New phylogenetic insights into Saprolegniales (Oomycota, Straminipila) based upon studies of specimens isolated from Brazil and Argentina

Abstract

Saprolegniales is a complex and monophyletic order of oomycetes. Their members inhabit terrestrial, freshwater, and marine ecosystems and have a worldwide distribution. In these ecosystems, they are found as saprobes, parasites, or even pathogens of animals and plants of economic importance. In this study, a concatenate phylogeny of the partial LSU and complete ITS rDNA regions is presented, including isolates from Brazil and Argentina, which were sequenced after a detailed morphological analysis. Among the sequenced species, Achlya orion, Leptolegnia eccentrica, Phragmosporangium uniseriatum, and Pythiopsis irregularis are included for the first time in a phylogeny. Our results are in agreement with the recent informal proposals outlined in taxonomic overviews of the Oomycota of G.W. Beakes and collaborators, who placed the family Verrucalvaceae into the Saprolegniales and introduced the family Achlyaceae to group Achlya s.s., Brevilegnia, Dictyuchus, and Thraustotheca. These results also support the transference of Achlya androgyna to Newbya. Leptolegnia appears as paraphyletic, with the separation of L. eccentrica from the other species of this genus. In addition, Phragmosporangium, which is herein sequenced for the first time, clustered as sister to some species of Aphanomyces, including the type species, A. stellatus.

A revision of Salispina, its placement in a new family, Salispinaceae (Rhipidiales), and description of a fourth species, S. hoi sp. nov

“…2007, Hulvey et al . 2007, Steciow et al 2013, Sandoval-Sierra et al 2014, Steciow et al 2014, Rocha et al 2018), the Rhipidiales has received relatively little attention, probably owing to a lower degree of cultivation success from environmental samples due to their often microaerophilic to anaerobic nature. Thus, it seems promising to undertake targeted sampling in oxygen-depleted limnic environments in order to gain further insights into these understudied organisms which might play an important role in nutrient cycling.…”

Taxonomical and functional diversity of Saprolegniales in Anzali lagoon, Iran

“…Saprolegniales are mainly predominantly freshwater saprophytes of plant and animal debris (Beakes and Sekimoto 2009). This order contains three families: Achlyaceae (four genera), Saprolegniaceae (11 genera) and Verrucalvaceae (7 genera) Molloy et al 2014;Beakes and Thines 2017;Rocha et al 2018). Amongst these, Achlya, Brevilegnia, Dictyuchus, Leptolegnia, Plectospira, Saprolegnia and Thraustotheca have been commonly reported to inhabit freshwater ecosystems (Czeczuga et al 2005;Mousavi et al 2009;Marano et al 2011).…”

Characterization of Achlya americana and A. bisexualis (Saprolegniales, Oomycota) Isolated from Freshwater Environments in Korea

“…Before the replacement to this family, the genus Achlya was classified under the family Saprolegniaceae [5,6]. In members of this genus, primary aplanospores are discharged from sporangium, and before swimming away, stay near the exit of the sporangium until a ball of spores is formed [4,7]. Molecular phylogenetic studies have shown that Achlya s. lat.…”

“…As a result, Rocha et al. [7] have transferred Achlya androgyna to Newbya . To date, approximately 80 species have been accepted in the genus Achlya (www.indexfungorum.org; [7]).…”