First Insights into the Subterranean Crustacean Bathynellacea Transcriptome: Transcriptionally Reduced Opsin Repertoire and Evidence of Conserved Homeostasis Regulatory Mechanisms

Abstract

Bathynellacea (Crustacea, Syncarida, Parabathynellidae) are subterranean aquatic crustaceans that typically inhabit freshwater interstitial spaces (e.g., groundwater) and are occasionally found in caves and even hot springs. In this study, we sequenced the whole transcriptome of Allobathynella bangokensis using RNA-seq. De novo sequence assembly produced 74,866 contigs including 28,934 BLAST hits. Overall, the gene sequences were most similar to those of the waterflea Daphnia pulex. In the A. bangokensis transcriptome, no opsin or related sequences were identified, and no contig aligned to the crustacean visual opsins and non-visual opsins (i.e. arthropsins, peropsins, and melaopsins), suggesting potential regressive adaptation to the dark environment. However, A. bangokensis expressed conserved gene family sets, such as heat shock proteins and those related to key innate immunity pathways and antioxidant defense systems, at the transcriptional level, suggesting that this species has evolved adaptations involving molecular mechanisms of homeostasis. The transcriptomic information of A. bangokensis will be useful for investigating molecular adaptations and response mechanisms to subterranean environmental conditions.

A chromosome‐level genome of the mud crab (Scylla paramamosain estampador) provides insights into the evolution of chemical and light perception in this crustacean

“…Therefore, it is hypothesized that opsin gene numbers might be associated with habitat in decapod crustaceans, which was also indicated by Veldsman et al (2019). No opsin genes were found in the transcriptome of a subterranean aquatic crustacean in a previous study (Kim et al, 2017), which supports this hypothesis.…”

Determining the toxicity and potential for environmental transport of pyridine using the brown crabCancer pagurus(L.)

“…A similar base-exchange mechanism has been described earlier for the human NAD + -ase CD38 (Preugschat et al, 2008). Recently, structurally-and functionally-related proteins have been reported in crustaceans, including toll-like receptors (TLRs) and SARM homologues (Kim et al, 2017;Habib and Zhang, 2020).…”

“…A similar base-exchange mechanism has been described earlier for the human NAD + -ase CD38 (Preugschat et al, 2008). Recently, structurally- and functionally-related proteins have been reported in crustaceans, including toll-like receptors (TLRs) and SARM homologues (Kim et al, 2017;Habib and Zhang, 2020). These have been described to exert important roles in host defense of crustaceans against their pathogens, but it is likely that these proteins exert other roles, much like their mammalian counterparts, that remain undiscovered.…”

Crustacean conundrums: a review of opsin diversity and evolution

“…The two extant orders within Syncarida consist of exclusively fresh and brackish water crustaceans, which most often live in interstitial groundwater [87]. Previous transcriptomic analysis of the subterranean, interstitial filter feeder Allobathynella bangokenisis (Bathynellacea) found no opsins [88]. However, we identified five visual opsins (four LWS one SWS/UVS) from a transcriptome of the species Anaspides tasmaniae (Anaspidacea), which lives in moving streams, is carnivorous, and has a caridoid escape response [89].…”