Comparison of the gut microbiota from soldier and worker castes of the termite Reticulitermes grassei (original) (raw)
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Characterization of the Core and Caste-Specific Microbiota in the Termite, Reticulitermes flavipes
Frontiers in Microbiology, 2016
The hindgut of the termite Reticulitermes flavipes harbors a complex symbiotic community consisting of protists, bacteria, and archaea. These symbionts aid in the digestion of lignocellulose from the termite's wood meal. Termite hindguts were sampled and the V4 hyper-variable region of the 16S rRNA gene was sequenced and analyzed from individual termites. The core microbiota of worker termites consisted of 69 OTUs at the 97% identity level, grouped into 16 taxa, and together accounted for 67.05% of the sequences from the bacterial community. The core was dominated by Treponema, which contained 36 different OTUs and accounted for ∼32% of the sequences, which suggests Treponema sp. have an important impact on the overall physiology in the hindgut. Bray-Curtis beta diversity metrics showed that hindgut samples from termites of the same colony were more similar to each other than to samples from other colonies despite possessing a core that accounted for the majority of the sequences. The specific tasks and dietary differences of the termite castes could have an effect on the composition of the microbial community. The hindgut microbiota of termites from the alate castes differed from the worker caste with significantly lower abundances of Treponema and Endomicrobia, which dominated the hindgut microbiota in workers and soldiers. Protist abundances were also quantified in the same samples using qPCR of the 18S rRNA gene. Parabasalia abundances dropped significantly in the winged alates and the Oxymonadida abundances dropped in both alate castes. These data suggest that the changes in diet or overall host physiology affected the protist and bacterial populations in the hindgut. The in-depth bacterial characterization and protist quantification in this study sheds light on the potential community dynamics within the R. flavipes hindgut and identified a large and complex core microbiota in termites obtained from multiple colonies and castes.
2000
The Formosan subterranean termite, Coptotermes formosanus Shiraki, is a highly destructive invasive pest species in many tropical and subtropical regions. The survival of this termite is dependent on its gut microbes (protozoa and bacteria). Therefore, alternative strategies may be devised in the future using the gut flora of termites as tools and targets for ecologically sound termite control. To facilitate development of such strategies, detailed knowledge of the microbial diversity in the termite gut is sorely needed. Also, it is important to know, which part of the gut flora can be cultured in order to test the physiological contributions of the bacteria to termite survival and to be able to manipulate them, e.g., by genetic engineering. In this study we used culture-independent 16S rDNA sequencing in conjunction with classical culture methods to describe the bacterial species composition in the gut of C. formosanus. The communal bacteria DNA from two termite colonies was extracted, cloned and sequenced. The 105 clones sequenced from both colonies resulted in 12 different bacteria strains from four different groups (Bacteroides, Treponema, Spirochaeta, Clostridiaceae). Bacteroides was the dominant group comprising over 80% of the gut flora in both colonies. The bacteria taxa identified in the gut of C. formosanus using culture-independent 16S rDNA sequencing were different from the bacteria we were able to culture from the gut of the same species. To date, we have cultured over 25 strains of bacteria, including species belonging to the Enterobacteriacea, Bacteroidales and Lactobacillales. All of the species identified by their 16S sequences and most of the cultured strains were novel species found exclusively in the termite gut. Bacteria culture and culture-independent techniques identified different parts of the termites' gut community. Thus, it is recommended to use both methods in a complementary way to describe the microbial diversity and ecology in the termite gut.
Phylogenetic Diversity of Bacterial Symbionts in the Guts of Wood-Feeding Termites
Kasetsart Journal. Natural Sciences, 2004
The diversity of bacterial symbionts in termite guts was investigated by analyses of 16S rDNA clone libraries and terminal restriction fragment length polymorphism (T-RFLP). Two wood-feeding termites, consisting of a lower termite, Reticulitermes speratus and a higher termite, Microcerotermes sp. were collected. Almost full length of 16S rRNA genes were amplified directly from DNA extracted from termite guts by PCR using several sets of bacterial specific primers. PCR products were then cloned and sequenced. 2184 clones from R. speratus and 288 clones from M. sp. were analyzed and sorted to 320 and 141 phylotypes, respectively. In both termite species, spirochetes, were found to be the most dominant gut bacteria, accounting for more than half of sequenced clones and detected T-RFs, while Clostridia and Bacteroides constituted the second-most dominant groups. Interestingly, more than 90% of the phylotypes obtained in this study were found for the first time, and several termite-specific lineages, including a novel bacterial division, Termite Group I, which are as-yet unculturable bacteria, were revealed. These results indicate that termite guts are really great reservoirs of new bacterial species, and that the termite gut is still a new frontier to microbiologists.
