Transcriptomic signatures during soldier differentiation through the regulation of social interactions in termites
Hajime Yaguchi, Ryutaro Suzuki , Masatoshi Matsunami , Shuji Shigenobu , Kiyoto Maekawa , Hajime Yaguchi
Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, Japan; Graduate school of Science and Engineering, University of Toyama, Toyama, Japan ; Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan ; National Institute for Basic Biology, Aichi, Japan ; Graduate school of Science and Engineering, University of Toyama, Toyama, Japan ; Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, Japan
Phenotypic plasticity is the adaptive ability against environmental variations without genomic changes, which leads to evolutionary success of social insects. In ants, bees and termites, multiple phenotypes (i.e. castes) occur from a single genotype by receiving social signals through intra-colonial interactions among castes during developmental course. However, intrinsic mechanism during caste differentiation is still far from fully understandings. Here, we focused on the soldier differentiation in an incipient colony of the damp-wood termite Zootermopsis nevadensis. In this species, the soldier- and worker-destined individuals can be identified under natural conditions, and the frequency of proctodeal trophallaxis from reproductives is highly observed in the former than the latter. This study was conducted to uncover the transcriptomic profiles underlying caste differentiations through the inter-individual interactions in an incipient colony of Z. nevadensis. By performing RNA-seq analysis, huge numbers of differentially expressed genes (DEGs) were identified between the soldier- and worker-destined individuals, respectively. The DEGs were represented as GO terms including cell division and cell proliferation in the soldier-destined individuals. On the other hand, specific GO terms including neural activity and chemical reception as well as various metabolic pathways were detected in the DEGs observed in the worker-destined individuals. KEGG enrichment analyses showed that several signal pathways were up-regulated in the soldier-destined individuals. These results listed here should provide a good opportunity to examine molecular mechanisms underlying polyphenic caste differentiations in termites. We will discuss about this issue based on the gene expression and function analysis of candidate genes identified.