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1.
Fusarium head blight (FHB) caused byFusarium graminearum is a devastating disease that results in extensive yield losses to wheat and barley. A green fluorescent protein (GFP) expressing plasmid pRP22-GFP was constructed for monitoring the colonization of two biocontrol agents,Brevibacillus brevis ZJY-116, on the spikes of barley and their effect on suppression of FHB. Survival and colonization of theBrevibacillus brevis ZJY-1 andBacillus subtilis ZJY-116 strains on spikes of barley were observed by tracking the bacterial transformants with GFP expression. Our field study revealed that plasmid pRP22-GFP was stably maintained in the bacterial strains without selective pressure. The retrieved GFP-tagged strains showed that the bacterial population fluctuation accorded with that of the rain events. Furthermore, both biocontrol strains gave significant protection against FHB on spikes of barley in fields. The greater suppression of barley FHB disease was resulted from the treatment of barley spikes with biocontrol agents before inoculation withF. graminearum. Project supported by the National Natural Science Foundation of China (No. 30230250) and Science and Technology Committee of Zhejiang Province (No. 2003C22029), China  相似文献   

2.
INTRODUCTION Crops production in greenhouses is a method foreconomically maintaining a warm environment dur-ing cool seasons and to protect crops, especiallyvegetables, from unfavourable weather conditions.However, root-knot nematodes and soil borne fungigreatly affect plant growth and yield in greenhouses.Plant-growth promoting rhizobacteria (PGPR) havebeen identified as a biological control alternative topesticide use for disease suppression without negativeeffects on the user, consum…  相似文献   

3.
黄瓜枯萎病是一种严重危害黄瓜的土传性真菌病害,且防治困难.为了筛选出对黄瓜枯萎病菌防治效果较好的生物制剂,从新乡市牧野菜区蔬菜种植区黄瓜根际土壤筛选、分离经温室内消毒土壤处理选育出一株杆菌B1,通过对该菌的形态特征的观察和一系列的生理生化鉴定实验,鉴定属于芽孢杆菌.经室内平板对峙实验发现其对黄瓜枯萎病致病菌有很强的拮抗作用,抑制强度与其发酵滤液浓度呈显著正相关.苗期盆栽实验表明该生防菌株对黄瓜枯萎病菌的防效达70.10%,具有潜在的应用价值.  相似文献   

4.
新品系小麦赤霉病抗性的研究   总被引：3，自引：0，他引：3  
以禾谷镰刀菌(Fusarium gram inearum Schwabe)菌株同年在大田和网室进行穗部单花滴注接种,评价江苏省农科院遗传农业生物遗传生理研究所新育成的14个新品系赤霉病抗性及白粉病田间发病情况.结果表明,所有新品系赤霉病抗性均表现出抗或中抗水平,利用与已报道的与赤霉病抗性QTL相关SSR引物对新品系进行PCR扩增,单倍型分析n1004在3BSc和4B上具有与苏麦3号完全一致的位点,n1005在2D和6B染色体上具有与苏麦3号一致的位点,在4B染色体是具有与望水白一致的位点.  相似文献   

5.
用十二烷基硫酸钠消除枯草芽孢杆菌中的质粒   总被引：3，自引：0，他引：3  
为获得宿主菌 ,研究了十二烷基硫酸钠 (SDS)对枯草芽孢杆菌中质粒的消除 .将过夜培养的枯草芽孢杆菌2 4/pMX45接种于含SDS( 0— 0 .0 0 8% )的LB培养基中 ,当SDS浓度 (w /v)大于或等于 0 .0 0 6 %时 ,菌体不能生长 .SDS的亚致死浓度为 0 .0 0 5 % ,其致死率达 99% .菌液稀释后涂LB平板 ,再随机挑选单菌落至抗性平板 ,检测由质粒编码的红霉素抗性是否丢失 .氯化铯 溴化乙锭梯度离心及质粒DNA的电泳图像证实了 2 4/pMX45的衍生菌株A7中的质粒已完全被消除 .A7延迟期较短 ,并且细胞浓度高于 2 4/pMX45 .用SDS处理 8h后 ,2 4/pMX45的遗传标记开始丢失 ,消除率持续增高至 2 2h ,随之消除质粒的菌体量保持恒定 .在未经SDS处理的对照实验中 ,相同条件下培养 2 4h及 48h后 ,没有发现质粒自然丢失的现象 ,因此SDS能消除枯草芽孢杆菌中的质粒  相似文献   

