Trichoderma viride Strains against Vegetable Grey Mold in Greenhouse

[Objective] The paper aimed to study the control effects of live spore preparations of Trichoderma viride strains against vegetable grey mold in greenhouse. [Method] Trichoderma viride strains NW-411 live spore preparations were prepared by solid-state fermentation,106-107 spore/g diluent was made to conduct field control experiment,traits change of cucumber and tomato plants inoculated grey mold were investigated,control effect was calculated. [Result] Cucumber and tomato plants without dilution treatment of T. viride spores could be infected with different changes in trait. T. viride spore preparations had a significant preventive effect on greenhouse cucumber and tomato gray mold,the optimal concentration of spores was in the range of 2.3×10^6-2.3×10^7 spore/g. The incidence of cucumber and tomato plants were reduced to 4.2% and 3.1%,the incidence rate decreased 29.8% and 39.1% compared with plants without treatment,biological control effect was over 87%,and the plant growth can be enhanced obviously. [Conclusion] Live spores preparation of T. viride not only had a significant effect on grey mold,but also significantly enhanced the plants growth in greenhouse,which is a safety and environmental protection biological agent,and worthy to be widely spread in large-scale green vegetable production.

Trichoderma viride菌生物量测定及其纤维素酶合成特征

利用HPLC法测定Trichodermaviride菌固态发酵曲中的麦角固醇含量。研究了麦角固醇与菌丝体间的关系。该菌固态曲中麦角固醇分离条件以 1∶2 5 (m/v)的丙酮抽提 1 5h为最佳。当固态发酵培养至 69h时 ,曲中的生物量达到最大值 ,为每克干曲中含有 0 5 75 g菌丝体。此时该菌所产生CMC酶和FP酶活力均达到最大值 ,呈现正相关性 ,说明这 2种酶的合成特征均为同步合成型 ,而C1 酶活力高峰滞后 ,出现在 72h。

绿色木霉(Trichoderma viride)_(867)产壳聚糖酶的发酵工艺条件的优化

系统研究了碳源、氮源、初始pH、培养温度、培养基装液量、接种量和培养时间等因素对绿色木霉867产壳聚糖酶的影响.结果表明,最佳碳、氮源分别为可溶性壳聚糖和蛋白胨,在初始pH5.0,培养温度28℃,培养基装量75 mL/250 mL,接种量6%和培养时间(180 r/min)40 h时最利于产酶.在此基础上通过均匀设计法优化了发酵培养基配方.优化后的培养基配方为:可溶性壳聚糖0.9%,氨基葡萄糖0.5%,蛋白胨0.9%,K2HPO40.016%,CaCl2.2H2O 0.055%.在该条件下,壳聚糖酶活为0.291 u/mL,比原基础培养条件下酶活提高29.9%.

Physicochemical properties and release characteristics of calcium alginate microspheres loaded with Trichoderma viride spores

Novel agroformulations for simultaneous delivery of chemical and biologically active agents to the plants were prepared by encapsulation of Trichoderma viride spores in calcium alginate microspheres.The impact of calcium ions concentration on the viability and sporulation of T.viride spores as well as on the microsphere important physicochemical properties were investigated.Intermolecular interactions in microspheres are complex including mainly hydrogen bonds and electrostatic interactions.T.viride germination inside matrix and germ tubes penetration out of microspheres revealed calcium alginate microspheres provide a supportive environment for T.viride growth.Differences in physicochemical properties and bioactive agents release behaviour from microspheres were ascribed to the changes in microsphere structure.Fitting to Korsmeyer-Peppas empirical model revealed the underlying T.viride release mechanism as anomalous transport kinetics(a combination of two diffusion mechanisms and the Type II transport(polymer swelling and relaxation of the polymeric matrix)).The increasing amount of T.viride spores in the surrounding medium is closely related to the release from microspheres and germination.The rate controlling mechanism of calcium release is Fickian diffusion.A decrease in the release rate with increasing calcium ion concentrations is in accordance with the calcium ions effect on the strength of the alginate network structure.T.viride germination inside microsphere diminished the amount of released calcium ions and slowed release kinetics in comparison with microspheres prepared without T.viride.The results indicated investigated agroformulations have a great potential to be used for plant protection and nutrition.

