Pathogens of brown algae: culture studies of Anisolpidium ectocarpii and A. rosenvingei reveal that the Anisolpidiales are uniflagellated oomycetes

Miracula Moenusica , a New Member of the Holocarpic Parasitoid Genus from the Invasive Freshwater Diatom Pleurosira Laevis

“…However, the finding that some oomycete lineages diverged before the two major classes (Hudspeth et al 2003), has spurred some interest in holocarpic oomycetes and has revealed the genera Haptoglossa and Eurychasma as the earliest-diverging lineages (e.g. Sekimoto et al 2008, Gachon et al 2017, a placement that only recently has been contested by the holocarpic diatom parasitoid Miracula helgolandica (Buaya et al 2017). Miracula helgolandica parasitises the filamentous diatoms of the genus Pseudo-nitzschia (Hanic et al 2009, Buaya et al 2017 and could not be assigned to any of the five holocarpic genera known to parasitize diatoms (Aphanomycopsis, Ectrogella, Lagenidium, Lagenisma, and Olpidiopsis), which was the reason the new genus Miracula had been introduced.…”

Host and pathogen autophagy are central to the inducible local defences and systemic response of the giant kelp Macrocystis pyrifera against the oomycete pathogen Anisolpidium ectocarpii

“…This study was performed using monoeukaryotic, bacterized cultures of the obligate biotrophic oomycete Anisolpidium ectocarpii CCAP 4001/1 (Gachon et al , ). Healthy female gametophytes of Macrocystis pyrifera CCAP 1323/1 were used as host to propagate A. ectocarpii , similar to the protocol described by Strittmatter et al .…”

“…Among them, Anisolpidium is a genus of obligate biotrophic pathogens that infects marine brown algae. Anisolpidium ectocarpii has a broad host spectrum, spanning ≥ 20 species across nine orders (Gachon et al , ); this includes the genome model Ectocarpus siliculosus and the gametophytic life stages of several kelps, including of the giant Pacific kelp Macrocystis pyrifera . Phylogenetically, Anisolpidium is closely related to marine species of Olpidiopsis , and recently described clades of diatom pathogens named OOM_1 and OOM_2 (Garvetto et al , ).…”

“…Olpidiopsis is a cosmopolitan genus that encompasses devastating pathogens of red algae, including laver, the most valuable seaweed crop in the world (Klochkova et al , ; Badis et al , ); the OOM_1 and OOM_2 clades contain pathogens potentially relevant to the control of phytoplankton dynamics and consequently, biogeochemical cycling. Finally, the early‐diverging position of Anisolpidium among oomycetes (Gachon et al , ) makes it an ideal model to address the physiology and evolutionary origin of pathogenicity and biotrophy in oomycetes. Conversely, the capacity of A. ectocarpii to infect a huge diversity of hosts suggests that its virulence targets are shared by many brown algae; therefore, A. ectocarpii also is a good model to investigate the core set of defence responses conserved across brown algae (Murúa, ).…”

Analysis of algal growth- and morphogenesis- promoting factors in an integrated multi-trophic aquaculture system for farming Ulva spp.

“…Recent research has enabled a rapid expansion of knowledge focusing on many individual aspects of interactions between marine algae and their associated microbiota. Characterisation of the chemical interactions between microbiome and host (Goecke et al 2010), the structuring of microbial communities on the surface of algal host (Burke et al 2011), bacterial diversity (Lachnit et al 2009, Barott et al 2011, and algal pathogens and diseases (Gachon et al 2017) have all been carried out.…”