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1.
Li Y  Cai SH 《Current microbiology》2011,62(5):1400-1404
A set of six specific primers was designed by targeting intergenic spacer region (IGS) sequences. With Bst DNA polymerase, the products could be clearly amplified for 60 min at 62°C in a simple water bath. The sensitivity of the loop-mediated isothermal amplification (LAMP) for detecting Metarhizium anisopliae var. anisopliae was about 0.01 pg fungal DNA per reaction (equivalent to 27 conidia). LAMP products could be judged with agar gel or naked eye after addition of SYBR Green I. There were no cross reactions with other fungal isolates indicating high specificity of the LAMP. The LAMP could detect the presence of M. anisopliae var. anisopliae from soil. The detection limits for M. anisopliae var. anisopliae of LAMP reaction was 50 conidia per reaction in soil.  相似文献   

2.
Rice and oat flours were analyzed as media for the production of conidia by M. anisopliae var. lepidiotum. The presence of peptone increased conidia yield regardless of the substrate used; however, the highest yield was achieved on oat flour media. The effect of oxygen on conidia production using oat-peptone medium was also studied at two levels: Normal atmosphere (21% O2) and Oxygen-rich pulses (26% O2). Maximum conidia production (4.25 × 107 conidia cm−2) was achieved using 26% O2 pulses after 156 h of culture, which was higher than 100% relative to conidial levels under normal atmosphere. Conidia yield per gram of biomass was 2.6 times higher with 26% O2 (1.12 × 107 conidia mg−1). Conidia quality parameters, such as germination and hydrophobicity, did not show significant differences (P < 0.05) between those treatments. Bioassays parameters, using Tenebrio molitor adults, were analyzed for conidia obtained in both atmospheres and data were fitted to an exponential model. The specific mortality rates were 2.22 and 1.26 days−1, whereas lethal times for 50% mortality were 3.90 and 4.31 days, for 26% O2 pulses and 21% O2 atmosphere, respectively. These results are relevant for production processes since an oxygen increase allowed superior levels of conidia by M. anisopliae without altering quality parameters and virulence toward Tenebrio molitor adults.  相似文献   

3.
The entomopathogenic fungus Metarhizium anisopliae is currently used as an efficient biological control agent against different insects. The prevalence and genetic variability of the entomopathogenic fungus Metarhizium anisopliae var. anisopliae in Asian countries (China, Laos, Singapore and South Korea) and a European country (The Netherlands) was examined. The fungus was found to be widespread in agricultural and forest soils throughout China especially in the south and south western regions, with a maximum recovery percentage of 81.6, while in Laos it was found to be abundant in the forest soils only, the soil of Netherlands also seemed to be an excellent source of entomopathogens with a significant recovery of insect pathogenic fungi. Simple sequence repeats (SSR) and ITS-rDNA sequence data showed that the isolates are closely linked to each other. The gene diversity (He) and polymorphic information content values of sixty two isolates showed mean values of 0.37 and 0.63. The majority of the isolates belonged to one of the closely related genotypes and these were found to be dominant in the agricultural as well as forest ecosystem. Genetic distances among the isolates according to locations and different sources showed minimal variation ranging from 0.23 to 0.34%, with maximum genetic distance of 0.34% among the isolates from Laos and The Netherlands. The reason for the limited variation is uncertain, however even the similarity index among the isolates can endow with sufficient knowledge for the implications of the methods to develop this fungus as a microbial control agent.  相似文献   

