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Deciphering the role of Rhodnius prolixus CYP4G genes in straight and methyl‐branched hydrocarbon formation and in desiccation tolerance
Author(s) -
Dulbecco A. B.,
Moriconi D. E.,
Lynn S.,
McCarthy A.,
Juárez M. P.,
Girotti J. R.,
CalderónFernández G. M.
Publication year - 2020
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.12653
Subject(s) - biology , rhodnius prolixus , desiccation , insect , cuticle (hair) , biochemistry , arthropod cuticle , gene , botany , microbiology and biotechnology , genetics
Insect cuticle hydrocarbons are involved primarily in waterproofing the cuticle, but also participate in chemical communication and regulate the penetration of insecticides and microorganisms. The last step in insect hydrocarbon biosynthesis is carried out by an insect‐specific cytochrome P450 of the 4G subfamily (CYP4G). Two genes ( CYP4G106 and CYP4G107 ) have been reported in the triatomines Rhodnius prolixus and Triatoma infestans . In this work, their molecular and functional characterization is carried out in R . prolixus , and their relevance to insect survival is assessed. Both genes are expressed almost exclusively in the integument and have an expression pattern dependent on the developmental stage and feeding status. CYP4G106 silencing diminished significantly the straight‐chain hydrocarbon production while a significant reduction – mostly of methyl‐branched chain hydrocarbons – was observed after CYP4G107 silencing. Molecular docking analyses using different aldehydes as hydrocarbon precursors predicted a better fit of straight‐chain aldehydes with CYP4G106 and methyl‐branched aldehydes with CYP4G107. Survival bioassays exposing the silenced insects to desiccation stress showed that CYP4G107 is determinant for the waterproofing properties of the R . prolixus cuticle. This is the first report on the in vivo specificity of two CYP4Gs to make mostly straight or methyl‐branched hydrocarbons, and also on their differential contribution to insect desiccation.