<I>Salisapiliaceae</I> – a new family of oomycetes from marsh grass litter of southeastern north America

Abstract

Several filamentous oomycete species of the genus Halophytophthora have recently been described from marine environments, mostly from subtropical and tropical ecosystems. During a survey of oomycetes from leaf litter of Spartina alterniflora in salt marshes of southeastern Georgia, isolates of four taxa were recovered that bore similarity to some members of Halophytophthora but were highly divergent from isolates of Halophytophthora s.str. based on a combined sequence analysis of two nuclear loci. In phylogenetic analyses, these isolates were placed basal to a monophyletic group comprised of Pythium of the Pythiaceae and the Peronosporaceae. Sequence and morphology of these taxa diverged from the type species Halophytophthora vesicula, which was placed within the Peronosporaceae with maximum support. As a consequence a new family, the Salisapiliaceae, and a new genus, Salisapilia, are described to accommodate the newly discovered species, along with one species previously classified within Halophytophthora. Morphological features that separate these taxa from Halophytophthora are a smaller hyphal diameter, oospore production, lack of vesicle formation during sporulation, and a plug of hyaline material at the sporangial apex that is displaced during zoospore release. Our findings offer a first glance at the presumably much higher diversity of oomycetes in estuarine environments, of which ecological significance requires further exploration.

One stop shop: backbones trees for important phytopathogenic genera: I (2014)

“…The remaining ten clades (A-J) can be divided into two groups: species with filamentous zoosporangia (clades A-D) and species with globose zoosporangia (clades E-J) (Lévesque and de Cock 2004), calling to mind early suggestions of splitting the genus based on this character (Schröter 1893;Sparrow 1931). This division is echoed to varying degrees by phylogenies of the 28S rRNA, ITS, cytochrome c oxidase subunits 1 and 2 (cox1 and cox2), and β-tubulin, although the different gene trees are often incongruent and support for internal nodes low or absent (Martin 2000;Riethmüller et al 2002;Villa et al 2006;Hulvey et al 2010;Robideau et al 2011). Despite the shortcomings of these gene regions, Uzuhashi et al (2010) used 28S and cox2 phylogenies to divide Pythium into five genera: Pythium (clades A-D), Globisporangium (clades E-G, I and J), Elongisporangium (clade H), Ovatisporangium (clade K, syn.…”

Phytopythium leanoi sp. nov. and Phytopythium dogmae sp. nov., Phytopythium species associated with mangrove leaf litter from the Philippines

“…To date, approximately 2000 species striving in different habitats ranging from the arctic to tropics have been described [1]. The discovery of new lineages that branch outside the major genera of Peronosporales [2][3][4][5][6][7] has fueled research into the evolution and diversity of cultivable oomycetes of the Peronosporales [8]. Of the recently-described oomycete lineages, the former K-clade Pythium species [5,9] have attracted intense research and were segregated taxon from Pythium in 2010 [2] as members of the new genus Phytopythium on the basis of phylogenetic position and morphology.…”

11 Hyphochytriomycota, Oomycota and Perkinsozoa (Super-group Chromalveolata )

“…The genus Halophytophthora was originally erected to accommodate species found as decomposers of leaf litter in marine environments, which were formerly described in Phytophthora (Ho and Jong 1990). Members of the genus exhibit zoospore release with or without the presence of a vesicle or with a semi-persistent vesicle (Hulvey et al 2010). These characters, together with other asexual characters, were initially employed to segregate the species of Halophytophthora from Phytophthora .…”