牛场沼液对几种蔬菜病原菌抑制作用的研究

实验室条件下,用不同贮存时间的牛场沼液原液和滤液对7种蔬菜病原菌（番茄叶霉病菌、番茄灰霉病菌、番茄早疫病菌、辣椒疫病病菌、辣椒绵腐病菌、黄瓜炭疽病菌、茄子灰霉病菌）的抑菌效果进行试验研究,为沼液应用于蔬菜病害农田防治的进一步研究提供基础数据。结果表明,新鲜沼液原液对番茄灰霉病菌、番茄早疫病菌、辣椒疫病病菌、辣椒绵腐病菌、黄瓜炭疽病菌和茄子灰霉病菌均有较强的抑制作用;随着贮存时间的增加,沼液原液对番茄灰霉病菌、番茄早疫病菌、黄瓜炭疽病菌和茄子灰霉病菌的抑菌率没有显著变化,对辣椒疫病病菌和辣椒绵腐病菌的抑菌率显著下降;新鲜沼液滤液对番茄灰霉病菌和茄子灰霉病菌有较好的抑制作用,但对其他5种病原菌的抑制效果不明显;随着贮存时间的增加,滤液对番茄灰霉病菌的抑菌率没有显著变化,对茄子灰霉病的抑制率表现出先显著下降而后升高的趋势。     

青枯菌侵染对烟草叶片H202代谢、叶绿素荧光参数的影响及其与抗病性的关系

对青枯病菌抗性的不同2个烟草品种接种青枯菌后,随接种时间的延长,病株叶片中过氧化氢(H2O2)、超氧物阴离子自由基(O2)、丙二醛(MDA)累积明显高于健株,感病品种"红花大金元"累积幅度大于抗病品种"岩烟97",抗病、感病品种间差异达到显著、极显著水平;病菌感染初期叶片超氧物歧化酶(SOD)活性下降,随后升高,抗病品种活性高于感病品种;过氧化氢酶(CAT)活性先上升而后下降,感病品种降幅高于抗病品种;过氧化物酶(POD)活性先下降而后上升,感病品种升幅大于抗病品种;病株叶绿素可变荧光(Fv)、光系统Ⅱ原初光能转换效率(Fv/Fm)及光系统Ⅱ的潜在活性(Fv/Fo)均受到抑制,感病品种受抑制程度大于抗病品种,这表明烟草品种对青枯菌的抗性与H2O2代谢以及叶绿素荧光参数有着密切关系.     

胨冻样芽孢杆菌(Bacillus mucilaginosus)对烟草灰霉病菌(Botrytis cinerea)的抑制作用

本文首次报道胨冻样芽孢杆菌XDB1和D4B1对烟草灰霉病菌(Botrytis cinerea)的抑制作用。实验表明,XDB1和D4B1的发酵原液和无细胞提取物具有相同的抑菌效果,而经121℃处理30分钟后,抑菌活性丧失。D481菌株的抑菌活性高于XDB1,钾长石作为基质时的活性高于土壤矿物。但是,XDB1和D481对立枯丝核病菌(R..solani)、西瓜尖孢镰刀菌(F.oxysporum)、腐霉(Pythium sp)、小麦全蚀病菌(G.graminis)、烟炭疽病菌(C.gloeosporides)、烟草赤星病菌(A.alternata)、烟草黑胫病菌(P.nicotianae、串珠镰刀病菌(F.moniliforme)和水稻稻瘟病菌(P.grisea)无抑制作用。     

