Protists with Uncertain Phylogenetic Affiliations for Resolving the Deep Tree of Eukaryotes.

Resolving the eukaryotic tree of life (eToL) remains a fundamental challenge in biology. Much of eukaryotic phylogenetic diversity is occupied by unicellular microbial eukaryotes (i.e.

n. sp.: a novel predatory flagellate illuminates the character evolution within the eukaryotic clade CRuMs.

Culturing protists offers a powerful approach to exploring eukaryotic diversity, especially for deep-branching lineages. In this study, we cultured and described a novel protist species, named n sp. within the poorly studied and unclassified genus .

Massive RNA Editing in Ascetosporean Mitochondria.

Ascetosporeans are parasitic protists of invertebrates. A deep sequencing ana-lysis of species within the orders Mikrocytida, Paramyxida, and Haplosporida using metagenomic approaches revealed that their mitochondria were functionally reduced and their organellar genomes were lacking. Ascetosporeans belonging to the order Paradinida have not been sequenced, and the nature of their mitochondria remains unclear.

An expanded phylogenomic analysis of Heterolobosea reveals the deep relationships, non-canonical genetic codes, and cryptic flagellate stages in the group.

The phylum Heterolobosea Page and Blanton, 1985 is a group of eukaryotes that contains heterotrophic flagellates, amoebae, and amoeboflagellates, including the infamous brain-eating amoeba Naegleria fowleri. In this study, we investigate the deep evolutionary history of Heterolobosea by generating and analyzing transcriptome data from 16 diverse isolates and combine this with previously published data in a comprehensive phylogenomic analysis. This dataset has representation of all but one of the major lineages classified here as orders.

Dinotoms possess two evolutionary distinct autophagy-related ubiquitin-like conjugation systems.

Autophagy is an intracellular degradation mechanism by which cytoplasmic materials are delivered to and degraded in the lysosome-fused autophagosome (autolysosome) and proposed to have been established at an early stage of eukaryotic evolution. Dinoflagellates harboring endosymbiotic diatoms (so-called "dinotoms"), which retain their own nuclei and mitochondria in addition to plastids, have been investigated as an intermediate toward the full integration of a eukaryotic phototroph into the host-controlled organelle (i.e.

Transcriptome data sets of free-living diplomonads, sp. and sp.

Most species belonging to the diplomonad genera, and , are considered to have secondarily adapted to free-living lifestyles from the parasitic ancestor. Here, we report the annotated transcriptome data of sp. NIES-1444 and sp.

Genome sequencing reveals the genetic architecture of heterostyly and domestication history of common buckwheat.

Common buckwheat, Fagopyrum esculentum, is an orphan crop domesticated in southwest China that exhibits heterostylous self-incompatibility. Here we present chromosome-scale assemblies of a self-compatible F. esculentum accession and a self-compatible wild relative, Fagopyrum homotropicum, together with the resequencing of 104 wild and cultivated F.

Recent expansion of metabolic versatility in Diplonema papillatum, the model species of a highly speciose group of marine eukaryotes.

Background: Diplonemid flagellates are among the most abundant and species-rich of known marine microeukaryotes, colonizing all habitats, depths, and geographic regions of the world ocean. However, little is known about their genomes, biology, and ecological role.

Results: We present the first nuclear genome sequence from a diplonemid, the type species Diplonema papillatum.

Comparative Plastid Genomics of Green-Colored Dinoflagellates Unveils Parallel Genome Compaction and RNA Editing.

Dinoflagellates possess plastids that are diverse in both pigmentation and evolutionary background. One of the plastid types found in dinoflagellates is pigmented with chlorophylls and (Chl + ) and originated from the endosymbionts belonging to a small group of green algae, Pedinophyceae. The Chl + -containing plastids have been found in three distantly related dinoflagellates spp.

Evolutionary diversification of the autophagy-related ubiquitin-like conjugation systems.

Two autophagy-related (ATG) ubiquitin-like conjugation systems, the ATG12 and ATG8 systems, play important roles in macroautophagy. While multiple duplications and losses of the ATG conjugation system proteins are found in different lineages, the extent to which the underlying systems diversified across eukaryotes is not fully understood. Here, in order to understand the evolution of the ATG conjugation systems, we constructed a transcriptome database consisting of 94 eukaryotic species covering major eukaryotic clades and systematically identified ATG conjugation system components.

