engleski

Symbiotic bacteria from crayfish cuticle: a possibility for biocontrol of crayfish plague disease?

Microorganism Aphanomyces astaci (Schikora, 1906) causes the lethal disease crayfish plague, one of the reasons for decline of native decapod crayfish populationsin Europe. While A. astaci zoospores penetrate through the crayfish cuticle during the infection process, they encounter epibiontic bacterial communities on the cuticle surface. We have hypothesized that bacterial isolates originating from crayfish cuticle could inhibit the growth of A. astaci mycelium. To test this, we took cuticle swabs from five narrow-clawed crayfish, Astacus leptodactylus Eschscholtz, 1823 and five signal crayfish, Pacifastacus leniusculus (Dana, 1852) and inoculated them on PG1 medium. Next, we have isolated morphologically different individual colonies and taxonomically identified each isolate by MALDI–TOF mass spectrometry and 16S rRNA gene sequencing. Dominant bacterial genera among isolates were Pseudomonas and Acinetobacter. Furthermore, we tested the potential of isolates to inhibit the growth of A. astaci mycelium by plate inhibition assay. Out of 33 isolates from narrow-clayed crayfish, 20exhibited great potential for A. astaci inhibition, while out of 25 isolates from signal crayfish, only 2 showed great inhibition potential. This result was surprising since narrow-clawed crayfish is known to be more sensitive to A. astaci than signal crayfish, but could be explained by a small sample size. Further, most of the potent inhibitors from both crayfish species belonged to genus Pseudomonas, for which the inhibition of fish pathogenic oomycete from genus Saprolegnia was previously shown. In conclusion, we have characterized cultivable symbiotic bacterial communities of crayfish and shown their potential for biocontrol of crayfish plague.

Biocontrol ; Aphanomyces astaci ; Pseudomonas ; Astaciculture

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