PGPR调控植物响应逆境胁迫的作用机制

盐碱、干旱等非生物胁迫是限制植物生长和产量的重要环境因子。植物根际促生菌(PGPR)是一类定殖于植物根系的有益微生物,利用其生物学功能制成的生物菌剂具有低成本、高效和环保等优点,不仅可促进植物生长与作物产量,还能提高植物对非生物胁迫的耐受性。本研究对PGPR定义和种类、生物学功能及其在植物响应盐碱、干旱、高低温及重金属等非生物胁迫中的作用加以综述,并对其未来研究方向进行展望,以期为今后PGPR介导植物抗逆性的研究与生物菌剂的开发和应用提供理论支撑。

AMF和PGPR联合芦苇修复重金属污染河道底泥的效应

研究旨在探究河道底泥重金属污染下丛枝菌根真菌(Arbuscular Mycorrhizal Fungi,AMF)与植物根际促生菌(Plant Growth-Promoting Rhizobacteria,PGPR)对芦苇生长、磷吸收以及重金属去除的效应。以沈阳市浑河河道底泥为研究对象,对芦苇接种AMF双网无梗囊霉(Acaulospora bireticulata,AM1)、摩西斗管囊霉(Funneliformis mosseae,AM2)、PGPR黏质沙雷氏菌(Serratia marcescens,PG)、双网无梗囊霉+黏质沙雷氏菌(APG1)、摩西斗管囊霉+黏质沙雷氏菌(APG2)和不接种对照(CK)共6个处理。结果显示,AMF能够促进PGPR在芦苇根区土壤以及根内的定殖数量,而PGPR能够促进AMF侵染发育,增加其侵染率、泡囊数以及孢子数。AMF、PGPR或AMF+PGPR处理均显著增加了芦苇生物量以及地上部和根系磷质量比,促进了植物对底泥中重金属(Cd、Zn、Pb、Cu)的吸收,降低了土壤中重金属含量。在各处理下,APG2处理对底泥中重金属的去除率最高,达33.24%~55.51%,土壤中过氧化氢酶、蔗糖酶、脲酶和碱性磷酸酶活性也显著高于AM1、AM2、PG和CK处理。此外,底泥重金属在芦苇内的分布均为根系大于地上部,可见芦苇根系对重金属的吸收和富集能力较强,且以APG2处理下对Cd、Zn、Pb的吸收效果最好,分别是CK处理的2.4倍、2.0倍以及1.7倍。因此,AMF和PGPR双接种可提高芦苇P吸收量以及土壤酶活性,促进芦苇生长,而AMF和PGPR能够相互促进,增加对底泥重金属的去除效率,其中APG2是最佳组合。

PGPR促进植物生长及增强植物耐镉机制研究进展

随着现代农业的发展,传统化肥与农药的应用已不符合现代农业可持续发展的观念,生物防治将成为农业发展主流。植物根际促生菌(PGPR)对植物生长、抗逆有重要的调控作用,引起了土壤微生物学、微生态学和植物学学者的广泛关注。本文从PGPR研究现状入手,总结了PGPR提升植物对氮、磷、铁元素的吸收,调控植物根系激素水平来促进植物生长发育以及通过各种间接作用增强植物对逆境的耐受性的作用机制,并且以重金属镉胁迫为例系统阐述了PGPR增强植物对逆境的耐受性机制,以期为后续利用PGPR为原料合成生物菌剂的开发研究提供科学依据。

