1
|
Fujiwara K, Karasawa A, Hanada T, Tobo M, Kaneko T, Usui M, Maekawa K. Caste-specific expressions and diverse roles of takeout genes in the termite Reticulitermes speratus. Sci Rep 2023; 13:8422. [PMID: 37225771 DOI: 10.1038/s41598-023-35524-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 05/19/2023] [Indexed: 05/26/2023] Open
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.
Collapse
Affiliation(s)
- Kokuto Fujiwara
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama, 930-8555, Japan
| | - Akimi Karasawa
- Department of Biology, Faculty of Science, University of Toyama, Gofuku, Toyama, 930-8555, Japan
| | - Takumi Hanada
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama, 930-8555, Japan
| | - Mutsuaki Tobo
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama, 930-8555, Japan
| | - Tousuke Kaneko
- Department of Biology, Faculty of Science, University of Toyama, Gofuku, Toyama, 930-8555, Japan
| | - Mizuna Usui
- Department of Biology, Faculty of Science, University of Toyama, Gofuku, Toyama, 930-8555, Japan
| | - Kiyoto Maekawa
- Faculty of Science, Academic Assembly, University of Toyama, Gofuku, Toyama, 930-8555, Japan.
| |
Collapse
|
2
|
Soldier Caste-Specific Protein 1 Is Involved in Soldier Differentiation in Termite Reticulitermes aculabialis. INSECTS 2022; 13:insects13060502. [PMID: 35735839 PMCID: PMC9224846 DOI: 10.3390/insects13060502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 05/22/2022] [Accepted: 05/23/2022] [Indexed: 01/27/2023]
Abstract
Termite soldiers are a unique caste among social insects, and their differentiation can be induced by Juvenile hormone (JH) from workers through two molts (worker–presoldier–soldier). However, the molecular mechanism underlying the worker-to-soldier transformation in termites is poorly understood. To explore the mechanism of soldier differentiation induced by JH, the gene soldier caste-specific protein 1 (RaSsp1, NCBI accession no: MT861054.1) in R. aculabialis was cloned, and its function was studied. This gene was highly expressed in the soldier caste, and the protein RsSsp1 was similar to the JHBP (JH-binding protein) domain-containing protein by Predict Protein online. In addition, JHIII could be anchored in the hydrophobic cage of RaSsp1 as the epoxide of the JHBP-bound JH according to the protein ligand molecular docking online tool AutoDock. The functional studies indicated that knocking down of the RaSsp1 shorted the presoldier’s head capsule, reduced mandible size, delayed molting time and decreased molting rate (from worker to presoldier) at the beginning of worker gut-purging. Furthermore, knocking down of the RaSsp1 had a more pronounced effect on soldier differentiation (from presoldier to soldier), and manifested in significantly shorter mandibles, rounder head capsules, and lower molting rate (from worker to presoldier) at the beginning of presoldier gut-purging. Correspondingly, the expressions of JH receptor Methoprene-tolerant (Met), the JH-inducible transcription factor Krüppel homolog1 (Kr-h1) and ecdysone signal genes Broad-complex (Br-C) were downregulated when knocking down the RaSsp1 at the above two stages. All these results that RaSsp1 may be involved in soldier differentiation from workers by binding and transporting JH.
