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Zhen Huang - One of the best experts on this subject based on the ideXlab platform.
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lack of resistance development in bemisia tabaci to Isaria fumosorosea after multiple generations of selection
Scientific Reports, 2017Co-Authors: Zhaolei Wang, Zhen Huang, Yu Huang, Nemat O KeyhaniAbstract:: The emergence of insecticide resistant insect pests is of significant concern worldwide. The whitefly, Bemisia tabaci, is an important agricultural pest and has shown incredible resilience developing resistance to a number of chemical pesticides. Entomopathogenic fungi such as Isaria fumosorosea offer an attractive alternative to chemical pesticides for insect control, and this fungus has been shown to be an effective pathogen of B. tabaci. Little is known concerning the potential for the development of resistance to I. fumosorosea by B. tabaci. Five generations of successive survivors of B. tabaci infected by I. fumosorosea were assayed with I. fumosorosea. No significant differences in susceptibility to I. fumosorosea, number of ovarioles, or ovipostioning were seen between any of the generations tested. Effects of I. fumosorosea and cell-free ethyl acetate fractions derived from the fungus on the B. tabaci fat body, ovary, and vitellogenin were also investigated. These data revealed significant deformation and degradation of ovary tissues and associated vitellogenin by the fungal mycelium as well as by cell-free ethyl acetate fungal extracts. These data indicate the lack of the emergence of resistance to I. fumosorosea under the conditions tested and demonstrate invasion of the insect reproductive tissues during fungal infection.
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the ifchit1 chitinase gene acts as a critical virulence factor in the insect pathogenic fungus Isaria fumosorosea
Applied Microbiology and Biotechnology, 2016Co-Authors: Zhen Huang, Yu Huang, Nemat O KeyhaniAbstract:The filamentous fungus, Isaria fumosorosea, is a promising insect biological control agent. Chitinases have been implicated in targeting insect cuticle structures, with biotechnological potential in insect and fungal control. The I. fumosorosea chitinase gene, Ifchit1, was isolated and determined to encode a polypeptide of 423 amino acids (46 kDa, pI = 6.53), present as a single copy in the I. fumosorosea genome. A split marker transformation system was developed and used to construct an Ifchit1 gene knockout. The ΔIfchit1 strain displayed minor alterations in mycelial growth on diverse media at 26 °C compared to the wild type and complemented (ΔIfchit1::Ifchit1) strains; however, colony morphology was affected, and the mutant strain had a temperature sensitive phenotype (32 °C). Although sporulation was delayed for the mutant, overall conidial production was almost twice than that of wild type. Biochemical assays indicated decreased chitinase activity during growth in Czapek-Dox liquid media for the ΔIfchit1 strain. Insect bioassays using diamondback moth, Plutella xylostella, larvae revealed decreased infectivity, i.e., increased LC50 (threefold to fourfold) and a significantly delayed time to death, LT50 from 3 to 6 days, for the ΔIfchit1 strain compared to the wild type and complemented strains. These data indicate an important role for the Ifchit1 chitinase as a virulence factor in I. fumosorosea.
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the effect of alkanes on the physiology and metabolism of the entomopathogenic fungus Isaria fumosorosea
Biocontrol Science and Technology, 2014Co-Authors: Muhammad Hamid Bashir, Zhen HuangAbstract:The influence of different alkanes on spore morphology, glyoxlate pathway enzyme activities, total lipid contents and fatty acid composition of Isaria fumosorosea were investigated under laboratory conditions. Fungal spores grown on different alkanes showed higher germination and mycelial growth when compared to control. A strong induction of glyoxlate cycle enzymes in cell-free extracts was observed for cells grown on different alkanes when compared to glucose and control. Higher activities of glyoxlate cycle enzymes were observed for cells grown on alkanes when compared to other treatments. Even numbered fatty acids accounted for the majority of fatty acid production with a significant increase in relative amounts of linoleic acid and palmatic acid observed for conidia grown on alkanes. These results indicate that addition of alkanes to culture media can be a tool to pre-induce metabolic adaptations that can facilitate successful infection of insect host by entomopathogenic fungi.
