Transcriptome modulation during host shift is driven by secondary metabolites in desert Drosophila

Area of Science:

• * Evolutionary Biology
• * Genomics
• * Entomology

Background:

• * High-throughput transcriptome studies explore organismal responses to diverse environments.
• * Understanding the genetic basis of host plant adaptation is crucial.
• * Drosophila buzzatii utilizes Opuntia cacti as a primary substrate and Trichocereus terscheckii as a secondary, potentially harmful host.

Purpose of the Study:

• * To investigate genome-wide expression in Drosophila buzzatii larvae under different environmental conditions.
• * To assess transcriptomic responses to Opuntia sulphurea and Trichocereus terscheckii, including the effects of T. terscheckii alkaloids.
• * To elucidate the genetic mechanisms underlying adaptation to toxic host plants.

Main Methods:

• * Rearing Drosophila buzzatii larvae on Opuntia sulphurea and Trichocereus terscheckii substrates.
• * Supplementing T. terscheckii substrate with extracted alkaloids.
• * Performing whole-genome expression profiling to analyze transcriptomic changes.

Main Results:

• * Rearing environment significantly modulated whole-genome expression profiles, primarily due to T. terscheckii alkaloids.
• * Differentially expressed genes were predominantly associated with detoxification, oxidation-reduction, and stress responses.
• * Genes involved in development and neurobiological processes were also identified as differentially expressed.

Conclusions:

• * Transcriptional plasticity plays a significant role in the adaptation of Drosophila buzzatii to alternative rearing environments.
• * Exposure to T. terscheckii alkaloids induces substantial genetic responses related to detoxification and stress.
• * The study provides novel insights into the genetic basis of insect adaptation to toxic plant defenses.