Collapse
|
3
|
Hojo M, Shigenobu S, Maekawa K, Miura T, Tokuda G. Duplication and soldier-specific expression of geranylgeranyl diphosphate synthase genes in a nasute termite Nasutitermes takasagoensis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 111:103177. [PMID: 31228516 DOI: 10.1016/j.ibmb.2019.103177] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/18/2019] [Accepted: 06/16/2019] [Indexed: 06/09/2023]
Abstract
In the evolutionarily-derived termite subfamily Nasutitermitinae (family Termitidae), soldiers defend their nestmates by discharging polycyclic diterpenes from a head projection called the "nasus." The diterpenes are synthesised in the frontal gland from the precursor geranylgeranyl diphosphate (GGPP), which is generally used for post-translational modification of proteins in animals. In this study, we constructed a comprehensive gene catalogue to search for genes involved in the diterpene biosynthesis by assembling RNA sequencing reads of Nasutitermes takasagoensis, identifying eight gene copies for GGPP synthase (GGPPS). The number of gene copies is much larger in contrast to other related insects. Gene cloning by reverse transcription-PCR and rapid amplification of cDNA ends confirmed that seven GGPPS genes (NtGGPPS1 to NtGGPPS7) have highly variable untranslated regions. Molecular phylogenetic analysis showed that the NtGGPPS7 gene was grouped with homologs obtained from ancestral termites that have only a single copy of the gene, and the NtGGPPS6 gene was grouped with homologs obtained from a basal lineage of termitids, in which soldiers do not synthesise diterpenes. As the sister group to this clade, furthermore, a monophyletic clade included all the other NtGGPPS genes (NtGGPPS1 to NtGGPPS5). Expression analyses revealed that NtGGPPS7 gene was expressed in all the examined castes and tissues, whereas all the other genes were expressed only in the soldier head. These results suggest that gene duplication followed by subfunctionalisation of the GGPPS genes might have accompanied the evolution of chemical defence in the nasute termite lineage.
Collapse
Affiliation(s)
- Masaru Hojo
- Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, 903-0213, Japan.
| | - Shuji Shigenobu
- NIBB Core Research Facilities, National Institute for Basic Biology, Okazaki, 444-8585, Japan
| | - Kiyoto Maekawa
- Graduate School of Science and Engineering, University of Toyama, Toyama, 930-8555, Japan
| | - Toru Miura
- Misaki Marine Biological Station, School of Science, The University of Tokyo, Miura, Kanagawa, 238-0225, Japan
| | - Gaku Tokuda
- Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, 903-0213, Japan
| |
Collapse
|
4
|
Comparative transcriptomics of social insect queen pheromones. Nat Commun 2019; 10:1593. [PMID: 30962449 PMCID: PMC6453924 DOI: 10.1038/s41467-019-09567-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 03/19/2019] [Indexed: 12/18/2022] Open
Abstract
Queen pheromones are chemical signals that mediate reproductive division of labor in eusocial animals. Remarkably, queen pheromones are composed of identical or chemically similar compounds in some ants, wasps and bees, even though these taxa diverged >150MYA and evolved queens and workers independently. Here, we measure the transcriptomic consequences of experimental exposure to queen pheromones in workers from two ant and two bee species (genera: Lasius, Apis, Bombus), and test whether they are similar across species. Queen pheromone exposure affected transcription and splicing at many loci. Many genes responded consistently in multiple species, and the set of pheromone-sensitive genes was enriched for functions relating to lipid biosynthesis and transport, olfaction, production of cuticle, oogenesis, and histone (de)acetylation. Pheromone-sensitive genes tend to be evolutionarily ancient, positively selected, peripheral in the gene coexpression network, hypomethylated, and caste-specific in their expression. Our results reveal how queen pheromones achieve their effects, and suggest that ants and bees use similar genetic modules to achieve reproductive division of labor.
Collapse
|
5
|
He S, Johnston PR, Kuropka B, Lokatis S, Weise C, Plarre R, Kunte HJ, McMahon DP. Termite soldiers contribute to social immunity by synthesizing potent oral secretions. INSECT MOLECULAR BIOLOGY 2018; 27:564-576. [PMID: 29663551 DOI: 10.1111/imb.12499] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The importance of soldiers to termite society defence has long been recognized, but the contribution of soldiers to other societal functions, such as colony immunity, is less well understood. We explore this issue by examining the role of soldiers in protecting nestmates against pathogen infection. Even though they are unable to engage in grooming behaviour, we find that the presence of soldiers of the Darwin termite, Mastotermes darwiniensis, significantly improves the survival of nestmates following entomopathogenic infection. We also show that the copious exocrine oral secretions produced by Darwin termite soldiers contain a high concentration of proteins involved in digestion, chemical biosynthesis, and immunity. The oral secretions produced by soldiers are sufficient to protect nestmates against infection, and they have potent inhibitory activity against a broad spectrum of microbes. Our findings support the view that soldiers may play an important role in colony immunity, and broaden our understanding of the possible function of soldiers during the origin of soldier-first societies.
