Hepatincolaceae (Alphaproteobacteria) Symbionts of Snapping Shrimp Alpheus brevicristatus: Genomic Capacity for Functions Beyond Nutrient Scavenging

Genomic, spatial, and evolutionary insights into a dominant Mycoplasmatota symbiont colonizing the body wall of deep-sea holothurians

This study provides genome- and spatially resolved views of dominant SCB in holothurians and offers evolutionary insights into host-interface diversification in the deep-sea holothurian body wall.

Caught in transition: facultative intracellularity and genome evolution of Symbiopectobacterium in Rhodnius species

Blood-feeding insects typically depend on obligate intracellular bacterial symbionts that provide essential B vitamins absent from vertebrate blood. In contrast, kissing bugs (Triatominae) have long been considered atypical because they rely primarily on extracellular gut-associated bacteria. Recent reports of the genus Symbiopectobacterium in Rhodnius species raise questions about the diversity and evolution of symbiosis in these insects. Here, we investigate the distribution, genome evolution, and tissue localization of Symbiopectobacterium in the genus Rhodnius. Using comparative metagenomics, phylogenomics, fluorescence in situ hybridization, transmission electron microscopy, and hemolymph screening, we characterize a Symbiopectobacterium genome from Rhodnius prolixus and assess its occurrence across publicly available datasets representing multiple Rhodnius species. The R. prolixus strain possesses a large, highly dynamic genome enriched in mobile genetic elements, pseudogenes, and remnants of secretion systems, while retaining biosynthetic pathways for several B vitamins. Comparative analysis revealed variation in genome reduction among Rhodnius-associated strains, suggesting ongoing and potentially independent transitions toward host-restricted symbiosis. Localization analyses detected Symbiopectobacterium intracellularly within posterior midgut epithelial cells and occasionally in the hemolymph, consistent with a facultative intracellular lifestyle. However, no bacteriomes or stable intracellular structures were observed. Together, these findings indicate that Symbiopectobacterium represents an intermediate stage in the transition from environmentally associated bacteria to obligate intracellular mutualists in Triatominae.

Red-Algal Endosymbiotic Gene Transfer in Secondary Plastid-Bearing Dinoflagellates: A Systematic Review and Phylogenomic Evidence Map

The plastids of peridinin-containing dinoflagellates ultimately derive from a red alga acquired by secondary endosymbiosis, an event that required extensive endosymbiotic gene transfer (EGT) from the endosymbiont to the host nucleus. Although many individual studies have recovered a red-algal phylogenetic signal in nucleus-encoded, plastid-targeted dinoflagellate proteins, this evidence remains scattered across genome papers, transcriptome surveys, plastid-proteome predictions and single-gene phylogenies, and has never been compiled systematically. Conducted and reported in accordance with the PRISMA 2020 guideline adapted for evolutionary genomics, this systematic review aimed to map and grade that evidence at the level of individual genes, lineages and functional categories. Bibliographic databases and sequence repositories, including Web of Science, Scopus, PubMed, MMETSP and EukProt, were searched up to 31 January 2026, and a four-tier evidence-grading scheme (strong, moderate, weak, ambiguous) together with a phylogenomic risk-of-bias appraisal was applied. Twenty-four studies met the eligibility criteria. The strongest and most consistent red-algal signals were recovered among nucleus-encoded proteins of the photosynthetic electron-transport chain, the Calvin–Benson cycle, tetrapyrrole and carotenoid biosynthesis, and plastid gene expression, consistent with a chromalveolate origin of the peridinin plastid. Peridinean lineages carried the clearest red-derived signal, whereas haptophyte-derived (Kareniaceae) and diatom-derived (dinotom) lineages showed a younger layer of donor-specific ancestry that frequently obscured the original red signal. The number of recovered EGT candidates was also an order of magnitude greater in secondary than in tertiary plastid contexts.

The genome, transcriptome and metabolome of Aspergillus welwitschiae Ocstreb1 from wild halophytic rice, Oryza coarctata, indicates its distinctiveness.

An integrated omics study provides foundational insights into the endophytic potential and genomic distinctiveness of AwOcstreb1, isolated from halophytic rice, and opens new avenues for exploring A. welwitschiae for sustainable agriculture and fungal biology.

Comparative metagenomic analysis of gut microbiota in Anacanthotermes turkestanicus and A. ahngerianus reveals diet- and habitat-driven functional divergence

The gut microbiome of termites plays a crucial role in lignocellulose degradation and nutrient recycling. This study presents the first metagenomic characterization of the gut microbiota in two lower termite species, Anacanthotermes ahngerianus and Anacanthotermes turkestanicus, collected from distinct ecological habitats. In Uzbekistan, the first lives in building a mound in nature in the West part while the second mainly lives in contact with human constructions in the East part without building a proper mound. Both species showed similar bacterial dominance (~53%) in their guts but A. ahngerianus exhibited higher overall microbial diversity (Shannon index: 4.046 vs. 3.363; Simpson’s index: 0.927 vs. 0.776). Moreover, both termite species showed differences in microbial profiles, including bacterial taxa and eukaryotic groups relevant to lower-termite gut symbiosis. Protist-associated eukaryotic reads were retained because flagellated protists are essential symbionts of lower termites, whereas unexpected non-protist eukaryotic assignments were interpreted cautiously and were not used as evidence of functional gut symbionts or host adaptation. Functional profiling revealed enrichment of pathways related to carbohydrate metabolism, amino acid transport, and energy production in both species. However, A. turkestanicus exhibited stronger bacterial dominance associated with lignocellulose degradation and nitrogen cycling, while A. ahngerianus maintained a more balanced representation of bacteria, fungi, and viruses. These findings suggest that species identity and ecological habits may be associated with differences in gut microbiome structure and predicted functional potential.

Ca. Steroidedax gorgoniicola, a heterotrophic coral associate with horizontally acquired genes from Endozoicomonadaceae