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antioxidant enzyme influences germination stress tolerance and virulence of Isaria fumosorosea
Journal of Basic Microbiology, 2012Co-Authors: Zhen Huang, Huaxing Li, Muhammad Hamid BashirAbstract:: Antioxidizing enzymes (superoxide dismutase, catalase, and glutathione peroxidae) are important enzymatic systems used to degrade hydrogen peroxide into water and oxygen, thereby lowering intracellular hydrogen peroxide levels. Entomopathogenic fungi display increased activities of antioxidizing enzymes during growth and germination, which is necessary to counteract the hyperoxidant state produced by oxidative metabolism. We studied the influence of different carbon sources on antioxidizing enzyme production by Isaria fumosorosea to determine the importance of antioxiding enzymes induction in fungal germination, stress tolerance and virulence. Conidia produced by colonies grown on hydrocarbons showed higher rates of enzyme activities compared to the control and the enzyme activities of the conidia produced on n-octacosane were higher than all the other treatments. The lipid peroxidation activities were observed as an indicative marker of oxidative damage to cells and the lowest levels of lipid peroxidation activities were observed for n-octacosane treatment. The increased enzyme activities of n-octacosane- grown conidia were accompanied by higher levels of resistance to exogenous hydrogen peroxide, reduction in germination time and higher virulence against Spodoptera exigua. Our study has helped to identify that increased activities of antioxidizing enzymes can improve the germination and tolerance to antioxidant stress response of I. fumosorosea.
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the effect of insecticides on growth germination and cuticle degrading enzyme production by Isaria fumosorosea
Biocontrol Science and Technology, 2012Co-Authors: Zhen Huang, Muhammad Hamid Bashir, Zeqing WangAbstract:Abstract The influence of six chemical insecticides on growth, sporulation, conidial germination and cuticle-degrading enzyme production by Isaria fumosorosea were investigated under laboratory conditions. Maximum reduction in vegetative growth, sporulation and conidial germination in relation to the control treatment was observed for Chloranthraniliprole whereas Indoxacarb proved to be the safest insecticide causing lowest reduction in these parameters. Chloranthraniliprole, Chlorpyrifos and Chlorfenapyr caused higher reduction in enzyme activities (chitinase, Pr1, Pr2 and lipase) at all three concentrations whereas very low reduction in enzyme activities was caused by Hubendamide+ Avermectin and Indoxacarb when used at 10 µg/ml. The data presented can be used for future recommendations of these insecticides in IPM programmes where I. fumosorosea is an important control agent.
Yeon Ho Je - One of the best experts on this subject based on the ideXlab platform.
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an oil based formulation of Isaria fumosorosea blastospores for management of greenhouse whitefly trialeurodes vaporariorum homoptera aleyrodidae
Pest Management Science, 2013Co-Authors: Yeon Ho Je, Margaret Skinner, Bruce L ParkerAbstract:BACKGROUND: To date, emphasis has been placed on studying the virulence of Isaria fumosorosea conidia rather than the virulence of their blastospores. In the present study, a comparison was made of the efficacy of blastospores of I. fumosorosea (SFP-198) versus conidia against greenhouse whitefly (GWF) Trialeurodes vaporarioum nymphs and thermotolerance at 50 ◦ C. To improve thermotolerance and potency, the blastospores were suspended in corn oil with a wetting and an insect-filming agent. RESULTS:BlastosporeshadsimilarefficacyagainstGWFnymphstoconidiainglasshouseconditionsbuthadlessthermotolerance than conidia. However, blastospores in corn oil had increased thermotolerance, comparable with that of conidia in corn oil. Application of SFP-198 blastospore oil-based formulation containing isotridecyl alcohol ethoxylated-3EO (TDE-3) and sodium alginate (SA) as adjuvants showed enhanced efficacy (95.7% mortality), compared with the SA-free oil formulation (72.8%) in 10days. CONCLUSION: SFP-198 blastospores can be used as an effective biological control agent, given their virulence against GWF, the enhanced thermotolerance in corn oil and the oil-based formulation studies to enhance their efficacy. Blastospores can be easily produced in liquid cultures in less than 4days, which is significantly shorter than using traditional solid cultures for conidial production. c � 2013 Society of Chemical Industry