爵床提取物的抑菌杀虫活性研究

爵床(Justicia procumbens var.procumbens L.)是一种传统中药。为探明爵床提取物的抑菌杀虫活性,采用冷浸和超声波提取相结合的方法,分别获得了爵床甲醇、氯仿、丙酮、乙酸乙酯和正己烷等溶剂提取物;并应用抑菌圈法研究了5种提取物对柑橘炭疽病菌(Colletotrichum gloeosprioides)、芦笋茎枯病菌(Phomopsisasparagi)、稻瘟病菌(Pyricularia grisea)、棉花红腐病菌(Fusarium graminearum)和草莓灰霉病菌(Botrytiscinerea)等5种植物病原真菌的抑制效果,测定了甲醇提取物对柑橘炭疽病、芦笋茎枯病、草莓灰霉病和柑橘溃疡病(Xanthomonas campestris)等4种植物病菌及白蚊伊蚊(Aedes albopictus)、家蝇(Musca domestica)和菜青虫(Pieris rapae)等3种害虫的毒力。结果表明,不同极性溶剂提取物8 mg.mL 1对5种植物病原真菌均有一定的抑制作用,其中甲醇提取物对柑橘炭疽病菌、芦笋茎枯病菌、草莓灰霉病菌的抑制率均达50%以上。爵床甲醇提取物具有较强的抑菌杀虫活性,对柑橘炭疽病菌、芦笋茎枯病菌和草莓灰霉病菌菌丝生长的抑制中浓度(EC50)分别为5.94 mg.mL 1、4.61 mg.mL 1和5.27 mg.mL 1,EC90分别为63.69 mg.mL 1、58.01 mg.mL 1和54.57 mg.mL 1;0.25~1.00 mg.mL 1爵床甲醇提取物对柑橘溃疡病病菌显示强抑菌作用,0.125 mg.mL 1显示中度抑菌作用,最小抑制浓度(MIC)为0.062 5 mg.mL 1;爵床甲醇提取物对白蚊伊蚊、家蝇和菜青虫的致死中浓度(LC50)分别为0.195 8 mg.mL 1、0.351 4 mg.mL 1和0.287 7 mg.mL 1,LC95分别为0.988 4 mg.mL 1、3.053 2mg.mL 1和2.584 4 mg.mL 1。因此,爵床提取物作为生物农药,在农业生产中具有较好的应用前景。     

大蒜废弃物对农作物病原菌的抑制效果

我国大蒜废弃物资源丰富,为引导其合理化、资源化利用,测定了大蒜提取物对大豆尖孢镰刀菌（Fusarium oxysporum fsp.tracheiphilum）、油菜菌核病菌（Sclerotinia sclerotiorum（Lib.）d eBary）、大豆细菌性斑点病菌（Pseudomonas.s yringae pv.glycinea）和水稻白叶枯病菌（Xanthomonas oryzae pv.oryzae〔Ishiyama〕Dye,Xoo）4种植物病原菌的抑制作用,并通过大蒜提取物、大蒜渣、大蒜肥对土壤中大豆尖孢镰刀菌的抑制试验,测定了其在土壤中对土传病原菌的抑制效果。结果表明,高浓度的大蒜提取物对这4种植物病原菌有抑制作用,随着提取物浓度的升高,抑菌效果也更为明显。质量浓度为500mg.mL-1时对大豆尖孢镰刀菌、大豆细菌性斑点病菌和水稻白叶枯病菌的抑菌效果最好。培养基中提取物浓度达100mg.mL-1时对两种真菌的抑制达100%。同时,含大蒜提取物0.05mL.g-1、大蒜渣5%或大蒜肥25%的土壤能抑制土传病原菌大豆尖孢镰刀菌在土壤中的定殖。     

