Screening for the Strain Highly Producing Antagonistic Substance from Bacillus subtilis B47 by UV Mutagenesis

[Objective] The aim of this study was to breed new strains which have higher inhibitory effects on the pathogens of watermelon fusarium wilt.[Method] The endophytic Bacillus subtilis B47 strain was obtained from tomato stems by UV mutagenesis for two consecutive times,then genetic stability as well as physiological and biochemical properties of mutant strains were studied.[Result] The antibacterial activity of all the three mutant strains F303,F304 and F305 was higher than that of B74 strain.After subculture of 10 successive generations,the antibacterial activity of all the three mutant strains for the pathogens of watermelon fusarium wilt decreased,but the antibacterial activity of F305 strain decreased the least,indicating its best genetic stability among the tested strains.The antibacterial circle diameter of F305 strain was 5 mm larger than that of wild strain B47 under the same condition.The mutant strain F305 was in logarithmic growth phase within 36 h and in stationary phase within 36-96 h,while its optimum growth temperature was 35 ℃.F305 strain could grow in sodium salt with the concentration of 1%-10%,but it grew best at the concentration of 1%.Physiological and biochemical responses of F305 strain were in accordance with those of wild strain B47.[Conclusion] This study lays the foundation for the factorial production of antagonistic substance by B47 strain and new methods of preventing from the pathogens watermelon fusarium wilt.     

枯草芽孢杆菌B47高产拮抗物质菌株的紫外诱变选育(英文)

[Objective] The aim of this study was to breed new strains which have higher inhibitory effects on the pathogens of watermelon fusarium wilt.[Method] The endophytic Bacillus subtilis B47 strain was obtained from tomato stems by UV mutagenesis for two consecutive times,then genetic stability as well as physiological and biochemical properties of mutant strains were studied.[Result] The antibacterial activity of all the three mutant strains F303,F304 and F305 was higher than that of B74 strain.After subculture of 10 successive generations,the antibacterial activity of all the three mutant strains for the pathogens of watermelon fusarium wilt decreased,but the antibacterial activity of F305 strain decreased the least,indicating its best genetic stability among the tested strains.The antibacterial circle diameter of F305 strain was 5 mm larger than that of wild strain B47 under the same condition.The mutant strain F305 was in logarithmic growth phase within 36 h and in stationary phase within 36-96 h,while its optimum growth temperature was 35 ℃.F305 strain could grow in sodium salt with the concentration of 1%-10%,but it grew best at the concentration of 1%.Physiological and biochemical responses of F305 strain were in accordance with those of wild strain B47.[Conclusion] This study lays the foundation for the factorial production of antagonistic substance by B47 strain and new methods of preventing from the pathogens watermelon fusarium wilt.     

棉花黄萎病拮抗细菌7-30菌株的筛选与鉴定(英文)

[Objective]The aim of this study was to screen the antagonistic spore-forming bacteria of Verticillium dahliae and identify its physiological and biochemical characteristics.[Method]Taking the cotton verticillium wilt pathogen Verticillium dahliae V-190 as the test microorganism,the antagonistic spore-forming bacteria were screened.Through the preliminary screening and secondary screening,an antagonistic bacteria strain 7-30 with stronger antibacterial activity was obtained,and its morphological characteristics,physiological and biochemical characteristics were also identified.[Result]84 antagonistic bacteria strains were isolated from soil in various places by the preliminary screening.Especially,18 strains with better antagonistic ability were screened again,so an antagonistic bacteria strain 7-30 with the diameter of inhibition zone 18.9 mm and stronger antibacterial activity was obtained.According to its morphological characteristics,physiological and biochemical characteristics,the antagonistic bacteria strain 7-30 was identified as Bacillus subtilis primarily.[Conclusion]The strain 7-30 was obtained as the antagonistic spore-forming bacteria of Verticillium dahliae.     

西瓜枯萎病土壤拮抗菌的筛选(英文)

[Objective] The aim of this study was to screen bacteria strains with stable antagonistic effect against watermelon fusarium wilt from soil and investigate the biological control of watermelon fusarium wilt by applying the antagonistic bacteria strains into soil.[Method] Actinomycete strains,fluorescent bacteria strains and bacillus strains were isolated from soil samples by the dilution-plate method,then its resistance was screened respectively by the improved confront culture method after colonies were purified.Finally,bacteria strains with better antagonistic effect were identified.[Result] 29 bacteria strains with stable antagonistic effect against watermelon fusarium wilt were screened from 39 soil samples,which contained 15 fluorescent bacteria strains,5 bacillus strains and 9 actinomycete strains.Furthermore,three antagonistic bacteria strains of FM2,FM3 and FM4 with the strongest antagonism were identified primarily.[Conclusion] According to cultural characteristics,morphological observation,biochemical and physiological tests,FM2 belongs to bacillus subtilis,while FM3 and FM4 belong to micrococcus.     