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Persistence of Isaria fumosorosea (Hypocreales: Cordycipitaceae) SFP-198 Conidia in Corn Oil-Based Suspension
Mycopathologia, 2011Co-Authors: Yeon Ho Je, Jong Sung ParkAbstract:Long-term persistence of entomopathogenic fungi as biopesticides is a major requirement for successful industrialization. Corn oil carrier was superior in maintaining germination rates of Isaria fumosorosea SFP-198 conidia during exposure to 50°C for 2 h, when compared with other oils, such as soybean oil, cottonseed oil, paraffin oil, and methyl oleate. The corn oil-based conidial suspension (91.6% germination) was also better in this regard than conidial powder (28.4% germination) after 50°C for 8 h. Long-term storage stabilities of corn oil-based conidial suspension and conidial powder at 4 and 25°C for 24 months were investigated, based on the correlation of germination rate with insecticidal activity against greenhouse whiteflies, Trialeurodes vaporariorum . Viability of conidia in corn oil was more than 98.4% for up to 9 months of storage at 25°C, and followed by 23% at 21 months. However, conidial powder had only 34% viability after 3 months of storage at 25°C, after which its viability rapidly decreased. The two conidial preparations stored at 4°C had better viabilities than those at 25°C, showing the same pattern as above. These results indicate that corn oil-based conidial suspension can be used to improve conidial persistence in long-term storage and be further applied to the formulation of other thermo-susceptible biological control agents.
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complementary effect of phloxine b on the insecticidal efficacy of Isaria fumosorosea sfp 198 wettable powder against greenhouse whitefly trialeurodes vaporariorum west
Pest Management Science, 2010Co-Authors: Yeon Ho Je, Jaeyoung ChoiAbstract:BACKGROUND: Insecticidal activities of five photoactive dyes against greenhouse whitefly (GWF), Trialeurodes vaporariorum West., in tomatoes were investigated to improve the control efficacy of an entomopathogenic fungal product, Isaria fumosorosea SFP-198 wettable powder (WP). Azorubine, Eosin B, Erythrosine, Brilliant Green and Phloxine B were used in this work, accompanying pyriproxyfen emulsifiable concentrate (EC) as a commercial standard for comparison. RESULTS: Phloxine B had the highest control efficacy in glasshouse conditions. The most suitable dose of Phloxine B was determined as 0.005 g L−1, given the dosage-dependent control efficacy and phytotoxicity of the dye, and its influence on the germination of SFP-198 conidia. In field conditions, SFP-198 WP + Phloxine B (2 + 0.005 g L−1; tank mix) showed 89.1 and 95.3% control efficacy 7 and 14 days post-application, which was significantly higher than the efficacy of SFP-198 WP alone (43.5 and 64.0%), Phloxine B (47.5 and 30.7%) or pyriproxyfen EC (67.7 and 80.2%). CONCLUSION: Phloxine B cooperates with SFP-198 WP complementarily, possibly in the order of killing action (early: Phloxine B; late: SFP-198 WP). The dye can be incorporated into SFP-198 WP to improve its efficacy and applied to other Hypocrelean entomopathogenic fungal products. Copyright © 2010 Society of Chemical Industry
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Complementary effect of Phloxine B on the insecticidal efficacy of Isaria fumosorosea SFP‐198 wettable powder against greenhouse whitefly, Trialeurodes vaporariorum West.