4.
A genetic variant of the entomopathogenic fungus Metarhizium anisopliae var. anisopliae, isolated from a soil in Alberta, Canada, from a location with a history of severe grasshopper infestations, was evaluated for pathogenicity in bioassays of living grasshoppers. Mortality in treated individuals drawn from a laboratory colony was 99% (LT50 = 6.7 days, LT90 = 9.6 days) at 12 days post-inoculation compared to 100% (LT50 = 4.1 days, LT90 = 5.8 days) mortality at 8 days in insects exposed to a commercial isolate of M. anisopliae var. acridum (IMI 330189). Experimental infection of field-collected grasshoppers under laboratory conditions with the native isolate of M. anisopliae var. anisopliae resulted in 100% (LT50 = 4.4 days, LT90 = 5.4 days) mortality attained within 7 days compared to 100% (LT50 = 4.7 days, LT90 = 6.3 days) mortality in 9 days in insects treated with M. anisopliae var. acridum. Amplification of fungal genomic DNA from the indigenous isolate with primers for the specific detection of M. anisopliae var. anisopliae produced a product almost 300 bp larger than expected based on previously known isolates. This is the first demonstration of a highly virulent, indigenous non-chemical control agent of grasshoppers in North America. GenBank Accession Nos. DQ342236, DQ342237.  相似文献   

5.
Field trials were conducted to evaluate the efficacy of wheat bran bait formulations of Paranosema locustae and Metarhizium anisopliae for controlling grasshoppers in southeast Niger. Treatments consisted of wheat bran baits mixed with M. anisopliae, P. locustae + M. anisopliae or with P. locustae spores and P. locustae + sugar. Oedaleus senegalensis, Pyrgomorpha cognata and Acrotylus blondeli were the predominant species at the time of application representing ca. 94% of the total population. Bran application was done when O. senegalensis (ca. 75% of the population) was at its early developmental stages, with first, second and third instars accounting for 64–85%. Grasshopper population reduction, P. locustae prevalence and level of infections in the predominant species were monitored. Manual application of P. locustae and M. anisopliae formulated in wheat bran has proven to induce consistent pathogen infection in grasshopper populations. Population density over the three weeks monitoring, typically decreased by 44.7 ± 6.9%, 52.8 ± 8.4%, 73.7 ± 5.5% and 89.1 ± 1.8% in P. locustae, P. locustae + sugar, M. anisopliae and P. locustae + M. anisopliae treated plots respectively. Paranosema locustae prevalence in surviving adult grasshoppers at 28 after application was 48.1 ± 2.3%, 28.9 ± 4.8% and 27.4 ± 3.7%, with infection level of 6.2 ± 0.8 × 106, 2.3 ± 0.3 × 104 and 2.1 ± 0.3 × 103 spores mg−1 host weight in O. senegalensis, A blondeli and P. cognate respectively. Other species that each accounted for <2% of the community, namely Aiolopus thalassinus, A. simulatrix, Acorypha glaucopsis, Acrotylus patruelis, Anacridium melanorhodon, Diabolocatantops axillaris, Kraussaria angulifera and Schistocerca gregaria were found to show sign of infection. The results from this study suggest that wheat bran application of M. anisopliae and P. locustae alone or in combination, targeting early instars grasshopper could be a valuable option in grasshopper control programs.  相似文献   

6.
Extracellular enzymes produced by Metarhizium anisopliae are believed to play a key role in cuticle hydrolysis. The in-vitro production of cuticle-degrading enzymes, such as chitinase, proteinase, caseinase, lipase and amylase in fourteen isolates of M. anisopliae exhibited significant natural isolate variability. The isolates were also evaluated for chitinase and proteinase enzyme assays in order to quantify the enzyme production. The growth characteristics and colony morphology of the isolates showed variation and few isolates formed sectors and the colonies were either fluffy or powdery. Among the isolates studied, isolate UM2 was found to show good consistence with the results on enzyme measurements as well as the growth characteristics and colony morphology. Such characterization of isolate variability could rationally be used in the selection of isolates for the production of improved myco-pesticides in the integrated pest management programs.  相似文献   