Collapse
Affiliation(s)
- S He
- Institute of Biology, Freie Universität Berlin, Berlin, Germany
- Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Berlin, Germany
| | - P R Johnston
- Institute of Biology, Freie Universität Berlin, Berlin, Germany
- Berlin Center for Genomics in Biodiversity Research, Berlin, Germany
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
| | - B Kuropka
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - S Lokatis
- Institute of Biology, Freie Universität Berlin, Berlin, Germany
- Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Berlin, Germany
| | - C Weise
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - R Plarre
- Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Berlin, Germany
| | - H-J Kunte
- Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Berlin, Germany
| | - D P McMahon
- Institute of Biology, Freie Universität Berlin, Berlin, Germany
- Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Berlin, Germany
| |
Collapse
|
6
|
Korb J. Genes Underlying Reproductive Division of Labor in Termites, with Comparisons to Social Hymenoptera. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00045] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
|
7
|
Negulescu H, Guo Y, Garner TP, Goodwin OY, Henderson G, Laine RA, Macnaughtan MA. A Kazal-Type Serine Protease Inhibitor from the Defense Gland Secretion of the Subterranean Termite Coptotermes formosanus Shiraki. PLoS One 2015; 10:e0125376. [PMID: 25978745 PMCID: PMC4433142 DOI: 10.1371/journal.pone.0125376] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 03/24/2015] [Indexed: 11/28/2022] Open
Abstract
Coptotermes formosanus is an imported, subterranean termite species with the largest economic impact in the United States. The frontal glands of the soldier caste termites comprising one third of the body mass, contain a secretion expelled through a foramen in defense. The small molecule composition of the frontal gland secretion is well-characterized, but the proteins remain to be identified. Herein is reported the structure and function of one of several proteins found in the termite defense gland secretion. TFP4 is a 6.9 kDa, non-classical group 1 Kazal-type serine protease inhibitor with activity towards chymotrypsin and elastase, but not trypsin. The 3-dimensional solution structure of TFP4 was solved with nuclear magnetic resonance spectroscopy, and represents the first structure from the taxonomic family, Rhinotermitidae. Based on the structure of TFP4, the protease inhibitor active loop (Cys8 to Cys16) was identified.
Collapse
Affiliation(s)
- Horia Negulescu
- Department of Biological Sciences, Division of Biochemistry and Molecular Biology, Louisiana State University and A&M College, Baton Rouge, LA 70803, United States of America
| | - Youzhong Guo
- Currently at the Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, United States of America
| | - Thomas P Garner
- Currently at the Department of Biochemistry, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY 10461, United States of America
| | - Octavia Y Goodwin
- Department of Chemistry, Louisiana State University and A&M College, Baton Rouge, LA 70803, United States of America
| | - Gregg Henderson
- Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, United States of America
| | - Roger A Laine
- Department of Chemistry, Louisiana State University and A&M College, Baton Rouge, LA 70803, United States of America; Department of Biological Sciences, Division of Biochemistry and Molecular Biology, Louisiana State University and A&M College, Baton Rouge, LA 70803, United States of America
| | - Megan A Macnaughtan
- Department of Chemistry, Louisiana State University and A&M College, Baton Rouge, LA 70803, United States of America
| |
Collapse
|
8
|
Pitt C, Robert JA, Bonnett TR, Keeling CI, Bohlmann J, Huber DPW. Proteomics indicators of the rapidly shifting physiology from whole mountain pine beetle, Dendroctonus ponderosae (Coleoptera: Curculionidae), adults during early host colonization. PLoS One 2014; 9:e110673. [PMID: 25360753 PMCID: PMC4215907 DOI: 10.1371/journal.pone.0110673] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 09/16/2014] [Indexed: 01/08/2023] Open
Abstract
