芘降解菌Pseudomonas sp.PR3的植物促生特性及其对芘胁迫下水稻生长的影响北大核心CSCD

农田中不断积累的多环芳烃不仅严重影响作物生长,同时增加粮食安全风险。筛选兼具促进植物生长特性和降解污染物功能的微生物菌株是解决上述问题的一种有效手段。从油田附近生长的植物根表分离得到一株具有芘降解能力,同时还具有溶磷、产吲哚乙酸和铁载体等植物促生特性的菌株PR3,经16S rDNA序列同源性分析确定为假单胞菌(Pseudomonas sp.)。菌株PR3在无机盐培养液中生长14 d后,对芘(20 mg/L)的降解率可达94%,对萘(50 mg/L)、菲(50 mg/L)、苯并(a)芘(10 mg/L)的降解率也分别达到92%,84%和47%。同时,该菌株7 d内最大溶磷量为756.25 mg/L,2 d内IAA合成量可达14.46 mg/L,4 d内生成铁载体的活性单位可达58.53%。在不同芘污染浓度处理下的盆栽实验表明,接种PR3可有效促进水稻生长并提高根际土壤中芘的降解,去除率可达72.02%-86.22%,同时显著降低水稻根及地上部中的芘含量,分别为21.81%-53.01%和49.81%-57.17%。因此,菌株PR3有助于实现芘污染土壤的生态修复以及降低作物芘暴露的风险。     

两株具促生作用的苜蓿内生菌的分离纯化与鉴定

【目的】分离具有植物促生功能的苜蓿内生菌。【方法】从苜蓿的新鲜组织中分离纯化菌株,进行16S r RNA基因序列分析,生理生化鉴定并检测内生菌对苜蓿的促生特性。【结果】获得两株苜蓿内生菌,成团泛菌ASR16和短小芽孢杆菌ALR33。两株菌株均能产生植物生长激素IAA和嗜铁素,能溶解磷,对苜蓿的促生作用明显。【结论】获得两株具有植物促生特性的苜蓿内生菌ASR16和ALR33,可作为微生物菌肥的研究基础。     

薄层菌L28的分离鉴定及其对马铃薯快繁苗生长的促进作用

【背景】薄层菌(Hymenobacter)是不利生长环境(如营养贫瘠的荒漠土壤)中的优势细菌类群,目前对该类菌的研究集中于分离鉴定,尚无对植物促生相关的研究报道。【目的】从浑善达克荒漠土壤分离鉴定细菌,并分析菌株对马铃薯快繁苗生长的影响。【方法】基于选择性培养基,以涂布划线方法进行细菌的分离培养;扩增16SrRNA基因并测序,分析序列相似性和系统发育,并参考形态和生理生化特征对菌株进行初步分类鉴定;以选择性培养基或比色法等方法对纯培养物进行促生性状分析;采用MS固体培养基分析菌株对马铃薯快繁苗生长的影响。【结果】分离得到一株编号为L28的细菌,其16S rRNA基因序列与Hymenobacter koreensis GYR3077T的相似性最高,为96.46%;菌株L28具有固氮、解磷酸钙-磷、解植酸磷-磷、产吲哚-3-乙酸(indole-3-acetic acid,IAA)(7.51 mg/L)、产铁载体(D/d为2.47)和有1-氨基环丙烷羧酸(1-amino-cyclopropane-1-carboxylicacid,ACC)脱氨酶活性等多种植物促生特性;接种L28相比不接种显著...     

