The mushroom Coprinopsis cinerea is a classic experimental model for multicellular development in fungi because it grows on defined media, completes its life cycle in 2 weeks, produces some 10 ⁸ synchronized meiocytes, and can be manipulated at all stages in development by mutation and transformation. The 37-megabase genome of C. cinerea was sequenced and assembled into 13 chromosomes. Meiotic recombination rates vary greatly along the chromosomes, and retrotransposons are absent in large regions of the genome with low levels of meiotic recombination. Single-copy genes with identifiable orthologs in other basidiomycetes are predominant in low-recombination regions of the chromosome. In contrast, paralogous multicopy genes are found in the highly recombining regions, including a large family of protein kinases (FunK1) unique to multicellular fungi. Analyses of P450 and hydrophobin gene families confirmed that local gene duplications drive the expansions of paralogous copies and the expansions occur in independent lineages of Agaricomycotina fungi. Gene-expression patterns from microarrays were used to dissect the transcriptional program of dikaryon formation (mating). Several members of the FunK1 kinase family are differentially regulated during sexual morphogenesis, and coordinate regulation of adjacent duplications is rare. The genomes of C. cinerea and Laccaria bicolor , a symbiotic basidiomycete, share extensive regions of synteny. The largest syntenic blocks occur in regions with low meiotic recombination rates, no transposable elements, and tight gene spacing, where orthologous single-copy genes are overrepresented. The chromosome assembly of C. cinerea is an essential resource in understanding the evolution of multicellularity in the fungi.

Information on genetic diversity of picoeukaryotes (<2–3 μm) comes mainly from traditional gene cloning and sequencing, but this method suffers from cloning biases and limited throughput. In this study, we explored the feasibility of using the cloning-independent and massively parallel 454 pyrosequencing technology to study the composition and genetic diversity of picoeukaryotes in the coastal waters of the subtropical western Pacific using the hypervariable V4 region of the 18S rRNA gene. Picoeukaryote assemblages between two sites with different hydrography and trophic status were also compared. The approach gave a high coverage of the community at genetic difference ⩾5% but still underestimated the total diversity at a genetic difference ⩽2%. Diversity of picoeukaryotes was higher in an oligomesotrophic bay than in a eutrophic bay. Stramenopiles, dinoflagellates, ciliates and prasinophytes were the dominant groups comprising approximately 27, 19, 11 and 11%, respectively, of the picoeukaryotes. Water samples collected from the two bays contained different high-level taxonomic groups and phylotype operational taxonomic units of picoeukaryotes. Our study represents one of the first and most comprehensive examinations of marine picoeukaryotic diversity using the 454 sequencing-by-synthesis technology.

Background The human gut microbiota has profound influence on host metabolism and immunity. This study characterized the fecal microbiota in patients with nonalcoholic steatohepatitis (NASH). The relationship between microbiota changes and changes in hepatic steatosis was also studied. Methods Fecal microbiota of histology-proven NASH patients and healthy controls was analyzed by 16S ribosomal RNA pyrosequencing. NASH patients were from a previously reported randomized trial on probiotic treatment. Proton-magnetic resonance spectroscopy was performed to monitor changes in intrahepatic triglyceride content (IHTG). Results A total of 420,344 16S sequences with acceptable quality were obtained from 16 NASH patients and 22 controls. NASH patients had lower fecal abundance of Faecalibacterium and Anaerosporobacter but higher abundance of Parabacteroides and Allisonella . Partial least-square discriminant analysis yielded a model of 10 genera that discriminated NASH patients from controls. At month 6, 6 of 7 patients in the probiotic group and 4 of 9 patients in the usual care group had improvement in IHTG (P = 0.15). Improvement in IHTG was associated with a reduction in the abundance of Firmicutes (R 2 = 0.4820, P = 0.0028) and increase in Bacteroidetes (R 2 = 0.4366, P = 0.0053). This was accompanied by corresponding changes at the class, order and genus levels. In contrast, bacterial biodiversity did not differ between NASH patients and controls, and did not change with probiotic treatment. Conclusions NASH patients have fecal dysbiosis, and changes in microbiota correlate with improvement in hepatic steatosis. Further studies are required to investigate the mechanism underlying the interaction between gut microbes and the liver.

Whole-genome duplication (WGD) results in new genomic resources that can be exploited by evolution for rewiring genetic regulatory networks in organisms. In metazoans, WGD occurred before the last common ancestor of vertebrates, and has been postulated as a major evolutionary force that contributed to their speciation and diversification of morphological structures. Here, we have sequenced genomes from three of the four extant species of horseshoe crabs—Carcinoscorpius rotundicauda, Limulus polyphemus and Tachypleus tridentatus. Phylogenetic and sequence analyses of their Hox and other homeobox genes, which encode crucial transcription factors and have been used as indicators of WGD in animals, strongly suggests that WGD happened before the last common ancestor of these marine chelicerates >135 million years ago. Signatures of subfunctionalisation of paralogues of Hox genes are revealed in the appendages of two species of horseshoe crabs. Further, residual homeobox pseudogenes are observed in the three lineages. The existence of WGD in the horseshoe crabs, noted for relative morphological stasis over geological time, suggests that genomic diversity need not always be reflected phenotypically, in contrast to the suggested situation in vertebrates. This study provides evidence of ancient WGD in the ecdysozoan lineage, and reveals new opportunities for studying genomic and regulatory evolution after WGD in the Metazoa.

Bacteria, archaea and fungi play crucial roles in wetland biogeochemical processes. However, little is known about their community structure, dynamics and interactions in subtropical coastal wetlands. Here, we examined communities of the three kingdoms in mangrove and mudflat sediments of a subtropical coastal wetland using Ion Torrent amplicon sequencing and co-occurrence network analysis. Bacterial, archaeal and fungal communities comprised mainly of members from the phyla Proteobacteria and Bacteroidetes, Bathyarchaeota and Euryarchaeota, and Ascomycota, respectively. Species richness and Shannon diversity were highest in bacteria, followed by archaea and were lowest in fungi. Distinct spatiotemporal patterns were observed, with bacterial and fungal communities varying, to different extent, between wet and dry seasons and between mangrove and mudflat, and archaeal community remaining relatively stable between seasons and regions. Redundancy analysis revealed temperature as the major driver of the seasonal patterns of bacterial and fungal communities but also highlighted the importance of interkingdom biotic factors in shaping the community structure of all three kingdoms. Potential ecological interactions and putative keystone taxa were identified based on co-occurrence network analysis. These findings facilitate current understanding of the microbial ecology of subtropical coastal wetlands and provide a basis for better modelling of ecological processes in this important ecosystem.