Isolation and Identification of an Endophytic Strain with Antibiosis Ability from Davidia involucrate Brail.

[Objective]The aim was to isolate and identify an endophytic bacteria strain with antimicrobial activity from Davidia involucrate Brail.[Method]Endophytic strain with antibiosis ability was isolated from D.involucrate Brail by using cylinder-plate method.Then,it was identified through physiological and biochemical tests,16S rDNA homology analysis as well as some gene-specific sequence analysis.[Result]B221 stain had antimicrobial activity against a variety of rice plant pathogens,and it was identified as Bacillus subtilis.[Conclusion]This study enriches the research on endophyte within D.involucrate Brail,application of Bacillus bio-control,and therefore has laid a good foundation for the development of fungus used in biological control of crop pathogens.     

低叶绿素b水稻突变体的抗氧化酶系统研究(英文)

[Objective] The mitigative effect of antioxidase system of a rice mutant with low chlorophyll b on photooxidative damage was studied.[Method] A rice mutant with low chlorophyll b and its wild type were taken as experimental materials to comparatively research their peroxide (H2O2) contents, the activity and isozymes of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in chloroplast.[Result] Compared with the wild type, there were many kinds of SOD, POD and CAT isozymes in leaf cells and chloroplast cell of mutant, and the activity of SOD, POD and CAT isozymes in leaf cells and chloroplast cell of mutant was also correspondingly higher. Under intense light condition, the H2O2 content of chloroplast in mutant was less than that in the wild type. [Conclusion] The higher activity of scavenging active oxygen can relieve the photooxidative damage made by excessive light energy of intense light on photosynthetic membrane, which is an important reason for higher photosystem Ⅱ (PS II) stability of this mutant.     

沙葱提取物抗菌效果的研究(英文)

[Objective] Study on antibacterial activity and stability of the ethanol extracts from Allium mongolicum Regel.[Method] Taking Allium mongolicum Regel.(AMR)as experimental material,the antibacterial and stability test,antibacterial capacity and antibacterial activity substance stability of extracts were studied.[Result] Size order of antibacterial effect of extracts on these 5 strains tended to be:Saccharomyces cerevisiae > Penicillium sp.> Aspergillusniger> Staphylococcusaureus> Escherichia coli;under neutral or slight alkaline conditions,optimum antibacterial effect presented best;and UV light irradiation basically had no influence on tested strains.[Conclusion] Antibacterial effect of ethanol extract shows great difference among these strains,and antibacterial activity substance is of good heat and UV light stability.     

沙葱提取物抗菌效果的研究(英文)

[Objective] Study on antibacterial activity and stability of the ethanol extracts from Allium mongolicum Regel.[Method] Taking Allium mongolicum Regel.(AMR)as experimental material,the antibacterial and stability test,antibacterial capacity and antibacterial activity substance stability of extracts were studied.[Result] Size order of antibacterial effect of extracts on these 5 strains tended to be:Saccharomyces cerevisiae > Penicillium sp.> Aspergillusniger> Staphylococcusaureus> Escherichia coli;under neutral or slight alkaline conditions,optimum antibacterial effect presented best;and UV light irradiation basically had no influence on tested strains.[Conclusion] Antibacterial effect of ethanol extract shows great difference among these strains,and antibacterial activity substance is of good heat and UV light stability.     

Antibacterial Effect of Extracts from Allium mongolicum Regel

[Objective] Study on antibacterial activity and stability of the ethanol extracts from Allium mongolicum Regel.[Method] Taking Allium mongolicum Regel.(AMR)as experimental material,the antibacterial and stability test,antibacterial capacity and antibacterial activity substance stability of extracts were studied.[Result] Size order of antibacterial effect of extracts on these 5 strains tended to be:Saccharomyces cerevisiae > Penicillium sp.> Aspergillusniger> Staphylococcusaureus> Escherichia coli;under neutral or slight alkaline conditions,optimum antibacterial effect presented best;and UV light irradiation basically had no influence on tested strains.[Conclusion] Antibacterial effect of ethanol extract shows great difference among these strains,and antibacterial activity substance is of good heat and UV light stability.     

Introduction of T-DNA into Watermelon by Stigma Smeared Method and Its Molecular Marker Research

[Objective]The aim was to introduce T-DNA into watermelon for its molecular marker research.[Method]Based on the method of foreign DNA introduced to Arabidopsis thaliana via dipping flowers,the stigma smear was used to transfer T-DNA into watermelon and its molecular marker research was carried out.[Result]The ideal transformed species was ZXG01078 for the highest fruit setting rate and the most deviant seedlings.The best concentration of kanamycin for treating watermelon seeds was 500-700 mg/L with differences among the species.The best position was spire leaf or young leaf and the best concentration of kanamycin for treating the watermelon leaf was 4 000-8 000 mg/L with no significant difference among species.The steadily variation appearing of growing pointless and conjoined twin seedlings indicated that the normal growth had been interfered by foreign DNA in the progeny.[Conclusion]This study had provided basis for the further research on watermelon.     