化感水稻内生真菌发酵产物的抑菌活性评价及其对水稻保护性酶活性的影响

为探究化感水稻内生真菌对植物病原真菌的抑制作用及其对水稻生理特性的影响,本研究采用来自化感水稻6173中分离得到的12株内生真菌菌株,以水稻纹枯病、稻瘟病、恶苗病菌为指示菌株,通过平板对峙法研究了内生真菌菌株的抑菌活性,再采用牛津杯扩散法对初筛获得的抗性菌株进行抑菌活性复筛,并对筛选到的抑菌菌株抗菌物质的热稳定性及其对非化感水稻93067相关保护性酶活性的影响进行了研究。结果表明,菌株REF-04抑菌活性强,其对纹枯病菌抑制率达到50.63%,发酵液乙酸乙酯提取物抑制效果显著,抑菌圈直径达到18.6 mm;菌株REF-04发酵液乙酸乙酯提取物中抗菌成分具有较强的热稳定性,其发酵液能显著提高水稻苯丙氨酸解氨酶(PAL)、超氧化物歧化酶(SOD)、过氧化物酶(POD)活性。本研究筛选获得的水稻内生真菌REF-04具有较好的抗菌活性,同时还能促进水稻幼苗保护性酶活性的提高,其作为生物农药具有一定的应用价值和开发前景。     

3种接种方法对十字花科黑腐病菌Xcc8004菌株在拟南芥Col-0上致病力的影响

十字花科黑腐病菌（Xanthomonas campestris pathovar carnpestris,Xcc）是引起十字花科植物黑腐病的病原菌,也是研究寄主与病原微生物相互作用分子机理的模式菌之一。Xcc可以感染白菜、萝卜和甘蓝等十字花科农作物,也可以感染重要的模式植物拟南芥（AroJoidopsisthaliana）。由于拟南芥的全基因组测序已经完成,因此,拟南芥是研究寄主植物对Xcc浸染的防卫反应的分子机理的最理想的寄主材料。但是,到现在为止,一套完善的在拟南芥上进行xcc致病检测的实验系统还没有建立。为此,本研究比较了“叶片压渗法”、“剪叶法”和“叶片中脉穿刺法”这3种常用的病原细菌接种方法对Xcc的实验室菌株8004f以下简称Xcc8004）在哥伦比亚生态型拟南芥似．thanlianaecoype Colombia0,Col-0）上的致病力的影响。结果发现,在拟南芥Col-0叶片上用“叶片压渗法”接种Xcc8004可以引起明显致病症状,而用“剪叶法”和“叶片中脉穿刺法”接种均不能引起病症。这一结果说明,不同的接种方法的对Xcc在拟南芥上的致病力有很大的影响。因此,要在拟南芥Col-0上进行Xcc8004的致病力检测,本研究建议采用“叶片压渗法”而不用“剪叶法’和“叶片中脉穿刺法”。此外,本研究还建立了一套简易的拟南芥试验用苗的栽培方法。     

烯效唑抑制小麦黑胚病及促进黑胚粒发芽作用的研究

试验结果表明，烯效唑对小麦黑胚病菌有强烈的抑制作用，低浓度(5～15mg／kg)烯效唑可抑制黑胚病对黑胚粒发芽、出苗的影响，促进黑胚粒的发芽和出苗；高浓度(20mg／kg)烯效唑则抑制黑胚粒发芽和出苗；用10～15mg/kg烯效唑浸种可预防和防治小麦黑胚病发生，而且幼苗生长旺盛，根系发达。目前河北省推广的小麦品种黑胚率为11．1%，严重者高达 42．8%。链格孢菌(Atternaria tenuis)是导致小麦黑胚病发生的主要病原菌，占病原分离物的91．4%。     

开口箭提取物对采后香蕉抗炭疽病菌活性的研究

为探讨植物提取物对香蕉采后病害的防治，采用孢子萌发法和菌丝生长速率测定百合科植物开口箭的甲醇提取物及其乙酸乙酯分部萃取物和正丁醇分部萃取物对香蕉炭疽病菌的离体抗菌活性，选用正丁醇分部萃取物进行耐高温(121℃处理20 min)、紫外光照射(30 W紫外灯距50 cm直射15 h)和酸处理(调节pH 3)的抗菌稳定性研究，并进行了提取物处理香蕉的贮藏防病试验。结果表明，开口箭甲醇提取物及其乙酸乙酯分部萃取物和正丁醇分部萃取物抑制香蕉炭疽病菌孢子萌发的半效应浓度(EC₅₀)分别为1490.27，638.40，1112.65 μg/mL，抑制香蕉炭疽病菌菌丝生长的EC₅₀分别为1262.16，451.02，955.58 μg/mL，正丁醇分部萃取物的抗菌活性不受热、紫外线和酸等因子的影响，用开口箭提取物处理采后香蕉果实，具有明显降低其潜伏性炭疽病发病率的作用。     

