The two-spotted spider mite,Tetranychus urticae Koch,is one of the most harmful pests in many agroecosystems worldwide.To effectively manage this pest,there is an urgent need to develop novel bio-active acaricides tha...The two-spotted spider mite,Tetranychus urticae Koch,is one of the most harmful pests in many agroecosystems worldwide.To effectively manage this pest,there is an urgent need to develop novel bio-active acaricides that support integrated pest management strategies targeting T.urticae.In this study,we explored the acaricidal effects of xenocoumacin 1 (Xcn1) on T.urticae and its predator Neoseiulus californicus using the highly puri?ed compound.Xcn1 was extracted and purified from the cell-free supernatant of the Xenorhabdus nematophila CB6 mutant constructed by the easy promoter activated compound identi?cation (easyPACId) method.When the concentration of Xcn1 exceeded 100μg mL~(–1),the survival rate of spider mite adults declined to below 40%and the fecundity was decreased by 80%at six days post-application.At concentrations of 25 and 50μg mL~(–1),Xcn1 signi?cantly impeded spider mite development by inhibiting the molt.However,neither concentration had any adverse effects on the survival or reproduction of the predatory mite N.californicus.The results from laboratory and semi-?eld experiments consistently demonstrated the effectiveness of the antimicrobial metabolite Xcn1 in controlling pest mites at both the molecular and physiological levels.Our study offers a promising possibility that combines the compatible biocontrol agents of Xcn1 and predatory mites for integrated pest mite control.展开更多
Plant-mediated RNA interference(RNAi)has emerged as a promising technology for insect control.The green peach aphid,Myzus persicae,feeds on over 400 species of host plants.Brassica napus(rape)is the second most import...Plant-mediated RNA interference(RNAi)has emerged as a promising technology for insect control.The green peach aphid,Myzus persicae,feeds on over 400 species of host plants.Brassica napus(rape)is the second most important oilseed crop worldwide.Myzus persicae is highly reproductive and causes severe damage to the rape plants due to its quite flexible life cycle.In this study,we tested the RNAi effects of transgenic rape plants on M.persicae.By in vitro feeding M.persicae with artificial diets containing double-stranded RNAs(dsRNAs)targeting seven aphid genes,we identified a new gene encoding the partitioning-defective protein 6(Par6)as the most potent RNAi target.Tissue-and stage-expression analysis of Par6 suggested this gene is highly expressed in the embryo and adult stage of M.persicae.We next generated transgenic rape plants expressing ds Par6 by Agrobacteriummediated transformation and obtained nine independent transgenic lines.Compared to wild-type control plants,transgenic rape lines expressing ds Par6 showed strong resistance to M.persicae.Feeding assays revealed that feeding transgenic rape plants to M.persicae significantly decreased MpPar6 expression and survival rate and impaired fecundity.Furthermore,we showed that the resistance levels to M.persicae are positively correlated with ds Par6 expression levels in transgenic rape plants.Our study demonstrates that transgenic rape plants expressing ds Par6 are efficiently protected from M.persicae.Interfering with the genes involved in embryo development could be the effective RNAi targets for controlling aphids and potentially other insect pests.展开更多
The rice planthopper,Sogatella furcifera,is a piercing-sucking insect pest of rice,Oryza sativa.It is responsible for significant crop yield losses,and has developed moderate to high resistance to several commonly use...The rice planthopper,Sogatella furcifera,is a piercing-sucking insect pest of rice,Oryza sativa.It is responsible for significant crop yield losses,and has developed moderate to high resistance to several commonly used chemical insecticides.We investigated the effects of the insect fungal pathogen Isaria javanica,alone and in combination with the chemical insecticide dinotefuran,on S.furcifera under both laboratory and field conditions.Our results show that I.javanica displays high infection efficiency and mortality for different stages of S.furcifera,reducing adult survival,female oviposition and ovary development.Laboratory bioassays showed that the combined use of I.javanica with a low dose(4-16 mg L^(-1))of dinotefuran resulted in higher mortality in S.furcifera than the use of I.javanica or dinotefuran alone.The combined treatment also had more significant effects on several host enzymes,including superoxide dismutase,catalase,peroxidase,and prophenol oxidase activities.In field trials,I.javanica effectively suppressed populations of rice planthoppers to low levels(22-64%of the level in untreated plots).Additional field experiments showed synergistic effects,i.e.,enhanced efficiency,for the control of S.furcifera populations using the combination of a low dose of I.javanica(1×10^(4) conidia mL^(-1))and a low dose of dinotefuran(~4.8-19.2%of normal field use levels),with control effects of>90%and a population level under 50 insects per 100 hills at 3-14 days post-treatment.Our findings indicate that the entomogenous fungus I.javanica offers an attractive biological control addition as part of the integrated pest management(IPM)practices for the control of rice plant pests.展开更多
