The holobiont concept: the case of xylophagous termites and cockroaches

Abstract

The rapid growth in microbiome research, particularly during the last 15 years, has revealed the crucial contributions of microbial communities to numerous physiological functions in animals, including digestion, immunity and reproduction.The permanent coexistence of these various bionts forms the holobiont (namely, the host and its microbiota). This review describes the relationships between xylophagous insects and their microbiota in an attempt to understand the characteristics that have determined bacterial fidelity over generations and throughout evolutionary history.Symbiotic interactions have probably played a central role in the evolutionary success of these insects, allowing their adaptation to unexploited ecological niches that are nutritionally deficient and/or unbalanced. Moreover, insect symbionts have provided the enzymatic capabilities that enable the synthesis of nutrients (carbon and nitrogen sources for the host) from recalcitrant plant polymers (cellulose, hemicellulose, pectin or lignin).

Living together in biofilms: the microbial cell factory and its biotechnological implications

“…Microbial consortia have played important roles throughout the history of life on Earth, from the microbial mats (a type of biofilm) that were probably the first ecosystems in the early Archean (about 3850–3500 million years ago), to the complex microbiota of the intestinal tract of different animals [ 21 , 24 ]. Cell to cell communication is ubiquitously employed by individual microorganisms as well as microbial communities to coordinate different physiological processes and to initiate cooperative activities that depend on the production and secretion of small diffusible auto inducers (quorum sensing signals), such as acyl-homoserine lactones, and oligopeptides [ 25 ].…”

“…In natural communities, microbial populations interact constantly with each other, establishing complex ecological webs [ 95 ]. The wide-ranging metabolic plasticity of microbial communities includes the efficient catalysis of many processes, by combining the metabolic pathways and enzymatic systems of the different resident organisms [ 24 , 96 ].…”

The gut microbiota of insecticide-resistant insects houses insecticide-degrading bacteria: A potential source for biotechnological exploitation

“…Besides, the gut microbiota of insects has been shown to be amenable to community changes in response to pesticides [ 48 ] and evolution of pesticide resistance [ 49 ]. As current data have demonstrated that phenotypes are the result of the expression of the genomes of all organisms living in a close association [ 50 , 51 ], we hypothesized that laboratory insect strains selected for insecticide resistance would also carry bacteria selected to degrade the pesticides their hosts were selected against, and as such serve as potential new sources for the target-oriented selection of bacteria for bioremediation applications.…”

Microbiome shifts associated with the introduction of wild Atlantic horseshoe crabs (Limulus polyphemus) into a touch-tank exhibit

“…Termites and cockroaches are well-studied arthropod model organisms in symbiosis research and several studies have demonstrated the importance that symbiotic interactions played in their evolution, particularly their expansion into previously unoccupied niches, such as plant polymer degradation (Berlanga and Guerrero 2016). In addition, marine symbioses are also quite well researched, with various studies detailing the biotechnological potential of and interactions between host-symbiont in deep-sea hydrothermal vents (Ho et al 2017; Zimmermann et al 2014), coral reefs (Venn et al, 2008), sponges (Venn et al, 2008), and polychaetes (Goffredi et al 2005).…”