Molecular Ecology, 2005
The fungus-growing termites Macrotermes cultivate the obligate ectosymbiontic fungi, Termitomyces. While their relationship has been extesively studied, little is known about the gut bacterial symbionts, which also presumably play a crucial role for the nutrition of the termite host. In this study, we investigated the bacterial gut microbiota in two colonies of Macrotermes gilvus, and compared the diversity and community structure of bacteria among nine termite morphotypes, differing in caste and/or age, using terminal restriction fragment length polymorphism (T-RFLP) and clonal analysis of 16S rRNA. The obtained molecular community profiles clustered by termite morphotype rather than by colony, and the clustering pattern was clearly more related to a difference in age than to caste. Thus, we suggest that the bacterial gut microbiota change in relation to the food of the termite, which comprises fallen leaves and the fungus nodules of Termitomyces in young workers, and leaves degraded by the fungi, in old workers. Despite these intracolony variations in bacterial gut microbiota, their T-RFLP profiles formed a distinct cluster against those of the fungus garden, adjacent soil and guts of sympatric wood-feeding termites, implying a consistency and uniqueness of gut microbiota in M. gilvus. Since many bacterial phylotypes from M. gilvus formed monophyletic clusters with those from distantly related termite species, we suggest that gut bacteria have co-evolved with the termite host and form a microbiota specific to a termite taxonomic and/or feeding group, and furthermore, to caste and age within a termite species.
Applied and Environmental Microbiology, 2005
We investigated the bacterial gut microbiota from 32 colonies of wood-feeding termites, comprising four Microcerotermes species (Termitidae) and four Reticulitermes species (Rhinotermitidae), using terminal restriction fragment length polymorphism analysis and clonal analysis of 16S rRNA. The obtained molecular community profiles were compared statistically between individuals, colonies, locations, and species of termites. Both analyses revealed that the bacterial community structure was remarkably similar within each termite genus, with small but significant differences between sampling sites and/or termite species. In contrast, considerable differences were found between the two termite genera. Only one bacterial phylotype (defined with 97% sequence identity) was shared between the two termite genera, while 18% and 50% of the phylotypes were shared between two congeneric species in the genera Microcerotermes and Reticulitermes, respectively. Nevertheless, a phylogenetic analysis of 228 phylotypes from Microcerotermes spp. and 367 phylotypes from Reticulitermes spp. with other termite gut clones available in public databases demonstrated the monophyly of many phylotypes from distantly related termites. The monophyletic "termite clusters" comprised of phylotypes from more than one termite species were distributed among 15 bacterial phyla, including the novel candidate phyla TG2 and TG3. These termite clusters accounted for 95% of the 960 clones analyzed in this study. Moreover, the clusters in 12 phyla comprised phylotypes from more than one termite (sub)family, accounting for 75% of the analyzed clones. Our results suggest that the majority of gut bacteria are not allochthonous but are specific symbionts that have coevolved with termites and that their community structure is basically consistent within a genus of termites.
