Maullinia ectocarpii gen. et sp. nov. (Plasmodiophorea), an Intracellular Parasite in Ectocarpus siliculosus (Ectocarpales, Phaeophyceae) and other Filamentous Brown Algae

Gall-forming protistan parasites infect southern bull kelp across the Southern Ocean, with prevalence increasing to the south

“…4). N o sequences were shared between Australia and Chile, although the published M. ectocarpii sequence of Maier et al (2000) from Chile was closely related to Australian Maullinia (Fig. 2).…”

“…in Goecke et al 2012;now M. braseltonii: Murúa et al 2017). Although Australian Durvillaea populations have not yet been confirmed to host Maullinia, galls resembling those of the parasite were observed at Sorrento in southern Australia several decades ago (Jahnke 1978), and samples of M. ectocarpii were confirmed by Maier et al (2000) on local populations of Ectocarpus siliculosus.…”

“…While some research has described phytomyxids, including Maul linia, as parasites that infect hosts without directly leading to mortality (Neuhauser et al 2014), on flexible species such as D. antarctica the formation of galls has been suggested to reduce the host's ability to survive in high-energy wave environments (Eggert et al 2010). In laboratory cultures, Maullinia ectocarpii was also found to heavily infect the gametophytes of algal species such as Macrocystis pyrifera (Maier et al 2000), which could reduce the reproductive potential of its host. The host range, life cycle and infection pathway of M. ectocarpii are relatively well characterised, but the factors shaping its virulence in natural populations are not.…”

“…Maullinia is a recently identified genus of phytomyxean parasite that can infect several brown algal genera including Macrocystis, Ectocarpus and Acineto spora (Maier et al 2000, Goecke et al 2012. The microscopic organisms produce motile zoospores which disperse and infect new hosts, causing galllike hypertrophies of host tissue (N euhauser et al 2011).…”

Single-cell chlorophyll fluorescence kinetic microscopy ofPylaiella littoralis(Phaeophyceae) infected byChytridium polysiphoniae(Chytridiomycota)

“…Ectocarpalean brown algae are plagued by a variety of pathogens: Mu¨ller et al (1998) mention a number of virus infections; Maier et al (2000) described Maullinia ectocarpii as a novel plasmodiophoralean pathogen of Ectocarpus siliculosus. Kü pper & Mu¨ller (1999) reported frequent epidemics of the heterokont and fungal Correspondence to: Claire M. M. Gachon.…”