Omic research in termites: an overview and a roadmap

Abstract

Many recent breakthroughs in our understanding of termite biology have been facilitated by “omics” research. Omic science seeks to collectively catalog, quantify, and characterize pools of biological molecules that translate into structure, function, and life processes of an organism. Biological molecules in this context include genomic DNA, messenger RNA, proteins, and other biochemicals. Other permutations of omics that apply to termites include sociogenomics, which seeks to define social life in molecular terms (e.g., behavior, sociality, physiology, symbiosis, etc.) and digestomics, which seeks to define the collective pool of host and symbiont genes that collaborate to achieve high-efficiency lignocellulose digestion in the termite gut. This review covers a wide spectrum of termite omic studies from the past 15 years. Topics covered include a summary of terminology, the various kinds of omic efforts that have been undertaken, what has been revealed, and to a degree, what the results mean. Although recent omic efforts have contributed to a better understanding of many facets of termite and symbiont biology, and have created important new resources for many species, significant knowledge gaps still remain. Crossing these gaps can best be done by applying new omic resources within multi-dimensional (i.e., functional, translational, and applied) research programs.

GC×GC-TOFMS for the Analysis of Metabolites Produced by Termites (Reticulitermes flavipes) Bred on Different Carbon Sources

“…The main variations included polyols and uric acid production, potentially related to redox imbalance, carbon storage and nitrogen recycling. This report demonstrated that in-depth study of metabolites could complement other approaches [11,41] and contribute to a better understanding of how the termite gut ecosystem degrades lignocellulose.…”

Saccharification of Agricultural Lignocellulose Feedstocks and Protein-Level Responses by a Termite Gut-Microbe Bioreactor

“…Enzymatic strategies modeled after enzymatic mechanisms of organisms specializing on wood diets have utility for pretreatment of lignocellulosic biomasses (Ke et al, 2011). The termite studied here, R. flavipes, has been an excellent model system for identifying potential enzymes involved in the breakdown of both forest and agricultural feedstocks via the process of diet adaptation (Scharf, 2015a). Through preceding work, we studied the metatranscriptome profiles of R. flavipes guts fed on CS and SR relative to paper in an attempt to identify novel transcripts responding to the respective diets; however, while results showed shifts in gut microbe profiles, few differences in the functional profiles of termite guts fed on CS and SR relative to paper were identifiable (Rajarapu et al, 2015).…”

“…In recent years, wood feeding insects have gained attention for biofuel production due to their inherent ability to enzymatically degrade recalcitrant lignocellulose. Specifically, two groups of wood-feeding insects, wood-boring beetles, and termites (both higher and lower) have been studied for the purpose of deciphering lignocellulose unlocking mechanisms (Geib et al, 2008;Sun and Scharf, 2010;Scharf, 2015a). Termites along with their gut symbiota efficiently degrade lignocellulose.…”

“…Termites along with their gut symbiota efficiently degrade lignocellulose. Higher termites including Nasutitermes takasagoensis and lower termites including Coptotermes formosanus, C. gestroi, and Reticulitermes flavipes have been extensively studied from genes to function to dissect their lignocellulose digestive physiology (Tokuda et al, 1997;Cairo et al, 2011;Zhang et al, 2012;Scharf, 2015a). There is ample evidence of termites having endogenous cellulases that aid in cellulose digestion independent of symbiont action (Watanabe et al, 1998;Zhou et al, 2007), but clearly a synergistic collaboration exists between the termite and its symbiota that achieves efficient lignocellulose digestion (Scharf et al, 2011a,b).…”

Caste‐specific microRNA expression in termites: insights into soldier differentiation

“…Soldiers can be differentiated from workers (or totipotent larvae) by increasing the haemolymphatic juvenile hormone (JH) titre (Watanabe et al , ; Korb, ). Although numerous caste‐specific genes have been identified in some taxa (reviewed by Miura and Scharf, ; Scharf, ), the regulatory mechanisms governing the expression of these genes are largely unknown. One possible mechanism that could potentially explain the missing links amongst termite castes is epigenetic regulation (Yan et al , ; ).…”