Halioticida noduliformans infection in eggs of lobster (Homarus gammarus) reveals its generalist parasitic strategy in marine invertebrates

• Published in: Journal of Invertebrate Pathology
• Main Authors: Holt, C, Foster, R, Daniels, CL, van der Giezen, M, Feist, SW, Stentiford, GD, Bass, D
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2018
• Subjects: Halioticida noduliformans; Homarus gammarus; Haliphthoros; Oomycete; 18S rRNA gene; European lobster
• Online Access: http://hdl.handle.net/10871/32942; https://doi.org/10.1016/j.jip.2018.03.002

This is the final version of the article. Available from the publisher via the DOI in this record. A parasite exhibiting Oomycete-like morphology and pathogenesis was isolated from discoloured eggs of the European lobster (Homarus gammarus) and later found in gill tissues of adults. Group-specific Oomycete primers were designed to amplify the 18S ribosomal small subunit (SSU), which initially identified the organism as the same as the ‘Haliphthoros’ sp. NJM 0034 strain (AB178865.1) previously isolated from abalone (imported from South Australia to Japan). However, in accordance with other published SSU-based phylogenies, the NJM 0034 isolate did not group with other known Haliphthoros species in our Maximum Likelihood and Bayesian phylogenies. Instead, the strain formed an orphan lineage, diverging before the separation of the Saprolegniales and Pythiales. Based upon 28S large subunit (LSU) phylogeny, our own isolate and the previously unidentified 0034 strain are both identical to the abalone pathogen Halioticida noduliformans. The genus shares morphological similarities with Haliphthoros and Halocrusticida and forms a clade with these in LSU phylogenies. Here, we confirm the first recorded occurrence of H. noduliformans in European lobsters and associate its presence with pathology of the egg mass, likely leading to reduced fecundity. This work was conducted within the Centre for Sustainable Aquaculture Futures, a joint initiative between the University of Exeter and the Centre for Environment, Fisheries and Aquaculture Science (Cefas) and funded by a Cefas-Exeter University Alliance PhD Studentship to CH. Work was also supported through the Agri-Tech Catalyst, Industrial Stage Awards, Lobster Grower 2 project funded by Innovate UK (102531) and BBSRC (BB/N013891/1) and Defra contracts C6560 and C7277 to DB