Diet alters performance and transcription patterns in Oedaleus asiaticus (Orthoptera: Acrididae) grasshoppers

Abstract

We reared Oedaleus asiaticus grasshoppers under four different single-plant diets to examine the relationships among diet, performance, stress, and transcription patterns. Grasshoppers fed only Artemisia frigida (Asteraceae) were stressed, as indicated by their lower growth, size, development, and survival, in comparison to grasshoppers fed on any of three grasses, Cleistogenes squarrosa, Leymus chinensis, or Stipa krylovii (all Poaceae). We then used transcriptome analysis to examine how gene expression levels in O. asiaticus were altered by feeding on these diets. Nymphs fed A. frigida had the largest variation in gene expression profiles with a total of 299 genes significantly up- or down-regulated compared to those feeding on the three grasses: down-regulated genes included those involved in cuticle biosynthesis, DNA replication, biosynthesis and metabolism of nutrition. The up-regulated genes included stress-resistant and detoxifying enzymes. GO and KEGG enrichment analysis also showed that feeding on A. frigida could down-regulate biosynthesis and metabolism related pathways, and up-regulate stress-resistant and detoxification terms and pathways. Our results show that diet significantly altered gene-expression, and that unfavorable, stressful diets induce more transcriptional changes than favorable diets. Altered gene-expression represents phenotypic plasticity, and many such changes appear to be evolved, adaptive responses. The ease and regularity by which individuals shift phenotypes via altered transcription suggests that populations consist not of similar, fixed phenotypes, but of a collection of ever-changing, divergent phenotypes.

Transcription and Activity of Digestive Enzymes of Nezara viridula Maintained on Different Plant Diets

“…Other diet-induced changes involve the active degradation of anti-nutritional factors that might otherwise limit nutrition (Girard et al, 1998). The response to host plant is not limited to digestive enzymes, but involves other metabolic processes including detoxification, stress response, and immunity pathways (Huang et al, 2017). However, diet-dependent changes in transcription in hemipteran species may not be as pronounced or even involve digestive enzymes.…”

“…Some corn varieties produce cysteine proteases that damage the peritrophic membrane lining the insect gut (Pechan et al, 2000), but insects can upregulate inhibitors of these enzymes (Li et al, 2009). Changes in protease activities or gene transcription profiles have been noted in several insects including in response to phytotoxins (Halon et al, 2015), diet source (Coudron et al, 2007;Huang et al, 2017;Rivera-Vega et al, 2017), or adaptation to the presence of plant protease inhibitors (Lara et al, 2000;Oppert et al, 2005;Brioschi et al, 2007). Key proteases or defense mechanisms are potential targets for disruption for stink bug management through the application of protease inhibitors (Schlüter et al, 2010) or gene knockdown (Joga et al, 2016;Ghosh et al, 2017).…”

Comparative gut transcriptome analysis of Diatraea saccharalis in response to the dietary source

“…Diet is one of the main factors that influence physiology and development in insects, especially in the larval stages of holometabolous insects [2]. The transcriptional responses of different insect species fed on natural and artificial diets have been described by comparing their mRNA profiles [9,51,52]. These studies emphasize that detoxification and nutrition are the processes that exhibit higher variation, influenced by different food sources.…”

Short term transcriptional responses of P450s to phytochemicals in insects and mites

“…Therefore, it is also crucial to study transcriptional responses after short-term host-plant shifts, and a number of recent studies have quantified genome-wide responses to the biological mix of allelochemicals in planta ( Table 2 ). Transfer of phytophagous arthropods to plants rich in alkaloids or polyphenolic compounds results in induction of several Clan 3 (CYP6) P450 genes [ 20 , 21 , 22 , 23 , 24 , 25 , 26 • ]. In some cases, the patterns after host-shift were further investigated by controlled administration.…”

“…In some cases, the patterns after host-shift were further investigated by controlled administration. For example, rutin is a flavonoid present in Artemisia and RNA-seq expression analysis revealed the upregulation of Clan 3 (CYP6) P450 genes when the grasshopper Oedaleus asiaticus was switched from feeding on grasses to Artemisia [ 23 ]. In a follow-up experiment, artificially administering of rutin to O. asiaticus larvae resulted in a similar response of CYP6 genes, suggesting that rutin in Artemisia lies at the basis of the P450 response upon transfer to Artemisia [ 23 , 27 ].…”