系，通过绿色荧光蛋白标记的钩状木霉菌株灌根接种辣椒植株，通过平板拮抗试验和温室盆栽试验，检测钩状木霉菌在辣椒植株及根际的定殖情况，及其对辣椒疫病的生物防治效果。结果表明，钩状木霉菌在辣椒根、茎和叶等组织中和辣椒根际土壤中均能够定殖。在辣椒根际土壤中，钩状木霉菌呈动态变化的定殖过程。灌根接种1～25 d，钩状木霉菌定殖量呈缓慢增长，在第33 d，达到最高值(700×107 conidia·g-1)，然后逐渐下降，呈现先增加后减少的动态变化过程。钩状木霉菌在辣椒根际和植株的定殖过程中，对辣椒疫病具有生物防治作用，防治效果达到5333％。综上，钩状木霉菌能够成为辣椒根际微生态中的有益微生物，可以有效预防辣椒疫病的发生，研究为辣椒疫病的生物防治提供了理论依据和有效途径。     

Coupling of the chemical niche and microbiome in the rhizosphere: implications from watermelon grafting

Grafting is commonly used to overcome soil-borne diseases. However, its effects on the rhizodeposits as well as the linkages between the rhizosphere chemical niche and microbiome remained unknown. In this paper, significant negative correlations between the bacterial alpha diversity and both the disease incidence (r = −0.832, P = 0.005) and pathogen population (r = −0.786, P = 0.012) were detected. Moreover, our results showed that the chemical diversity not only predicts bacterial alpha diversity but also can impact on overall microbial community structure (beta diversity) in the rhizosphere. Furthermore, some anti-fungal compounds including heptadecane and hexadecane were identified in the rhizosphere of grafted watermelon. We concluded that grafted watermelon can form a distinct rhizosphere chemical niche and thus recruit microbial communities with high diversity. Furthermore, the diverse bacteria and the antifungal compounds in the rhizosphere can potentially serve as biological and chemical barriers, respectively, to hinder pathogen invasion. These results not only lead us toward broadening the view of disease resistance mechanism of grafting, but also provide clues to control the microbial composition by manipulating the rhizosphere chemical niche.     

Modification of total and phosphorus mineralizing bacterial communities associated with Zea mays L. through plant development and fertilization regimes

Harnessing the rhizospheric microbiome, including phosphorus mineralizing bacteria (PMB), is a promising technique for maintaining sustainability and productivity in intensive agricultural systems. However, it is unclear as to which beneficial taxonomic group populations in the rhizosphere are potentially associated with the changes in soil microbiomes shifted by fertilization regimes. Herein, we analyzed the diversity and community structure of total bacteria and PMB in the rhizosphere of maize (Zea mays L.) grown in soils under 25 years of four fertilization regimes (compost, biocompost, chemical, or non-fertilized) via selective culture and Illumina sequencing of the 16S rRNA genes. Plant development explained more variations (29 and 13%, respectively) in the composition of total bacteria and PMB in the rhizosphere of maize than the different fertilization regimes. Among those genera enriched in the rhizosphere of maize, the relative abundances of Oceanobacillus, Bacillus, Achromobacter, Ensifer, Paracoccus, Ramlibacter, and Luteimonas were positively correlated with those in the bulk soil. The relative abundance of Paracoccus was significantly higher in soils fertilized by compost or biocompost than the other soils. Similar results were also observed for PMB affiliated with Ensifer, Bacillus, and Streptomyces. Although plant development was the major factor in shaping the rhizospheric microbiome of maize, fertilization regimes might have modified beneficial rhizospheric microbial taxa such as Bacillus and Ensifer.