基金supported by the National Natural Science Foundation of China(32070402)the Beijing Natural Science Foundation,China(6222052)。
文摘The two-spotted spider mite,Tetranychus urticae Koch,is one of the most harmful pests in many agroecosystems worldwide.To effectively manage this pest,there is an urgent need to develop novel bio-active acaricides that support integrated pest management strategies targeting T.urticae.In this study,we explored the acaricidal effects of xenocoumacin 1 (Xcn1) on T.urticae and its predator Neoseiulus californicus using the highly puri?ed compound.Xcn1 was extracted and purified from the cell-free supernatant of the Xenorhabdus nematophila CB6 mutant constructed by the easy promoter activated compound identi?cation (easyPACId) method.When the concentration of Xcn1 exceeded 100μg mL~(–1),the survival rate of spider mite adults declined to below 40%and the fecundity was decreased by 80%at six days post-application.At concentrations of 25 and 50μg mL~(–1),Xcn1 signi?cantly impeded spider mite development by inhibiting the molt.However,neither concentration had any adverse effects on the survival or reproduction of the predatory mite N.californicus.The results from laboratory and semi-?eld experiments consistently demonstrated the effectiveness of the antimicrobial metabolite Xcn1 in controlling pest mites at both the molecular and physiological levels.Our study offers a promising possibility that combines the compatible biocontrol agents of Xcn1 and predatory mites for integrated pest mite control.
基金supported by the National Natural Science Foundation of China(32102297 and 32272634)。
文摘Plant-mediated RNA interference(RNAi)has emerged as a promising technology for insect control.The green peach aphid,Myzus persicae,feeds on over 400 species of host plants.Brassica napus(rape)is the second most important oilseed crop worldwide.Myzus persicae is highly reproductive and causes severe damage to the rape plants due to its quite flexible life cycle.In this study,we tested the RNAi effects of transgenic rape plants on M.persicae.By in vitro feeding M.persicae with artificial diets containing double-stranded RNAs(dsRNAs)targeting seven aphid genes,we identified a new gene encoding the partitioning-defective protein 6(Par6)as the most potent RNAi target.Tissue-and stage-expression analysis of Par6 suggested this gene is highly expressed in the embryo and adult stage of M.persicae.We next generated transgenic rape plants expressing ds Par6 by Agrobacteriummediated transformation and obtained nine independent transgenic lines.Compared to wild-type control plants,transgenic rape lines expressing ds Par6 showed strong resistance to M.persicae.Feeding assays revealed that feeding transgenic rape plants to M.persicae significantly decreased MpPar6 expression and survival rate and impaired fecundity.Furthermore,we showed that the resistance levels to M.persicae are positively correlated with ds Par6 expression levels in transgenic rape plants.Our study demonstrates that transgenic rape plants expressing ds Par6 are efficiently protected from M.persicae.Interfering with the genes involved in embryo development could be the effective RNAi targets for controlling aphids and potentially other insect pests.
基金funded by grants from the Science and Technology Planning Project of Guangzhou,China(202002020029)the Science and Technology Planning Project of Guangdong Province,China(2019B020217003)+1 种基金the National Key R&D Program of China(2018YFD02003)the National Key Technology Support Program of China(201303019-02)。
文摘The rice planthopper,Sogatella furcifera,is a piercing-sucking insect pest of rice,Oryza sativa.It is responsible for significant crop yield losses,and has developed moderate to high resistance to several commonly used chemical insecticides.We investigated the effects of the insect fungal pathogen Isaria javanica,alone and in combination with the chemical insecticide dinotefuran,on S.furcifera under both laboratory and field conditions.Our results show that I.javanica displays high infection efficiency and mortality for different stages of S.furcifera,reducing adult survival,female oviposition and ovary development.Laboratory bioassays showed that the combined use of I.javanica with a low dose(4-16 mg L^(-1))of dinotefuran resulted in higher mortality in S.furcifera than the use of I.javanica or dinotefuran alone.The combined treatment also had more significant effects on several host enzymes,including superoxide dismutase,catalase,peroxidase,and prophenol oxidase activities.In field trials,I.javanica effectively suppressed populations of rice planthoppers to low levels(22-64%of the level in untreated plots).Additional field experiments showed synergistic effects,i.e.,enhanced efficiency,for the control of S.furcifera populations using the combination of a low dose of I.javanica(1×10^(4) conidia mL^(-1))and a low dose of dinotefuran(~4.8-19.2%of normal field use levels),with control effects of>90%and a population level under 50 insects per 100 hills at 3-14 days post-treatment.Our findings indicate that the entomogenous fungus I.javanica offers an attractive biological control addition as part of the integrated pest management(IPM)practices for the control of rice plant pests.
