Insect lytic polysaccharide monooxygenases(LPMO15s)are newly discovered copper-dependent enzymes that promote chitin degradation in insect through oxidative cleavage of glycosidic bonds.They are potential pesticide ta...Insect lytic polysaccharide monooxygenases(LPMO15s)are newly discovered copper-dependent enzymes that promote chitin degradation in insect through oxidative cleavage of glycosidic bonds.They are potential pesticide targets due to their critical role for chitin turnover in the integument,trachea,and peritrophic matrix of the midgut during insect molting.However,the knowledge about whether and how LPMO15s participate in chitin turnover in other tissues is still insufficient.Here,using the orthopteran pest Locusta migratoria as a model,a novel alternative splicing site of LmLPMO15-1 was discovered and it produces 2 variants,LmLPMO15-1a and LmLPMO15-1b.The transcripts of LmLPMO15-1a and LmLPMO15-1b were specifically expressed in the trachea and foregut,respectively.RNA interference targeting LmLPMO15-1(a common fragment shared by both LmLPMO15-1a and LmLPMO15-1b),a specific region of LmLPMO15-1a or LmLPMO15-1b all significantly reduced survival rate of nymphs and induced lethal phenotypes with developmental stasis or molt failure.Ultrastructure analysis demonstrated that LmLPMO15-1b was specifically involved in foregut old cuticle degradation,while LmLPMO15-1a was exclusively responsible for the degradation of the tracheal old cuticle.This study revealed LmLPMO15-1 achieved tissue-specific functional differentiation through alternative splicing,and proved the significance of the spliced variants during insect growth and development.It provides new strategies for pest control targeting LPMO15-1.展开更多
Bioinsecticides are naturally-occurring substances from different sources that control insect pests.Ideal bioinsecticides should have low toxicity to non-target organisms.They should also be easily degraded in sewage ...Bioinsecticides are naturally-occurring substances from different sources that control insect pests.Ideal bioinsecticides should have low toxicity to non-target organisms.They should also be easily degraded in sewage treatment works and natural environments,highly effective in small quantities and affect target pests only.Public concerns about possible side-effects of synthetic pesticides have accelerated bioinsecticide research and development.However,to develop bioinsecticides into mainstream products,their high production costs,short shelf-life and often uncertain modes of action need to be considered.This review summarizes current progress on bioinsecticides which are categorized as biochemical insecticides and their derivatives,plant-incorporated protectants,and microbial bioinsecticides.The current constraints that prevent bioinsecticides from being widely used are discussed and future research directions are proposed.展开更多
Locust(Locusta migratoria)has a single striated muscle myosin heavy chain(Mhc)gene,which contains 5 clusters of alternative exclusive exons and 1 differently included penultimate exon.The alternative exons of Mhc gene...Locust(Locusta migratoria)has a single striated muscle myosin heavy chain(Mhc)gene,which contains 5 clusters of alternative exclusive exons and 1 differently included penultimate exon.The alternative exons of Mhc gene encode 4 distinct regions in the myosin motor domain,that is,the N-terminal SH3-like domain,one lip of the nucleotide-binding pocket,the relay,and the converter.Here,we investigated the role of the alternative regions on the motor function of locust muscle myosin.Using Sf9-baculovirus protein expression system,we expressed and purified 5 isoforms of the locust muscle myosin heavy meromyosin(HMM),including the major isoform in the thorax dorsal longitudinal flight muscle(FL1)and 4 isoforms expressed in the abdominal intersegmental muscle(AB1 to AB4).Among these 5 HMMs,FL1-HMM displayed the highest level of actin-activated adenosine triphosphatase(ATPase)activity(hereafter referred as ATPase activity).To identify the alternative region(s)responsible for the elevated ATPase activity of FL1-HMM,we produced a number of chimeras of FL1-HMM and AB4-HMM.Substitution with the relay of AB4-HMM(encoded by exon-14c)substantially decreased the ATPase activity of FL1-HMM,and conversely,the relay of FL1-HMM(encoded by exon-14a)enhanced the ATPase activity of AB4-HMM.Mutagenesis showed that the exon-14a-encoded residues Gly474 and Asn509 are responsible for the elevated ATPase activity of FL1-HMM.Those results indicate that the alternative relay encoded by exon-14a/c play a key role in regulating the ATPase activity of FL1-HMM and AB4-HMM.展开更多
基金supported by the National Key R&D Program of China(2022YFD1700204)the National Natural Science Foundation of China(31872972 and 32170501).
