玫烟色拟青霉北京变种

1980年,自北京农家温室内,温室白粉虱(Trialeurodes vaporartorum)上分离到玫烟色拟青霉(Paecilomyces fumosoroseus)的若干菌株。用13号菌株的典型培养与本菌的原种做比较,发现在形态上与原种相似,但菌落色泽、生长速度及形成孢梗束的能力不同。故定名为玫烟色拟青霉北京变种(P.fumosoroseus var.beijingensis Fang et Q.T.Chen n.var.)。     

玫烟色拟青霉最适液体培养条件的研究

通过对不同营养和不同培养条件下玫烟色拟青霉菌丝生物量和产孢量的研究,结果表明:葡萄糖为玫烟色拟青霉液体培养的最适碳源,蛋白胨为该菌生长的最适氮源,C/N为10∶1~20∶1最适于玫烟色拟青霉菌丝生长和产孢;25℃2、4 h全光照条件,对该菌生长和产孢均有利。接种后144~168 h时,菌丝生物量和产孢量均达到高峰,分别为31.72 mg/mL、24.62孢子/mL,为黑暗条件下的1.5倍和18.3倍,因此玫烟色拟青霉液体发酵终点应选择在接种后144~168 h为最好。     

玫烟色拟青霉和吡虫啉对烟粉虱种群的联合控制作用

利用生命表技术评价了在网室条件下玫烟色拟青霉和吡虫啉对烟粉虱种群的控制作用。在0·3%吡虫啉 1×106分生孢子/ml、0·1%吡虫啉 1×106分生孢子/ml、10%吡虫啉、1·0×106个孢子/ml菌液、1·0×106个孢子/ml菌液连续施用2次等5个不同的处理区,玫烟色拟青霉对第一代和第二代烟粉虱的种群干扰作用控制指数(IIPC)分别为0·5476、0·6836、0·3123、0·7278、0·4959和0·1566、0·1625、0·9830、0·2532、0·1349。其中,以使用0·3%吡虫啉 1·0×106分生孢子/ml处理区对烟粉虱种群的控制效果最好。玫烟色拟青霉与低浓度的吡虫啉混合使用能较好地发挥联合控制作用,对玫烟色拟青霉的累积控制效应无负面影响。     

害虫防治用玫烟色拟青霉分生孢子粉的干燥工艺优化

用液－固两相法生产的玫烟色拟青霉Paecilomyces fumosoroseus Pfr116菌株的分生孢子粉,在高真空冷冻干燥,高真空室温抽干,35℃下烘干和低真空低热干燥条件下进行不同程序的干燥处理,以筛选适合该菌孢子粉生产的干燥工艺条件。结果表明,低真空（0.1MPa),低热（30℃）抽干20－24h的干燥方法最适合用于该菌孢子粉的干燥,既能保证含水量在9.0%以下,又能保证87％以上的活孢率和1130亿－1310亿／g的含孢量,而且操作简便,成本较低,可作为高纯度孢子粉生产的首选干燥工艺,高真空（15.86Pa)条件下无论冻干还是室温抽干,虽然孢子粉的含水量（2．2％－8．7％）和含孢量（1270亿－1360亿/g)指标符合生产要求,但活孢率仅62％,说明该菌孢子不适合在高真空条件干燥,在35℃下烘干24h所获孢子粉含水量,24h萌发率和含孢量分别为9．6％,82．8％和1200亿／g。该方法也可在生产中应用,但其活孢率显著低于（P＜0．05）,低真空低热抽干≤24h的孢子粉。     