鸭粪提取物对水稻纹枯病菌的影响及其有效成分分析

为探明稻鸭共养模式抑制水稻纹枯病发生的原因,以稻鸭共养模式的鸭粪提取物为研究对象,对其抑菌活性及有效成分进行了测定和分析,以期为水稻纹枯病生物防治提供新的途径。结果表明:鸭粪乙醇提取物对水稻纹枯病菌有抑制作用,24h内最高菌丝生长抑制率和EC50分别为88.64%、26.11mg·mL-1;鸭粪乙醇提取物经萃取分离得到石油醚和乙酸乙酯两种组分,其中石油醚组分抑菌效果较弱,乙酸乙酯组分抑菌能力较强,其对水稻纹枯病菌抑制率为89.70%,EC50为15.52mg·mL-1;对乙酸乙酯组分进行硅胶柱层析分离得到5种流份,其中第2流份有显著抑菌活性,在24h和48h内对水稻纹枯病菌的抑制率分别为89.58%和80.36%。GC-MS分析表明,鸭粪的抑菌物质主要为酚酸类和含硫醇有机物质,进一步纯化和鉴定有待研究。     

新鲜猪沼液和牛沼液对农作物病原真菌抑制作用的比较研究

本试验在实验室条件下,研究大中型沼气工程猪沼和牛沼两种沼液原液及其离心上清液对大豆尖孢镰刀菌、大豆菌核病菌、小麦纹枯病菌、小麦根腐病菌、水稻纹枯病菌、玉米大斑病菌和玉米小斑病菌等7种农作物病原真菌的抑制作用。结果表明：猪沼原液和牛沼原液对其中的大豆尖孢镰刀菌、大豆菌核病菌、小麦纹枯病菌、小麦根腐病菌和水稻纹枯病菌5种病原真菌具有较好的抑制作用,其菌丝生长抑制率均在72%以上,但对玉米大斑病菌和玉米小斑病菌的菌丝生长基本没有抑制作用;相比之下,猪沼和牛沼离心上清液对以上5种病菌的菌丝生长抑制作用明显减弱,除猪沼离心上清液对大豆菌核病菌的菌丝生长抑制率大于70%以外,试验中猪沼和牛沼离心上清液对实验病原菌的菌丝生长抑制率基本都在60%以下。试验结果显示猪沼液和牛沼液对农作物病原真菌具有潜在的植物病害防治作用,为养殖场大中型沼气工程沼液应用新技术的开发提供科学依据。     

Antifungal activity of beta-asarone from rhizomes of Acorus gramineus

An antifungal substance was isolated from the extract of Acorus gramineus using various chromatographic procedures. The antibiotic was identified as beta-asarone, cis-2,4,5-trimethoxy-1-propenylbenzene, on the basis of the high-resolution EI-mass, NMR, and UV spectral data. Beta-asarone completely inhibited mycelial growth of some plant pathogenic fungi, Cladosporium cucumerinum,Colletotrichum orbiculare, Magnaporthe grisea, and Pythium ultimum, in a range of 0.5-30 microg/mL. The growth of Bacillus subtilis, Erwinia carotovora subsp. carotovora, Ralstonia solanacearum, and Xanthomonas campestris pv. vesicatoria was slightly suppressed by beta-asarone. As the concentration of beta-asarone increased, M. grisea infection was drastically inhibited on rice leaves. Treatment with 500 microg/mL of beta-asarone also greatly suppressed lesion formation of Co. orbiculare on cucumber leaves. This is the first study to demonstrate in vitro and in vivo antifungal activity of beta-asarone against plant fungal pathogens M. grisea and C. orbiculare.     

