Transcriptome and Neuroendocrinome Responses to Environmental Stress in the Model and Pest Insect Spodoptera frugiperda

Abstract

The fall armyworm, Spodoptera frugiperda, is one of the most notorious pest insects, causing damage to more than 350 plant species, and is feared worldwide as an invasive pest species since it exhibits high adaptivity against environmental stress. Here, we therefore investigated its transcriptome responses to four different types of stresses, namely cold, heat, no water and no food. We used brain samples as our interest was in the neuroendocrine responses, while previous studies used whole bodies of larvae or moths. In general, the responses were complex and encompassed a vast array of neuropeptides (NPs) and biogenic amines (BAs). The NPs were mainly involved in ion homeostasis regulation (ITP and ITPL) and metabolic pathways (AKH, ILP), and this was accompanied by changes in BA (DA, OA) biosynthesis. Cold and no-water stress changed the NP gene expression with the same patterns of expression but clearly separated from each other, and the most divergent pattern of expression was shown after no-food stress. In conclusion, our data provide a foundation in an important model and pest insect with candidate NPs and BAs and other marker candidate genes in response to environmental stress, and also potential new targets to manage pest insects.

Keywords: brain; environmental constraint; fall armyworm; neuropeptide receptors; neuropeptides; transcriptome.

Figure 1

(A) Volcano plot of the DEGs in the brain of S. frugiperda under four different stress conditions. (B) Venn diagram of the number of DEGs (up- and downregulated genes). Note: G0 represents Control vs. Cold (4 °C), G1 represents Control vs. No-water, G2 represents Control vs. Heat (42 °C), G3 represents Control vs. No-food. (C) Pathway enrichment statistics for all transcripts mRNA under different environmental stresses.

Figure 2

Principal component analysis (PCA) displaying the two first principal components (PC1 vs. PC2) based on expression profiles of neuropeptides (NPs) identified in the brain of Spodoptera frugiperda after Cold, Heat, No-water and No-food stresses. The first two principal components (PCs) comprise 93.86% of the variability—82.23% and 11.63% for PCs 1 and 2, respectively.

Figure 3

Cartoon model with involvement of brain neuropeptides (NPs) and biogenic amines (BAs) in the regulation of S. frugiperda physiological processes in cold stress. The green arrows indicate downregulation while the red arrows upregulation.

Figure 4

Model with involvement of brain neuropeptides (NPs) and biogenic amines (BAs) in the regulation of S. frugiperda physiological processes in heat stress. The green arrows indicate downregulation while the red arrows upregulation.