基于基因组的一株土壤固氮菌分离菌株鉴定及其促生作用

[目的] 为获得高效固氮菌株,充分研究利用土壤固氮菌资源。[方法] 选取固氮能力较高的紫色土发育水稻土,采用富集纯化法分离固氮微生物菌株。通过16S rRNA基因系统发育分析和全基因组相关指数比较对新分离菌株进行物种鉴定。采用乙炔还原法和¹⁵N₂示踪法定量测定新分离菌株的固氮能力,通过培养特性和接种效果初步研究固氮菌株的促生作用。[结果] 从紫色土发育水稻土中分离得到1株可在无氮培养基上快速生长的菌株P208。基于16S rRNA基因和基因组92个核心基因的系统发育分析结果表明,新分离菌株P208与Azotobacter chroococcum IAM 12666^T（=ATCC 9043^T）系统发育距离最近（16S rRNA基因相似度为99.79%）。菌株P208与A.chroococcum ATCC 9043^T的基因组平均核苷酸一致性（ANI）、平均氨基酸一致性（AAI）和数字DNA-DNA杂交值（dDDH）高于物种分类阈值（ANI>95%-96%,AAI>95%-96%,dDDH>70%）,最大唯一匹配指数（MUMi）低于物种分类阈值（<0.33）,得出新分离菌株P208为褐球固氮菌（A.chroococcum）。A.chroococcum P208固氮活性为模式菌株A.chroococcum ATCC 9043^T的2.61倍。除固氮能力外,A.chroococcum P208具有IAA生成、溶磷活性和铁载体生成等促进植物生长潜力的培养特性,室内培养条件下接种A.chroococcum P208能够促进水稻、小麦幼苗根系的生长。[结论] 从固氮能力较强的水稻土中分离纯化得到1株具有较强固氮、促生潜力的固氮菌,具有潜在的开发应用价值,可为研究利用生物固氮提供微生物资源。     

四株红树林促生菌的遗传分析鉴定及其促生能力

【目的】鉴定四株供试菌株的种属地位,了解菌株所具有的促进植物生长能力。【方法】运用nifH与16S rRNA基因序列对供试菌株进行遗传分析,采用钼锑抗比色法和乙炔还原法分别测定菌株的溶磷、固氮能力。通过接种试验验证菌株促进红树植物生长的能力。【结果】通过对菌株nifH与16S rRNA的同源性、系统发育树分析,HN011与需钠弧菌(Vibrio natriegens)的相似性最高,SZ7-1、SZ7-2与产酸克雷伯氏菌(Klebsiella oxytoca)的相似性最高。而SZ002在16S rRNA的系统发育分析中归属为类芽孢杆菌属(Paenibacillus sp.),却在nifH基因分析中与克雷伯氏菌(Klebsiella sp.)的相似性最高。供试菌株都具有较强的溶磷能力和高固氮酶活性。接种后植株有较好的生长表现,部分接种植株在干重、全氮、全磷含量等方面较对照有显著地增加(P0.05)。【结论】首次发现兼具溶磷-固氮两种能力的红树林植物促生菌,接种试验也表现菌株具有良好的促生能力,为红树林人工接种促生菌的应用提供了可靠的理论依据。     

鄱阳湖-乐安河段湿地耐Cu、Zn、Pb植物促生菌的分离、筛选及鉴定

【背景】植物促生菌因其对植物生长促进及增强抗逆性等优点在植物-微生物联合修复重金属污染土壤中具有良好应用潜力。在污染土壤中,土著植物促生菌能够更好地定殖并保证促植物生长能力的发挥。【目的】从常年受上游多种重金属污染的鄱阳湖-乐安河段湿地分离出一批具有多种重金属抗性的优势土著植物促生菌,以期为植物-微生物联合修复重金属污染湿地提供一批优质的菌种资源。【方法】从乐安河流域戴村受重金属污染的湿地土壤及水体中分离具有Cu、Zn、Pb抗性菌株,测定菌株的促植物生长特性[产IAA(Indole acetic acid)、溶磷、产铁载体及ACC(1-Aminocyclopropane-1-carboxylic acid)脱氨酶活性],挑选促生特性较好的菌株进行16S r RNA基因序列分析鉴定,并测定菌株对其他胁迫条件(抗生素、酸碱、盐)的耐受能力。【结果】分离得到22株能够同时耐受Cu 50 mg/L、Zn 400 mg/L、Pb 800 mg/L的菌株,其中10株表现出较好的促植物生长特性,对其进行16S r RNA基因序列分析鉴定,有4株属于Ralstonia sp.,3株属于Burkholderia sp.,另3株则分别属于Cupriavidus sp.、Stenotrophomonas sp.和Novosphingobium sp.。基于这10株菌抗性特征的聚类分析及主成分分析,结果与系统发育树分析结果高度一致。【结论】耐受多种重金属的土著植物促生菌的分离鉴定为重金属污染土壤的植物-微生物联合原位修复提供良好的微生物资源。     