Signs of the plastid: Enzymes involved in plastid-localized metabolic pathways in a eugregarine species.

Apicomplexa mainly comprises parasitic species and some of them, which infect and cause severe diseases to humans and livestock, have been extensively studied due to the clinical and industrial importance. Besides, apicomplexans are a popular subject of the studies focusing on the evolution initiated by a secondary loss of photosynthesis. By interpreting the position in the tree of eukaryotes and lifestyles of the phylogenetic relatives parsimoniously, the extant apicomplexans are predicted to be the descendants of a parasite bearing a non-photosynthetic (cryptic) plastid.

Barthelonids represent a deep-branching metamonad clade with mitochondrion-related organelles predicted to generate no ATP.

We here report the phylogenetic position of barthelonids, small anaerobic flagellates previously examined using light microscopy alone. spp. were isolated from geographically distinct regions and we established five laboratory strains.

Dinoflagellates with relic endosymbiont nuclei as models for elucidating organellogenesis.

Nucleomorphs are relic endosymbiont nuclei so far found only in two algal groups, cryptophytes and chlorarachniophytes, which have been studied to model the evolutionary process of integrating an endosymbiont alga into a host-governed plastid (organellogenesis). However, past studies suggest that DNA transfer from the endosymbiont to host nuclei had already ceased in both cryptophytes and chlorarachniophytes, implying that the organellogenesis at the genetic level has been completed in the two systems. Moreover, we have yet to pinpoint the closest free-living relative of the endosymbiotic alga engulfed by the ancestral chlorarachniophyte or cryptophyte, making it difficult to infer how organellogenesis altered the endosymbiont genome.

Extensive molecular tinkering in the evolution of the membrane attachment mode of the Rheb GTPase.

Rheb is a conserved and widespread Ras-like GTPase involved in cell growth regulation mediated by the (m)TORC1 kinase complex and implicated in tumourigenesis in humans. Rheb function depends on its association with membranes via prenylated C-terminus, a mechanism shared with many other eukaryotic GTPases. Strikingly, our analysis of a phylogenetically rich sample of Rheb sequences revealed that in multiple lineages this canonical and ancestral membrane attachment mode has been variously altered.

Fates of Evolutionarily Distinct, Plastid-type Glyceraldehyde 3-phosphate Dehydrogenase Genes in Kareniacean Dinoflagellates.

The ancestral kareniacean dinoflagellate has undergone tertiary endosymbiosis, in which the original plastid is replaced by a haptophyte endosymbiont. During this plastid replacement, the endosymbiont genes were most likely flowed into the host dinoflagellate genome (endosymbiotic gene transfer or EGT). Such EGT may have generated the redundancy of functionally homologous genes in the host genome-one has resided in the host genome prior to the haptophyte endosymbiosis, while the other transferred from the endosymbiont genome.

Global Kinetoplastea phylogeny inferred from a large-scale multigene alignment including parasitic species for better understanding transitions from a free-living to a parasitic lifestyle.

All members of the order Trypanosomatida known to date are parasites that are most likely descendants of a free-living ancestor. Trypanosomatids are an excellent model to assess the transition from a free-living to a parasitic lifestyle, because a large amount of experimental data has been accumulated for well-studied members that are harmful to humans and livestock (Trypanosoma spp. and Leishmania spp.

Metabolic Capacity of Mitochondrion-related Organelles in the Free-living Anaerobic Stramenopile Cantina marsupialis.

Functionally and morphologically degenerate mitochondria, so-called mitochondrion-related organelles (MROs), are frequently found in eukaryotes inhabiting hypoxic or anoxic environments. In the last decade, MROs have been discovered from a phylogenetically broad range of eukaryotic lineages and these organelles have been revealed to possess diverse metabolic capacities. In this study, the biochemical characteristics of an MRO in the free-living anaerobic protist Cantina marsupialis, which represents an independent lineage in stramenopiles, were inferred based on RNA-seq data.