Disease control effect of strevertenes produced by Streptomyces psammoticus against tomato fusarium wilt

During screening of microorganisms producing antifungal metabolites, Streptomyces psammoticus strain KP1404 was isolated. The culture extract of this strain showed potent disease control efficacy against Fusarium wilt on tomato plants. The antifungal metabolites ST-1 and ST-2 were isolated from the culture extract using a variety of chromatographic procedures. On the basis of MS and NMR spectrometric analysis, the structures of the antifungal active compounds ST-1 and ST-2 were determined to be the polyene antibiotics strevertene A and strevertene B, respectively. In vitro, strevertenes A and B showed inhibitory effects against the mycelial growth of Alternaria mali , Aspergillus oryzae , Cylindrocarpon destructans , Colletotrichum orbiculare , Fusarium oxysporum f.sp. lycopersici, and Sclerotinia sclerotiorum , even at concentrations of 4-16 μg/mL. Fusarium wilt development on tomato plants was strongly retarded by treatment with 1 μg/mL of these strevertenes. The disease control efficacies of strevertenes on Fusarium wilt were as remarkable as that of benomyl.     

Fungistatic and bacteriostatic activities of alkamides from Heliopsis longipes roots: affinin and reduced amides

This work demonstrates the fungistatic and bacteriostatic activities of affinin, the main alkamide of Heliopsis longipes (Gray) Blake (Asteraceae) roots and two alkamides obtained by catalytic reduction of affinin: N-isobutyl-2E-decenamide and N-isobutyl-decanamide. The bioactivity was tested against Rhizoctonia solani groups AG3 and AG5, Sclerotium rolfsii, Sclerotium cepivorum, Fusarium sp., Vertcillium sp., phytopathogenic fungi; Phytophthora infestans, a phytopathogenic Chromista; Saccharomyces cerevisiae, a nonphytopathogenic ascomycete; and Escherichia coli, Erwinia carotovora, and Bacillus subtilis, bacteria. Affinin, being the primary component of the lipidic fraction, is expected to be responsible for the fungitoxic activity observed in roots of this plant species. Four of the assayed fungi showed an important sensitivity to the presence of affinin: S. rolfsii, S. cepivorum, P. infestans, and R. solani AG-3 and AG-5, displaying a growth inhibition of 100%. S. cerevisiaeshowed a similar growth inhibition with affinin. None of the alkamides obtained by catalytic reduction of affinin showed a fungitoxic activity. Affinin had a definite negative effect on the growth of E. coli and B. subtilis, but E. carotovora carotovora was not sensitive to the highest dose of affinin assayed. N-Isobutyl-2E-decenamide displayed a higher bacteriostatic activity against E. coli and E. carotovora carotovora. In both cases, this alkamide was more potent than affinin. On the other hand, only N-isobutyl-decanamide displayed a significant activity on the growth of B. subtilis.     

Broad-spectrum antimicrobial activity in vitro of the synthetic peptide D4E1.

Broad-spectrum antimicrobial activity of a synthetic peptide, D4E1, is documented in this paper. D4E1 inhibited the growth of several fungal phytopathogens belonging to four classes-Ascomycetes, Basidiomycetes, Deuteromycetes, and Oomycetes, and two bacterial pathogens, Pseudomonas syringae pv. tabaci and Xanthomonas campestris pv. malvacearum race 18. The minimum inhibitory concentration (MIC) of D4E1 required to completely inhibit the growth of all fungi studied ranged from 4.67 to 25 microM. Fungal pathogens highly sensitive to D4E1 include Thielaviopsis basicola, Verticillium dahliae, Fusarium moniliforme, Phytophthora cinnamomi, and Phytophthora parasitica. Comparatively, the least sensitive fungal pathogens were Alternaria alternata, Colletotrichum destructivum, and Rhizoctonia solani. The two bacterial pathogens, P. syringae pv. tabaci and X. campestris pv. malvacearum race 18, were most sensitive to D4E1 with MIC values of 2.25 and 1.25 microM, respectively. Microscopic analysis of D4E1 effects on fungal morphology of Aspergillus flavus and R. solani revealed abnormal hyphal growth and discontinuous cytoplasm. After 8 h of exposure to 25 microM D4E1, A. flavus spore germination was reduced by 75%. The suitability of peptide D4E1 to enhance disease resistance in transgenic crop plants is discussed.     