Purification and characterization of the kinetic parameters of cellulase produced from wheat straw by Trichoderma viride under SSF and its detergent compatibility

This paper reports the purification and characterization of kinetic parameters of cellulase produced from Trichoderma viride under still culture solid state fermentation technique using cheap and an easily available agricultural waste material, wheat straw as growth supported substrate. Trichoderma viride was cultured in fermentation medium of wheat straw under some previously optimized growth conditions and maximum activity of 398±2.43U/mL obtained after stipulated fermentation time period. Cellulase was purified 2.33 fold with specific activity of 105U/mg in comparison to crude enzyme extract using ammonium sulfate precipitation, dialysis and Sephadex-G-100 column chromatography. The enzyme was shown to have a relative low molecular weight of 58kDa by sodium dodecyl sulphate poly-acrylamide gel electrophoresis. The purified enzyme displayed 6.5 and 55oC as an optimum pH and temperature respectively. Using carboxymethyl cellulose as substrate, the enzyme showed maximum activity (Vmax) of 148U/mL with its corresponding KM value of 68μM. Among activators/inhibitors SDS, EDTA, and Hg2+ showed inhibitory effect on purified cellulase whereas, the enzyme activated by Co2+ and Mn2+ at a concentration of 1mM. The purified cellulase was compatible with four local detergent brands with up to 20 days of shelf life at room temperature suggesting its potential as a detergent additive for improved washing therefore, it is concluded that it may be potentially useful for industrial purposes especially for detergent and laundry industry.

Construction of biological control strain of Trichoderma viride and study of their ability to induce plant disease resistance

Plant diseases heavily affct plant growth and crop yield even in modern agriculture. Control its difficult because pathogens mutate frequently, and this leads in frequent breaking of disease resistance in commercial cultivars. The excessive application of chemical pesticides is not only producing pesticide-resistant pathogens, but it is harming the environment threatening the health of human beings. Therefore, the use of biological control agents (BCA) may provide an environmental friendly alternative to chemicals for plant disease control. Hypersensitive response (HR) and systemic acquired resistance (SAR) are the typical expressions of plant defense reactions. Once SAR is established,, the plants exhibits a broad-spectrum of disease resistance against pathogen attack. Researchers have identified elicitor proteins, such as elicitins and harpins, which activate plant defense reactions. It would be useful to explore the possibility of using biological control agents to induce a status of SAR in crop plants. Trichoderma viride is an ubiquitous soil saprophyte and a biological control agent acting by competition for nutrients, antibiosis, and mycoparasitism. If T. viride could be used as a producer and carrier of an elicitor protein, it may be used as a novel BCA specifically active on some plants. To test this possibility, we used cryptogein, a proteinaceous elicitor secreted by Phytophthora cryptogea, to bio-engineering T. viride . The plasmid containing the Crypt gene or its mutated form, was introduced into T. viride genome by using the restriction enzyme mediated integration (REMI) method. The transformed T. viride was able to produce the Crypt protein and to improve disease resistance when the mutants were applied on tobacco plants. In summary our study included: 1. Construction of pCSNTCC and pCSNTCCm plasmids: Crypt gene was mutated by changing the K at position 13 of Crypt into a V (the mutated form was named CryK13V) as described elsewhere. In order allow secretion of the transgenic protein in T. viride cells, a signal sequence of a chitinase gene from Trichoderma (ThChi) was fused to the 5’ end of Crypt and CryK13V. The chimeric genes were placed under the control of trpC promoter in the vector pCSN43. A hygromycin resistant gene was introduced into the vectors, thus obtaining the plasmids pCSNTCC (for Crypt gene) and pCSNTCCm (CrypK13V) . 2. Establishment of a T. viride transformation system:The optimum conditions for T. viride protoplasts isolation and regeneration from were determined. For protoplast isolation, 24 hours-old hyphae of T. viride were digested with 4 mg/mL of Glucanex in phosphate buffer (pH 6.98) for 4 hours at 30 ℃, with a protoplast yield of 4.7×107 colony forming unit/mL. The maximum regeneration rate (14.5%) was obtained in the CM medium containing 0.3 mol/L KCl and 0.3 mol/L inositol. Plasmids pCSNTCC and pCSNTCCm were transformed into the protoplasts of T. viride by a Xho I restriction enzyme-mediated integration, with an efficiency of 1-2 transformants per microgram of DNA. Thirty transformants were obtained, TV-1 to TV-20 for Crypt gene and TV-21 to TV-30 for CrypK13V gene. The presence of the hygromycin resistance gene in the transformants was determined by polymerase chain reactions. The elicitor protein was detected in the culture media by western blot analysis but not inside the cells. The result indicated that the exogenous gene was expressed in T. viride , but the transgenic protein was entirely secreted into the culture media. 3. Expression of Crypt gene in T. viride enhanced plant disease resistance:Tobacco plants (4-6 week-old) were treated with spores of the transgenic or the wild-type T. viride applied to the soil. After ten days the plants or detached leaves were inoculated with Phytophthora parasitica var nicotianae, Alternaria alternata, Pseudomonas syringae pv. tabaci (Pst), or Tobacco mosaic virus (TMV). The lesions caused by TMV were suppressed by the treatment with the transgenic T. viride as compared with the wild-type