文摘Insect lytic polysaccharide monooxygenases(LPMO15s)are newly discovered copper-dependent enzymes that promote chitin degradation in insect through oxidative cleavage of glycosidic bonds.They are potential pesticide targets due to their critical role for chitin turnover in the integument,trachea,and peritrophic matrix of the midgut during insect molting.However,the knowledge about whether and how LPMO15s participate in chitin turnover in other tissues is still insufficient.Here,using the orthopteran pest Locusta migratoria as a model,a novel alternative splicing site of LmLPMO15-1 was discovered and it produces 2 variants,LmLPMO15-1a and LmLPMO15-1b.The transcripts of LmLPMO15-1a and LmLPMO15-1b were specifically expressed in the trachea and foregut,respectively.RNA interference targeting LmLPMO15-1(a common fragment shared by both LmLPMO15-1a and LmLPMO15-1b),a specific region of LmLPMO15-1a or LmLPMO15-1b all significantly reduced survival rate of nymphs and induced lethal phenotypes with developmental stasis or molt failure.Ultrastructure analysis demonstrated that LmLPMO15-1b was specifically involved in foregut old cuticle degradation,while LmLPMO15-1a was exclusively responsible for the degradation of the tracheal old cuticle.This study revealed LmLPMO15-1 achieved tissue-specific functional differentiation through alternative splicing,and proved the significance of the spliced variants during insect growth and development.It provides new strategies for pest control targeting LPMO15-1.
基金This work was supported by the National Natural Science Foundation of China(31872972,31830076)the Shenzhen Science and Technology Program(KQTD20180411143628272)。
文摘Bioinsecticides are naturally-occurring substances from different sources that control insect pests.Ideal bioinsecticides should have low toxicity to non-target organisms.They should also be easily degraded in sewage treatment works and natural environments,highly effective in small quantities and affect target pests only.Public concerns about possible side-effects of synthetic pesticides have accelerated bioinsecticide research and development.However,to develop bioinsecticides into mainstream products,their high production costs,short shelf-life and often uncertain modes of action need to be considered.This review summarizes current progress on bioinsecticides which are categorized as biochemical insecticides and their derivatives,plant-incorporated protectants,and microbial bioinsecticides.The current constraints that prevent bioinsecticides from being widely used are discussed and future research directions are proposed.
基金supported by the National Natural Science Foundation of China(31672359 and 31970657)State Key Laboratory of Integrated Management of Pest Insects and Rodents(Grant No.IPM1601).
文摘Locust(Locusta migratoria)has a single striated muscle myosin heavy chain(Mhc)gene,which contains 5 clusters of alternative exclusive exons and 1 differently included penultimate exon.The alternative exons of Mhc gene encode 4 distinct regions in the myosin motor domain,that is,the N-terminal SH3-like domain,one lip of the nucleotide-binding pocket,the relay,and the converter.Here,we investigated the role of the alternative regions on the motor function of locust muscle myosin.Using Sf9-baculovirus protein expression system,we expressed and purified 5 isoforms of the locust muscle myosin heavy meromyosin(HMM),including the major isoform in the thorax dorsal longitudinal flight muscle(FL1)and 4 isoforms expressed in the abdominal intersegmental muscle(AB1 to AB4).Among these 5 HMMs,FL1-HMM displayed the highest level of actin-activated adenosine triphosphatase(ATPase)activity(hereafter referred as ATPase activity).To identify the alternative region(s)responsible for the elevated ATPase activity of FL1-HMM,we produced a number of chimeras of FL1-HMM and AB4-HMM.Substitution with the relay of AB4-HMM(encoded by exon-14c)substantially decreased the ATPase activity of FL1-HMM,and conversely,the relay of FL1-HMM(encoded by exon-14a)enhanced the ATPase activity of AB4-HMM.Mutagenesis showed that the exon-14a-encoded residues Gly474 and Asn509 are responsible for the elevated ATPase activity of FL1-HMM.Those results indicate that the alternative relay encoded by exon-14a/c play a key role in regulating the ATPase activity of FL1-HMM and AB4-HMM.