6.
报道采用热变性温度法(Tm)测定枯草芽孢杆菌和短小芽孢杆菌的DNA中G+C mol%分别为42.7mol%和40.26 mol%,与文献报道相一致,说明该法可为细菌分类学提供可靠的分子生物学数据.采用复性速率液相杂交法测定上述两菌DNA-DNA杂交度为9.66%,显示枯草芽孢杆菌与短小芽孢杆菌为同属中相互关系并不十分密切的两个种.  相似文献   

7.
After deregulating the purine and riboflavin synthesis in the Gram-positive bacterium Bacillus subtilis,it is critical to amplify riboflavin operon with appropriate dosage in the host strain for remarkable increase of riboflavin production. Bacillus subtilis RH13, a riboflavin-producing strain, was selected as host strain in the construction of engineering strains by protoplast fusion. The integrative plasmid pRB63 and autonomous plasmid pRB49, pRB62 containing riboflavin operon of B. subtilis 24 were constructed and transformed into the host strain respectively. Increasing one operon copy in B. subtilis RH13 results in about 0. 4 g/L improvement in riboflavin yield and the appropriate number of operon copies was about 7--8. Amplifying more riboflavin operons is of no use for further improvement of yield of riboflavin. Furthermore, excessive operon dosage results in metabolic unbalance and is fatal to the host cells producing riboflavin.  相似文献   

8.
An antifungal protein was isolated from a culture of Bacillus subtilis strain B29. The isolation procedure comprised ion exchange chromatography on diethylaminoethyl (DEAE)-52 cellulose and gel filtration chromatography on Bio-Gel P-100.The protein was absorbed on DEAE-cellulose and Bio-Gel P-100. The purified antifungal fraction was designated as B29I, with a molecular mass of 42.3 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), pl value 5.69 by isoelectric focusing (IEF)-PAGE, and 97.81% purity by high performance liquid chromatography (HPLC). B29I exhibited in-hibitory activity on mycelial growth in Fusarium oxysporum, Rhizoctonia solani, Fusarium moniliforme, and Sclerotinia scle-rotiorum. The 50% inhibitory concentrations (IC50) of its antifungal activity toward Fusarium oxysporum and Rhizoctonia solani were 45 and 112 μmol/L, respectively. B291 also demonstrated an inhibitory effect on conidial spore germination of Fusarium oxysporum and suppression of germ-tube elongation, and induced distortion, tumescence, and rupture of a portion of the germi-nated spores.  相似文献   

9.
为了筛选得到对玉米茎腐病菌室内抑制活性较高的杀菌剂,采用菌丝生长速率法测定了不同化学杀菌剂对肿囊腐霉菌（Pythium inflatum）和禾谷镰孢菌（Fusarium graminearum）2种致病菌的抑制活性。结果表明,丙森锌、雷多米尔·锰锌、烯酰吗啉和氟吡菌胺4种杀菌剂对肿囊腐霉菌的毒力较高,其EC50。分别为O．40μgZmL、0．47μg／mL、0．61μg／mL和2．64μg／mL;禾谷镰孢菌对咯菌腈、戊唑醇和多菌灵3种杀菌剂的敏感性较高,其EC50分别为0．06μg／,mL、0．32μg／mL和0．85μg／mL,苯醚甲环唑和腈菌唑2种杀菌剂对禾谷镰孢菌的抑制活性稍差,其EC50。分别为1．71μg／mL和1．80μg／mL。上述筛选到的9种药剂对玉米茎腐病菌的室内抑菌活性较高,可以作为供试药剂进行大田药效试验。  相似文献   