砷胁迫下接种PGPR对水生植物砷累积及生理特性的影响

为探究水生植物芦苇、灯芯草与根围促生细菌(PGPR)组合对重金属污染水体中砷(As)的富集作用以及生理响应,模拟水体As质量浓度(0、5、15、30 mg/L)并添加PGPR菌株荧光假单胞菌(Pseudomonas fluorescens,Pf)、贝莱斯芽孢杆菌(Bacillus velezensis,Bv)以及不添加菌株(对照,CK)共设计24个处理。结果表明,低质量浓度As对芦苇、灯芯草生长具有促进作用,而高浓度下产生抑制。添加PGPR能够增加芦苇和灯芯草株高和生物量,提高叶绿素含量以及叶绿素荧光参数,改善芦苇和灯芯草的根系构型并提高根系活力,增加植物地上部和根系的氮吸收量,增强根系对As的富集能力。5 mg/L As质量浓度下,与CK相比,添加Pf处理芦苇株高、生物量、根系氮吸收量和地上部氮吸收量分别增加54.6%、38.5%、11.5%、48.4%,叶绿素总含量增加23.4%,PSⅡ最大光化学效率(Fv/Fm)和PSⅡ潜在活性(Fv/Fo)分别提高6.7%、20.6%,根系总长度、根系总投影面积、根系总体积和根分叉数分别增加4.8%、19.3%、27.4%、14.8%;添加Bv处理芦苇株高、生物量、根系氮吸收量、叶绿素总含量、叶绿素荧光参数以及根系构型参数也有不同程度的提高。5 mg/L As质量浓度下,与CK相比,添加Pf和Bv处理灯芯草株高、生物量、叶绿素含量、叶绿素荧光参数以及根系构型等也有所提高。在30 mg/L As质量浓度下,Pf处理芦苇地上部和根部As含量达到最大值,分别为126.1、432.1 mg/kg。综上,芦苇+Pf对As的吸收和富集效果最好,可应用于重金属As污染水体的生态修复。

持续干旱下接种PGPR对核桃苗抗氧化系统的影响

为探讨植物根际促生细菌(PGPR)对持续干旱胁迫下核桃叶片抗氧化系统的影响,采用盆栽试验,以1年生核桃苗为试验材料,研究持续干旱胁迫下接种PGPR对核桃苗株高和茎粗、叶片ROS积累和膜脂过氧化产物以及抗氧化酶活性、非酶类抗氧化物质含量的影响。结果表明,与正常浇水相比,持续干旱胁迫使核桃苗的株高和茎粗显著降低19.47%和15.49%,叶片超氧阴离子(O_(2)^(-·))、过氧化氢(H_(2)O_(2))和丙二醛(MDA)含量显著升高,同时,叶片超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)与单脱氢抗坏血酸还原酶(MDHAR)活性以及还原型谷胱甘肽(GSH)含量均明显升高。在持续干旱逆境下接种PGPR则能显著促进株高和茎粗生长,有效减少叶片内ROS积累和MDA含量,显著提高叶片SOD、CAT、APX和MDHAR活性以及还原型抗坏血酸(AsA)、GSH含量,并不同程度提高叶片AsA/DHA(双脱氢抗坏血酸)和GSH/GSSG(氧化型谷胱甘肽)比值。以上分析认为,持续干旱逆境下核桃苗接种PGPR,可通过提高叶片抗氧化酶活性和非酶类抗氧化物质含量来有效清除活性氧,从而增强核桃苗的耐旱能力,促进其生长。

Plant growth-promoting rhizobacteria(PGPR)and its mechanisms against plant diseases for sustainable agriculture and better productivity

Plant growth-promoting rhizobacteria(PGPR)are specialized bacterial communities inhabiting the root rhizosphere and the secretion of root exudates helps to,regulate the microbial dynamics and their interactions with the plants.These bacteria viz.,Agrobacterium,Arthobacter,Azospirillum,Bacillus,Burkholderia,Flavobacterium,Pseudomonas,Rhizobium,etc.,play important role in plant growth promotion.In addition,such symbiotic associations of PGPRs in the rhizospheric region also confer protection against several diseases caused by bacterial,fungal and viral pathogens.The biocontrol mechanism utilized by PGPR includes direct and indirect mechanisms direct PGPR mechanisms include the production of antibiotic,siderophore,and hydrolytic enzymes,competition for space and nutrients,and quorum sensing whereas,indirect mechanisms include rhizomicrobiome regulation via.secretion of root exudates,phytostimulation through the release of phytohormones viz.,auxin,cytokinin,gibberellic acid,1-aminocyclopropane-1-carboxylate and induction of systemic resistance through expression of antioxidant defense enzymes viz.,phenylalanine ammonia lyase(PAL),peroxidase(PO),polyphenyloxidases(PPO),superoxide dismutase(SOD),chitinase andβ-glucanases.For the suppression of plant diseases potent bio inoculants can be developed by modulating the rhizomicrobiome through rhizospheric engineering.In addition,understandings of different strategies to improve PGPR strains,their competence,colonization efficiency,persistence and its future implications should also be taken into consideration.