Pest Management Science, 2010Co-Authors: Yeon Ho Je, Jaeyoung ChoiAbstract:BACKGROUND: Insecticidal activities of five photoactive dyes against greenhouse whitefly (GWF), Trialeurodes vaporariorum West., in tomatoes were investigated to improve the control efficacy of an entomopathogenic fungal product, Isaria fumosorosea SFP-198 wettable powder (WP). Azorubine, Eosin B, Erythrosine, Brilliant Green and Phloxine B were used in this work, accompanying pyriproxyfen emulsifiable concentrate (EC) as a commercial standard for comparison. RESULTS: Phloxine B had the highest control efficacy in glasshouse conditions. The most suitable dose of Phloxine B was determined as 0.005 g L−1, given the dosage-dependent control efficacy and phytotoxicity of the dye, and its influence on the germination of SFP-198 conidia. In field conditions, SFP-198 WP + Phloxine B (2 + 0.005 g L−1; tank mix) showed 89.1 and 95.3% control efficacy 7 and 14 days post-application, which was significantly higher than the efficacy of SFP-198 WP alone (43.5 and 64.0%), Phloxine B (47.5 and 30.7%) or pyriproxyfen EC (67.7 and 80.2%). CONCLUSION: Phloxine B cooperates with SFP-198 WP complementarily, possibly in the order of killing action (early: Phloxine B; late: SFP-198 WP). The dye can be incorporated into SFP-198 WP to improve its efficacy and applied to other Hypocrelean entomopathogenic fungal products. Copyright © 2010 Society of Chemical Industry
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Production of thermotolerant entomopathogenic Isaria fumosorosea SFP-198 conidia in corn-corn oil mixture
Journal of Industrial Microbiology & Biotechnology, 2010Co-Authors: Yeon Ho JeAbstract:Low thermotolerance of entomopathogenic fungi is a major impediment to long-term storage and effective application of these biopesticides under seasonal high temperatures. The effects of high temperatures on the viability of an entomopathogenic fungus, Isaria fumosorosea SFP-198 (KCTC 0499BP), produced on different substrates amended with various additives were explored. Ground corn was found to be superior in producing the most thermotolerant conidia compared to yellow soybean, red kidney bean, and rice in a polyethylene bag production system. Using ground corn mixed with corn oil as a substrate resulted in only 7% reduction in germination compared to ground corn alone (67% reduction) after exposure of conidia to 50°C for 2 h. Corn oil as an additive for ground corn was followed by inorganic salts (KCl and NaCl), carbohydrates (sucrose and dextrin), a sugar alcohol (sorbitol), and plant oils (soybean oil and cotton seed oil) in ability to improve conidial thermotolerance. Unsaturated fatty acids, such as linoleic acid and oleic acid, the main components of corn oil, served as effective additives for conidial thermotolerance in a dosage-dependant manner, possibly explaining the improvement by corn oil. This finding suggests that the corn-corn oil mixture can be used to produce highly thermotolerant SFP-198 conidia and provides the relation of unsaturated fatty acids as substrates with conidial thermotolerance.
Gabriel Moura Mascarin - One of the best experts on this subject based on the ideXlab platform.
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host plants influence susceptibility of whitefly bemisia tabaci hemiptera aleyrodidae to the entomopathogenic fungus Isaria fumosorosea hypocreales cordycipitaceae
Biocontrol Science and Technology, 2016Co-Authors: Jing Tian, Steven P Arthurs, Hongliang Diao, Li Liang, Gabriel Moura MascarinAbstract:ABSTRACTWe quantified the tritrophic effect of host plant on the susceptibility of the sweetpotato whitefly Bemisia tabaci (Genn.) to a fungal pathogen in the laboratory. Second-instar whiteflies reared on cucumber, eggplant, tomato and bean plants for six generations were exposed to conidial suspensions of Isaria fumosorosea isolate IF-1106. Our results did not detect differences in response (proportional survival or median lethal time, LT50 days) among insect populations derived from different plants that were treated with 107 conidia/ml. However, at concentrations ≤ 5×106 conidia/ml, whiteflies reared on bean and tomato died significantly more quickly (i.e. LT50 of 4–5 days) compared with cucumber and eggplant reared populations (5–7 days). Bean and tomato-reared populations were also more susceptible to mycosis (LC50 ≈ 6 × 105 conidia/ml) compared with those reared on cucumber (1.9 × 106 conidia/ml) and eggplant (1.5 × 106 conidia/ml). A separate study confirmed that this differential response of whit...
