The use of entomopathogenic fungi (EF) in recent years has been highly effective against the different orders of insects considered pests of agricultural importance and their conidia have been commonly applied, but it...The use of entomopathogenic fungi (EF) in recent years has been highly effective against the different orders of insects considered pests of agricultural importance and their conidia have been commonly applied, but it has been reported that these are sensitive to the environmental conditions. For this reason, biopesticides products have been formulated based on secondary metabolites, recently. These biomolecules participate as biological control agent, such as: cyclic depsipeptides, amino acids, polyketides, polyphenols and terpenoids, affecting their morphology, life cycle and insect behavior. The use of secondary metabolites of entomopathogenic fungi opens the possibility of application in a more efficient way for the control of agricultural pests in a compatible with the environment and human health;therefore, it is important to know, analyzing the type of molecules, their effects, and their different methods of application.展开更多
Entomopathogenic fungi (EF) are recognized biological control agents of insects. Basically, the entomopathogenic fungi pathogen activity depends on the ability of its enzymatic equipment, consisting of lipases, protea...Entomopathogenic fungi (EF) are recognized biological control agents of insects. Basically, the entomopathogenic fungi pathogen activity depends on the ability of its enzymatic equipment, consisting of lipases, proteases and chitinases, which are in charge of breaking down the insect’s integument. Lipases are the first enzymes synthesized by the entomopathogenic fungi. Recently, a cytochrome P450 subfamily, referred as CYP52XI and MrCYP52 has been identified in Beauveria bassiana and Metarhizium robertsii, respectively. These break down long-chain alkenes and fatty acids to become initial nutrients. Subsequently, subtilisin type (Pr1) proteases sintetize;these enzymes are considered as virulence indicators and they are regulated by a signal transduction mechanism activated by the protein kinase A (PKA) mediated by AMPc. Through the employment of genetic engineering, it has been possible to increase virulence producing Pr1 recombinants with Androctonus australis neurotoxins or with chitinases, reducing the insect’s time of death. In the course of time, the Pr1 protease gene has presented evolutionary adaptations by gene duplication or horizontal transfer infecting different orders of insects. In the same way, the entomopathogenic fungi chitinases have presented a functional diversification. Currently, these have been phylogenetically classified into three subgroups, in accordance to the catalytic site domain and the chitin binding domain. The chitinolytic activity has increased through a directed evolution processes and genetic recombination with Bombyx mori chitinase. Recently, enzymes have been employed as control agents for insects and phytopathogenic fungi (disease originator) opening new potentialities in order to improve the entomopathogenic fungi use. Solid state fermentation is a bioprocess that would produce at great scale enzymes and some other metabolites in grade of increasing the entomopathogenic fungi virulence, in the control of insects and potentially in some diseases affecting plants.展开更多
The application of enzymatic extracts and conidia of Beauveria bassiana in Metamasius spinolae and Cyclocephala lunulata was evaluated. The variables were mortality and time of death. In M. spinolae, mortality with ex...The application of enzymatic extracts and conidia of Beauveria bassiana in Metamasius spinolae and Cyclocephala lunulata was evaluated. The variables were mortality and time of death. In M. spinolae, mortality with extracts 29%, conidia 27% and the combination of both 31%, all had a time of death of four days. Although with different symptoms, used enzymatic extracts: contraction and softening of the joints;by conidia: mycelium in the joints;in the combination of conidia and enzymatic extracts: abundant aerial mycelium. In C. lunulata, 100% mortality in all treatments;Time of death: enzymatic extracts and extracts with conidia 1.2 days;conidia 2.8 days. Symptoms were different, enzymatic extracts: melanization and internal tissue lysis;enzymatic extract and conidia: mycelium emerged and melanization;conidia: mycelium emerged. Enzymatic extracts showed insecticidal activity in M. spinolae and C. lunulata. These results suggest the potential of enzymatic extracts as biocontrol agents to improve the use of entomopathogenic fungi.展开更多
文摘The use of entomopathogenic fungi (EF) in recent years has been highly effective against the different orders of insects considered pests of agricultural importance and their conidia have been commonly applied, but it has been reported that these are sensitive to the environmental conditions. For this reason, biopesticides products have been formulated based on secondary metabolites, recently. These biomolecules participate as biological control agent, such as: cyclic depsipeptides, amino acids, polyketides, polyphenols and terpenoids, affecting their morphology, life cycle and insect behavior. The use of secondary metabolites of entomopathogenic fungi opens the possibility of application in a more efficient way for the control of agricultural pests in a compatible with the environment and human health;therefore, it is important to know, analyzing the type of molecules, their effects, and their different methods of application.
文摘Entomopathogenic fungi (EF) are recognized biological control agents of insects. Basically, the entomopathogenic fungi pathogen activity depends on the ability of its enzymatic equipment, consisting of lipases, proteases and chitinases, which are in charge of breaking down the insect’s integument. Lipases are the first enzymes synthesized by the entomopathogenic fungi. Recently, a cytochrome P450 subfamily, referred as CYP52XI and MrCYP52 has been identified in Beauveria bassiana and Metarhizium robertsii, respectively. These break down long-chain alkenes and fatty acids to become initial nutrients. Subsequently, subtilisin type (Pr1) proteases sintetize;these enzymes are considered as virulence indicators and they are regulated by a signal transduction mechanism activated by the protein kinase A (PKA) mediated by AMPc. Through the employment of genetic engineering, it has been possible to increase virulence producing Pr1 recombinants with Androctonus australis neurotoxins or with chitinases, reducing the insect’s time of death. In the course of time, the Pr1 protease gene has presented evolutionary adaptations by gene duplication or horizontal transfer infecting different orders of insects. In the same way, the entomopathogenic fungi chitinases have presented a functional diversification. Currently, these have been phylogenetically classified into three subgroups, in accordance to the catalytic site domain and the chitin binding domain. The chitinolytic activity has increased through a directed evolution processes and genetic recombination with Bombyx mori chitinase. Recently, enzymes have been employed as control agents for insects and phytopathogenic fungi (disease originator) opening new potentialities in order to improve the entomopathogenic fungi use. Solid state fermentation is a bioprocess that would produce at great scale enzymes and some other metabolites in grade of increasing the entomopathogenic fungi virulence, in the control of insects and potentially in some diseases affecting plants.
文摘The application of enzymatic extracts and conidia of Beauveria bassiana in Metamasius spinolae and Cyclocephala lunulata was evaluated. The variables were mortality and time of death. In M. spinolae, mortality with extracts 29%, conidia 27% and the combination of both 31%, all had a time of death of four days. Although with different symptoms, used enzymatic extracts: contraction and softening of the joints;by conidia: mycelium in the joints;in the combination of conidia and enzymatic extracts: abundant aerial mycelium. In C. lunulata, 100% mortality in all treatments;Time of death: enzymatic extracts and extracts with conidia 1.2 days;conidia 2.8 days. Symptoms were different, enzymatic extracts: melanization and internal tissue lysis;enzymatic extract and conidia: mycelium emerged and melanization;conidia: mycelium emerged. Enzymatic extracts showed insecticidal activity in M. spinolae and C. lunulata. These results suggest the potential of enzymatic extracts as biocontrol agents to improve the use of entomopathogenic fungi.