Using of green fluorescent reporter gene (GFP) to monitor the fate of Fusarium moniliforme mycoparasitized by Trichoderma viride

Fusarium moniliforme Sheld.is a rice pathogenic fungus and causes the disease called Bakanae,which has increasingly damaged rice production in the recent years. Trichoderma spp. has been one of the most widely used biological control agent of plant disease. By geneticaly labelling F. moniliforme with the GFP reporter gene, we have studied the antagonistic action of Trichoderma viride against this pathogenic fungus. The binary GFP reporter vector pCHF3-35S∷GFP was constructed, which carries the gfp gene driven by the CaMv35S promoter. The vector was transformed into F. moniliforme via Agrobacterium.The mycoparasitism of T.viride against F.moniliforme was tested by dual culture and examined with fluorescence microscope. The result of the dual culture showed that the T.viride maintained a strong competitive ability against F. moniliforme , by growing on the top of the pathogen colony. Fluorescence microscope observation indicated that attacked hyphae of F. moniliform were distorted, swollen or broken. This indicate an enzymatic by T.viride to degrade the host cell walls and used the cell contents as a source of nutrients (Fig 1) .

Effect of Trichoderma viride on activities of polygalacturonase of Rhizoctonia

The pectin is a backbone of the plant cell wall, its network structure will systemicly resolve when the plant cell splits up and forms. The pectinase produced by Rhizoctonia mainly acts on the pectin of cell wall, and causes the maceration of tissue and the death of protoplast. Polygalacturonase (PG) can decompose the galacturonic acid of disease tissue. The research defined the PG activities of extracellular metabolite of the different virulence Rhizoctonia isolates, and testifid the effect of Trichoderma viride to PG activities, and clarified the mechanisms of biocontrol by Trichoderma. The test methods as following: Firstly, to select the isolates of different virulence: WK-47, WK-141 and WK-160 strain of Rhizoctonia AG-D and YW-2 strain of Rhizoctonia AG1-IA and TCS-1 strain of Trichoderma viride. Secondly, to culture TCS-1 on PD, and draw a group of fermented liquid in every 24 hours, and draw 7 times. Thirdly, to culture quietly Rhizoctonia isolates with Czapek-Dox at 25℃ for 15 days, filter and centrifuge (2350 g×30 min), fetch the clear liquid, put it into the ammonium sulfate according to 60% saturation degree, put it quietly for 30 min at 4℃, centrifuge (21000 g×30 min) at 4℃, remove the clear liquid, dissolve the deposit with sodium acetate buffer (25 mmol/L, pH5.5), dialysis for 48 h in the same buffer,and change the buffer every 12 h, Fourthly, to put TCS-1 fermented broth of different times in the tubes, one mL per a tube, add 0.5 mL PG to every tube, react for 4 h in 30 ℃ water, the same time fetch the test tube filled with the same treated liquid that was not dealed in 30℃ water.Finally,to testify PG activities with DNS’s test. In all, PG of Rhizoctonia had high activities and virulence. The conrtrol efficacy of T.viride to PG activities of WK-47, WK-141, WK-160 and YW-2 were 95%,94%,95%,92% separately, fermented time had a great influence to control efficacy, the third fermented broth did the best. Through effect to PG activities T. viride can reduce the virulence of Rhizoctonia, and protect the hosts. The specific mechanism, qualitative and quantitative research of antagonistic substance in the fermented broth will be further carried out.