10.
目的：研究检验报告单的带菌情况,并行菌属及菌种类型分析。方法：在检验报告单上直接取样增菌接种于血琼脂平板和麦康凯平板培养,用形态学检验及生化反应鉴定到种。结果：1 000份检验报告单,血琼脂平板共生长细菌719株,其中葡萄球菌属518株占72.04%,肠道杆菌175株占24.34%,枯草杆菌26株占3.62%。麦康凯平板共生长细菌369株,其中葡萄球菌属299株占81.03%,肠道杆菌70株占18.97%。结论：检验报告单主要带菌为葡萄球菌和肠道杆菌,其中葡萄球菌以表皮葡萄球菌和金黄色葡萄球菌为主,肠道杆菌以耶氏菌和志贺氏菌为主。  相似文献   

11.
用微生物菌剂（枯草芽孢杆菌）的原始发酵菌液稀释3,4,5,6倍,对烤烟进行根施,调查其防治烤烟脉斑病毒病的效果.结果表明,该微生物菌剂对烤烟脉斑病有一定的防治作用,以原始发酵菌液稀释3倍的防治效果较好,可达到48.55%,且环保,无公害.  相似文献   

12.
In this study, plant growth-promoting rhizobacteria (PGPR) were evaluated as potential biocontrol agents against postharvest pathogens of apple fruits. In vitro bioassays revealed that, out of 30 isolates screened, isolates APEC136 and APEC170 had the most significant inhibitory effects against the mycelial growth of several fungal pathogens. Analysis of 16S ribosomal RNA (rRNA) sequences identified the two effective isolates as Paenibacillus polymyxa and Bacillus subtilis, respectively. The two strains showed greater growth in brain-heart infusion broth than in other growth media. Treatment of harvested apples with suspensions of either strain reduced the symptoms of anthracnose disease caused by two fungal pathogens, Colletotrichum gloeosporioides and Colletotrichum acutatum, and white rot disease caused by Botryosphaeria dothidea. Increased productions of amylase and protease by APEC136, and increased productions of chitinase, amylase, and protease by APEC170 might have been responsible for inhibiting mycelial growth. The isolates caused a greater reduction in the growth of white rot than of anthracnose. These results indicate that the isolates APEC136 and APEC170 are promising agents for the biocontrol of anthracnose and white rot diseases in apples after harvest, and suggest that these isolates may be useful in controlling these diseases under field conditions.  相似文献   

13.
从大米厂、淀粉厂周边环境土壤中筛选到三株产淀粉酶能力较强的菌株Jz1、Jz2、Jz3。经形态特征及染色等初步鉴定,菌株Jz1和Jz3为芽孢杆菌属(Bacillus),菌株Jz2为短小杆菌属(Curtobacterium)。采用YoungJ.Y00改良法测定此三株菌株的淀粉酶活力分别为47.29 U/mL、48.48 U/mL、49.74 U/mL,具有较好的应用潜力。  相似文献   

14.
大叶黄杨白粉病近年来在河南省南阳市发生严重.对大叶黄杨植株春梢进行叶面喷施生防菌枯草芽孢杆菌Bv10菌株的发酵液,进行白粉病小区生防试验,结果显示:喷施7 d后,枯草芽孢杆菌Bv10发酵液对大叶黄杨白粉病的防治效果达70.37%,低于对照药剂粉锈宁;喷施14 d后,该生防菌的防效降低至25.26%.  相似文献   

15.
INTRODUCTIONRiceseedharborsadozenofplantpathogen icbacteria (Gotoetal.,1 988;Xieetal.,1 998) .Thebacterialpathogenscausearangeofricediseases,someverydestructivewhileothershavenoeffectonricecropgrowth .Inthisstudy ,wefoundalargenumberofbacteriaasso ciatedw…  相似文献   

16.
An antifungal protein was isolated from a culture of Bacillus subtilis strain B29. The isolation procedure comprised ion exchange chromatography on diethylaminoethyl (DEAE)-52 cellulose and gel filtration chromatography on Bio-Gel® P-100. The protein was absorbed on DEAE-cellulose and Bio-Gel® P-100. The purified antifungal fraction was designated as B29I, with a molecular mass of 42.3 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), pI value 5.69 by isoelectric focusing (IEF)-PAGE, and 97.81% purity by high performance liquid chromatography (HPLC). B29I exhibited inhibitory activity on mycelial growth in Fusarium oxysporum, Rhizoctonia solani, Fusarium moniliforme, and Sclerotinia sclerotiorum. The 50% inhibitory concentrations (IC50) of its antifungal activity toward Fusarium oxysporum and Rhizoctonia solani were 45 and 112 μmol/L, respectively. B29I also demonstrated an inhibitory effect on conidial spore germination of Fusarium oxysporum and suppression of germ-tube elongation, and induced distortion, tumescence, and rupture of a portion of the germinated spores.  相似文献   

