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

Chenxu Ye,Xiaohong Su,Lianxi Xing,Humaira Rasheed,Yuehua Ran,Xiaojuan Yang

doi:10.1186/s12864-019-6037-y

Abstract

BackgroundThe 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.ResultsWe 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.ConclusionWe 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.

Highlights

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
The differential expression of the Catalase gene related to longevity were found in Morphological changes of the workers developing into neotenic reproductives The differentiation of neotenic reproductives (NRs) was induced by isolating late instar workers of R. labralis (Fig. 1)
The most surprising finding is that, according to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis, five signal transduction pathways in profile 5 were classified into environmental information processing, which indicated that these signal transduction pathways were involved in the transition of workers into reproductives after the workers were isolated from their natal colonies

Summary

Introduction

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. Workers have unique flexibility in that a worker has the capability to develop into apterous neotenic reproductives that develop in the absence of reproductives to provide for continued growth of the colony [4, 8, 9]. The reproductive plasticity of workers provides colonies with tremendous flexibility to respond to environmental changes and the deterioration of the nest and food resources. This caste system of termites is considered to be the basis for their evolutionary and ecological success [4]

Methods

Results

Discussion

Conclusion