Comparison of gene expression profiles among caste differentiations in the termite Reticulitermes speratus

Abstract

Termite castes express specialized phenotypes for their own tasks and are a good example of insect polyphenism. To understand the comprehensive gene expression profiles during caste differentiation, RNA-seq analysis based on the genome data was performed during the worker, presoldier, and nymphoid molts in Reticulitermes speratus. In this species, artificial induction methods for each molt have already been established, and the time scale has been clarified. Three different periods (before the gut purge (GP), during the GP, and after the molt) were discriminated in each molt, and two body parts (head and other body regions) were separately sampled. The results revealed that many differentially expressed genes (head: 2884, body: 2579) were identified in each molt. Based on the independent real-time quantitative PCR analysis, we confirmed the different expression patterns of seven out of eight genes in the presoldier molt. Based on the GO and KEGG enrichment analyses, the expressions of genes related to juvenile hormone titer changes (e.g., JH acid methyltransferase), nutrition status (e.g., Acyl-CoA Delta desaturase), and cell proliferation (e.g., insulin receptor), were shown to specifically fluctuate in each molt. These differences may have a crucial impact on caste differentiation. These data are important resources for future termite sociogenomics.

Feeding cessation after feeding on 20‐hydroxyecdysone in the Formosan subterranean termite

“…Our second experiment revealed that bait ingestion with either 100 or 1000 ppm of 20E caused rapid feeding cessation after 1 day of feeding. This observation is critical as 20E-exposed termites may abruptly terminate their intermolt period and enter their pre-molt fasting period by purging their guts, 29,[49][50][51] functionally stopping further 20E intake for individual foragers. Feeding cessation after ingestion of 20E agonists is a common symptom observed in various insect pests.…”

Meta-analysis of public RNA sequencing data revealed potential key genes associated with reproductive division of labor in social Hymenoptera and termites

“…Meta-analysis revealed 20 genes with differential expression between queens and workers. Among these genes, vitellogenin and vitellogenin receptors, which are highly expressed in queens across many social insects [11,30,41–46], showed the highest QW score (Figure 1). This suggests that the current meta-analysis method is suitable for identifying differences in gene expression between queens and workers.…”

“…Vg synthesis and uptake into ovary are promoted by JH [Soller et al 1999]. Vg and its receptors are highly expressed in the reproductive castes of various social insects [11,30,41–46] . The regulation of the secretion of neuropeptide and neurotransmitter plays a central role in controlling the reproductive division of labor.…”

Transmission dynamics of symbiotic protist communities in the termite gut: association with host adult eclosion and dispersal

“…Immediately before ecdysis, workers were sampled from two colonies. Pre-moult workers were distinguished from others by the yellowish-white colouration of the abdomen due to the gut purge [33]. The workers were isolated in 24-well plates (Stem, Tokyo, Japan) at 25°C and observed daily for moulting.…”