玫烟色拟青霉对小菜蛾致病力的时间-剂量-死亡率模型模拟

小菜蛾Plutella xylostella是我国南方十字花科蔬菜上的重要害虫,已对田间常用的化学杀虫剂产生了严重的抗性。为寻找有效的小菜蛾生物防治措施,本实验研究了一株分离自家白蚁的玫烟色拟青霉Paecilomyces fumosoroseus (SCAU-PFCF01)对小菜蛾2～4龄幼虫的致病力。实验采用浸液法,供试浓度为1×10³、1×10⁴、1×10⁵、1×10⁶和1×10⁷个孢子/mL。结果表明：随玫烟色拟青霉孢子浓度的升高,小菜蛾的感病死亡率增加,在浓度为1×10⁷ /mL时,小菜蛾2、3和4龄幼虫的累计死亡率分别为96%、85%和80%。玫烟色拟青霉对小菜蛾各龄幼虫的致病力与供试龄期有关,其感病的敏感顺序为2龄、3龄和4龄。用时间 剂量 死亡率模型（time-dose-mortality model,TDM）对各龄幼虫的致病力数据进行模拟,所建模型均顺利通过Hosmer-Lemeshow拟合异质性检验,表明模型拟合良好,并由模型估计出了该菌株对小菜蛾各龄幼虫的致死剂量与致死时间。2龄幼虫接种后第7天、3龄幼虫接种后第5天、4龄幼虫接种后第4天的LC₅₀估计值分别为1.17×10⁴、1.44×10⁴和5.21×10⁴ /mL,LC₉₀估计值分别为1.98×10⁶、3.82×10⁷和1.29×10⁸ /mL。玫烟色拟青霉对小菜蛾幼虫的致死时间与浓度相关,供试各龄幼虫的LT₅₀值随着孢子悬浮液浓度的增加而递减,在1×10⁵～1×10⁷ /mL的范围内,2龄幼虫的LT₅₀值从3.16天降低到1.72天,3龄幼虫的LT₅₀从3.21天降低到1.83天,4龄幼虫的LT₅₀从3.69天降低到2.04天。即2龄幼虫致死所需的时间最短,其次为3龄幼虫,4龄幼虫致死所需的时间最长。结果显示了该株玫烟色拟青霉在小菜蛾的生物防治中具较强的应用潜力。     

菜青虫感染玫烟色拟青霉后血淋巴蛋白质含量及几种保护酶活力的变化

对玫烟色拟青霉Paecilomyces fumosoroseus侵染3、4龄菜青虫Pieris rapae后,其血淋巴中蛋白质含量、体内保护酶及谷胱甘肽S-转移酶活力进行了研究。结果表明,感病的3、4龄菜青虫血淋巴中蛋白质含量明显低于同期未感染的幼虫;感病虫体内超氧化物歧化酶、过氧化氢酶和过氧化物酶的活力发生了不同程度的改变,其中对3龄菜青虫体内酶活力的影响比4龄幼虫大。此外被侵染的3、4龄菜青虫体内谷胱甘肽S-转移酶活力在感病前期显著高于同期未感染的菜青虫,而在感病后期明显低于同期未感染的菜青虫。     

碳源对玫烟色虫草菌丝生长、芽生孢子产生及其耐热性的影响

提高虫生真菌孢子应对热胁迫的能力是生防菌应用研究的关键,为研究菌丝培养阶段碳源对玫烟色虫草Cordyceps fumosorosea IF-1106耐热性的影响,选择了麦芽糖、可溶性淀粉、蔗糖、葡萄糖、果糖、海藻糖为碳源的培养基对玫烟色虫草IF-1106进行液体培养,评估了不同碳源条件下菌丝的生长、产孢及所产芽生孢子的耐热性。结果表明,在菌株培养阶段,培养基中碳源的种类及浓度对菌丝产量、产孢量及所产芽生孢子的耐热性有显著影响,其中蔗糖为碳源时,所产芽生孢子的耐热性强,45 ℃热胁迫条件下LT₅₀为1.65 h;蔗糖浓度为40 g/L时,可产生大量耐热芽生孢子,液体培养3 d后产孢量可达3.43×10⁷个孢子/mL。为探索不同培养条件下所产芽生孢子耐热性不同的原因,提取了孢子内的海藻糖并采用离子色谱法对其进行了定量分析,发现耐热性高的芽生孢子胞内海藻糖含量普遍较低,可见海藻糖是与芽生孢子耐热性密切相关的内源物质。综上所述,选择适宜的培养基是调控孢子耐热性的有效途径,本研究为生产高耐热的玫烟色虫草生防制剂提供了有益的指导。     

温湿度对玫烟色棒束孢IF‐1106菌株孢子萌发及对烟粉虱致病力的影响(英文)

B型烟粉虱Bemisia tabaci Gennadius是一种重要的世界性农业害虫。玫烟色棒束孢Isaria fumosorosea是防治烟粉虱的一种重要的虫生真菌。对不同温度(20、23、26、29、32℃)、不同湿度(53%、65%、75%、85%、95%)下玫烟色棒束孢IF‐1106菌株分生孢子萌发及其对烟粉虱的致病力进行了测定。结果表明:温度对孢子的萌发有显著影响,26℃时孢子萌发率最高。当相对湿度低于75%时,孢子不萌发或萌发率较低;当相对湿度为85%–95%时,孢子萌发率显著升高。26℃时,烟粉虱2龄若虫的累计死亡率最高。随着相对湿度增大,病菌的致病力增强。当相对湿度为53%–95%时,烟粉虱2龄若虫累计死亡率从54.55%增加到88.89%。玫烟色棒束孢的致病力与孢子萌发率呈正相关,但温度比相对湿度对其影响更明显。结果表明,玫烟色棒束孢IF‐1106菌株侵染烟粉虱的最佳条件是温度26℃和相对湿度大于85%。     

