Transcriptome changes reveal the genetic mechanisms of the reproductive plasticity of workers in lower termites

Abstract

Background The reproductive plasticity of termite workers provides colonies with tremendous flexibility to respond to environmental changes, which is the basis for evolutionary and ecological success. Although it is known that all colony members share the same genetic background and that differences in castes are caused by differences in gene expression, the pattern of the specific expression of genes involved in the differentiation of workers into reproductives remains unclear. In this study, the isolated workers of Reticulitermes labralis developed into reproductives, and then comparative transcriptomes were used for the first time to reveal the molecular mechanisms underlying the reproductive plasticity of workers. Results We identified 38,070 differentially expressed genes and found a pattern of gene expression involved in the differentiation of the workers into reproductives. 12, 543 genes were specifically upregulated in the isolated workers. Twenty-five signal transduction pathways classified into environmental information processing were related to the differentiation of workers into reproductives. Ras functions as a signalling switch regulates the reproductive plasticity of workers. The catalase gene which is related to longevity was up-regulated in reproductives. Conclusion We demonstrate that workers leaving the natal colony can induce the expression of stage-specific genes in the workers, which leads to the differentiation of workers into reproductives and suggests that the signal transduction along the Ras-MAPK pathway crucially controls the reproductive plasticity of the workers. This study also provides an important model for revealing the molecular mechanism of longevity changes.

Why and how do termite kings and queens live so long?

“…In particular, the catalase activities of termite queens were higher than those of certain solitary insects and social Hymenoptera, reflected by an increased expression of the catalase gene RsCAT1 [46]. In addition, a study on another subterranean termite R. chinensis revealed that differentiation of workers into neotenic reproductives was associated with increased catalase gene expression [48]. These studies partially support the hypothesis that transition to a reproductive state is associated with a gradual decrease in the extent of oxidative damage to body tissues (the oxidative shielding hypothesis) [72].…”

Oxidative stress and senescence in social insects: a significant but inconsistent link?

“…Increased expression of antioxidant-encoding genes occurs in young queens and old workers, but not in old queens in Apis mellifera honeybees and Lasius niger ants [ 13 , 19 , 20 ], and the activity of antioxidant enzymes is not necessarily higher in long-lived castes [ 8 , 19 , 20 ]. In Reticulitermes termites, in which reproductives outlive workers and accumulate less damage to DNA, proteins, and lipids, catalase and peroxiredoxin gene expression is higher in queens, and so is catalase activity [ 16 , 21 ]. While the expression of superoxide dismutase genes does not differ between workers and reproductives, Sod activity is higher in reproductives [ 22 ].…”

Integrating miRNA and mRNA Profiling to Assess the Potential miRNA–mRNA Modules Linked With Testicular Immune Homeostasis in Sheep

“…The 470- to 500-bp size ligation products were enriched to generate a strand-specific cDNA library for mRNA-seq. Construction of the mRNA libraries was performed as described earlier ( 20 ). A total of eight prepared cDNA libraries from two age groups were sequenced on Illumina HiSeq™ 4000 by Gene Denovo Biotechnology Co., Ltd. (Guangzhou, China).…”