The insect group ll chitinase(ChtIl,also known as Cht10)is a unique chitinasewith multiple catalytic and chitin-binding domains.It has been proven genetically to be anessential chitinase for molting.However,Chtll'...The insect group ll chitinase(ChtIl,also known as Cht10)is a unique chitinasewith multiple catalytic and chitin-binding domains.It has been proven genetically to be anessential chitinase for molting.However,Chtll's role in chitin degradation during insectdevelopment remains poorly understood.Obtaining this knowledge is the key to fullyunderstanding the chitin degradation system in insects.Here,we investigated the roleof OfChtll during the molting of Ostrinia furnacalis,a model lepidopteran pest insect.OfChtll was expressed earlier than OfChtI(OfCht5)and OfChi-h,at both the gene andprotein levels during larva-pupa molting as evidenced by quantitative polymerase chainreaction and western blot analyses.A truncated OfChtII,OfChtII-B4C1,was recombinantlyexpressed in Pichia pastoris cells and purified to homogeneity.The recombinant OfChtll-B4C1 loosened compacted chitin particles and produced holes in the cuticle surface asevidenced by scanning electron microscopy.It synergized with OfChtl and OfChi-h whenhydrolyzing insoluble a-chitin.These findings suggested an important role for ChtIl duringinsect molting and also provided a strategy for the coordinatdd degradation of cuticularchitin during insect molting by Chtll,Chtl and Chi-h.展开更多
Lytic polysaccharide monooxygenases(LPMOs)are important enzymes that boost the hydrolysis of recalcitrant polysaccharides,such as chitin.They are found extensively in different insect species and are classified as aux...Lytic polysaccharide monooxygenases(LPMOs)are important enzymes that boost the hydrolysis of recalcitrant polysaccharides,such as chitin.They are found extensively in different insect species and are classified as auxiliary activities family 15(AA15)LPMOs(LPMO15).Some of them were identified from the insect midgut and proven to act on chitin.However,knowledge about their physiological roles during insect growth and development remains limited.Here,we found that midgut-specific LPMO15s are widely distributed in different insect orders,such as the orthopteran Locusta migratoria and the lepidopteran Bombyx mori.Using L.migratoria as a model insect,the function of midgut-specific LmLPMO15-3 during development was investigated.Double-stranded RNA-mediated downregulation of LmLPMO15-3 expression at the 4th or 5th instar nymph stage severely decreased the survival rate and resulted in lethal phenotypes.Hematoxylin and eosin staining results indicated that the deficient individuals exhibited incompletely digested peritrophic matrix(PM),which suggested that LmLPMO15-3 is essential for the deconstruction of the PM during molting.This study provides direct evidence of the physiological importance of a midgut-specific LPMO15 during insect development.As L.migratoria is one of the most destructive agricultural pests,LmLPMO15-3 is a potential target for pest management.展开更多
基金the National Key R&D Program of China(2017YFD0201207)Natural Science Foundation of China(31402015,31830076)+1 种基金the Open Research Project from State Key Laboratory for Biology of Plant Diseases and Insect Pests(SKLOF201801)the Shenzhen Science and Technology Program(KQTD20180411143628272).
文摘The insect group ll chitinase(ChtIl,also known as Cht10)is a unique chitinasewith multiple catalytic and chitin-binding domains.It has been proven genetically to be anessential chitinase for molting.However,Chtll's role in chitin degradation during insectdevelopment remains poorly understood.Obtaining this knowledge is the key to fullyunderstanding the chitin degradation system in insects.Here,we investigated the roleof OfChtll during the molting of Ostrinia furnacalis,a model lepidopteran pest insect.OfChtll was expressed earlier than OfChtI(OfCht5)and OfChi-h,at both the gene andprotein levels during larva-pupa molting as evidenced by quantitative polymerase chainreaction and western blot analyses.A truncated OfChtII,OfChtII-B4C1,was recombinantlyexpressed in Pichia pastoris cells and purified to homogeneity.The recombinant OfChtll-B4C1 loosened compacted chitin particles and produced holes in the cuticle surface asevidenced by scanning electron microscopy.It synergized with OfChtl and OfChi-h whenhydrolyzing insoluble a-chitin.These findings suggested an important role for ChtIl duringinsect molting and also provided a strategy for the coordinatdd degradation of cuticularchitin during insect molting by Chtll,Chtl and Chi-h.
基金supported by the National Natural Science Foundation of China(31872972,31830076)the Shenzhen Science and Technology Program(KQTD20180411143628272).
文摘Lytic polysaccharide monooxygenases(LPMOs)are important enzymes that boost the hydrolysis of recalcitrant polysaccharides,such as chitin.They are found extensively in different insect species and are classified as auxiliary activities family 15(AA15)LPMOs(LPMO15).Some of them were identified from the insect midgut and proven to act on chitin.However,knowledge about their physiological roles during insect growth and development remains limited.Here,we found that midgut-specific LPMO15s are widely distributed in different insect orders,such as the orthopteran Locusta migratoria and the lepidopteran Bombyx mori.Using L.migratoria as a model insect,the function of midgut-specific LmLPMO15-3 during development was investigated.Double-stranded RNA-mediated downregulation of LmLPMO15-3 expression at the 4th or 5th instar nymph stage severely decreased the survival rate and resulted in lethal phenotypes.Hematoxylin and eosin staining results indicated that the deficient individuals exhibited incompletely digested peritrophic matrix(PM),which suggested that LmLPMO15-3 is essential for the deconstruction of the PM during molting.This study provides direct evidence of the physiological importance of a midgut-specific LPMO15 during insect development.As L.migratoria is one of the most destructive agricultural pests,LmLPMO15-3 is a potential target for pest management.