A novel strain of <i>Trichoderma viride</i>shows complete lignocellulolytic activities

In this study we describe a novel dark-green strain of Trichoderma viride exhibiting complete ensemble of cellulase, hemicellulase and ligninase activities on specific plate assays. To assess the cellulase production in detail, basal salt medium (BSM) was fortified with synthetic (carboxymethyl cellulose (CMC), glucose, sucrose, dextrose, lactose or maltose) and natural (flours of banana, banana peel, jack seed, potato or tapioca) carbon as well as nitrogen (yeast extract, beef extract, peptone, NaNO3 or NH4NO3) sources. Temperature and pH optima were 28°C and 4, respectively for the growth of the fungus in CMC-BSM with 137 U/mL cellulase activity, which was enhanced to 173 U/mL at 1.25% CMC concentration. Flours of potato and banana peel supported comparable yields of cellulase to that of CMC, while sodium nitrate was the preferred nitrogen source. The water soluble bluish-green pigment (a probable siderophore) extracted from the spores showed an absorption maximum at 292 nm. To sum up, the complete lignocellulolytic potential of this fungus offers great industrial significance, coupled with the production of a new pigment.

Effect of Trichoderma viride biofertilizer on ammonia volatilization from an alkaline soil in Northern China

Ammonia（NH3） volatilization is one of the primary pathways of nitrogen（N） loss from soils after chemical fertilizer is applied, especially from the alkaline soils in Northern China, which results in lower efficiency for chemical fertilizers. Therefore, we conducted an incubation experiment using an alkaline soil from Tianjin（p H 8.37–8.43） to evaluate the suppression effect of Trichoderma viride（T. viride） biofertilizer on NH3 volatilization, and compared the differences in microbial community structure among all samples. The results showed that viable T. viride biofertilizer（T） decreased NH3 volatilization by 42.21% compared with conventional fertilizer（（CK）, urea）, while nonviable T. viride biofertilizer（TS） decreased NH3 volatilization by 32.42%. NH3 volatilization was significantly higher in CK and sweet potato starch wastewater（SPSW） treatments during the peak period. T. viride biofertilizer also improved the transfer of ammonium from soil to sweet sorghum. Plant dry weights increased 91.23% and 61.08% for T and TS, respectively, compared to CK. Moreover, T. viride biofertilizer enhanced nitrification by increasing the abundance of ammonium-oxidizing archaea（AOA） and ammonium-oxidizing bacteria（AOB）. The results of high-throughput sequencing indicated that the microbial community structure and composition were significantly changed by the application of T. viride biofertilizer. This study demonstrated the immense potential of T. viride biofertilizer in reducing NH3 volatilization from alkaline soil and simultaneously improving the utilization of fertilizer N by sweet sorghum.

