AcMNPV ChiA protein disrupts the peritrophic membrane and alters midgut physiology of Bombyx mori larvae

• Published in: Insect biochemistry and molecular biology Vol. 34; no. 11; pp. 1205 - 1213
• Main Authors: Rao, Rosa, Fiandra, Luisa, Giordana, Barbara, de Eguileor, Magda, Congiu, Terenzio, Burlini, Nedda, Arciello, Stefania, Corrado, Giandomenico, Pennacchio, Francesco
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.11.2004
• Subjects: Animals; Autographa californica multiple nucleopolyhedrovirus; Base Sequence; Bioinsecticides; Bombyx - growth & development; Bombyx - physiology; Bombyx - virology; Bombyx mori; chitinase; Chitinases - genetics; Chitinases - metabolism; digestive physiology; Digestive System - virology; Digestive System Physiological Phenomena; DNA, Viral - genetics; enzyme activity; Escherichia coli - genetics; Genome, Viral; Gut absorption; intestinal absorption; Larva - physiology; Larva - virology; larvae; membrane permeability; Microscopy, Electron, Scanning; midgut; mortality; Nucleopolyhedrovirus - enzymology; Nucleopolyhedrovirus - genetics; Peritrophic membrane; Permeability; Pest Control, Biological; Recombinant protein; recombinant proteins; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; silkworms; Viral chitinase; viral chitinase A; viral insecticides; Peritrophic membrane; Bioinsecticides; Permeability; Recombinant protein; Viral chitinase; Gut absorption
• ISSN: 0965-1748; 1879-0240
• DOI: 10.1016/j.ibmb.2004.08.002

Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) chitinase A (ChiA) is a protein which promotes the final liquefaction of infected host larvae. The potential of this viral molecule as a new tool for insect control is explored here. The ChiA gene was isolated from the AcMNPV genome by PCR and expressed in E. coli. The recombinant protein, purified by affinity chromatography, showed both exo- and endo-chitinase activities and produced perforations on the peritrophic membrane (PM) of Bombyx mori larvae which increased in number and in size, in a dose-dependent manner. This structural alteration resulted into a significant increase of PM permeability to methylene blue and to the small neuropeptide proctolin. When the fifth instar larvae of B. mori were fed on a artificial diet supplemented with the recombinant ChiA, 100% mortality was observed at a dose of 1 μg/g of larval body weight (LW), while at sub-lethal doses of 0.56 μg/g LW, a reduced larval growth was recorded. These results indicate that AcMNPV-ChiA may offer interesting new opportunities for pest control.