Molecular and morphological delimitation and generic classification of the family Oocystaceae (Trebouxiophyceae, Chlorophyta)

Abstract

The family Oocystaceae (Chlorophyta) is a group of morphologically and ultrastructurally distinct green algae that constitute a well-supported clade in the class Trebouxiophyceae. Despite the family's clear delimitation, which is based on specific cell wall features, only a few members of the Oocystaceae have been examined using data other than morphological. In previous studies of Trebouxiophyceae, after the establishment of molecular phylogeny, the taxonomic status of the family was called into question. The genus Oocystis proved to be paraphyletic and some species were excluded from Oocystaceae, while a few other species were newly redefined as members of this family. We investigated 54 strains assigned to the Oocystaceae using morphological, ultrastructural and molecular data (SSU rRNA and rbcL genes) to clarify the monophyly of and diversity within Oocystaceae. Oonephris obesa and Nephrocytium agardhianum clustered within the Chlorophyceae and thus are no longer members of the Oocystaceae. On the other hand, we transferred the coenobial Willea vilhelmii to the Oocystaceae. Our findings combined with those of previous studies resulted in the most robust definition of the family to date. The division of the family into three subfamilies and five morphological clades was suggested. Taxonomical adjustments in the genera Neglectella, Oocystidium, Oocystis, and Ooplanctella were established based on congruent molecular and morphological data. We expect further taxonomical changes in the genera Crucigeniella, Eremosphaera, Franceia, Lagerheimia, Oocystis, and Willea in the future.

<p><strong><em>Dispora speciosa</em></strong><strong>, a new addition to the genus <em>Parallela</em> and the first coccoid member of the family Microsporaceae</strong></p>

“…Despite the similarity in coenobial shape and structure, our analyses also show ACOI 1508 as distant from all available lineages of the former Crucigenoideae, now known to be polyphyletic (Hepperle et al 2000, Hegewald et al 2010, Bock et al 2013, Štenclová et al 2017. Our own analyses only show Crucigenia pulchra West & G.S.…”

“…A typical trait defining crucigenoid algae is the propagation by autospores, which have not been reported in Dispora spp. Further, much like the Radiococcaceae, crucigenoid algae also are demonstrably polyphyletic, and their members are distributed throughout the green algal phylogeny and inside both the classes Trebouxiophyceae (Hepperle et al 2000, Bock et al 2013, Štenclová et al 2017 and Chlorophyceae (Hegewald et al 2010, Bock et al 2013. The relationship of the genus Dispora to radiococcacean and crucigenoid lineages is suspected but remains unexplored.…”

In vitro anticancer activity of methanolic extract of Granulocystopsis sp., a microalgae from an oligotrophic oasis in the Chihuahuan desert

“…The resulting sequence was aligned in the NCBI database (http://www.ncbi.nlm.nih.gov/) using the Basic Local Alignment Search Tool (BLAST) in order to identify the closest related sequences at genus-level affiliations to the Chu2 microalgae rbcL gene (GenBank MH370163). After BLAST analysis of the sequenced gene, a data set of 37 rbcL genes from the well characterized and validated genus of the Oocystaceae family (Stenclova et al, 2017) was used to construct the phylogenetic tree. The tree was rooted with Chlorella vulgaris (Chlorellaceae family) rbcL gene.…”

Quadricoccopsis gen. nov., a new genus of Quadricoccus-like algae in Oocystaceae from China (Trebouxiophyceae, Chlorophyta)

“…The Oocystaceae, as summarized by Komárek & Fott (1983), are traditionally characterized by an Oocystis-like cell wall ultrastructure that is multi-layered with cellulose fibrils in each layer perpendicular to those of the adjoining layer. However, though some genera were affirmed to possess the ultrastructure (Štenclová et al 2017), the Planctonema-like algae, including the genus Planctonemopsis Liu et Liu, which was positioned within the core Oocystaceae, was an exception (Štenclová et al 2017;Liu et al 2017). The genus Quadricoccopsis also shows no obvious Oocystis-like ultrastructure by our research herein.…”