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liquid culture fermentation for rapid production of desiccation tolerant blastospores of beauveria bassiana and Isaria fumosorosea strains
Journal of Invertebrate Pathology, 2015Co-Authors: Mark A Jackson, Gabriel Moura Mascarin, Nilce Naomi Kobori, Robert W Behle, Italo DelaliberaAbstract:Abstract A major constraint to the commercial use of fungal biocontrol agents is the availability of low-cost production media and processes. Previous attempts in producing Beauveria blastospores using liquid culture fermentation processes required long fermentation times (6–8 days) and produced cells that had poor survival after desiccation and storage. In this study, isolates of Beauveria bassiana and Isaria fumosorosea were evaluated for blastospore yield, desiccation tolerance, storage stability, and biocontrol efficacy using fermentation media containing acid hydrolyzed casein or cottonseed flour as the nitrogen source. Cultures of B. bassiana and I. fumosorosea grown in media containing cottonseed flour produced high blastospore concentrations (>1 × 109 mL−1) after 3 days which is comparatively less expensive nitrogen source than acid hydrolyzed casein. The resultant air-dried blastospores ( 14 months in contrast to 9.2–13.1 months for I. fumosorosea. Blastospores of B. bassiana and I. fumosorosea killed Bemisia tabaci whitefly nymphs faster and required lower concentrations compared with aerial conidia. Our findings support the use of liquid culture fermentation as a cost-effective process to rapidly produce high yields of stable and infective blastospores of either B. bassiana or I. fumosorosea. These results support further evaluation of blastospore sprayable formulations for the control of soft-bodied insects.
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culture media selection for mass production of Isaria fumosorosea and Isaria farinosa
Brazilian Archives of Biology and Technology, 2010Co-Authors: Gabriel Moura Mascarin, Sergio Batista Alves, Rogerio Biaggioni LopesAbstract:This work investigated the production of the fungi Isaria fumosorosea and Isaria farinosa in biphasic fermentation using agro-industrial products and residues. Combinations of natural liquid substrates, alternative to the complete medium and potato dextrose medium, were evaluated. The best liquid media were sugarcane molasses + rice broth, rice broth + yeast and sugarcane molasses + yeast + rice broth, which resulted in the highest viable propagule concentration. The molasses + rice broth medium was selected for the next phase of the study in which the production of both fungal isolates was evaluated in solid grain substrates. In solid-state fermentation, the best conidia production was achieved with the soybean meal and broken corn for I. farinosa, and whole rice and broken rice for I. fumosorosea. Results demonstrated that the two fungal species could be rapidly produced with higher yield of conidia on agro-industrial resources by using biphasic fermentation techniques.
Octavio Loera - One of the best experts on this subject based on the ideXlab platform.
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Comparison between superficial and solid-state cultures of Isaria fumosorosea: conidial yields, quality and sensitivity to oxidant conditions
World Journal of Microbiology and Biotechnology, 2016Co-Authors: Facundo Muñiz-paredes, Gustavo Viniegra-gonzález, Paul Misael Garza-lópez, Octavio LoeraAbstract:Conidia production and quality from mycoinsecticides in solid-state cultures (SSC) are frequently inferred from superficial culture (SC) results. Both parameters were evaluated for two Isaria fumosorosea strains (ARSEF 3302 and CNRCB1), in SC and SSC, using culture media with the same chemical composition. For both strains, conidia production was higher in SC than SSC in terms of conidia per gram of dry substrate. Germination in both strains did not show significant differences between SC and SSC (>90 %). Similarly, conidia viability in ARSEF 3302 strain did not show differences at early stages between SC and SSC, but was higher in SC compared to SSC in the late stage of culture; in contrast, conidia from CNRCB1 strain did not differ between both culture systems. Some infectivity parameters improved in conidia from SSC, compared to SC at the early stages, but these differences disappeared at the final stage, independently of the strain. Both strains showed decreased conidia production when 26 % O_2 pulses were applied; nevertheless, conidiation in SSC was two orders of magnitude more sensitive to oxidant pulses. In SC with 26 % O_2 pulses, conidia viability for both strains at early stages, was higher than in normal atmospheric conditions. Infectivity towards Galleria mellonella larvae was similar between conidia from normal atmosphere and oxidant conditions; notably, for the strain ARSEF 3302 infectivity decreased at the final stage. This study shows the intrinsic differences between SC and SSC, which should be considered when using SC as a model to design production processes in SSC.