We developed proteome profiles for host colonizing mountain pine beetle adults, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae). Adult insects were fed in pairs on fresh host lodgepole pine, Pinus contorta Dougl. ex Loud, phloem tissue. The proteomes of fed individuals were monitored using iTRAQ and compared to those of starved beetles, revealing 757 and 739 expressed proteins in females and males, respectively, for which quantitative information was obtained. Overall functional category distributions were similar for males and females, with the majority of proteins falling under carbohydrate metabolism (glycolysis, gluconeogenesis, citric acid cycle), structure (cuticle, muscle, cytoskeleton), and protein and amino acid metabolism. Females had 23 proteins with levels that changed significantly with feeding (p<0.05, FDR<0.20), including chaperones and enzymes required for vitellogenesis. In males, levels of 29 proteins changed significantly with feeding (p<0.05, FDR<0.20), including chaperones as well as motor proteins. Only two proteins, both chaperones, exhibited a significant change in both females and males with feeding. Proteins with differential accumulation patterns in females exhibited higher fold changes with feeding than did those in males. This difference may be due to major and rapid physiological changes occurring in females upon finding a host tree during the physiological shift from dispersal to reproduction. The significant accumulation of chaperone proteins, a cytochrome P450, and a glutathione S-transferase, indicate secondary metabolite-induced stress physiology related to chemical detoxification during early host colonization. The females' activation of vitellogenin only after encountering a host indicates deliberate partitioning of resources and a balancing of the needs of dispersal and reproduction.
Collapse
Affiliation(s)
- Caitlin Pitt
- Ecosystem Science and Management Program, University of Northern British Columbia, Prince George, BC, Canada
- * E-mail: (DH); (CP)
| | - Jeanne A. Robert
- Ecosystem Science and Management Program, University of Northern British Columbia, Prince George, BC, Canada
| | - Tiffany R. Bonnett
- Ecosystem Science and Management Program, University of Northern British Columbia, Prince George, BC, Canada
| | | | - Jörg Bohlmann
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Dezene P. W. Huber
- Ecosystem Science and Management Program, University of Northern British Columbia, Prince George, BC, Canada
- * E-mail: (DH); (CP)
| |
Collapse
|
9
|
Hamiaux C, Basten L, Greenwood DR, Baker EN, Newcomb RD. Ligand promiscuity within the internal cavity of Epiphyas postvittana Takeout 1 protein. J Struct Biol 2013; 182:259-63. [DOI: 10.1016/j.jsb.2013.03.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Revised: 03/25/2013] [Accepted: 03/26/2013] [Indexed: 10/27/2022]
|
10
|
Raychoudhury R, Sen R, Cai Y, Sun Y, Lietze VU, Boucias DG, Scharf ME. Comparative metatranscriptomic signatures of wood and paper feeding in the gut of the termite Reticulitermes flavipes (Isoptera: Rhinotermitidae). INSECT MOLECULAR BIOLOGY 2013; 22:155-71. [PMID: 23294456 DOI: 10.1111/imb.12011] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Termites are highly eusocial insects that thrive on recalcitrant materials like wood and soil and thus play important roles in global carbon recycling and also in damaging wooden structures. Termites, such as Reticulitermes flavipes (Rhinotermitidae), owe their success to their ability to extract nutrients from lignocellulose (a major component of wood) with the help of gut-dwelling symbionts. With the aim to gain new insights into this enzymatic process we provided R. flavipes with a complex lignocellulose (wood) or pure cellulose (paper) diet and followed the resulting differential gene expression on a custom oligonucleotide-microarray platform. We identified a set of expressed sequence tags (ESTs) with differential abundance between the two diet treatments and demonstrated the source (host/symbiont) of these genes, providing novel information on termite nutritional symbiosis. Our results reveal: (1) the majority of responsive wood- and paper-abundant ESTs are from host and symbionts, respectively; (2) distinct pathways are associated with lignocellulose and cellulose feeding in both host and symbionts; and (3) sets of diet-responsive ESTs encode putative digestive and wood-related detoxification enzymes. Thus, this study illuminates the dynamics of termite nutritional symbiosis and reveals a pool of genes as potential targets for termite control and functional studies of termite-symbiont interactions.
