Molecular ecology of white-clawed crayfish (Austropotamobius pallipes) in Ireland.

Abstract

The white-clawed crayfish (Austropotamobius pallipes, Lereboullet 1858) is a large freshwater invertebrate that has important functions in maintaining ecosystems. Historically, the species was broadly distributed across western Europe, but populations have been significantly reduced and fragmented due to habitat loss, competition with non-indigenous crayfish species (NICS) and outbreaks of crayfish plague caused by the aquatic mould Aphanomyces astaci. Ireland remains free of NICS, but five outbreaks of the plague have been recorded since 2015. Regardless of these recent outbreaks, crayfish populations in Ireland remain the healthiest across Europe. Conservation management plans for the species suggest Irish populations of A. pallipes are a suitable restocking source for European locations where the species has been lost but genetic analyses in the early 2000s indicate the stock is genetically homogeneous and lacks diversity. To access this, crayfish were samples from special areas of conservation in Ireland, a region of the 16S rDNA molecular marker was sequenced and genetic diversity was compared within and between populations. Statistically significant pairwise comparisons and molecular analysis of variance values indicate genetic diversity and population structure does exist within Irish white-clawed crayfish populations. Furthermore, to characterise host-pathogen interactions between A. pallipes and A. astaci, the overexpression of a Kazal type serine protease inhibitor (KP12) was optimised in an E. coli host. The fusion protein was purified by affinity chromatography, cleaved and isolated by gel filtration. Appropriate finial concentrations for inhibitory assays were not achieved. However, the optimised overexpression workflow has been detailed and will serve for the future overexpression of KP12 and potentially other Kazal protease inhibitors from the species.