枯草芽孢杆菌B47高产拮抗物质菌株的紫外诱变选育

[目的]为选育对西瓜枯萎病病菌具更强抑制作用的新菌株。[方法]对从番茄茎内分离获得的内生枯草芽孢杆菌B47菌株进行连续2次紫外线诱变,并对诱变菌株的遗传稳定性和生理生化特性进行测定。[结果]筛选获得3株抑菌活性高于B47菌株的诱变菌株F303、F304、F305,经10代传代培养后,3株诱变菌株对西瓜枯萎病病菌的抑菌活性都有所下降,但F305的抑菌活性下降最小,遗传稳定性最好,在同等条件下其抑菌圈直径仍比野生菌株B47大5 mm。诱变菌株F305在36 h内处于对数生长期,在36~96 h内处于稳定期;最适宜生长温度为35℃;在浓度为1%~10%的钠盐中皆能生长,但以浓度为1%时生长最好,该菌株的生理生化反应与野生菌株B47的反应一致。[结论]该研究为利用B47菌株进行工厂化生产拮抗性物质产品和探讨防治西瓜枯萎病的新方法奠定了基础。     

西瓜枯萎病土壤拮抗菌的初步筛选

[目的]从土壤中筛选对西瓜枯萎病具有稳定拮抗作用的细菌,以反施于土壤进行枯萎病生物防治。[方法]采用稀释分离平板法分离土样中的放线菌、荧光菌和芽孢杆菌,纯化菌落后用改良对峙培养法作抗性筛选,并对拮抗效果最佳的菌株进行鉴定归属。[结果]从39份土样中共筛选出29株对西瓜枯萎病具有稳定拮抗作用的细菌,其中荧光菌15株,芽孢菌5株,放线菌9株。从中选出拮抗作用最强的3个拮抗菌FM2F、M3F、M4进行初步鉴定。[结论]菌株的培养特征和形态学观察及生理生化测试结果表明,FM2为枯草芽孢杆菌,FM3F、M4为微球菌属。     

菠菜内生细菌SEB的鉴定及拮抗作用

[目的]从菠菜上筛选内生细菌,防治菠菜主要病害。[方法]用稀释分离法从菠菜植株内分离内生细菌,培养基平板对峙法测定内生细菌的拮抗作用,并依据形态特征和生理生化特性,使用B iolog细菌鉴定系统鉴定。[结果]从菠菜植株根分离到具有生防活性的细菌SEB,对菠菜枯萎病菌等5种病原菌有较强的拮抗作用,鉴定为芽孢杆菌属。[结论]SEB菌株对多种病原真菌有拮抗作用,对菠菜枯萎病菌抑制率最高,具有开发成微生物制剂,防治园艺作物和农作物病害枯萎病的价值。     

甜瓜枯萎病拮抗菌的筛选及鉴定

[目的]筛选对甜瓜枯萎病菌有较强拮抗活性的菌株,并对拮抗菌株进行分类鉴定,为丰富热带地区甜瓜枯萎病生防菌资源库及田间应用提供参考.[方法]以前期筛选获得的82株菌株为试验材料,通过平板对峙、继代培养、发芽率及盆栽试验筛选出对甜瓜枯萎病菌有较强拮抗活性的菌株,并通过形态特征、生理生化特征及16S rDNA序列分析对筛选获得的菌株进行分类鉴定.[结果]筛选出一株对甜瓜枯萎病菌有较强拮抗活性的放线菌菌株D2,其对枯萎病的防治效果达73.53%.D2菌株可形成气生菌丝和孢子丝,孢子丝呈螺旋形,孢子卵呈圆形,且与利迪链霉菌(Streptomyces lydicus)聚于同一分支中,其同源性达99.6%;综合D2菌株的形态特征及生理生化特性,可鉴定其为利迪链霉菌( S. lydicus ).[结论]D 2菌株对甜瓜枯萎病有较好的防治效果,具有开发成生物农药或生物肥料的潜力.     