Collapse
Affiliation(s)
- R Raychoudhury
- Department of Entomology, Purdue University, West Lafayette, IN 47907, USA
| | | | | | | | | | | | | |
Collapse
|
11
|
Schwinghammer MA, Zhou X, Kambhampati S, Bennett GW, Scharf ME. A novel gene from the takeout family involved in termite trail-following behavior. Gene 2011; 474:12-21. [DOI: 10.1016/j.gene.2010.11.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 11/13/2010] [Accepted: 11/26/2010] [Indexed: 10/18/2022]
|
12
|
Koshikawa S, Cornette R, Matsumoto T, Miura T. The homolog of Ciboulot in the termite (Hodotermopsis sjostedti): a multimeric beta-thymosin involved in soldier-specific morphogenesis. BMC DEVELOPMENTAL BIOLOGY 2010; 10:63. [PMID: 20529303 PMCID: PMC2896938 DOI: 10.1186/1471-213x-10-63] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 06/08/2010] [Indexed: 11/23/2022]
Abstract
Background Caste differentiation in social insects is a type of polyphenism that enables division of labor among members of a colony. This elaborate social integration has attracted broad interest, although little is known about its regulatory mechanisms, especially in Isoptera (termites). In this study, we analyzed soldier differentiation in the damp-wood termite Hodotermopsis sjostedti, focusing on a possible effector gene for caste development. The gene for an actin-binding protein, HsjCib, which shows a high level of expression in developing mandibles during soldier differentiation, is characterized in detail. Results To examine the HsjCib gene, full-length cDNAs were obtained by rapid amplification of cDNA ends-polymerase chain reaction (RACE-PCR) and sequencing. Multiple isoforms were identified, and on the basis of the results of northern and Southern hybridization analyses, these isoforms were considered to be transcriptional variants from a single gene. On the basis of their sequence similarity to homologous genes of other organisms, functions in actin assembly were assumed to be different among isoforms. Expression analysis revealed high expression in the head during soldier differentiation, which was consistent with their allometric growth. Although isoform expression was observed in various tissues, different expression levels were observed among tissues, suggesting the possibility of tissue-specific morphogenetic regulation by HsjCib isoforms. Conclusion This study revealed the characteristics and dynamics of the HsjCib gene during soldier differentiation as a potential representative of downstream effector genes in caste-specific morphogenesis. From the expression patterns observed, this gene is considered to be involved in cephalic morphogenesis and neural reorganization, resulting in the establishment of caste-specific morphology and behavior.