蝉拟青霉LB菌株的生物学特性

本文研究碳源、氮源、温度、湿度、pH值和光照等对蝉拟青霉LB菌株生长、产孢和孢子萌发的影响.结果表明,适合该菌株菌落生长和产孢的最佳碳源是可溶性淀粉和蔗糖,最佳氮源为蛋白胨;菌丝生长和孢子萌发的最适温度范围是25℃～27℃,产生分生孢子的最适温度是25℃;分生孢子萌发所需湿度范围是RH 90%～100%,当RH低于90%时很难萌发;在pH值4～10的范围内该菌能生长和产孢,菌丝生长最适pH为6,产生分生孢子和孢子萌发最适pH范围为6-7;光照处理对该菌产孢有一定的影响;分生孢子的致死条件为55℃ 10min.生物学特性显示,蝉拟青霉LB菌株是一株对营养要求不高、对环境适应能力较强的昆虫病原真菌.     

两种表面活性剂对玫烟色棒束孢PF904菌株侵染小菜蛾幼虫的影响

[目的]在前期筛选试验的基础上,比较表面活性剂对玫烟色棒束孢Isaria fumosoroseus PF904菌株侵染小菜蛾Plutella xylostella 3龄幼虫的增效作用,获得可提高玫烟色棒束孢PF904防治效果的助剂.[方法]通过扫描电镜观察和室内致病力试验,测定喷施分别添加表面活性剂聚二甲基硅氧烷(OF...     

Electrophoretic karyotyping of the entomogenous fungus Paecilomyces fumosoroseus

Pulsed-field gel electrophoresis was used to compare the electrophoretic karyotypes of isolates of Paecilomyces fumosoroseus. Electrophoretic karyotypes of P. fumosoroseus exhibit a high degree of similarity among the isolates. However, hybridization data indicated that similar sized chromosomes among the isolates did not always bear the same genetic information.     

Inactivation of Paecilomyces fumosoroseus conidia by diffuse and total solar radiation

Abstract: The detrimental photic effects of natural solar radiation on the conidial persistence of the entomopathogenic hyphomycete Paecilomyces fumosoroseus were investigated by exposing quiescent conidia either to total solar radiation or to its diffuse component. A given amount of UVB diffuse radiation was found to be as detrimental, and sometimes twice as detrimental, as the same amount of total solar radiation. The variability in quantity and spectral distribution of the diffuse component of UVB solar radiation reaching the earth's surface, observed through spectral measurements, may be responsible for the difference in biological effects.     

Transformation of the entomopathogenic fungus Paecilomyces fumosoroseus with Agrobacterium tumefaciens

AIMS: To test the suitability of the Agrobacterium tumefaciens-mediated transformation (AMT) method with Paecilomyces fumosoroseus, a fungal pathogen that causes diseases in a wide range of insects including whiteflies. METHODS AND RESULTS: Conidia of P. fumosoroseus were successfully transformed to hygromycin B resistance using the hph gene of Escherichia coli as the selectable marker. Transformation frequencies were 58.3 +/- 18.5, 98.3 +/- 24.8 and 169.7 +/- 35.5 (+/-SEM) transformants per 10(5), 10(6) and 10(7) target conidia respectively. After confirmation by PCR, transformants were subjected to Southern analysis, and the results revealed that 45% (four of nine) of the transformants contained single-copy integration of the T-DNA. CONCLUSIONS: In our AMT system, we efficiently transformed conidia of P. fumosoroseus. The employment of this method circumvents time-consuming protoplast preparation and allows the isolation of transformants containing single-copy integration of the T-DNA. SIGNIFICANCE AND IMPACT OF THE STUDY: Considering the efficiency of Ag. tumefaciens-mediated transformation, this method represents a useful tool for insertional mutagenesis to characterize genes that are important for the pathogenicity of P. fumosoroseus.     