绿色木霉对甜瓜立枯病防治效果及其生理机制初探

研究了一株绿色木霉菌Trichoderma viride Tv286对立枯丝核菌Rizoctonia solani(Rs)侵染引起的甜瓜立枯病的防治效果,并测定了Tv286对甜瓜幼苗生长、生理特性的影响。结果显示,Tv286处理对甜瓜枯萎病的盆栽防效超过85%,能显著促进甜瓜幼苗的生长,提高幼苗的生理活性。其中以土壤施入106cfu/g Tv286菌剂的处理对甜瓜立枯病的防效最高,对幼苗的生长和生理活性的促进作用最强。与病菌对照处理相比,其幼苗株高、茎粗、叶面积、全株鲜重、全株干重、根冠比和壮苗指数分别提高了51.64%、39.93%、44.49%、36.99%、119.18%、79.45%和122.73%;叶片总叶绿素含量、根系活力、硝态氮含量、硝酸还原酶活性、可溶性糖和可溶性蛋白含量分别提高了40.02%、43.64%、13.85%、118.34%、105.46%和153.78%;根体积、总吸收面积、活跃吸收面积、根系活跃吸收面积百分比、根比表面积分别提高了32.02%、74.18%、135.09%、34.97%和31.96%。上述结果说明,本研究的绿色木霉Tv286通过提高甜瓜幼苗生理特性,促进了幼苗生长,提高了对立枯病的抗性。

稀释接种法和二次发酵法制备的绿色木霉生物有机肥肥料效应比较研究

生物有机肥中的功能性微生物是生物有机肥肥效的核心,生物有机肥的制造工艺决定了功能性微生物的数量和应用效果,绿色木霉兼具的促生和生防功能现已被广泛应用于生物有机肥的制备中。分别采用稀释接种法和二次发酵法在不同腐熟度(种子发芽指数GI值为50%、80%、100%)的堆肥物料接种绿色木霉制备生物有机肥,采用盆栽试验,研究两种工艺类型的生物有机肥在辣椒根系定殖能力及其对辣椒疫病的防控作用。结果发现,施用生物有机肥24 d后,经过二次发酵法生产的生物有机肥(分别在堆肥物料GI值为50%、80%和100%时接种绿色木霉进行二次发酵生产的生物有机肥)的绿色木霉在辣椒植株根系定殖量分别为1.5×10^(5)、2.3×10^(5)和1.02×10^(5)CFU/g,按照稀释接种法生产的生物有机肥(分别在堆肥物料GI值为50%、80%和100%时,按照稀释倍数接种绿色木霉生产的生物有机肥)的绿色木霉定殖量分别为0.29×10^(5)、0.72×10^(5)和0.24×10^(5)CFU/g;在GI值为80%的堆肥物料条件接种绿色木霉,经过二次发酵生产的生物有机肥,绿色木霉在辣椒根际定殖能力最强;经过二次发酵的生物有机肥处理的辣椒疫病防治效果显著高于按照稀释倍数接种绿色木霉制成的生物有机肥处理,且以GI值为80%的堆肥物料条件生产的生物有机肥的辣椒疫病防治效果最好。研究结果发现,以GI值为80%的堆肥物料接种绿色木霉后,采用二次发酵方式生产的生物有机肥,7 d后的绿色木霉菌增殖量为3.91倍,表现出功能性微生物最好的增殖和定殖效果。综上所述,在制备绿色木霉生物有机肥时的最佳方法是在腐熟度为80%的堆肥物料中接种绿色木霉进行二次发酵,可以提高绿色木霉的定殖效果,也可以提升绿色木霉生物有机肥的抗病效果。

绿色木霉碱性蛋白酶基因TvALP的克隆与原核表达

基于绿色木霉中抗菌蛋白质的de-novo质谱测定得到的部分肽段序列,通过BLASTp数据库检索,发现该肽段由碱性蛋白酶基因编码,采取同源克隆技术扩增出目的基因片段。生物信息学分析揭示,TvALP基因(GenBank编号KJ659907)完整开放读码框为1 230 bp,并编码了一个由409个氨基酸组成的蛋白质。该蛋白质的预测分子量约为43 kD,且含有一段由20个氨基酸组成的信号肽。根据分类,该蛋白质属于Peptidase inhibitor_I9超家族,并且是枯草杆菌蛋白酶家族丝氨酸蛋白酶S8家族的一个成员。利用双酶切法将测序正确的质粒连接至原核表达载体pET30a中,在宿主菌BL21(DE3)pLysS中诱导表达。结果在45 kD处显示出1条特异蛋白质条带,与生物性信息预测目的蛋白大小一致,表明切除信号肽的表达质粒pET30a-ΔTvALP(“Δ”表示切除信号肽)在宿主菌BL21(DE3)pLysS中成功表达。经超声波破碎后,蛋白形成了包涵体。但经体外复性技术,未能获得有活性的蛋白进行抗菌机理研究。