耐镉促生菌株的分离鉴定及对大豆的促生效应

【背景】华南地区镉（Cd）污染严重,与有益微生物共生能够使作物通过直接或间接的机制解除镉毒,提高抗逆性,进而促进生长。耐镉促生菌剂具有广泛的应用前景。【目的】从华南地区受镉污染植株的根内和根际筛选出耐镉且能促进大豆生长的促生菌,以丰富促进田间大豆生产的优异菌种资源。【方法】采用平板划线法从植株的根内或根际分离菌株,通过生理生化特性和16S rRNA基因序列分析对分离菌株进行初步研究,利用盆栽试验探究镉胁迫下菌株对大豆生长的影响,通过测定丙二醛含量和总抗氧化能力探究菌株的耐镉机制。【结果】分离获得4株菌D1、D2、D3和D4,促生特性试验证明4株菌均具有溶磷、产吲哚乙酸和铁载体的能力。经16S rRNA基因序列分析鉴定,D1、D2、D3和D4菌株分别属于不动杆菌属、微小杆菌属、类芽孢杆菌属和普罗威登斯菌属。用这4株菌进行不同镉处理的大豆（巴西10号）盆栽试验,结果表明,4株菌均具有耐镉和促进大豆生长的作用。不添加镉的条件下,大豆接种D4菌株的地上部干重、根部干重和株高分别增加了28%、35%和31%;在添加20mg/kg-CdCl₂·5/2H₂...     

两株芽孢杆菌对花生幼苗生长及其根际土壤微生物群落结构的影响

【背景】贝莱斯芽孢杆菌(Bacillus velezensis)和坚强芽孢杆菌(Bacillus firmus)对花生的促生作用及促生机制研究尚未见报道。【目的】从微生物群落结构和土壤氮磷钾有效养分两个方面综合解析两株芽孢杆菌(贝莱斯芽孢杆菌HP9和坚强芽孢杆菌HP10)对花生的促生机制。【方法】以两株芽孢杆菌为研究对象,通过单独灌根或混合灌根盆栽花生,测定其对花生生长及根际土壤氮磷钾有效养分的影响;利用高通量测序技术分析灌根组与对照组花生根际土壤的细菌和真菌群落结构及多样性。【结果】与对照组相比,3个灌根处理组均明显促进了花生幼苗茎部的伸长及鲜重的增加,根际土壤碱解氮含量显著提高,有效磷和速效钾含量有不同程度增加。芽孢杆菌对花生根际土壤的微生物多样性无显著影响,但影响了细菌和真菌的群落结构组成。灌根处理组根际土壤的拟杆菌门及Mortierellomycota等相对丰度显著增加,在属水平上,农杆菌属、节杆菌属、芽孢杆菌属、伯克霍尔德氏菌属、黄杆菌属、Pedobacter、极地单胞菌属、假单胞菌属、鞘脂单胞菌属、寡养单胞菌属等属的相对丰度明显提高,而且无色杆菌属、短波单胞菌属、金黄色杆菌...     

植物根际促生菌的筛选及其对玉米的促生效应

[目的]以不同植物根及根际土壤为研究材料,进行植物根际促生菌(PGPR)的筛选,并探索其植物促生作用机制.[方法]以解磷、固氮、产氨、产IAA和拮抗3种常见病原真菌为筛选标准,测定了初筛菌株的多项促生能力,并通过对这些菌分别单独回接和多菌混接的玉米盆栽试验,测定了其对玉米的促生效应.[结果]从渭南、成阳、安康、商洛和榆林5地分离得到的158株菌中有17株茵具有上述多种植物促生作用的菌株.盆栽试验的测定结果表明:单独接种和多菌混合接种在玉米株高、根长、茎长、茎平均直径和干重方面与对照组相比较都有所增加,尤其是在多个指标上,多菌混合接种所显示出的促生效应均明显优于单菌接种.[结论]所筛选到的具有多种促生能力的菌株,可以为进一步构建植物根际促生菌(PGPR)菌群提供良好的种质资源.     