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Critical Values of Porosity in Rice Cultures of Isaria fumosorosea by Adding Water Hyacinth: Effect on Conidial Yields and Quality
Applied Biochemistry and Biotechnology, 2015Co-Authors: Alejandro Angel-cuapio, Arturo Figueroa-montero, Isabelle Perraud-gaime, Ernesto Favela-torres, Gustavo Viniegra-gonzález, Octavio LoeraAbstract:Conidia of the entomopathogenic fungus Isaria fumosorosea are used to control insect pests in crops. Commercially available mycoinsecticides manufactured with this fungus are produced on a large scale via solid-state cultures (SSC). In order to favour gaseous exchange in SCC, texturizers can be added to increase porosity fraction (ε). This work presents results of water hyacinth (Eichhornia crassipes) as a novel texturizer. A mixture of parboiled rice (PR), with a ε = 0.23, was used as a substrate, which was then mixed with water hyacinth (WH amendment) as a texturizer at different proportions affecting ε. Strains CNRCB1 and ARSEF3302 of I. fumosorosea yielded 1.6 (1.49–1.71) × 109 and 7.3 (7.02–7.58) × 109 conidia per gram of initial dry rice after 8 days, at ε values of 0.34 and 0.36, respectively. Improvement of conidial yields corresponded to 1.33 and 1.55 times, respectively, compared to rice alone using WH amendment in the mixtures PR:WH (%) at 90–10 and 80–20. In addition, infectivity against Galleria mellonella larvae was maintained. This is the first report of the use of water hyacinth as a texturizer in SSC, affecting ε, which is proposed a key parameter in conidia production by I. fumosorosea, without affecting conidial infectivity.
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critical values of porosity in rice cultures of Isaria fumosorosea by adding water hyacinth effect on conidial yields and quality
Applied Biochemistry and Biotechnology, 2015Co-Authors: Alejandro Angelcuapio, Arturo Figueroamontero, Ernesto Favelatorres, G Viniegragonzalez, Isabelle Perraudgaime, Octavio LoeraAbstract:Conidia of the entomopathogenic fungus Isaria fumosorosea are used to control insect pests in crops. Commercially available mycoinsecticides manufactured with this fungus are produced on a large scale via solid-state cultures (SSC). In order to favour gaseous exchange in SCC, texturizers can be added to increase porosity fraction (e). This work presents results of water hyacinth (Eichhornia crassipes) as a novel texturizer. A mixture of parboiled rice (PR), with a e = 0.23, was used as a substrate, which was then mixed with water hyacinth (WH amendment) as a texturizer at different proportions affecting e. Strains CNRCB1 and ARSEF3302 of I. fumosorosea yielded 1.6 (1.49–1.71) × 109 and 7.3 (7.02–7.58) × 109 conidia per gram of initial dry rice after 8 days, at e values of 0.34 and 0.36, respectively. Improvement of conidial yields corresponded to 1.33 and 1.55 times, respectively, compared to rice alone using WH amendment in the mixtures PR:WH (%) at 90–10 and 80–20. In addition, infectivity against Galleria mellonella larvae was maintained. This is the first report of the use of water hyacinth as a texturizer in SSC, affecting e, which is proposed a key parameter in conidia production by I. fumosorosea, without affecting conidial infectivity.