Influence of culture conditions on production and freeze-drying tolerance of Paecilomyces fumosoroseus blastospores

With the goal of developing a defined medium for the production of desiccation-tolerant blastospores of the bioinsecticidal fungus Paecilomyces fumosoroseus, we evaluated the impact of various media components such as amino acids, carbohydrates, trace metals and vitamins on hyphal growth and sporulation of P. fumosoroseus cultures and on the freeze-drying tolerance of blastospores produced under these conditions. A comparison of 13 amino acids as sole nitrogen sources showed that glutamate, aspartate, glycine and arginine supported biomass accumulations (12–16 mg ml⁻¹) and blastospore yields (6–11 × 10⁸ blastospores ml⁻¹) comparable to our standard production medium which contains casamino acids as the nitrogen source. Using glutamate as the sole nitrogen source, tests with various carbohydrates showed that P. fumosoroseus grew best on glucose (18.8 mg biomass ml⁻¹) but produced similar blastospore concentrations (7.3–11.0 × 10⁸) when grown with glucose, glycerol, fructose or sucrose. P. fumosoroseus cultures grown in media with sodium citrate or galactose as the sole carbohydrate produced lower blastospore concentrations but more-desiccation-tolerant spores. Zinc was the only trace metal tested that was required for optimal growth and sporulation. In a defined medium with glutamate as the nitrogen source, vitamins were unnecessary for P. fumosoroseus growth or sporulation. When blastospores were freeze-dried in the absence of a suspension medium, residual glucose (>2.5% w/v) was required for enhanced spore survival. Thus, a defined medium containing basal salts, glucose, glutamate and zinc can be used to produce optimal concentrations of desiccation-tolerant blastospores of P. fumosoroseus. Received 27 October 1998/ Accepted in revised form 06 May 1999     

Influence of temperature preferences of two Paecilomyces fumosoroseus lineages on their co-infection pattern

In order to clarify the epidemiological potential of entomopathogenic fungi for insect pest control, the role of the temperature as one environmental constraint was investigated on the pattern of co-infection of Galleria mellonella by two distinct lineages of a hyphomycete, Paecilomyces fumosoroseus. The distribution of conidial populations collected on cadavers of hosts co-infected under 20 regimes, ranging from 13 to 35 degrees C, was examined. The apparent temperature tolerance of both fungal isolates was related to their in vitro colony growth and their in vivo sporulation ability. The conidial populations were characterized by molecular markers based on restriction fragment length polymorphisms of the internal transcribed spacers (ITS-RFLP) and random amplified polymorphic DNA (RAPD) contrasting profiles in combination with the conidial size. This study allowed a different temperature profile was identified for each isolate. Under most temperature regimes, only one lineage prevailed upon the infected insect; whereas both lineages coexisted at 20-25 and 25-25 degrees C. When one haplotype dominated, the displacement of the other one depended on its temperature tolerance. These results suggest that more consideration should be given to population-genetics analyses for evaluating the adaptability of microbial control agents to targeted environments.     

Isolation of dipicolinic acid as an insecticidal toxin from Paecilomyces fumosoroseus

Several entomopathogenic fungi produce toxins that could be used as bioinsecticides in integrated pest management programs. Paecilomyces fumosoroseus is currently used for the biological control of the whiteflies Bemisia tabaci and B. argentifolii. Supernatants from submerged batch culture, where the fungus produced abundant dispersed mycelium, conidia and blastospores, were toxic to the whitefly nymphs. The most abundant metabolite was purified by HPLC and identified by mass spectrometry and NMR as dipicolinic acid. Both the dipicolinic acid produced by the fungus and the chemically synthesized compound had insecticidal activity against third-instar nymphs of the insect. Dipicolinic acid was toxic to the whitefly nymphs in bioassays involving topical applications. In submerged culture, the specific growth rate of P. fumosoroseus was 0.054 h⁻¹, the specific glucose consumption rate was 0.1195 g g⁻¹ h⁻¹ and the specific dipicolinic acid production rate was 0.00012 g g⁻¹ h⁻¹. Dipicolinic acid was detected after 24 h when the fungus started growing; and dipicolinic acid production was directly correlated with fungal growth. Nevertheless, the yield was low and the maximal concentration was only 0.041 g l⁻¹. The maximal concentrations of conidia and blastospores (per milliliter) were 1.4×10⁸ and 7×10⁷, respectively.     

