Gene Expression and Diet Breadth in Plant-Feeding Insects: Summarizing Trends

Combining Experimental Evolution and Genomics to Understand How Seed Beetles Adapt to a Marginal Host Plant

“…However, some role of cytochrome P450s in lentil-adaptation is likely, as cytochrome P450 4d2 is among the genes showing evidence of parallel exceptional change across multiple lentil lines (L1 and L14A). There was some idiosyncratic and weak evidence of evolved differences in expression of digestive enzymes, which is again consistent with an emerging trend in analyses of herbivorous insects [76]. Moreover, C. maculatus has been shown to increase expression of proteases, including inhibitor-insensitive proteases, in response to plant protease inhibitors [75].…”

“…Nonetheless, we detected consistent differences in expression of cytochrome P450s between mung bean and lentil treatments. Cytochrome P450s are known to play a role in detoxification of plant secondary metabolites and insecticides [53,101,118,119], and this finding is consistent with a general pattern of increased plasticity of detoxification genes in herbivorous insects [76,120]. Because mortality is high for the M line when reared in lentil, we do not know if adaptation to lentil involved the evolution of increased plasticity of cytochrome P450s or if this differential expression was present in the ancestral M line and thus is mostly incidental to lentil adaptation.…”

“…By integrating these three sets of genomic data, we are able to quantify parallelism in terms of the genetic basis of performance traits and allele-frequency change during adaptation (we test for parallelism in each of these patterns rather than using parallelism as a test for the process of selection), and obtain a more complete understanding of the genes and traits that allow C. maculatus to adapt to and persist on a marginal host plant. In terms of the latter, we specifically test for roles of digestive enzymes and detoxification genes as these types of genes have been implicated in host-plant adaptation in other systems [53,75,76].…”

Consequences of pharmacophagous uptake from plants and conspecifics in a sawfly elucidated using chemical and molecular techniques

“…In comparison, in AC+ individuals two cytochrome P450 genes were upregulated compared to the control (C-). Cytochrome P450 genes often play a critical role in phase 1 of the metabolism and sequestration of plant specialised metabolites through the oxidation, reduction, or hydrolysis of compounds (Birnbaum and Abbot, 2020). One of the two genes upregulated in AC+ individuals, Cyp4c3, has been linked to xenobiotic resistance in Drosophila (Scanlan et al, 2020) and many genes in the insect CYP4 family play a role in detoxification in insects (Scott, 1999;Vogel et al, 2014).…”

The molecular mechanisms that determine different degrees of polyphagy in the Bemisia tabaci species complex

“…Specialists, on the other hand, may have “specialized genomes,” characterized by genomes that are “untested” in alternative environments (Huang et al., 2016). Most genes are expected to be constitutively expressed, and because the specialist can be considered “naïve” to new environments, initially non‐adaptive patterns of plastic expression is expected when new stressors are encountered (Birnbaum & Abbot, 2020).…”