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oxygen rich culture conditions enhance the conidial infectivity and the quality of two strains of Isaria fumosorosea for potentially improved biocontrol processes
Pest Management Science, 2014Co-Authors: Francisco Mirandahernandez, G Saucedocastaneda, Raquel Alatorrerosas, Octavio LoeraAbstract:BACKGROUND In addition to high production levels of conidia, the success of entomopathogenic fungi as biological control agents depends both on their prevalence under the environmental conditions found in open fields (resistance to stress) and on the capacity of these conidia to infect pests. This study compares conidium production, infectivity and resistance to thermal and osmotic stress in two strains of Isaria fumosorosea (ARSEF 3302 and CNRCB1) grown either under a normal atmosphere (21% O2) or using enriched oxygen pulses (26% O2). RESULTS After 180 h, the ARSEF 3302 strain with 26% O2 pulses increased conidium production nearly fivefold compared with the normal atmosphere, while conidium production by the CNRCB1 strain decreased by 50% under O2 pulses, relative to the values measured with the normal atmosphere. The conidia obtained with 26% O2 pulses had a greater germination rate and resistance to thermal and osmotic stress, in addition to improved infectivity against Galleria mellonella (Lepidoptera) larvae. These findings were associated with an increase in catalase activities for both strains. CONCLUSION An enriched oxygen atmosphere increases the quality of conidia of both strains of I. fumosorosea, with a variable effect on conidium production. © 2013 Society of Chemical Industry
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Oxygen‐rich culture conditions enhance the conidial infectivity and the quality of two strains of Isaria fumosorosea for potentially improved biocontrol processes
Pest Management Science, 2013Co-Authors: Francisco Miranda-hernández, Gerardo Saucedo-castañeda, Raquel Alatorre-rosas, Octavio LoeraAbstract:BACKGROUND In addition to high production levels of conidia, the success of entomopathogenic fungi as biological control agents depends both on their prevalence under the environmental conditions found in open fields (resistance to stress) and on the capacity of these conidia to infect pests. This study compares conidium production, infectivity and resistance to thermal and osmotic stress in two strains of Isaria fumosorosea (ARSEF 3302 and CNRCB1) grown either under a normal atmosphere (21% O2) or using enriched oxygen pulses (26% O2). RESULTS After 180 h, the ARSEF 3302 strain with 26% O2 pulses increased conidium production nearly fivefold compared with the normal atmosphere, while conidium production by the CNRCB1 strain decreased by 50% under O2 pulses, relative to the values measured with the normal atmosphere. The conidia obtained with 26% O2 pulses had a greater germination rate and resistance to thermal and osmotic stress, in addition to improved infectivity against Galleria mellonella (Lepidoptera) larvae. These findings were associated with an increase in catalase activities for both strains. CONCLUSION An enriched oxygen atmosphere increases the quality of conidia of both strains of I. fumosorosea, with a variable effect on conidium production. © 2013 Society of Chemical Industry
Qiongbo Hu - One of the best experts on this subject based on the ideXlab platform.
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secondary metabolites and the risks of Isaria fumosorosea and Isaria farinosa
Molecules, 2019Co-Authors: Qunfang Weng, Xiaofeng Zhang, Wei Chen, Qiongbo HuAbstract:Isaria fumosorosea and Isaria farinosa are important entomopathogenic fungi with a worldwide distribution and multiple host insects. However, the concerns about the safety risks of myco-pesticides have been attracting the attention of researchers and consumers. Secondary metabolites (SMs), especially the mycotoxins, closely affect the biosafety of Isaria myco-insecticides. In the last forty years, more than seventy SMs were identified and isolated from I. fumosorosea and I. farinose. The SMs of I. fumosorosea include the mycotoxins of non-ribosomal peptides (NRPs) (beauvericin and beauverolides), terpenes (trichocaranes and fumosorinone), lactone compounds (cepharosporolides), acids (dipicolinic acid and oxalic acid), etc. Meanwhile, the NRP mycotoxins (cycloaspeptides) and the terpene compounds (farinosones and militarinones) are the main SMs in I. farinosa. Although several researches reported the two Isaria have promised biosafety, the bioactivities and the safety risks of their SMs have not been studied in detail so far. However, based on existing knowledge, most SMs (i.e., mycotoxins) do not come from Isaria myco-insecticide itself, but are from the host insects infected by Isaria fungi, because only the hosts can provide the conditions for fungal proliferation. Furthermore, the SMs from Isaria fungi have a very limited possibility of entering into environments because many SMs are decomposed in insect cadavers. The biosafety of Isaria myco-insecticides and their SMs/mycotoxins are being monitored. Of course, SMs safety risks of Isaria myco-insecticides need further research.