强化龙葵富集镉根际促生菌的分离、筛选与鉴定

【背景】植物-微生物联合修复土壤重金属污染日渐兴起,获取与超富集植物高效互作的微生物是实现联合修复技术进步的关键。龙葵在镉农田污染修复中广泛应用。【目的】筛选可促进龙葵生长及富集镉的耐镉根际促生菌。【方法】从龙葵根际土分离耐镉菌株,筛选具有良好促生特性的菌株,水培试验考察镉胁迫下菌株对植物生长及镉富集能力的影响,确定可促进龙葵生长及富集镉的微生物菌株,通过生理生化特性和16S rRNA基因序列分析进行菌株的初步鉴定。【结果】分离得到NT1、AXY1、AW2和AW1四株强化龙葵富集镉促生菌,经鉴定分别为Lysinibacillus sp.、Beijerinckia fluminensis、Achromobacter animicus和Herbaspirillum huttiense。上述菌株均可有效促进龙葵生长,增加其株高和干物质积累,提高地上部镉富集量。其中,NT1可使株高、地上部干重分别增加31.33%和62.65%,AW2可使地上部镉富集量增加37.29%。【结论】筛选所得菌株可为提高植物修复效率提供实践依据,为研制田间施用生态功能菌剂做铺垫,用于农田镉污染的微生物-龙葵联合原位修复。     

Characterization of bacterial communities associated with Brassica napus L. growing on a Zn-contaminated soil and their effects on root growth

The interaction between plant growth-promoting bacteria (PGPB) and plants can enhance biomass production and metal tolerance of the host plants. This work aimed at isolating and characterizing the cultivable bacterial community associated with Brassica napus growing on a Zn-contaminated site, for selecting cultivable PGPB that might enhance biomass production and metal tolerance of energy crops. The effects of some of these bacterial strains on root growth of B. napus exposed to increasing Zn and Cd concentrations were assessed. A total of 426 morphologically different bacterial strains were isolated from the soil, the rhizosphere, and the roots and stems of B. napus. The diversity of the isolated bacterial populations was similar in rhizosphere and roots, but lower in soil and stem compartments. Burkoholderia, Alcaligenes, Agrococcus, Polaromonas, Stenotrophomonas, Serratia, Microbacterium, and Caulobacter were found as root endophytes exclusively. The inoculation of seeds with Pseudomonas sp. strains 228 and 256, and Serratia sp. strain 246 facilitated the root development of B. napus at 1,000 µM Zn. Arthrobacter sp. strain 222, Serratia sp. strain 246, and Pseudomonas sp. 228 and 262 increased the root length at 300 µM Cd.     

苎麻促生菌的筛选、鉴定及其促生效应

【目的】以苎麻(Boehmeria nivea L. Gaud)根及根围土壤为研究材料,进行苎麻促生菌的筛选,并初步探索其促生作用机制。【方法】首先,以溶磷和解钾为基本筛选标准,初筛菌株在实验室条件下测定多项促生能力进行复筛;然后通过种子萌发、盆栽试验测定菌株对苎麻的促生效应,最后,通过形态观察、生理生化特性和16S rRNA基因序列同源性分析,对促生菌株进行分类学鉴定。【结果】从苎麻根和根围土壤中分离得到了13株菌同时具备溶磷和解钾能力,其中4株菌(RA-2、RAM-2、RAM-5和RAM-6)具备产铁载体、产IAA和产氨能力。种子萌发和盆栽试验的测定结果显示：4株菌株均能促进苎麻种子的萌发和植株的生长,其中菌株RA-2和RAM-5相比于对照处理能显著提高苎麻种子的萌发率、幼根长、株高和根系干重。分类鉴定结果显示菌株RA-2和RAM-5均属于伯克霍德菌属(Burkholderia)。【结论】从苎麻根围筛选到具有促生能力的菌株,为进一步开发研制苎麻专型促生菌剂或专型微生物有机肥提供资源。     