Collapse
Affiliation(s)
- Shigeyuki Koshikawa
- Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810, Japan
| | | | | | | |
Collapse
|
13
|
Ishikawa Y, Okada Y, Ishikawa A, Miyakawa H, Koshikawa S, Miura T. Gene expression changes during caste-specific neuronal development in the damp-wood termite Hodotermopsis sjostedti. BMC Genomics 2010; 11:314. [PMID: 20482890 PMCID: PMC2887416 DOI: 10.1186/1471-2164-11-314] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2009] [Accepted: 05/20/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND One of the key characters of social insects is the division of labor, in which different tasks are allocated to various castes. In termites, one of the representative groups of social insects, morphological differences as well as behavioral differences can be recognized among castes. However, very little is known about the neuronal and molecular bases of caste differentiation and caste-specific behavior. In almost all termite species, soldiers play defensive roles in their colonies, and their morphology and behavior are largely different from workers (or pseudergates). Therefore, we predicted that some genes linked to defensive behavior and/or those required for neuronal changes are differentially expressed between workers and soldiers, or during the soldier differentiation, respectively. RESULTS Using the brain and suboesophageal ganglion (SOG) of the damp-wood termite Hodotermopsis sjostedti, we first screened genes specifically expressed in soldiers or during soldier differentiation by the differential display method, followed by quantitative real-time polymerase chain reaction. No distinctive differences in expression patterns were detected between pseudergates and soldiers. In the course of soldier differentiation, however, five genes were found to be up-regulated in brain and/or SOG: 14-3-3 epsilon, fibrillin2, beta-tubulin, ciboulot, and a hypothetical protein containing a SAP motif. Some of these genes are thought to be associated with cytoskeletal structure or motor-associated proteins in neuronal tissues. CONCLUSION The identified five genes could be involved in soldier-specific neuronal modifications, resulting in defensive behaviors in termite soldiers. The temporal expression patterns of these genes were consistent with the neuronal changes during soldier differentiation, suggesting that molecular machineries, in which the identified factors would participate, play important roles in behavioral differentiation of termite soldiers.
Collapse
Affiliation(s)
- Yuki Ishikawa
- Laboratory of Ecological Genetics, Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido, 060-0810, Japan
| | | | | | | | | | | |
Collapse
|
14
|
Weil T, Korb J, Rehli M. Comparison of queen-specific gene expression in related lower termite species. Mol Biol Evol 2009; 26:1841-50. [PMID: 19541881 DOI: 10.1093/molbev/msp095] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The molecular mechanisms regulating caste determination and reproductive division of labor, the hallmarks of insect societies, are poorly defined. The identification of key genes involved in these developmentally important processes will be essential to gain a better understanding of the mechanisms controlling one of the most impressive examples of polyphenism, the caste structure of eusocial species. Here, we applied representational difference analysis of cDNAs, to study differential gene expression between queens (female neotenics) and workers in the dry wood termite Cryptotermes cynocephalus and identified 13 genes that were highly expressed in queens. In addition, we partially cloned several homologous genes of the related termite species Cryptotermes secundus and compared the expression profiles of 10 homologous genes. In most cases, the preferential expression in female neotenics was not conserved between species, despite the close phylogenetic relationship of both Cryptotermes species. It is possible that these genes are associated with known species-specific differences in caste development modes. Only three genes (Neofem1, 2, and 3) showed a conserved and highly preferential expression in female neotenics, suggesting that their products may play important roles in female reproductives, in particular in controlling caste determination and reproductive division of labor.
Collapse
Affiliation(s)
- Tobias Weil
- Biology I, University of Regensburg, Regensburg, Germany
| | | | | |
Collapse
|
15
|
Tarver MR, Schmelz EA, Rocca JR, Scharf ME. Effects of soldier-derived terpenes on soldier caste differentiation in the termite Reticulitermes flavipes. J Chem Ecol 2009; 35:256-64. [PMID: 19198947 DOI: 10.1007/s10886-009-9594-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 12/03/2008] [Accepted: 01/08/2009] [Indexed: 11/28/2022]
Abstract
Primer pheromones play key roles in regulating division of labor, which is a fundamental and defining aspect of insect sociality. Primer pheromones are chemical messengers that transmit hormone-like messages among colony members; in recipients, these messages can either induce or suppress phenotypic caste differentiation. Here, we investigated soldier caste-derived chemicals as possible primer pheromones in the lower termite Reticulitermes flavipes, a species for which no primer pheromones have yet been identified. We determined that soldier head extracts (SHE), when provided to totipotent workers along with the insect morphogenetic juvenile hormone (JH), significantly enhanced soldier caste differentiation. When applied alone, however, SHE had no impacts on caste differentiation, survivorship, or any other aspect of worker biology. These findings support a function of soldier chemicals as primer pheromones that enhance the action of the endogenous JH. In accord with previous studies, gamma-cadinene and the corresponding aldehyde, gamma-cadinenal, were identified by gas chromatography-mass spectrometry and nuclear magnetic resonance analyses as the two most abundant components of R. flavipes SHE. Validative bioassays with commercially available cadinene confirmed activity. Several other terpenes, previously identified in R. flavipes soldiers, also were found to be active. These findings reveal a novel primer pheromone-like function for soldier-derived terpenes in termites and further suggest convergent evolution of terpene functions in enhancing JH-dependent soldier caste differentiation.