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effects of Isaria fumosorosea on tylcv tomato yellow leaf curl virus accumulation and transmitting capacity of bemisia tabaci
PLOS ONE, 2016Co-Authors: Bowen Zhang, Qiongbo HuAbstract:Tomato yellow leaf curl virus (TYLCV) is transmitted by the Bemisia tabaci pest Middle East-Asia Minor 1 (MEAM1) in China. Isaria fumosorosea is a fungal pathogen of B. tabaci. However, the effects of fungal infection on TYLCV expression and transmission by MEAM1 are unclear. In this study, potted tomatoes containing second instar nymphs of MEAM1 were treated with I. fumosorosea IfB01 strain and the relationship between fungal infection in MEAM1 and its TYLCV transmission capacity was investigated. The results indicated that a significantly (p < 0.05) decreased incidence of transmission of TYLCV-infected plants (ITYPs) transmitted by second instar nymphs of MEAM1 infected with fungus. Further, we found a negative correlation between fungal conidial concentrations and eclosion rates of MEAM1, and a positive correlation between ITYPs and eclosion. In addition, when each plant was exposed to three adults treated with fungus, a significantly decreased transmission of TYLCV (TYTE) was observed in the infected group. However, the incidence of TYLCV-carrying MEAM1 adults (ITYAs) was not significantly different in the infected and control groups (p < 0.05). Nevertheless, a significant decrease in viral accumulation using TYLCV AC2 gene as a marker was observed in the fungus-infected MEAM1. In conclusion, the results suggested that I. fumosorosea infection decreases TYLCV accumulation in MEAM1 and subsequently reduces its transmission. Our study provides new insights into the relationship between host plant, plant virus, insect vector, and entomopathogenic fungus.
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expression of dsrna in recombinant Isaria fumosorosea strain targets the tlr7 gene in bemisia tabaci
BMC Biotechnology, 2015Co-Authors: Xiurun Chen, Lin Li, Qiongbo Hu, Bowen Zhang, Wei Wu, Junxi JiangAbstract:Background RNA interference (RNAi) technology shows a great potential in controlling agricultural pests, despite the difficulty of introducing exogenous dsRNA/siRNA into target pests. Isaria fumosorosea is a common fungal pathogen of the B-biotype Bemisia tabaci (whitefly), which is a widespread pest. Entomopathogenic fungi directly penetrate the cuticle and invade insect hemocoel. Application of I. fumosorosea expressing dsRNA of whitefly immunity-related gene may aid in developing RNAi technology to effectively control whiteflies.
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joint action of the entomopathogenic fungus Isaria fumosorosea and four chemical insecticides against the whitefly bemisia tabaci
Biocontrol Science and Technology, 2014Co-Authors: Lin Li, Bowen Zhang, Tingyan Dong, Qiongbo HuAbstract:The strain IfB01 of Isaria fumosorosea (Paecilomyces fumosoroseus) is a promising myco-insecticide candidate for control of Bemisia tabaci. Joint action of strain IfB01 and four chemical insecticides [spirotetramat (Spi), acetamiprid (Ace), imidacloprid (Imi) and thiamethoxam (Thi)] against the whitefly B. tabaci was evaluated using the cooperative virulence index (c.f.). Substantial synergistic actions were found in the mixtures of IfB01 conidia with Spi, Imi and Thi 2–4 days after treatment. The greatest synergism was recorded in the mixture of IfB01 (2.5 × 106 conidia/L) and Imi (12.5 mg/L), which had a c.f. value of 184 at day 3 after treatment. Furthermore, the shorter LT50 values recorded in mixtures indicated that effectiveness improved when the conidia were applied with the chemical insecticides. However, no substantial synergisms were recorded with Ace and from day 5 onwards.