两株聚球藻伴生细菌分离纯化与促生功能鉴定

【背景】蓝藻周围存在伴生细菌,伴生细菌与蓝藻具有复杂的作用关系。【目的】研究淡水聚球藻伴生细菌对聚球藻生长的影响。【方法】采用高通量测序分析聚球藻伴生细菌多样性;平板划线法纯化聚球藻伴生细菌,通过形态观察结合16S rRNA基因序列同源性比对,对其种属关系进行确定;通过聚球藻和不同浓度伴生细菌共培养测定其叶绿素a浓度,分析伴生细菌对聚球藻生长的影响;采用种子发芽试验验证伴生细菌促生功能。【结果】淡水聚球藻伴生细菌优势菌属为产卟啉杆菌属(Porphyrobacter)、根瘤菌属(Rhizobium)、水单胞菌属(Aquimonas)和中慢生根瘤菌属(Mesorhizobium),从聚球藻分离获得了两株伴生细菌JQ1和JQ2,基于16S rRNA基因序列鉴定其分别属于Rhizobium和Peribacillus,通过在聚球藻与不同浓度伴生细菌共培养及水稻发芽试验验证,证明伴生细菌JQ1和JQ2在菌藻比例分别为5:1和15:1时具有促生作用,都对增强秧苗素质和根系发育有一定影响但JQ2与JQ1相比能显著提高水稻种子的发芽率。【结论】淡水聚球藻伴生细菌JQ1和JQ2在适宜的浓度均可显著促进聚球...     

Ability of cold-tolerant plants to grow in hydrocarbon-contaminated soil

Phytoremediation of hydrocarbons in soil involves plants and their associated microorganisms. Differences in environmental conditions and restrictions on species importation mean that each country may need to identify indigenous plants to use for phytoremedation. Screening plants for hydrocarbon tolerance before screening for degradation ability may prove more economical than screening directly for degradation. Thirty-nine cold-tolerant plants native, or exotic and naturalized, in western Canada were assessed for their ability to survive in crude oil-contaminated soil. Four naturalized grasses (i.e., Agropyron pectiniforme, Bromus inermis, Phleum pratense, and Poa pratensis), three naturalized legumes (i.e., Medicago sativa, Melilotus officinalis, and Trifolium repens), two native forbs (i.e., Artemisia frigida and Potentilla pensylvanica), one native grass (i.e., Bromus ciliatus) and two native legumes (i.e., Glycyrrhiza lepidota and Psoralea esculenta) exhibited phytoremediation potential, based on survival. We determined the effect of increasing crude oil concentrations on total and root biomass, and relative growth rate of those species with the highest survival. The addition of 0.5%, 1%, and 5% (crude oil wt/fresh soil wt) crude oil to soil significantly decreased both the total biomass by at least 22% of the control and the relative growth rate of all species except P. esculenta. Root biomass significantly decreased by at least 22% with crude oil addition in all species except P. esculenta and A. frigida. Total biomass production in contaminated soil had a significant negative correlation with the relative growth rate in uncontaminated soil.     

Improvement of phytoremediation of an aged petroleum hydrocarbon-contaminated soil by Rhodococcus erythropolis CD 106 strain

The aim of this study was to assess the impact of soil inoculation with the Rhodococcus erythropolis CD 106 strain on the effectiveness of the phytoremediation of an aged hydrocarbon-contaminated [approx. 1% total petroleum hydrocarbon (TPH)] soil using ryegrass (Lolium perenne). The introduction of CD 106 into the soil significantly increased the biomass of ryegrass and the removal of hydrocarbons in planted soil. The fresh weight of the shoots and roots of plants inoculated with CD 106 increased by 49% and 30%, respectively. After 210 days of the experiment, the concentration of TPH was reduced by 31.2%, whereas in the planted, non-inoculated soil, it was reduced by 16.8%. By contrast, the concentration of petroleum hydrocarbon decreased by 18.7% in non-planted soil bioaugmented with the CD 106 strain. The rifampicin-resistant CD 106 strain survived after inoculation into soil and was detected in the soil during the entire experimental period, but the number of CD 106 cells decreased constantly during the enhanced phytoremediation and bioaugmentation experiments.

The plant growth-promoting and hydrocarbon-degrading properties of CD 106, which are connected with its long-term survival and limited impact on autochthonous microflora, make this strain a good candidate for improving the phytoremediation efficiency of soil contaminated with hydrocarbons.     

Isolation from coastal sea water and characterization of bacterial strains involved in non-ionic surfactant degradation

A bacterial community degrading branched alkylphenol ethoxylate (APE) was selected from coastal sea water intermittently polluted by urban sewage. This community degraded more than 99% of a standard surfactant, TRITON X 100, but I.R. analysis of the remaining compound showed the accumulation of APE₂ (alkylphenol with a two units length ethoxylated chain) which seemed very recalcitrant to further biodegradation. Twenty-five strains were isolated from this community, essentially Gram negative and were related to Pseudomonas, Oceanospirillum or Deleya genera. Among these strains, only four were able to degrade APE_9–10 (TRITON X 100). They were related to the Pseudomonas genus and were of marine origin. Pure cultures performed with these strains on TRITON X 100 gave APE₅ and APE₄ as end products. These products were further degraded to APE2 by two other strains unable to degrade the initial surfactant.     