Collapse
Affiliation(s)
- Matthew R Tarver
- Entomology and Nematology Department, University of Florida, Gainesville, 32611-0620, USA
| | | | | | | |
Collapse
|
16
|
Smith CR, Toth AL, Suarez AV, Robinson GE. Genetic and genomic analyses of the division of labour in insect societies. Nat Rev Genet 2008; 9:735-48. [PMID: 18802413 DOI: 10.1038/nrg2429] [Citation(s) in RCA: 228] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Division of labour--individuals specializing in different activities--features prominently in the spectacular success of the social insects. Until recently, genetic and genomic analyses of division of labour were limited to just a few species. However, research on an ever-increasing number of species has provided new insight, from which we highlight two results. First, heritable influences on division of labour are more pervasive than previously imagined. Second, different forms of division of labour, in lineages in which eusociality has arisen independently, have evolved through changes in the regulation of highly conserved molecular pathways associated with several basic life-history traits, including nutrition, metabolism and reproduction.
Collapse
Affiliation(s)
- Chris R Smith
- Program in Ecology and Evolutionary Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | | | | | | |
Collapse
|
17
|
Hagai T, Cohen M, Bloch G. Genes encoding putative Takeout/juvenile hormone binding proteins in the honeybee (Apis mellifera) and modulation by age and juvenile hormone of the takeout-like gene GB19811. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2007; 37:689-701. [PMID: 17550825 DOI: 10.1016/j.ibmb.2007.04.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 03/25/2007] [Accepted: 04/03/2007] [Indexed: 05/15/2023]
Abstract
We identified and characterized eight genes encoding putative Takeout/juvenile hormone binding proteins (To/JHBP) in the honeybee genome. Phylogenetic analyses revealed nine distinct lineages within this gene family, including those containing Takeout (To) and JHBP for which there are no honeybee homologs. Their diversity and ubiquitous expression suggest that To/JHBP proteins are involved in diverse and important processes in insects. We further characterized the expression of one of these genes, GB19811 that is ubiquitously expressed. GB19811 transcript levels in the abdomen increased, and decreased in the head with worker age. There was no influence of colony environment or brood care behavior on GB19811 expression in young bees. Young bees treated with juvenile hormone (JH) showed a decrease in head GB19811 mRNA levels. This finding is consistent with the premise that JH, for which titers typically increase with age, is involved in age-related modulation of GB19811 expression. In contrast to Drosophila Takeout, the expression of GB19811 did not vary with diurnal or circadian rhythms. Taken together, these findings suggest that GB19811 is not an ortholog of Takeout, and is involved in JH-mediated regulation of adult honeybee worker development.
Collapse
Affiliation(s)
- Tzachi Hagai
- Department of Evolution, Systematics and Ecology, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | | | | |
Collapse
|
18
|
Hojo M, Matsumoto T, Miura T. Cloning and expression of a geranylgeranyl diphosphate synthase gene: insights into the synthesis of termite defence secretion. INSECT MOLECULAR BIOLOGY 2007; 16:121-31. [PMID: 17257214 DOI: 10.1111/j.1365-2583.2007.00709.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
In Nasutitermes takasagoensis, a termite in which soldiers perform specialized chemical defence, Nts19-1 gene is highly expressed exclusively in soldier head. In this study, two types of transcripts for this gene were obtained, and the full-length cDNAs were determined by rapid amplification of cDNA ends (RACE). These transcripts were putative homologues of the geranylgeranyl diphosphate (GGPP) synthase gene, involved in the condensation of dimethylallyl diphosphate with isopentenyl diphosphate in the isoprenoid biosynthetic pathway. The genes were thus termed NtGGPPS1. GGPP is a precursor of diterpenes in plants. In situ hybridization localized NtGGPPS1 expression to the epidermal secretory cells of the frontal gland reservoir where many kinds of diterpenes are produced, suggesting that NtGGPPS1 is involved in the biosynthesis of defence secretion.