木霉菌与多种杀菌剂生物相容性研究

【目的】探究哈茨木霉(Tcomp、TH1和TH3)和绿色木霉(TV1)菌株与防治种子传播和叶部病害的不同活性成分杀菌剂之间的生物相容性,以期在植保工作中减少化学农药的使用,响应综合防治的植保方针。【方法】通过菌丝生长、分生孢子产量、孢子萌发率评估7种不同杀菌剂(包含复配)对4株木霉菌株的抑制作用强弱,以期筛选出与之生物相容性最好的农药。【结果】从菌丝生长方面来看,4种木霉菌株与福满双的相容性最差,在中、高浓度下相容性均为0,4种木霉菌株与环酰菌胺的相容性最好,从14 d后,相容性均为100%。从孢子产量和萌发方面来看,4种木霉菌株与环酰菌胺的相容性最好,在最高浓度下,最低的相容性达到了22.5%。4种木霉菌株与嘧霉胺的相容性最差,各种浓度下4种木霉菌株的相容性均不超过20%,最低的为0。【结论】环酰菌胺与4株木霉菌株的相容性最好,其次为嘧菌胺。百菌清、吡唑醚菌酯+啶酰菌胺、嘧菌环胺+咯菌腈与4株木霉菌株的相容性相当,均为中等偏高,而福满双和嘧霉胺与4株木霉菌株的相容性最差。

绿色木霉B3菌株的抑菌谱及其抑菌活性

为探究绿色木霉(Trichoderma viride)B3菌株的抑菌谱及其抑菌作用活性,采用对峙培养与显微观察相结合的方法测定绿色木霉B3菌株的抑菌谱和抑菌作用活性。结果表明,绿色木霉B3菌株对供试的8种植物病原真菌具有拮抗效果,对丛梗孢(Monilia sp.)和灰葡萄孢(Botrytis cinerea)菌落生长的抑制作用最强,生长抑制率分别为90.8%和88.9%,拮抗等级为Ⅰ级;对苹果链格孢菌(Alternaria mali)的生长抑制作用最弱,生长抑制率仅为48.2%,拮抗等级为Ⅲ级。对峙培养发现,绿色木霉B3菌株对丛梗孢的抑制作用主要通过与病原菌竞争生长空间实现,在两菌落的接触处,病原菌菌丝出现附着、缠绕、膨大、缢缩等现象。综上,绿色木霉B3菌株对丛梗孢和灰葡萄孢具有显著的拮抗作用。

绿色木霉的生物学特性及对盐胁迫下玉米幼苗生长的影响

[目的]明确绿色木霉(Trichoderma viride)真菌的生物学特性及对盐胁迫下玉米幼苗的缓解机制。[方法]对前期筛选出一株绿色木霉菌株进行生物学特性分析,并通过测定绿色木霉对盐胁迫下玉米幼苗株高、根长、地上部分干质量、地下部分干质量、根冠比、叶绿素a含量、叶绿素b含量、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、多酚氧化酶(PPO)等指标的影响,探讨绿色木霉对盐胁迫下玉米幼苗生长及生理指标的影响。[结果]菌株的最适生长温度是25℃;24 h黑暗处理下菌落直径显著高于12 h黑暗+12 h光照、24 h光照2个处理;菌株在pH为5时生长最快。添加不同浓度绿色木霉孢子悬浮液后,盐胁迫下玉米幼苗株高、根长、地下部分及地上部分干质量、叶绿素a和叶绿素b含量、SOD活性、POD活性、CAT活性、PPO活性均呈现逐渐上升的趋势。[结论]研究结果可为提高玉米在盐碱土壤种植效率提供基础资料。