17.
The bglS gene encoding endo-1,3-1,4-β-glucanase from Bacillus subtilis was cloned and sequenced in this study. The bglS expression cassette, including PGK1 promoter, bglS gene fused to the signal sequence of the yeast mating pheromone α-factor (MFals), and ADH1 terminator with G418-resistance as the selected marker, was constructed. Then one of the PEP4 allele of Saccharomyces cerevisiae WZ65 strain was replaced by bglS expression cassette using chromosomal integration of polymerase chain reaction (PCR)-mediated homologous recombination, and the bglS gene was expressed simultaneously. The recombinant strain S. cerevisiae (SC-βG) was preliminarily screened by the clearing hydrolysis zone formed after the barley β-glucan was hydrolyzed in the plate and no proteinase A (PrA) activity was measured in fermenting liquor. The results of PCR analysis ofgenome DNA showed that one of the PEP4 allele had been replaced and bglS gene had been inserted into the locus of PEP4 gene in recombinant strains. Different endo-1,3-1,4-β-glucanase assay methods showed that the recombinant strain SC-βG had high endo-1,3-1,4-β-glucanase expression level with the maximum of 69.3 U/(h-ml) after 60 h of incubation. Meanwhile, the Congo Red method was suitable for the determination of endo-1,3-1,4-β-glucanase activity during the actual brewing process. The current research implies that the constructed yeast strain could be utilized to improve the industrial brewing property of beer.  相似文献   

18.
采用比浊法和菌丝体湿重法测定生物量,测定了初烤烟叶蒸馏水浸出物对4种细菌和3种真菌生长的影响.结果表明,烟叶浸出物对细菌和真菌生长的影响不同.在剂量范围内,烟叶浸出物对铜绿假单孢菌（Pseudo-monas aeruginosa）,大肠杆菌（Escherichia coli）,枯草芽孢杆菌（Bacillus subtilis）和金黄色葡萄球菌（Staphylococcusaureus）没有抑制作用,对爪哇毛霉（Mucor jaranicas）,灰葡萄孢（Botrytis cinerea）和白色念珠菌（Canadida albi-cans）有抑制作用,抑制率分别为89.5%,74.8%和19.4%.  相似文献   

19.
为了研究不同环境下二氧化氯的消毒效果及其稳定性,试验以大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌、白色念珠菌为测试菌株,采用菌悬液定量杀菌试验、压缩雾化法和平板计数的方法,对二氧化氯的杀菌效果进行试验。结果表明：在菌液密度为5×10^6 CFU/mL的条件下,90 mg/L的二氧化氯作用5 min,即可对测试菌株达到100%的杀灭效果。不同的pH值、温度及不同浓度有机物存在的条件下,二氧化氯同样具有极强的消毒效果。雾化的二氧化氯对空气自然菌及雾化菌液气溶胶的杀灭效果同样可以达到100%。试验表明二氧化氯作为一种高效、稳定的广谱消毒剂具有良好的杀菌效果。  相似文献   

20.
With the use of a seed washing technique, more than 4000 Gram negative bacteria were isolated by two improved isolation methods from 446 batches of 1 kg rice seed samples obtained from 22 provinces in the Philippines. They were initially characterized on the basis of colony morphology and results of biochemical and pathogenicity tests. Six hundred and fifty-two strains were further identified by Biolog, from which 133 were selected for fatty acid methyl ester (FAME) analysis together with 80 standard reference! strains. Six-teen species or types ofPseudomonas and 17 genera of non-pseudomonads were identified, more than one third of which have not been recorded in rice. The most predominant species observed wereP. putida andP. fulva. About 17% of the strains ofPseudomonas and 2% of the non-pseudomonads were antagonistic to one or more fungal or bacterial pathogens of rice. Rice seed is an important source of biological control agents. Project supported by Belgium government and Asia Development Bank. Part of the experiments conducted at the University of Gent, Belgium and IRRI during 1997–2000.  相似文献   

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