Caste-specific expressions and diverse roles of takeout genes in the termite Reticulitermes speratus

Abstract

Acquisition of novel functions caused by gene duplication may be important for termite social evolution. To clarify this possibility, additional evidence is needed. An important example is takeout, encoding juvenile hormone binding protein. We identified 25 takeouts in the termite Reticulitermes speratus genome. RNA-seq revealed that many genes were highly expressed in specific castes. Two novel paralogs (RsTO1, RsTO2) were tandemly aligned in the same scaffold. Real-time qPCR indicated that RsTO1 and RsTO2 were highly expressed in queens and soldiers, respectively. Moreover, the highest RsTO1 expression was observed in alates during queen formation. These patterns were different from vitellogenins, encoding egg-yolk precursors, which were highly expressed in queens than alates. In situ hybridization showed that RsTO1 mRNA was localized in the alate-frontal gland, indicating that RsTO1 binds with secretions probably used for the defence during swarming flight. In contrast, increased RsTO2 expression was observed approximately 1 week after soldier differentiation. Expression patterns of geranylgeranyl diphosphate synthase, whose product functions in the terpenoid synthesis, were similar to RsTO2 expression. In situ hybridization indicated RsTO2-specific mRNA signals in the soldier-frontal gland. RsTO2 may interact with terpenoids, with a soldier-specific defensive function. It may provide additional evidence for functionalization after gene duplication in termites.

takeoutgene expression is associated with temporal kin recognition

“…We used Geneious Prime (v. 2022.1.1) to blast the Nicrophorus orbicollis transcriptome (Won et al, 2018) for putative takeout homologues of D. melanogaster (Q9VBV3) and N. vespilloides (XP_017773976). To visualize protein conservation across takeout copies, we aligned protein sequences from Drosophila melanogaster (Sarov-Blat et al, 2000), Nicrophorus vespilloides, Locusta migratoria (Guo et al, 2011), Reticulitermes speratus (Fujiwara et al, 2023), Bombyx mori and Anopheles gambiae (Saito et al, 2006), and using Clustal Omega (https://www.ebi.ac.uk/Tools/msa/clustalo/) and produced plots with Javalview (Waterhouse et al, 2009).…”

takeout gene expression is associated with temporal kin recognition

“…We used Geneious Prime (v. 2022.1.1) to blast the Nicrophorus orbicollis transcriptome [23] for putative takeout homologues of Drosophila melanogaster (Q9VBV3) and Nicrophorus vespilloides (XP_017773976). To visualize protein conservation across takeout copies, we aligned protein sequences from D. melanogaster [9], N. vespilloides, Locusta migratoria [13], Reticulitermes speratus [24], Bombyx mori and Anopheles gambiae [25], and using Clustal Omega (https://www.ebi.ac.uk/Tools/msa/clustalo/) and produced plots with Javalview [26].…”