Abiotic and biotic stressors causing equivalent mortality induce highly variable transcriptional responses in the soybean aphid.
Bottom Line: Molecular responses showed little overlap across all three stressors.Exposure to host plant defenses elicited the weakest response, of which half of the genes were of unknown function.This study highlights the need for standardizing stress levels when comparing across stress types and provides a basis for understanding the role of general vs. stressor specific molecular responses in aphids.
Affiliation: Department of Entomology, University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0816.Show MeSH
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Mentions: All three stressors caused on average a 27% reduction in adult survival relative to benign control conditions, which was consistent across experimental blocks (Figure 1A). Post hoc tests revealed the three stressors had equivalent survival (P values > 0.20) that was significantly lower than under control conditions (P values < 0.05). These effects did not vary across the experimental blocks (Environment × Block: F6,132 = 0.39, P = 0.88). Stress levels with respect to mortality were therefore considered standardized across stress types and experimental blocks. There were significant differences in aphid reproduction under control, heat and plant defensive stress (Environment: F2,99 = 43.95, P < 0.001) and across experimental blocks (Environment × Block: F4,99 = 43.95, P < 0.001). Aphids exposed to plant defensive stress produced on average 55% fewer offspring than those under control and heat stressed conditions (P values < 0.001) across all blocks, whereas heat stressed and control aphids produced similar numbers of offspring (Figure 1B). Starved aphids did not produce offspring during the 36-hr period.
Affiliation: Department of Entomology, University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0816.