PGPR对土壤根际微生物菌群特性影响的研究进展及应用

近年来,通过植物根际促生菌(Plant Growth-Promoting Rhizobacteria,PGPR)来进行的作物促生与植物病害防治的研究已成为微生物研究与开发利用的一个热点。植物根际促生菌与微生物、土壤、植物健康等方面关系密切,PGPR能够刺激土壤酶活性的增加,促进植物生长。土壤接种PGPR后,对微生物群落多样性、土壤酶活性的增加以及微生物量的增加具有积极意义,同时,植物根系的分泌物反过来又可以促进微生物多样性的提高。为了解PGPR的主要种群以及促生与防病机理研究进展,综述了PGPR的定义、种群、PGPR在土壤中的定殖、PGPR对其他微生物菌群影响及作用机制。

Potential of Biostimulants Based on PGPR Rhizobacteria Native to Benin’s Soils on the Growth and Yield of Maize (<i>Zea mays </i>L.) under Greenhouse Conditions

The application of biostimulants in agriculture represents an environmentally friendly alternative while increasing agricultural production. The aims of the study were to develop solid biostimulants based on five rhizobacteria native to Benin’s soils and to evaluate their efficacy on the growth and biomass yield of maize under greenhouse conditions on ferrallitic and ferruginous soils. Clay and peat were used as a conservation binder for the preparation of the biostimulants. These binders were used alone or combined in the different formulations with maize flour and sucrose. 10 g of biostimulants were applied at sowing in pots containing five kilograms of sterilised soil. The experimental design was a completely randomised block of 24 treatments with three replicates. The results obtained showed significant improvements (P < 0.001) in height (49.49%), stem diameter (32.7%), leaf area (66.10%), above-ground biomass (97.12%) and below-ground biomass (53.98%) on ferrallitic soil with the application of the clay + Pseudomonas putida biostimulant compared to the control. On the other hand, the use of the peat biostimulant + Pseudomonas syringae was more beneficial for plant growth on ferruginous soil. The height, stem diameter, leaf area, above-ground biomass and below-ground biomass of the plants under the influence of this biostimulant were improved by 83.06%, 44.57%, 102.94%, 86.84% and 42.68%, respectively, compared to the control. Therefore, these results confirm that Rhizobacteria express their potential through biostimulants formulated on maize. The formulated biostimulants can later be used by producers to improve crop productivity for sustainable agriculture.

欧李多功能PGPR菌株筛选、鉴定及促生防病特性研究

【目的】从荒漠草原灌木欧李(Cerasus humilis)根际筛选具有优良促生防病特性的植物根际促生菌(plant growth promoting rhizobacteria,PGPR)。【方法】采用选择性培养基,筛选欧李根表面及根际土中细菌。通过乙炔还原法、Salkowski法、钼锑抗比色法和平板对峙法分别测定菌株固氮酶活性、分泌IAA、溶磷和拮抗病原菌的能力。并利用形态学、革兰氏染色及分子生物学方法对筛选出的10株优良根际促生菌进行初步鉴定。【结果】分离出的31株细菌,固氮酶活性在16.22~328.35 nmol C2H4/(h·mL);分泌IAA量在3.85~60.19μg/mL;解有机磷量在10.66~118.76μg/mL;溶无机磷量在1.42~289.93μg/mL;菌株WGB2对茄病镰刀菌(Fusarium solani)、麦根腐平脐蠕孢(Bipolaris soro⁃kiniana)、尖突赤霉菌(Gibberella acuminata)、禾谷镰刀菌(Fusarium graminearum)和串珠赤霉菌(Gib⁃berella moniliformi)均具拮抗作用,抑菌率分别为11.85%、39.91%、27.64%、59.84%和26.22%。初步鉴定10株优良根际促生菌菌株分属于Chryseomicrobium、动性球菌属(Planomicrobium)、假单胞菌属(Pseudomonas)、节杆菌属(Arthrobacter)、农杆菌属(Agrobacterium)和类芽孢杆菌属(Paenibacil⁃lus)。【结论】欧李PGPR菌株数量表现出根表面显著高于根际土,且菌株具有丰富的促生防病特性,可为后期微生物肥料的开发提供优质的菌种资源。