Environmental Microbiology, 2005
Differences in microenvironment and interactions of microorganisms within and across habitat boundaries should influence structure and diversity of the microbial communities within an ecosystem. We tested this hypothesis using the well characterized gut tract of the European subterranean termite Reticulitermes santonensis as a model. By cloning and sequencing analysis and molecular fingerprinting (terminal restriction fragment length polymorphism), we characterized the bacterial microbiota in the major intestinal habitats -the midgut, the wall of the hindgut paunch, the hindgut fluid and the intestinal protozoa. The bacterial community was very diverse ( > 200 ribotypes) and comprised representatives of several phyla, including Firmicutes (mainly clostridia, streptococci and Mycoplasmatales -related clones), Bacteroidetes , Spirochaetes and a number of Proteobacteria , all of which were unevenly distributed among the four habitats. The largest group of clones fell into the so-called Termite group 1 (TG-1) phylum, which has no cultivated representatives. The majority of the TG-1 clones were associated with the protozoa and formed two phylogenetically distinct clusters, which consisted exclusively of clones previously retrieved from the gut of this and other Reticulitermes species. Also the other clones represented lineages of microorganisms that were exclusively recovered from the intestinal tract of termites. The termite specificity of these lineages was underscored by the finding that the closest relatives of the bacterial clones obtained from R. santonensis were usually derived also from the most closely related termites. Overall, differences in diversity between the different gut habitats and the uneven distribution of individual phylotypes support conclusively that niche heterogeneity is a strong determinant of the structure and spatial organization of the microbial community in the termite gut.
The Open Microbiology …, 2010
We investigated the bacterial composition in the gut of Formosan subterranean termites (FST), Coptotermes formosanus Shiraki, collected from southern China (native range) vs. Louisiana, U. S. (introduced range) using 16S rRNA gene sequencing. Overall, we identified 213 bacteria ribotypes from thirteen phyla. The enemy release hypothesis could not be invoked to explain invasion success of FST since no pathogens were found among the bacterial gut community regardless of geographic origin. Invasion of new habitats did not significantly change the bacteria composition. Apparently, the tight co-evolutionary link between termites and their gut flora maintains a certain association of species and functional groups. Ribotype richness, bacteria diversity, and proportions of detected phyla were not influenced by geographic origin of FST samples; however, these parameters were affected by storage of the samples. Ethanol storage of termite samples (5 yrs) increased the relative proportions of gram-positive bacteria versus gram-negative bacteria.
Microbial Ecology, 2015
The gut microbiota of termites allows them to thrive on a variety of different materials such as wood, litter, and soil. For that reason, they play important roles in the decomposition of biomass in diverse biomes. This function is essential in the savanna, where litter-feeding termites are one of the few invertebrates active during the dry season. In this study, we describe the gut microbiota of workers (third and fourth instars) of the species Syntermes wheeleri, a litterfeeding termite from the Brazilian savanna. Results of 16S and 18S ribosomal RNA (rRNA) gene-targeted pyrosequencing using primers sets specific to each domain have revealed its bacterial, archaeal, and fungal diversities. Firmicutes accounted for more than half of the operational taxonomic units of the Bacteria domain. The most abundant fungal species were from the class Dothideomycetes of the phylum Ascomycota. The methanogenic orders Methanobacteriales, Methanosarcinales, and Methanomicrobiales of the phylum Euryarchaeota accounted for the greatest part of the Archaea detected in this termite. A comparison of the gut microbiota of the two instars revealed a difference in operational taxonomic unit (OTU) abundance but not in species richness. This description of the whole gut microbiota represents the first study to evaluate relationships among bacteria, archaea, fungi, and host in S. wheeleri.
Extremophiles, 2005
The first proctodeal (P1) segment in the hindgut of certain higher termites shows high alkalinity. We examined the bacterial diversity of the alkaline P1 gut segments of four species of higher termites by T-RFLP and phylogenetic analyses based on PCR-amplified 16S rRNA genes. The bacterial community of the P1 segment was apparently different from that of the whole gut in each termite. Sequence analysis revealed that Firmicutes (Clostridia and Bacilli) were dominant in the P1 segments of all four termites; however, the phylogenetic compositions varied among the termites. Although some of the P1 segment-derived sequences were related to the sequences previously reported from the alkaline digestive tracts of other insects, most of them formed phylogenetic clusters unique to termites. Such “termite P1 clusters” were distantly related to known bacterial species as well as to sequences reported from alkaline environments in nature. We successfully obtained enrichment cultures of Clostridia- and Bacilli-related bacteria, including putative novel species under anaerobic alkaline conditions from the termite guts. Our results suggest that the alkaline gut region of termites harbors unique bacterial lineages and are expected to be a rich reservoir of novel alkaliphiles yet to be cultivated.