A foam formulation of Paecilomyces fumosoroseus,an entomopathogenic biocontrol agent

Several classes of surfactants/foaming agents were screened for compatibility with blastospores of Paecilomyces fumosoroseus. The surfactants were assayed to determine their influence on the rate of germination, viability and conidia production by the blastospores. Surfactants compatible with blastospores were then assayed for their foam forming properties using a commercially available foam generator. These tests identified keratin hydrolysate as the only suitable surfactant in terms of biocompatibility and foam forming properties. Laboratory bioassays were conducted to determine the effect of keratin hydrolysate on the efficacy of blastospores against Formosan subterranean termites. The results showed keratin hydrolysate increased the efficacy of P. fumosoroseus and suggest that this foam formulation of P. fumosoroseus may be useful in controlling Formosan subterranean termites.     

玫烟色拟青霉适温性及抗多菌灵特性的种内变异

在15 ℃～35 ℃的温度范围内比较测定了玫烟色拟青霉(Paecilomyces fumosoroseus) 6株野生菌的菌落生长、产孢量及孢子活力.结果显示,3个指标均以25 ℃左右最好,但同一温度下菌株间或同一菌株在不同温度下的差异显著, 菌株Pfr116和Pfr6206具有相对稳定优良的生长、产孢及活孢率性状.对不同浓度多菌灵对6株野生菌的菌落生长和单孢菌落形成的影响测定表明,菌株间存在较大差异.不同多菌灵浓度对单孢菌落形成的抑制率观察值可用逻辑斯蒂模型较好地拟合(r²≥0.90).用所获参数估计的最低禁菌浓度MIC值显示,Pfr4205和Pfr116对多菌灵表现为低抗性（MIC≤20.0 μg·ml^-1）;Pfr153、Pfr612和Pfr2175属于低水平中抗,MIC值仅略大于20 μg·ml^-1;而Pfr6206的MIC值高达93.5 μg·ml^-1,接近MIC>100 μg·ml^-1的高抗标准.因此,Pfr6206为适温性和抗多菌灵特性俱佳的菌株,可作为抗多菌灵和适应不同季节或地区的害虫生防菌剂的候选菌株.     

Isolation and characterization of microsatellite loci from the entomopathogenic hyphomycete,Paecilomyces fumosoroseus

Nine microsatellite markers were isolated from the entomopathogenic haploid fungus Paecilomyces fumosoroseus. Genetic diversity was assessed in 26 P. fumosoroseus isolates originated from the whitefly Bemisia tabaci collected in various geoclimatic areas. Eight loci were polymorphic with an observed number of alleles ranging from two to six. The loci differentiated some isolates and group of isolates according to their geographical location, showing promise for the study of gene flow. All loci failed to give clear amplifications in P. fumosoroseus isolates from hosts other than B. tabaci. These microsatellite markers provide powerful tools for ecological, epidemiological, and population genetic studies.     

Effect of serial transfer of three strains of Paecilomyces fumosoroseus on growth in vitro, virulence, and host specificity

Serial passage of entomopathogenic Hyphomycetes has been shown to alter virulence and host specificity. We evaluated virulence, host specificity, biomass production, conidiation, conidial germination, and a genetic fingerprint of 3 strains of Paecilomyces fumosoroseus after passage in vitro or in vivo in Diuraphis noxia or Plutella xylostella. Strain 4461 did not change in virulence toward D. noxia or P. xylostella after 30 passages in vitro nor after 15 passages in D. noxia. However, it lost virulence toward D. noxia after 15 passages in P. xylostella and did not regain virulence after 5 passages in D. noxia. Passage in D. noxia did result in a loss in conidiation for strain 4461, and passage in vitro resulted in a reduction in the speed of germination. Strain 4481 was the least variable and did not change in any of our tests. Strain 4491 did not change in virulence after passage in vitro nor after passage in D. noxia. It lost virulence toward D. noxia after passage in P. xylostella but regained virulence after re-passage in D. noxia. Mycelial dry weight and conidiation were both reduced after passage in vitro, but were increased after passage in D. noxia. These two traits did not change after passage in P. xylostella. Germination speed was reduced after in vitro passage of strain 4491. No change in banding pattern was observed for any strain using 14 primers for RAPD-PCR. These results demonstrate the intraspecific variability and phenotypic plasticity of strains of P. fumosoroseus. Stability of virulence after in vitro passage is clearly a desirable trait for a mass-produced biocontrol agent. However, a change in host specificity or productivity in vitro, as we observed for some strains, must be monitored and minimized.