P450 gene family mediates allelochemical detoxification and tolerance to alkaloids in cactophilic Drosophila

CARREIRA, VALERIA; BOUZAS, SANTIAGO; PADRÓ, JULIÁN; SOTO, IGNACIO M.

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA

WILEY-BLACKWELL PUBLISHING, INC

Año: 2022

0013-8703

Cacti are characterized by the extensive production of a broad variety of toxicmetabolites as an anti-herbivore strategy but nevertheless cactophilic Drosophila spp.(Diptera: Drosophilidae) feed and breed on decaying cacti. The family of cytochromeP450 is a group of enzymes involved in the detoxification metabolism, which arecritical for the adaptation of phytophagous insects, especially populations ofDrosophila exploiting cacti. In this context, Drosophila buzzatii Patterson & Wheeler andDrosophila koepferae Fontdevila & Wasserman (Drosophilini), constitute an excellentmodel for the study of the genetic basis of tolerance to cacti allelochemicals. Theseclosely related species allow testing to what extent a relatively small set of genes canexplain host use patterns and their role in the divergent evolution of specialization.We evaluated the role of the P450 genes in the adaptation of these species to the useof one of their hosts, the columnar cactus Trichocereus terscheckii (Parm.) Friedrich &GD Rowley (Cactaceae). Experimentally evolved strains exhibiting different degreesof cactus specialization were exposed to artificial rearing media enriched with cactusallelochemicals and piperonyl butoxide (PBO), an inhibitor of P450 family activity.Our analyses showed a significant viability reduction in the presence of PBO, in thenon-tolerant strains of both species as well as in the strain historically subjected tomild concentrations of allelochemicals (the soft strain) of D. koepferae. We confirmedthe key role of P450 genes for the evolution of cactus specialization but also foundevidence for the evolution of other detoxification pathways.