Collapse
Affiliation(s)
- Masaru Hojo
- Department of Biology, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | | | | |
Collapse
|
19
|
Fujikawa K, Seno K, Ozaki M. A novel Takeout-like protein expressed in the taste and olfactory organs of the blowfly, Phormia regina. FEBS J 2006; 273:4311-21. [PMID: 16930135 DOI: 10.1111/j.1742-4658.2006.05422.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In insects, the functional molecules responsible for the taste system are still obscure. The gene for a 28.5 kDa protein purified from taste sensilla of the blowfly Phormia regina belongs to a gene family that includes takeout of Drosophila melanogaster. Molecular phylogenetic analysis revealed that the Phormia Takeout-like protein is most similar to the protein encoded by a member of the Drosophila takeout gene family, CG14661, whose expression and function have not been identified yet. Western blot analyses revealed that Phormia Takeout-like protein was exclusively expressed in antennae and labellum of the adult blowfly in both sexes. Immunohistochemical experiments demonstrated that Takeout-like protein was localized around the lamella structure of the auxiliary cells and in the sensillar lymph of the labellar taste sensillum. In antennae, Takeout-like protein was distributed at the base of the olfactory sensilla as well. No significant differences in Takeout-like protein expression were found between the sexes. Our results suggest that Phormia Takeout-like protein is involved in some early events concerned with chemoreception in both the taste and olfactory systems.
Collapse
Affiliation(s)
- Kazuyo Fujikawa
- Department of Applied Biology, Faculty of Textile Science, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, Japan
| | | | | |
Collapse
|
20
|
Zhou X, Oi FM, Scharf ME. Social exploitation of hexamerin: RNAi reveals a major caste-regulatory factor in termites. Proc Natl Acad Sci U S A 2006; 103:4499-504. [PMID: 16537425 PMCID: PMC1450200 DOI: 10.1073/pnas.0508866103] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2005] [Indexed: 11/18/2022] Open
Abstract
Lower termites express a unique form of eusocial polyphenism in that totipotent workers can differentiate into either soldier or reproductive caste phenotypes. In this initial effort using RNA interference in termites, we found that two hexamerin genes, Hex-1 and Hex-2, participate in the regulation of caste polyphenism. Our methodology involved a dual gene-silencing approach that used a single short-interfering RNA fragment to silence the two homologous hexamerin genes. We performed validation studies that evaluated effects on nontarget housekeeping genes, silencing of a nonhousekeeping control gene, and effects at the protein level. We found that the two hexamerin proteins, which are inducible by the morphogenetic juvenile hormone and which constitute a significant proportion of total termite protein, suppress juvenile-hormone-dependent worker differentiation to the soldier caste phenotype. This mechanism allows termite colonies to retain high proportions of altruistic worker caste members, thus apparently enhancing colony-inclusive fitness. These findings demonstrate a unique status quo regulatory mechanism for termite worker caste retention and provide an example of previously undescribed preadult developmental/caste-regulatory genes from any social insect.
Collapse
Affiliation(s)
- Xuguo Zhou
- Department of Entomology and Nematology, University of Florida, P.O. Box 110620, Gainesville, FL 32611-0620
| | - Faith M. Oi
- Department of Entomology and Nematology, University of Florida, P.O. Box 110620, Gainesville, FL 32611-0620
| | - Michael E. Scharf
- Department of Entomology and Nematology, University of Florida, P.O. Box 110620, Gainesville, FL 32611-0620
| |
Collapse
|
21
|
|