7.
Efficacy of culture filtrates of five strains of Metarhizium anisopliae isolated from insects were evaluated against Anopheles stephensi and Culex quinquefasciatus. The culture filtrates released from the strains of M. anisopliae in the YpSs and chitin broths were filtered and used for the bioassays after a growth of 7 days. Among the culture filtrates of five strains, M. anisopliae 892 was found to be more effective against both the mosquitoes. The LC(50) values of culture filtrates of M. anisopliae 892 in chitin broth was lower than the LC(50) of culture filtrates in YpSs broth against first and fourth instars of both the mosquitoes. The LC(50) values of culture filtrates were significantly different between first and fourth instars of A. stephensi (t test; P = 0.0001) and C. quinquefasciatus (t test; P = 0.02). The larvae of A. stephensi were more susceptible than C. quinquefasciatus except in two cases. This is the first report of efficacy of culture filtrates produced by M. anisopliae in chitin broth against mosquitoes and have potential as a biological control agent of mosquitoes.  相似文献   

8.
The list of fungal species with known complete genome and/or expressed sequence tag collections is extending rapidly during the last couple of years. Postgenomic gene function assignment is an obvious follow-up and depends on methodologies to test gene function in vivo. One of such methods is the generation of null mutants via homologous recombination at the wild–type loci by using inactivation cassettes. In this paper, the ability of Agrobacterium tumefaciens to genetically transform filamentous fungi was exploited to drive homologous recombination at the trp1 locus of the enthomopathogenic fungus Metarhizium anisopliae. The trp1 disruptants exhibited a clearly distinguishable phenotype from wild-type cells and were recovered with high efficiency of homologous recombination (22%). The complementation of such mutants with the wild-type gene generates only transformants with homologous integration.  相似文献   

9.
Seventeen isolates of Metarhizium anisopliae (Metschnikoff) Sorokin and two isolates of Beauveria bassiana (Balsamo) Vuillemin were evaluated for their pathogenicity against the tobacco spider mite, Tetranychus evansi Baker & Pritchard. In the laboratory all the fungal isolates were pathogenic to the adult female mites, causing mortality between 22.1 and 82.6%. Isolates causing more than 70% mortality were subjected to dose–response mortality bioassays. The lethal concentration causing 50% mortality (LC50) values ranged between 0.7×107 and 2.5×107 conidia ml−1. The lethal time to 50% mortality (LT50) values of the most active isolates of B. bassiana and M. anisopliae strains varied between 4.6 and 5.8 days. Potted tomato plants were artificially infested with T. evansi and treated with B. bassiana isolate GPK and M. anisopliae isolate ICIPE78. Both fungal isolates reduced the population density of mites as compared to untreated controls. However, conidia formulated in oil outperformed the ones formulated in water. This study demonstrates the prospects of pathogenic fungi for the management of T. evansi.  相似文献   

10.
Conidia of the entomopathogenic fungus, Metarhizium anisopliae, in oil/water formulation (1 × 108 conidia/ml) were sprayed at 3 weekly intervals on Rhipicephalus evertsi evertsi and Rhipicephalus (Boophilus) decoloratus ticks while feeding on Afrikana bulls grazing in paddocks for a period of 1 year. The fungus reduced the on-host tick populations by 83% 3 month after commencement of the experiment. The formulation by itself had only minimal effect on the tick population. Tick populations and fungal efficacy were highest at the peaks of rainfall and relative humidity or soon thereafter. Fed and unfed adult R. e. evertsi and R. (B.) decoloratus collected at the end of the experiment from the fungus-sprayed and from the control cattle and incubated in the laboratory exhibited a mortality of 93% in oil formulated conidia and 14% in oil control. The corresponding mortality in R. (B.) decoloratus was 100% in fungus and 11% in oil control. Ticks on the fungus-sprayed groups had significantly higher mortality (P < 0.05) than on the control groups. Furthermore, no significant difference (P < 0.05) was observed in fungus-induced mortality between the two tick species. Mortalities induced by Triton X-100 (0.05%), sunflower oil (20%) and water alone were low, suggesting that they were non-toxic to ticks at the concentrations used and no significant difference was observed among them. No physical or behavioral abnormalities were observed in the fungus-sprayed cattle at any time during the course of the experiment. All groups of cattle gained weights during the experimental period.  相似文献   