Isolation and characterization of plant growth promoting endophytic diazotrophic bacteria from Korean rice cultivars

We have isolated 576 endophytic bacteria from the leaves, stems, and roots of 10 rice cultivars and identified 12 of them as diazotrophic bacteria using a specific primer set of nif gene. Through 16S rDNA sequence analysis, nifH genes were confirmed in the two species of Penibacillus, three species of Microbacterium, three Bacillus species, and four species of Klebsiella. Rice seeds treated with these plant growth-promoting bacteria (PGPB) showed improved plant growth, increased height and dry weight and antagonistic effects against fungal pathogens. In addition, auxin and siderophore producing ability, and phosphate solubilizing activity were studied for the possible mechanisms of plant growth promotion. Among 12 isolates tested, 10 strains have shown higher auxin producing activity, 6 isolates were confirmed as strains with high siderophore producing activity while 4 isolates turned out to have high phosphate-solubilizing activity. These results strongly suggest that the endophytic diazotrophic bacteria characterized in this study could be successfully used to promote plant growth and inducing fungal resistance in plants.     

花生种子相关促生菌分离鉴定及功能评价

【背景】利用微生物促进植物健康生长是农业可持续发展的重要方向之一,而种子相关的促生菌可在植物生命周期早期与植物相互作用,对植物健康生长具有重要意义。【目的】发掘与利用种子相关促生菌的前提是筛选获得促生菌菌种资源,验证其益生能力,为其进一步应用与机理研究提供依据与支持。【方法】以花生种子为研究对象,从种子表面及种子内部分离纯化多株菌,测定菌株的固氮、解磷、解钾、吲哚乙酸合成和铁载体合成等促生能力,并验证菌株对常见植物病原菌的生长抑制特性;通过16S rRNA基因序列进行系统发育分析,确定分类地位;通过生物膜形成能力及根际定殖能力测定菌株在植物根际的生存能力;最后通过催芽及盆栽试验测定菌株对花生种子发芽及幼苗生长的影响。【结果】从花生种子表面、种子内和胚根内分离筛选到41株菌,均有吲哚乙酸合成能力,其中35株有固氮能力,2株有铁载体分泌能力,14株有植物病原菌生长抑制能力。各选一株为代表的菌株,即PS3、PE5和PR5,经16S rRNA基因序列比对分析鉴定为芽孢杆菌属(Bacillus)。PS3、PE5和PR5均可在MSgg液体培养基表面形成褶皱较强的生物膜,也可在花生根际形成有效定殖。催芽试验结果表明经过促生菌浸种后花生种子萌发率明显提高,在第2天时,PS5将发芽率由14.17%提高至38.33%,PE5发芽率提高至30.83%,PR5发芽率提高至39.17%。三株菌能够明显促进花生幼苗生长,PS5对花生幼苗苗高、根长、鲜重和干重分别提高21.82%、22.20%、37.11%和35.64%,PE5分别提高17.45%、18.93%、26.10%和21.18%,PR5分别提高23.11%、23.92%、38.66%和37.47%。【结论】筛选获得的花生种子相关促生菌,具有促进植物生长的潜力,明显促进种子萌发及幼苗生长,是良好的促生菌生物资源,具有较好的应用潜力。     

两株溶藻细菌的分离及初步研究

选择藻华现象严重的巢湖作为采样点,取3个不同位置的水样通过0.22μm的纤维滤膜过滤,培养后加入适应期的藻液中,取黄化藻液作为分离菌种的材料,初筛菌株经反复试验获得有较强抑藻能力的菌株,经生理生化鉴定及16S rDNA分子鉴定其种属。初筛得到45个菌株,有两个菌株WD1和WD2表现出溶藻作用。两株细菌的菌液经离心、高温灭菌、细胞破碎等处理对供试藻鱼腥藻也均有不同程度的抑制作用。分离得到两株溶藻细菌,WD1为约氏不动杆菌,WD2为门多萨假单胞菌。