Comparison of Gene Expression in the Red Imported Fire Ant, Solenopsis Invicta, in Different Temperature Conditions

The red imported fire ant (RIFA), Solenopsis invicta Buren is native to South America and is known as a global problematic invasive species. This study focused on the molecular response of RIFA by comparing gene expression profiles after exposing ants to low (10℃) and high (40℃) temperature stress and comparing to untreated controls (30℃). A total of 99,085 unigenes were obtained, of which 19,154 were annotated with gene descriptions, gene ontology terms, and metabolic pathways. 86 gene ontology (GO) functional sub-groups and 23 EggNOG terms resulted. Differentially expressed genes (DEGs) with log 2 FC ≥ 10 were screened and were compared at different temperatures. We found 203, 48, and 66 specific DEGs co-regulated at 10, 20, and 40℃. Comparing transcriptome profiles for differential gene expression resulted in various DE proteins and genes, including cytochrome P450, NADH dehydrogenase subunit 1, cuticle protein and heat shock protein (HSP) which have previously been reported to be involved in cold and high temperature resistance. GO analysis revealed that antioxidant activity up-regulated under high temperature stress. We verified the RNA-seq data by qPCR on 20 up and down-regulated DEGs. These finding provide a basis for the future understanding of adaptation mechanism of RIFA and molecular mechanism underlying the response to low and high temperatures.