PGPR联合不同添加量椰壳生物炭对镉污染土壤的修复效果

【目的】探究CSBC-PGPR-黑麦草联合修复体系对Cd污染黄壤土的修复效果。【方法】选取椰壳生物炭(coconut Shell Biochar,CSBC)耦合植物促生菌—伯克霍尔德氏菌(Burkholderia sp.)YXL1制备4种不同的生物炭材料,通过盆栽试验考察CSBC-PGPR-黑麦草联合修复体系修复前后黑麦草生物量、黑麦草中Cd富集量、土壤中Cd赋存形态及其理化性质、土壤酶活性等。【结果】相较于CK对照组,CSBCB(CSBC+YXL1)施用后黑麦草生物量最大增幅74.20%、有效态Cd最大增幅15.25%、黑麦草富集Cd最大增幅为434.90%;土壤理化性质有效提升,pH、全氮、有效磷最大提高了0.50个单位、0.48 g/kg和7.61 mg/kg;土壤脱氢酶、土壤脲酶、土壤酸性磷酸酶以及蔗糖酶活性较空白处理活性显著提高,最高分别提高了62.55%、70.05%、27.49%和73.57%。【结论】运用CSBC-PGPR-黑麦草联合修复体系强化黑麦草对Cd富集能力,有着良好的应用前景。

Effects of Plant Growth Promoting Rhizobacteria (PGPR) on In Vitro Bread Wheat (Triticum aestivum L.) Growth Parameters and Biological Control Mechanisms

Three endemic plants rhizosphere (Astragalus gombo Coss. & Dur., Daucus sahariensis Murb., Ononis angustissima Lam.), were used for actinomycetes isolation. Ninety-three (93) isolates have been screened to evaluate their antagonistic properties against phytopathogenic microorganisms and to determine their biocontrol properties against Fusarium culmorum, especially responsible for several cereal diseases like font’s seedlings, rust, and burn of ears. Four (04) isolates (D2, D5, D8, and AST1) have been in vitro tested to determine PGPR effect and biocontrol characters of bread wheat (Triticum aestivum L.), Hidhab (HD) variety cultivated in the Murashigue and Skoog (MS) culture medium. The aim of this study is the evaluation of antagonistic isolates of pathogenic fungi F. culmorum, without and within commercial fungicide (Tebuconazole, 60 g/l) solution. Our results showed clearly that these isolates have a significant effect on seed germination and seedling growth. However, results argue that these actinomycetes isolates show a very interesting activity compared to the commercial fungicide. As a result, these bacteria isolates can be used as biocontrol agents against Fusarium wilt disease of wheat, which have a beneficial effect on growth parameters.

PGPR菌剂对攀西高原植烟土壤nifH基因群落的影响

为研究植物根际促生菌(PGPR)菌剂处理下攀西高原植烟土壤氮素循环的微生物调控机制,本研究以凉山州会理市不同PGPR菌剂(Lysinibacillus sp.、Streptomyces Phaeochromogenes和Aspergillus niger)处理下的植烟田为研究对象,采集烤烟成熟期根际土壤,通过化学分析和高通量测序技术对土壤理化性质、固氮酶活性及nifH基因群落组成及多样性进行分析。结果表明,与常规施肥相比,施用PGPR菌剂会显著降低植烟土壤的pH值,同时显著提高有效磷含量和固氮酶活性(P<0.05)。总体而言,施用PGPR菌剂提高了植烟土壤nifH基因群落的多样性。植烟土壤优势菌群为变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)和蓝菌门(Cyanobacteria)。慢生根瘤菌属(Bradyrhizobium)、地杆菌属(Geobacter)和固氮螺菌属(Azospirillum)等是植烟土壤优势属。冗余分析结果表明,植烟土壤pH值、碱解氮和速效钾含量与nifH基因群落结构相关性最强。综上,PGPR菌剂能改善植烟土壤养分状况,提高土壤固氮酶活性,影响植烟根际土壤nifH基因群落组成及多样性,其中以细菌PGPR菌剂Lysinibacillus sp.效果最佳。本研究结果为植烟土壤科学施肥、培肥地力提供了理论依据。

