engleski

Interplay between crayfish host, its epibionts and oomycete pathogen Aphanomyces astaci, causative agent of crayfish plague

Aim Climate change affects freshwater organisms and their interactions, i.e. the pathogens are mostly predicted to increase their distribution. We have studied the complex relationship between crayfish host, its epibiontic communities and its pathogen Aphanomyces astaci at different water temperatures. Elevated water temperature caused by climate change simultaneously affects crayfish fitness, composition of cuticle- associated communities and the virulence of its pathogens. Methods We have infected two crayfish species, Austropotamobius torrentium and Astacus leptodactylus, with A. astaci zoospores at increased water temperature (22 ⁰C, simulation of climate change) and control temperature (18 ⁰) and monitored crayfish mortality. We took cuticle swabs before the experiment and immediately after death to test for A. astaci presence. Thus, we could determine the cause of death of each animal (A. astaci-induced or other causes). Also, we analyzed the epibiontic microbiome composition by Illumina Miseq. Results The composition of cuticle-associated microbial communities was mostly determined by temperature. Further, at increased temperature crayfish mortality was reduced and mostly could not be ascribed to A. astaci infection. The observed higher diversity of epibiontic communities at elevated temperature could have contributed to host resistance to A. astaci. Conclusions We present the first data on cuticle-associated microbiota of A. torrentium and A. leptodactylus, as well as their correlation with temperature and A. astaci. This can help to predict the spreading of crayfish plague, as one of the most important causes of decline of indigenous European crayfish, in the future climate change scenarios.

climate change, crayfish plague, epibiontic microbial communities, freshwater crayfish

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