engleski

Investigating the role of viral infections in the population of the Congeria kusceri

Congeria kusceri (Bole, 1962), a highly endangered freshwater bivalve endemic to the Dinaric Karst, belongs to the only extant genus of cave-dwelling bivalves. This cave clam lives in a unique habitat, which has been subjected to minimal environmental changes over the past five million years. Since the natural populations of C. kusceri have been quickly declining over the past few decades, a key question to be answered is whether the “living fossil” status of this species, i.e. the apparent lack of morphological and physiological changes compared with its fossil relatives, is linked with a scarce resilience to the impact of human activities on the subterranean environment. In particular, the alteration of the seasonal abundance of pathogens, linked with the modified influx of water in Karst caves, might pose a severe threat to the survival of this species. Here, through a transcriptomic approach, we describe the identification in the tissues of C. kusceri of 5 nearly- complete genomes of RNA viruses belonging to the Picornaviridae family, which displayed a strong tissue preference and a significantly changes in abundance over the summer season. RNA-seq data also allowed to investigate whether these viral infections had an impact on gene expression in different host tissues. Since numerous reports have previously implicated Picorna-like viruses in the mass mortality events observed in different bivalves, we suggest that the presence of the 5 identified viruses should be closely monitored, together with other biological and chemical parameters, to gather a better understanding of the causes underlying the quick decline of C. kusceri populations.

Congeria kusceri ; Dinaric Karst ; Picorna-like viruses

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