Insect Chitin: Metabolism, Genomics and Pest Management

Chitin is a polymer of N-acetyl glucosamine that forms the protective exoskeleton of all arthropods and is replaced periodically during growth and development. Chitin biosynthesis starts with the disaccharide trehalose, culminating in the polymerization of the N-acetyl glucosamine subunits by chitin synthase to produce chitin microfibrils. Chitin in the old exoskeleton is degraded by chitinases, deacetylases and hexosaminidases and recycled. Chitin synthesis has been used as a target for developing biorational insecticides such as benzoylphenyl ureas, diflubenzuron being the original such compound. Several benzoylphenyl ureas with diverse activity spectra have since been synthesized and widely used for pest control. Newer pesticides targeting not only chitinase and chitin synthase but also other novel sites are being developed. Understanding the various nuances of chitin metabolism and regulation with all the genomic resources on hand will undoubtedly pave the way for developing more target-oriented softer control agents that have minimal impact on the environment.