11.
Transmission of conidia between mates of the Asian longhorned beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), was studied using two isolates of the entomopathogenic fungus Metarhizium brunneum Petch (Hypocreales: Clavicipitaceae) (formerly M. anisopliae). After one beetle was inoculated and caged with a mate for 6 h, conidia were rinsed off each beetle using Tween-80 and pentane to count conidia transferred. Treated males transmitted more conidia to females than treated females transferred to males. Untreated partners did not die as quickly as their inoculated mates, but died significantly faster than controls. For beetles inoculated with ARSEF 7711, the difference in time to death between inoculated beetles and their untreated mates was shorter when males were inoculated than when females were inoculated. We hypothesize that greater conidial transmission from males to females was due to their relative positions during copulation and the prolonged post-copulatory mate-guarding characteristic of males.  相似文献   

12.
Protoplasts were isolated from two isolates each of Beauveria bassiana and Metarhizium anisopliae using lysing enzymes. Intra- and intergeneric protoplast fusion has been carried out using 40% polyethylene glycol. The fused protoplasts of B. bassiana and M. anisopliae have been regenerated on Czapek–Dox agar media, and a total of four fusants were selected for further studies. An increase in proteinase and chitinase enzyme activity was recorded with all fusants as compared to the wild-type isolates. To understand the nature of recombination process, random amplification of polymorphic DNA (RAPD) and restriction fragment length polymorphism (RFLP) were carried out on genomic DNA of fused and wild-type isolates. The present study demonstrates the scope and significance of the protoplast fusion technique as a rapid consistent method for identification of B. bassiana and M. anisopliae fused and wild-type isolates based on the banding pattern of RAPD and RFLP that can be reliably used ahead for further applications on these species.  相似文献   

13.
Termites, Coptotermes formosanus, reared individually, were highly susceptible to the entomopathogenic fungus, Metarhizium anisopliae, while termites reared in␣groups were highly resistant. When reared in groups, the termites treated with M.␣anisopliae conidia on the body surface were groomed by their nestmates and more than 80% of the conidia were removed from the cuticle within 3 h. However, there was not a significant reduction in the numbers of conidia on the body surfaces of termites reared individually. For the termites maintained in groups, conidia were found in foreguts, midguts and hindguts, but very few conidia were detected in the guts of termites reared individually. Conidia in the alimentary tracts did not germinate, but some of were alive. As a result, it seems that the removal of foreign bodies, such as fungal conidia, from the␣cuticle is one function of termite mutual grooming behavior and that conidia removed from the cuticle are eliminated through alimentary tracts. This study indicates that mutual grooming behavior is very effective in protecting these termites from M.␣anisopliae infection.  相似文献   

14.
Zhang C  Xia Y  Li Z 《Current microbiology》2011,62(5):1649-1655
Insect-pathogenic fungi penetrate their hosts directly through the cuticle. To better understand this process, we identified genes that were up-regulated by Metarhizium anisopliae germinating and differentiating on Locusta migratoria wings using suppression subtractive hybridization (SSH). A total of 78 unique expressed sequence tags (ESTs) up-regulated more than twofold during fungal growth on locust wings were identified. Among these 78 ESTs, 30 (38.5%) shared significant similarity with NCBI annotated hypothetical proteins, 16 (20.5%) shared low similarity to known or predicted genes, might represent novel genes, and 32 (41.0%) shared significant similarity with known proteins that are involved in various cell and molecular processes such as cell metabolism, protein metabolism, stress response and defense, and cell structure and function. Semi-quantitative RT-PCR analysis of six randomly selected genes confirmed the SSH results, verifying the fidelity of the SSH data. The results of this study provide novel information on genes expressed during early stages of infection with M. anisopliae, and improve current understanding of fungal pathogenesis.  相似文献   

15.
The inhibition of mycelial growth of Lagenidium giganteum by neem oil was lower than that of Metarhizium anisopliae in PYG and Emerson’s YpSs agar media. However, neem oil did not inhibit the mycelial growth of L. giganteum in sunflower seed extract agar medium, but did it inhibit the mycelial growth of M. anisopliae. The minimum inhibitory concentration of neem oil for L. giganteum was higher than that for M. anisopliae. The minimum fungicidal concentration of neem oil in PYG medium was lower than in YpSs for both fungi. The spores of L. giganteum grown in SFE medium could be used with neem oil for vector control.  相似文献   