Cloning of Endo-β-Glucanase Ⅲ and Expression in Eerevisiae Fermentum

Objective The aim was to construct bioengineering strains that could degrade the cellulosic solid waste. Method The cDNA of endo-β-glucanase III of Trichoderma vi ride AS313711 was cloned by RT-PCR method. After sequenced, this gene was constructed to expression vector pESP-2, and then the plasmid was transformed into competent cell of cerevisiae fermentum by electric shock, the transformant was then obtained. The enzyme activity of this transformant at the different temperatures and pH was measured by DNS method. Result The length of ORF of EG III was 1 257 bp, encoding 418 amino acids, while the deduced molecular weight was 44.1 × 103 kD. Conclusion The enzyme activity of EG III was the highest when it was at PH 4.9 and tempeture was of 60℃. Then the corresponding enzyme activity was about 100%.

绿色木霉TR-8菌株对尖镰孢的拮抗机制

对绿色木霉TR 8菌株抑制尖镰孢的拮抗机制进行了研究。平板对峙培养结果表明,绿色木霉生长快于尖镰孢FO G1,接触后FO G1生长停止,TR 8继续生长,覆盖FO G1的菌落并大量产孢,但不形成抑菌圈。观察了TR 8对FO G1的重寄生现象,TR 8菌丝首先向FO G1趋性生长,然后紧贴FO G1菌丝平行生长或穿入菌丝生长,最后FO G1菌丝瓦解。在扫描电镜下可以看到FO G1菌丝原生质凝结,菌丝上有孔洞出现。发酵7d,TR 8发酵液中β1,3 葡聚糖酶的活性为20 15U/ml,几丁质酶的活性为11 67U。发酵原液对FO G1菌丝生长和孢子萌发均无抑制作用,但TR 8的挥发性分泌物对病菌孢子萌发具有一定的抑制作用。含有TR 8分泌物的培养基对病菌孢子萌发有很强的抑制作用,抑制率高达75 06%。

西瓜枯萎病拮抗菌株筛选及田间防效试验

本试验通过大量分离筛选 ,共获得对西瓜枯萎病菌具有较强拮抗作用的木霉 9株及细菌 1 0株 ,其中以绿色木霉TR 8菌株和芽孢杆菌B6 7菌株的拮抗作用最强。将两菌株分别发酵后 ,制备成TR 8制剂和B6 7制剂 ,并将两菌株发酵物混合后制备成健根宝粉剂。室内人工接种试验表明 ,3种拮抗菌制剂对西瓜枯萎病均有较好的防治效果 ,尤以健根宝粉剂的防治效果最理想。田间试验表明 ,健根宝粉剂以 1∶50拌土在播种时穴施 ,对西瓜枯萎病的防效达80 %以上 ,显著高于常用药剂多菌灵和施特灵。此外 。

绿色木霉TR-8菌株的生物学特性研究

绿色木霉菌TR-8是一株具有生防潜力的拮抗菌。研究发现TR-8菌株在PDA培养基、查彼培养基和基本培养基上均能较好生长,在基本培养基上生长最快,3种培养基对孢子产生影响不大。温度对菌丝生长和孢子产生影响显著,30℃时菌丝生长最快,25℃时产孢量最大。TR-8菌株在pH值2～10范围内均可生长,pH值5～6时菌丝生长最快,pH值为7时孢子产生量最大。光照处理对菌丝生长影响不明显,但可明显促进孢子产生。葡萄糖和麦芽糖为菌丝生长和产孢的最佳碳源。天冬酰胺是菌丝生长和孢子产生的最佳氮源。不同维生素对菌丝生长和孢子产生作用不同,烟酸对菌丝生长最有利。微量元素对菌丝生长有一定的促进作用,Mn有利于孢子产生。镰刀菌的菌丝提取物对TR-8的孢子产生具有促进作用。