An antenna-biased carboxylesterase is specifically active to plant volatiles in Spodoptera exigua.

摘要: Odorant-degrading enzymes (ODEs) in sensillar lymph are proposed to play important roles the maintenance of sensitivity olfactory sensilla, by timely degrading odorants that have already fulfilled activation odorant receptor (OR). Here we reported cloning and characterization an ODE gene (SexiCXE10) from polyphagous insect pest Spodoptera exigua. SexiCXE10 is a carboxylesterase (CXE) gene, encoding protein with 538 amino acid residues, bearing typical characteristics Carboxyl/cholinesterase (CCE, EC 3.1.1.1.) family. Tissue-temporal expression pattern qPCR revealed mRNA was highly antenna biased, maintained at high level throughout adult stage. Further fluorescence situ hybridization demonstrated signal detected under sensilla basiconica short long trichodea. Finally, enzymatic study using purified recombinant enzyme showed had activity specifically for ester plant volatiles 7-10 carbon atoms, while no found S. exigua sex pheromone components more atoms. In addition, displayed lower acidic pH (pH 5.0), higher neutral alkaline conditions (pH 6.5-9.0). Our results suggest may role degradation host volatiles, thus contributes system S. exigua. Meanwhile, CXE would be potential target developing behavioral antagonists pesticides against