Comparative Analysis of Various Strains of Plant Growth Promoting Rhizobacteria on the Physiology of Garlic (Allium sativum)

Garlic is a most important medicinal herb belonging to the family Liliaceae. Both its leaves and bulb are edible. The current study was based on evaluating the growth promoting potential of plant growth promoting rhizobacteria (PGPR) on garlic (Allium sativum L.) growth and biochemical contents. Garlic cloves were inoculated with 3 kinds of PGPRs, Pseudomonas putida (KX574857), Pseudomonas stutzeri (Kx574858) and Bacillus cereus (ATCC14579) at 108 cells/mL prior to sowing. Under natural conditions, plants were grown in the net house. The PGPR significantly enhanced % germination, leaf and root growth and their biomass also increased the diameter of bulb and fresh and dry weight. The flavonoids, phenolics, chlorophyll, protein and sugar content were also significantly increased due to PGPR inoculation. The Pseudomonas stutzeri was found most effective for producing longer leaves with moderate sugar, high flavonoids (129%) and phenolics (263%) in bulb over control (Tap). The Pseudomonas putida exhibited a maximum increase in bulb diameter and bulb biomass with maximum phenolics and flavonoid contents.

Research Progress of Mechanism of Action of Plant Growth Promoting Rhizobacteria

The paper first introduces the definition and classification of plant growth promoting rhizobacteria （PGPR）, then reviews the research achievements on the mechanism of action of plant growth promoting rhizobacteria, including growth pro-moting mechanism and bio-control mechanism, subsequently lists the use of excel-lent plant growth promoting rhizobacteria strains in recent years, especial y Pseu-domonas and Bacil us strains, and final y discusses problems existing in this area and points out issues requiring further exploration, including PGPR screening meth-ods, preservation methods, mechanism of action, in order to commercialize PGPR as soon as possible and practical y realize its application to production.

PGPR与金属离子相互作用对植物根际影响的研究分析

文章阐述了植物根际促生菌的概念种类、作用机制,梳理分析了植物根际促生菌与金属离子相互作用对植物根系的影响,总结展望了根际促生菌在土壤污染的缓解和治理方面的应用前景。

ISSA PGPR技术在农业面源污染水体修复中的应用研究

为探究ISSA PGPR技术在农业面源污染水体修复中的应用效果,于2020年8月-2021年8月,以常年种植茶园坡面集水河道为研究对象,布设ISSA PGPR修复系统,监测水体主要污染物。结果表明,ISSA PGPR技术对水体中总氮(TN)、总磷(TP)、化学需氧量(COD_(cr))和五日生化需氧量(BOD_(5))平均消减率分别达60.98%、77.41%、42.64%和43.06%;该技术能够在3个月内有效去除污染物,对上游50 m~100 m范围水体有一定修复效果,对下游修复范围更加广泛。ISSA PGPR技术可有效修复长期承接农业坡面来水的沟渠、水塘等污染水体。

Influence of Isolated PGPR Rhizobacteria in Central and Northern Benin on Maize Germination and Greenhouse Growth

The objective of the study was to evaluate the effects of nine plant growth-promoting rhizobacteria (PGPR) alone or in combination on maize seed germination and seedling growth under laboratory and greenhouse conditions. The germination and growth tests were carried out in square petri dishes and pots. Maize seeds were inoculated with suspension of 108 CFU/ml of rhizobacteria. The experimental device was a random block of 16 treatments with four repetitions. Germination test results showed that seeds inoculated with PGPR including the control induced good germination in the range of 93.75% to 100%. The vigor index and root length of the seeds treated with Bacillus panthothenicus were significantly improved by 76.64% and 58.86%, respectively, while the maximal lengths of the seedlings were obtained with Pseudomonas cichorii with an increase of 118.95%. In greenhouse experience, data demonstrated that Serratia marcescens better improved the leaf area, height and underground biomass, respectively by 58.83%, 108.43%, and 59.16% as compared to the control. The highest fresh aerial biomass and air dry matter was obtained with plants treated only with Pseudomonas putida. These results show the potential to use such rhizobacteria as biofertilizers to improve maize productivity in Benin.

