title: An antennae-enriched carboxylesterase from Spodoptera exigua displays degradation activity in both plant volatiles and female sex pheromones.
abstract: 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, SexiCXE14, from Spodoptera exigua. The tissue-temporal expression pattern revealed that the mRNA level of SexiCXE14 is antennae-enriched, sex equivalent and peaks at 3 days after moth eclosion. Functional study using the recombinant enzyme determined that SexiCXE14 has high degrading activity (Vmax) to host plant volatiles, suggesting its role in degradation of these volatiles. In addition, SexiCXE14 may also play a role in the degradation of sex pheromone components, as the Vmax and affinity parameter (Km) 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, SexiCXE14 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.
authors.affiliation: Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China; State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Guizhou University, Ministry of Education, Guiyang, China.
authors.forename: P
authors.initials: P
authors.lastname: He
authors.forename: Y-N
authors.initials: YN
authors.lastname: Zhang
authors.forename: Z-Q
authors.initials: ZQ
authors.lastname: Li
authors.forename: K
authors.initials: K
authors.lastname: Yang
authors.forename: J-Y
authors.initials: JY
authors.lastname: Zhu
authors.forename: S-J
authors.initials: SJ
authors.lastname: Liu
authors.forename: S-L
authors.initials: SL
authors.lastname: Dong
mesh_terms: D000818:Animals; D057506:Arthropod Antennae / Q000201:enzymology* / Q000378:metabolism; D001483:Base Sequence; D043182:Carboxylesterase / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D019476:Insect Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010944:Plants / Q000737:chemistry; D012333:RNA, Messenger; D012724:Sex Attractants / Q000378:metabolism*; D018411:Spodoptera / Q000201:enzymology*; D055549:Volatile Organic Compounds / Q000378:metabolism
chemical_list: D019476:Insect Proteins; D012333:RNA, Messenger; D012724:Sex Attractants; D055549:Volatile Organic Compounds; D043182:Carboxylesterase
keywords: Carboxylesterase; Spodoptera exigua; antennae-enriched; kinetic parameter; odorant-degrading enzyme