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An antennae‐enriched carboxylesterase from S podoptera exigua displays degradation activity in both plant volatiles and female sex pheromones
Author(s) -
He P.,
Zhang YN.,
Li ZQ.,
Yang K.,
Zhu JY.,
Liu SJ.,
Dong SL.
Publication year - 2014
Publication title -
insect molecular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.955
H-Index - 93
eISSN - 1365-2583
pISSN - 0962-1075
DOI - 10.1111/imb.12095
Subject(s) - sex pheromone , exigua , biology , carboxylesterase , pheromone , enzyme , catabolism , spodoptera , insect , degradation (telecommunications) , enzyme assay , biochemistry , substrate (aquarium) , gene , stereochemistry , botany , recombinant dna , chemistry , ecology , telecommunications , computer science
Carboxyl/cholinesterase ( CCE ) is a large gene family of diverse functions, but in insects its function with respect to catabolism of sex pheromone components and plant volatiles is not well understood. In the present study, we cloned and functionally characterized one putative odorant‐degrading enzyme ( ODE ) of the CCE family, S exi CXE 14, from S podoptera exigua . The tissue‐temporal expression pattern revealed that the mRNA level of Sexi CXE 14 is antennae‐enriched, sex equivalent and peaks at 3 days after moth eclosion. Functional study using the recombinant enzyme determined that S exi CXE 14 has high degrading activity ( V max ) to host plant volatiles, suggesting its role in degradation of these volatiles. In addition, S exi CXE 14 may also play a role in the degradation of sex pheromone components, as the V max and affinity parameter ( K m ) values with the sex pheromones are similar to those of reported pheromone degrading enzymes ( PDEs ). Further analysis of the relationship between substrate structure and enzymatic activity demonstrated that carbon chain length is a major influential factor, while the number of double bonds also affects the enzymatic activity. In addition, Sexi CXE 14 displays lower activity at acidic pH levels ( pH 5.0) than in neutral conditions ( pH 6.5). By characterizing this new ODE the present study provides insights in understanding of the high sensitivity of the moth olfactory system.