Microbially derived,protein-based biopesticides have become a vital element in pest management strategies.Vip3 family proteins from Bacillus thuringiensis have distinct characteristics from known insecticidal Cry toxi...Microbially derived,protein-based biopesticides have become a vital element in pest management strategies.Vip3 family proteins from Bacillus thuringiensis have distinct characteristics from known insecticidal Cry toxins and show efficient insecticidal activity against several detrimental lepidopteran pests.They are considered to be a promising toxic candidate for the management of various detrimental pests.In this study,we found that in addition to the preliminary digestion sites lysine,there are multiple cleavage activation sites in the linker region between domain I(DI)and DII of Vip3Aa.We further demonstrated that by adding more cleavage sites between DI and DII of Vip3Aa,its proteolysis efficiency by midgut proteases can be significantly increased,and correspondingly enhance its insecticidal activity against Spodoptera frugiperda and Helicoverpa armigera larvae.Our study promotes the understanding of the insecticidal mechanism of Vip3 proteins and illustrates an eas-ily implementable strategy to increase the insecticidal potency of Vip3Aa.This facilitates their potential future development and efficient application for sustainable agriculture.展开更多
To study insecticidal mechanism of terpinen-4-ol, a main insecticidal composition in the essential oil of Sabina vulgaris, the 5th instar larvae of Mythimna separta, were investigated with terpinen-4-ol by topical app...To study insecticidal mechanism of terpinen-4-ol, a main insecticidal composition in the essential oil of Sabina vulgaris, the 5th instar larvae of Mythimna separta, were investigated with terpinen-4-ol by topical application. The activities of phosphatase, glutathione S-transferase （GSTs）, cytochrome P450 （P450）, and polyphenol oxidase （PPO） of tested insects were determined in all poisoning stages, including exciting stage, convulsing stage, paralysis stage, and recover stage. The result showed that the activities of both acid phosphatase （ACP） and alkaline phosphatase （AKP） in treated insects were induced by terpinen-4-ol, but ACP was inhibited in paralysis stage. The activities of GSTs were inhibited in exciting stage, convulsing stage, and paralysis stage, but gradually recovered in recover stage. O-demethylase activity of cytochrome P450 was inhibited by terpinen-4-ol, and the inhibition rate in all poisoning stages were 26.27, 46.03, 80.24, and 90.22%, respectively. PPO activities were strongly inhibited by terpinen-4-ol both in vitro and in vivo. In conclusion, the activities of P450, GSTs, and PPO could have relation with toxicity of terpinen-4-ol against larvae of the Mythimna separta, but recover stage of the poisoning insects might be related to GSTs induced. As a new insecticide or synergist, terpinen- 4-ol has a potential value in field of insecticide resistance management.展开更多
基金supported by the National Natural Science Foundation of China(3190194332122007,and 32272610)the Shandong Provincial Natural Science Foundation(ZR2021JQ09)+3 种基金the Major Basic Program of Natural Science Foundation of Shandong Province(ZR2019ZD21)the Key R&D Program of Shandong Province(2020CXGC011305)the Youth Interdisciplinary Innovative Research Group of Shandong Univer-sity(2020QNQT009)the China Postdoctoral Science Foundation funded project(2019T120585 and 2019M652370).
文摘Microbially derived,protein-based biopesticides have become a vital element in pest management strategies.Vip3 family proteins from Bacillus thuringiensis have distinct characteristics from known insecticidal Cry toxins and show efficient insecticidal activity against several detrimental lepidopteran pests.They are considered to be a promising toxic candidate for the management of various detrimental pests.In this study,we found that in addition to the preliminary digestion sites lysine,there are multiple cleavage activation sites in the linker region between domain I(DI)and DII of Vip3Aa.We further demonstrated that by adding more cleavage sites between DI and DII of Vip3Aa,its proteolysis efficiency by midgut proteases can be significantly increased,and correspondingly enhance its insecticidal activity against Spodoptera frugiperda and Helicoverpa armigera larvae.Our study promotes the understanding of the insecticidal mechanism of Vip3 proteins and illustrates an eas-ily implementable strategy to increase the insecticidal potency of Vip3Aa.This facilitates their potential future development and efficient application for sustainable agriculture.
基金supported by the National Natural Science Foundation of China(30600404)the Key Technologies R&D Program of China during the 10th Five-Year Plan Period(2004BA516A04).
文摘To study insecticidal mechanism of terpinen-4-ol, a main insecticidal composition in the essential oil of Sabina vulgaris, the 5th instar larvae of Mythimna separta, were investigated with terpinen-4-ol by topical application. The activities of phosphatase, glutathione S-transferase （GSTs）, cytochrome P450 （P450）, and polyphenol oxidase （PPO） of tested insects were determined in all poisoning stages, including exciting stage, convulsing stage, paralysis stage, and recover stage. The result showed that the activities of both acid phosphatase （ACP） and alkaline phosphatase （AKP） in treated insects were induced by terpinen-4-ol, but ACP was inhibited in paralysis stage. The activities of GSTs were inhibited in exciting stage, convulsing stage, and paralysis stage, but gradually recovered in recover stage. O-demethylase activity of cytochrome P450 was inhibited by terpinen-4-ol, and the inhibition rate in all poisoning stages were 26.27, 46.03, 80.24, and 90.22%, respectively. PPO activities were strongly inhibited by terpinen-4-ol both in vitro and in vivo. In conclusion, the activities of P450, GSTs, and PPO could have relation with toxicity of terpinen-4-ol against larvae of the Mythimna separta, but recover stage of the poisoning insects might be related to GSTs induced. As a new insecticide or synergist, terpinen- 4-ol has a potential value in field of insecticide resistance management.
