Effect of sulforaphane on gene expression in Spodoptera exigua and Trichoplusia ni
Cruciferous plants produce sulforaphane (SFN), an inhibitor of nuclear histone deacetylases (HDACs). In humans and other mammals, the consumption of SFN alters enzyme activities, DNA-histone binding, and gene expression within minutes. However, the ability of SFN to act as a HDAC inhibitor in nature, disrupting the epigenetic machinery of insects feeding on these plants, has not been explored. Here, we investigate the effect of SFN, as well as the pharmaceutical HDAC inhibitor Trichostatin A (TSA), consumed in the diet in the generalist grazer Spodoptera exigua and in the co-evolved specialist feeder Trichoplusia ni. To investigate the mechanisms of HDAC inhibition, we profiled transcriptome changes via RNA-seq in S. exigua and T. ni fat body tissues responding to SFN or TSA, in biological triplicate. Overall design: To investigate the effect on gene expression of HDAC inhibitors, we supplemented the standard artificial diet of two different species (S. exigua and T. ni) with SFN, TSA, or a control (EtOH). We obtained RNA-seq data from fat body tissues extracted from 10-day old larvae. To obtain sufficient tissue, fat bodies from 3 – 5 individual larvae were pooled per biological replicate. Differential gene expression analysis was performed for three biological replicates, comparing the mean expression for all pairwise combinations of treatments.