Acid-Phosphorus Activity of Wheat Varieties Rhizobacteria of Uzbekistan

In this work, local strains of phosphate-solubilizing microorganisms were isolated and identified from the wheat rhizosphere and exogenous acid phosphatase enzymes of locally active phosphate- and potassium-mobilizing rhizobacteria belonging to the genera Escherichia, Rahnella, Bacillus, Enterobacter, Pseudomonas, and Pantoea were studied. The efficiency of the physiological properties of rhizobacteria is determined by the production of soluble phosphorus, and the amount of phosphorus depends on the activity and biomass of bacteria that secrete phosphorus. This is done by phosphate solubilizing bacteria, and the habitat ecosystem is enriched with beneficial micronutrients. In these studies, active rhizobacteria activity of acid phosphatase in nutrient liquid was studied at different temperatures. Optimum pH activity index and temperature variability of enzymes were determined. It should be noted that in the most active phosphate-solubilizing strains the maximum enzymatic activity was observed in the culture fluid of R. aquatilis strain 17, which produced 1.086 μmol p-nitrophenol μmol/min/ml. P. agglomerans 22, P. agglomerans 20 and Ps. kilonensis 32 cultures phosphatase activity was 0.143 - 0.680 p-nitrophenol μmol/min/ml. It should be noted that the phosphatase activity of bacteria belonging to the same genus and species was very different from each other. That is, the enzyme activity of Rahnella aquatilis strain 17 was 9 times higher than the enzyme activity of Rahnella aquatilis strain 9. The pH optimum of sour phosphatase enzymes in Rahnella aquatilis strain 16 was 6.0. The optimum temperature of acid phosphatase activity was 45˚C and 50˚C. The reason for this may be that the strains were isolated in different soil and climate conditions. When the acid phosphatase activity of R. aquatilis 3, 9, E. cloacae 8 and P. agglomerans 22 cultures was determined at a temperature of 45˚C, it was observed that the enzyme activity increased by 2 - 4 times. Es. hermannii 1, Ps. kilonensis 26 and B. simplex 28 bacteria acid phosphatase activity was not significantly affected by temperature rise.

微生物肥料新型功能作用机理与根际定殖增强策略

微生物肥料是支撑农业绿色发展的重要投入品,根际益生菌是微生物肥料菌种的主要来源。我国农业发展对促进作物根系发育、增强作物耐盐胁迫能力等新型功能的微生物肥料提出了需求,然而目前对根际益生菌促进作物根系发育和增强耐盐胁迫的分子机理研究仍然薄弱,成为制约优异菌种选育的瓶颈。另一方面,微生物肥料的根际定殖能力低也是导致其田间应用效果差的重要因素。本文综述了根际益生菌调控根系发育、增强植物耐盐的活性物质和作用机理,分析其根际定殖的过程和菌植互作机制,提出了增强根际定殖的策略,以期为微生物肥料研究提供参考。

鞭毛主调控因子flhDC调控机制及其在PGPR定殖中的功能

细菌鞭毛结构和组装的高度复杂性要求鞭毛在合成过程中遵循严格的级联调控。flhDC位于级联调控的顶端,是革兰氏阴性菌鞭毛生物合成的主要调节因子。flhDC在调控鞭毛运动以应对外界环境和营养变化的同时也受到全局性调控、群体感应、新陈代谢和环境信号等因素的影响。根际生防微生物制剂的合理使用可以降低化学肥料和杀虫剂对土壤的污染。能够在植物根部定殖是植物生长促进根际细菌(PGPR)促生的前提,flhDC在此过程中发挥着不可或缺的作用。本文综述了革兰氏阴性菌中鞭毛主调控因子flhDC在转录水平、mRNA翻译水平、翻译后水平受到的多重调节,讨论了flhDC在PGPR植物根表定殖过程中发挥的作用,主要包括flhDC调控PGPR运动性,参与PGPR生物膜合成,提高PGPR在植物根表定殖的稳定性。