植物枯萎病拮抗细菌KL-1菌株的分离及鉴定

[目的]筛选、鉴定植物枯萎病菌拮抗细菌,为植物枯萎病生防制剂的研究奠定基础。[方法]采用对峙培养法筛选对植物枯萎病菌具有良好抑制作用的生防细菌,通过Biolog细菌自动鉴定系统和16SrDNA序列分析法鉴定其分类地位,并研究该菌株对棉花和小鼠的安全性。[结果]从棉花根际土壤中分离出的12株细菌中,有5株对多隔镰刀菌、香石竹尖孢镰刀菌、棉花枯萎病菌具有拮抗活性;其中,KL-1菌株对3株目标病原菌的抑菌活性分别达69.09%、80.78%、78.89%。Biolog细菌自动鉴定系统和16SrDNA序列分析法鉴定结果表明,KL-1菌株为解淀粉芽孢杆菌;生物安全性初步测定结果表明,KL-1菌株对棉花和小鼠安全无毒。[结论]解淀粉芽孢杆菌KL-1菌株具有对多种植物枯萎病菌的抑菌活性,且对棉花和小鼠安全无毒,是一株具有研究和开发潜能的生防菌株。     

印楝渣生物药肥对香蕉生长和香蕉枯萎病的影响

【目的】有效利用印楝渣废弃资源研制印楝渣生物药肥,并探讨其对香蕉Musa acuminata生长和香蕉枯萎病的影响。【方法】将耐药生防菌(解淀粉芽孢杆菌HN-11)与印楝渣混合发酵,制备印楝渣生物药肥;通过抑菌和盆栽试验,测定印楝渣生物药肥对香蕉生长的影响以及对香蕉枯萎病的防治效果;采用扫描电镜观察其对病原菌菌丝形态结构的影响。【结果】生防菌解淀粉芽孢杆菌HN-11对香蕉枯萎病菌Fusarium oxysporum f.sp.cubense 4号生理小种(Foc4)有明显的抑制作用,抑菌率为72.1%。生防菌株HN-11与印楝渣具有良好相容性,制备的印楝渣生物药肥施用质量分数为5%和10%时,处理组香蕉的长势好于对照,鲜质量、干质量、株高和茎粗均有不同程度的提高,与对照差异显著;施用印楝渣生物药肥组香蕉的病情指数分别为20和25,对香蕉枯萎病的防病率分别达到72.2%和77.8%;生防菌HN-11能降低土壤中病原菌Foc4孢子数,破坏菌丝形态结构。【结论】印楝渣与生防菌HN-11发酵腐熟施用可避免对香蕉产生药害,制成的印楝渣生物药肥对香蕉的生长具有明显促进作用,能有效控制香蕉枯萎病的发生。     

瓠瓜砧木嫁接西瓜苗对枯萎病的抗性综合评价

[目的]分析不同瓠瓜砧木西瓜嫁接苗对西瓜枯萎病的抗性表现及生长、生理指标差异,确立评价抗病性关键指标,为筛选砧用瓠瓜及抗病育种提供参考.[方法]选用6份不同类型的瓠瓜(H04、H05、H07、H10、H0405和H1004)为砧木嫁接西瓜栽培品种,以西瓜栽培品种自根嫁接苗为对照,采用苗期人工接种尖孢镰刀菌西瓜专化型2号生理小种鉴定瓠瓜砧木嫁接苗的抗病性,测定嫁接苗的株高、茎粗、最大叶片叶面积、叶绿素含量(SPAD值)及叶片过氧化物酶(POD)活性、丙二醛(MDA)含量等生长、生理指标,采用隶属函数法综合评价不同瓠瓜砧木嫁接苗对枯萎病的抗性.[结果]不同瓠瓜砧木嫁接西瓜苗对枯萎病的抗性表现不同,砧木H0405和H04的嫁接苗表现高抗,其最大叶片叶面积和叶绿素SPAD值最高,株高和茎粗增长较快,叶片POD活性显著高于自根嫁接苗(P<0.05,下同),MDA含量显著低于自根嫁接苗.以生长、生理指标的隶属函数值综合评价不同类型瓠瓜砧木嫁接西瓜苗的抗病性,排序结果与按株高、最大叶片叶面积、叶绿素SPAD值的大小排序和以病情指数鉴定抗病性的结果基本相同.[结论]瓠瓜高代自交系H04可作为抗西瓜枯萎病的砧用瓠瓜育种资源,其杂种一代H0405可作为抗西瓜枯萎病的优良砧木.通过测定嫁接苗的株高、最大叶片叶面积和叶绿素SPAD值可快速评价嫁接苗对西瓜枯萎病的抗病性强弱.     

防治西瓜枯萎病的微生物菌种的筛选与鉴定

[目的]对一组防治西瓜枯萎病的微生物菌种进行鉴定。[方法]以西瓜专化型尖孢镰刀菌为研究对象,从海洋海绵共生菌和土壤样品中筛选到6株具显著拮抗西瓜专化型尖孢镰刀菌的活性菌株,并对该6株活性菌株进行分子鉴定。[结果]分子鉴定显示该6株活性菌株均属于芽孢杆菌属的物种。[结论]试验结果为西瓜枯萎病类安全高效的生物农药及功能型生物肥料的创制提供了理论依据。