16.
Protease production by fourteen M. anisopliae isolates differing in geographical origin and host insect were investigated. Highest protease activity was observed during 4–8 days of culture incubation. Pr1 and Pr2 activity was investigated in various media containing different carbon and nitrogen source to evaluate the induction mechanism of these enzymes. Basal levels of Pr1 and Pr2 activity were observed in minimal medium suggesting constitutive production. Casein (1%) as an exogenous protein supplement was not able to induce significant release of Pr1 and Pr2 enzymes, whereas high levels of activity were observed in the medium containing colloidal chitin (2%) as sole carbon and nitrogen source. The pH, ammonia and oxalic acid production in in vitro conditions was also investigated and the alteration in pH for protease production was not significant in the different media used except for the medium containing casein (1%) as a supplement.  相似文献   

17.
Twenty-three isolates of Metarhizium anisopliae (Metschnikoff) Sokorin and three isolates of Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales: Clavicipitaceae) were assessed for their virulence against the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae). Based on the screening results, nine isolates of M. anisopliae and two isolates of B. bassiana were tested for their virulence against young adult (1- to 2-day-old) female T. urticae at constant temperatures of 20, 25, 30 and 35°C. At all temperatures tested, all the fungal isolates were pathogenic to T. urticae but mortality varied with isolates and temperatures. Fungal isolates were more virulent at 25, 30 and 35°C than at 20°C. The lethal time to 50% mortality (LT50) and lethal time to 90% mortality (LT90) values decreased with increased temperature. There were no significant differences in virulence between fungal isolates at 30 and 35°C; however, significant differences were observed at 20 and 25°C.  相似文献   

18.
Field observations and inoculation experiments revealed that Uromyces appendiculatus var. azukicola has an autoecious and macrocyclic life cycle and produces spermogonia, aecia, uredinia, and telia on Vigna angularis var. angularis and V. angularis var. nipponensis. From inoculation experiments, it was suggested that this rust fungus has different host relationships from other varieties. Morphological examinations revealed that the characteristics of urediniospores and teliospores are different among varieties, although aeciospores are morphologically similar to each other.Contribution no. 182, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba, Japan  相似文献   

19.
Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes.  相似文献   

20.
Three sugarcane fields in Bundaberg and four fields in each of the Burdekin, Tully and Innisfail (Queensland, Australia) were sampled for spores of Metarhizium anisopliae (Metchnikoff) (Deuteromycotina: Hyphomycetes). This entomopathogenic fungus is the active ingredient in the biocide “BioCaneTM”, which was developed for the management of the greyback canegrub Dermolepida albohirtum (Waterhosue) (Coleoptera: Scarabaeidae) and other scarabs in cane fields. Fields sampled were of different crop ages and all had a history of BioCaneTM treatment in Plant Cane in past years. Soil samples were taken in each field from four depths (0–10, 10–20, 20–30 and 30–40 cm below soil level) with the use of an auger. Spore levels were highest at the depths of 10–20 and 20–30 cm. Spore levels differed between locations with Innisfail and Tully recording the highest spore counts. Spores were also found in the inter-row space in plots sampled in Tully. Sampling statistics were determined for M. anisopliae spores at the four soil depths with 0.1 and 0.25 precision levels. Three sampling methods were compared (use of marker beads; use of 100 mm auger and 150 mm auger). Samples that relied on marker beads resulted in higher spore counts, however, an auger can still be used since BioCaneTM does not normally contain coloured markers. Results obtained demonstrate the ability of the pathogen to translocate in soil profile and across rows, most likely due to grub movements and other soil fauna. Sampling for M. anisopliae spores provides good monitoring of their levels in soil. The implications of this on grub management decisions are discussed.  相似文献   

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