In vitro effects of Fusarium blight-controlling fungicides on pathogens of Poa pratensis

An experimental iprodione fungicide,3-(3,5dichlorophenyl)-N-(1-methylethyl)-2,4-dioxo-1-imidazolidinecarboxamide, controls Fusarium blight of Kentucky bluegrass (Poa pratensis L.), but it also amplifies the proportion of crowns colonized by Fusarium and the number of its propagules in soils. In contrast, the disease, the proportion of infected crowns, and the numbers of propagules in soil are generally suppressed by benomyl, methyl 1-(butylcarbamoyl)-2-benzimidazolecarbamate. Triadimefon, 1-(4-chlorophenoxy)-3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl)-2-butanone, also controls the disease but is not stimulatory or inhibitory of fusaria. Iprodione and benomyl were studied for their effects on growth and sporulation of Fusarium acuminatum isolated from diseased crowns; iprodione had no or slightly stimulatory effects, and benomyl greatly suppressed these processes, except in a benomyl-tolerant strain.Toxicities of iprodione and benomyl to 1555 identified Fusarium isolates from Kentucky bluegrass turf were determined, as were the toxicities of iprodione to 23 turfgrass pathogens. Of the Fusarium spp, only F. solani was significantly inhibited by iprodione, whereas all were inhibited by benomyl. Iprodione-sensitive fungi included species of Bipolaris, Corticium, Curvularia, Drechslera, Rhizoctonia, Sclerotinia, and Typhula. Insensitive fungi included Colletotrichum, Fusarium, Gaeumannomyces, and Pythium.Investigations with selective fungicides indicate that the primary causal agent of Fusarium blight is not among the fusaria, and that re-interpretation of the disease and its etiology is necessary.     

转防治软腐病基因拟南芥的获得及其抗病性研究

AHLs是细菌群体感应中的关键信号分子,参与包括导致作物软腐病的胡萝卜软腐欧文氏菌在内的许多植物病原菌致病因子的表达。AHL内酯酶能降解AHLs使其达不到临界浓度,从而阻断了病原菌的致病过程。将克隆到的AHL内酯酶基因SS10置于CaMV 35S启动子下构建双元载体,通过根癌农杆菌介导转化拟南芥。通过抗性筛选和分离比获得纯合转基因植物种子,进行了PCR及RT-PCR鉴定,证明目的基因在转基因拟南芥中整合并表达。初步抗病性实验表明,部分转基因植株具有显著的抗软腐病能力。     

Erwinia chrysanthemi 分离株CSCL006 hrpN 基因的克隆与高效表达

通过构建Erwinia chrysanthemi分离株 CSCL006的DNA文库，克隆出hrpN CSCL006基因，测序结果显示该基因编码区长1 020 bp; 推导的harpinCSCL006与Erwinia chrysanthemi EC16和3937编码的harpin蛋白同源性高，但与其它软腐菌 的harpin蛋白同源性较低; 在大肠杆菌中(Escherichia coli) 高效表达了hrpN CSCL006基因，重组harpinCSCL006蛋白分子量为34 kD。以抗harpinEcc 的抗体为探针,Western blot 证实该蛋白确为harpin; 纯化的harpinCSCL006, 能引起烟叶的过敏反应。