Mycorrhizal fungi are mutualists that play crucial roles in nutrient acquisition in terrestrial ecosystems. Mycorrhizal symbioses arose repeatedly across multiple lineages of Mucoromycotina, Ascomycota, and Basidiomycota. Considerable variation exists in the capacity of mycorrhizal fungi to acquire carbon from soil organic matter. Here, we present a combined analysis of 135 fungal genomes from 73 saprotrophic, endophytic and pathogenic species, and 62 mycorrhizal species, including 29 new mycorrhizal genomes. This study samples ecologically dominant fungal guilds for which there were previously no symbiotic genomes available, including ectomycorrhizal Russulales, Thelephorales and Cantharellales. Our analyses show that transitions from saprotrophy to symbiosis involve (1) widespread losses of degrading enzymes acting on lignin and cellulose, (2) co-option of genes present in saprotrophic ancestors to fulfill new symbiotic functions, (3) diversification of novel, lineage-specific symbiosis-induced genes, (4) proliferation of transposable elements and (5) divergent genetic innovations underlying the convergent origins of the ectomycorrhizal guild.
SUMMARY The emergence of influenza A viruses (IAVs) from zoonotic reservoirs poses a great threat to human health. As seasonal vaccines are ineffective against zoonotic strains, and newly transmitted viruses can quickly acquire drug resistance, there remains a need for host-directed therapeutics against IAVs. Here, we performed a genome-scale CRISPR/Cas9 knockout screen in human lung epithelial cells with a human isolate of an avian H5N1 strain. Several genes involved in sialic acid biosynthesis and related glycosylation pathways were highly enriched post-H5N1 selection, including SLC35A1, a sialic acid transporter essential for IAV receptor expression and thus viral entry. Importantly, we have identified capicua (CIC) as a negative regulator of cell-intrinsic immunity, as loss of CIC resulted in heightened antiviral responses and restricted replication of multiple viruses. Therefore, our study demonstrates that the CRISPR/Cas9 system can be utilized for the discovery of host factors critical for the replication of intracellular pathogens.
pecies in the genus Aspergillus are of broad interest to medical 1 , applied 2,3 , and basic research 4. Members of Aspergillus section Nigri ('black aspergilli') are prolific producers of native and heterologous proteins 5,6 , organic acids (in particular citric acid 2,7,8), and secondary metabolites (including biopharmaceuticals and mycotoxins like ochratoxin A). Furthermore, the section members are generally very efficient producers of extracellular enzymes 9,10 ; they are the production organisms for 49 out of 260 industrial enzymes 11,12. Among the most important of these, in addition to A. niger, are A. tubingensis, A. aculeatus, and A. luchuensis (previously A. acidus, A. kawachii, and A. awamori 13-15 , respectively). Members of Aspergillus section Nigri are also known as destructive degraders of foods and feeds, and some isolates produce the potent mycotoxins ochratoxin A 16 and fumonisins 17-19. In addition, some species in this section have been proposed to be pathogenic to humans and other animals 20. It is thus of interest to further examine section Nigri for industrial exploitation, as well as prevention of food spoilage, toxin production, and pathogenicity caused by these fungi. A combined phylogenetic and phenotypic approach has shown that section Nigri contains at least 27 species 21-25. Recent results have shown that the section contains species with high diversity and may consist of two separate clades: the biseriate species and the uniseriate species 26 , which show differences in sexual states 27 , sclerotium formation 28 , and secondary metabolite production 29. In the section, only six species have had their genome sequenced: A. niger 2,8 , A. luchuensis 15,30 , A. carbonarius 31 , A. aculeatus 31 , A. tubingensis 31 , and A. brasiliensis 31. This section, with its combination of species richness and fungal species with a diverse impact on humanity, is thus particularly interesting for studying the diversification of fungi into species. In this study, we have de novo-sequenced the genomes of 20 species of section Nigri, thus completing a genome compendium of 26 described species in the section. Further, we have genome-sequenced three
Wild and weedy relatives of domesticated crops harbor genetic variants that can advance agricultural biotechnology. Here we provide a genome resource for the wild plant green millet (Setaria viridis), a model species for studies of C4 grasses, and use the resource to probe domestication genes in the close crop relative foxtail millet (Setaria italica). We produced a platinum-quality genome assembly of S. viridis and de novo assemblies for 598 wild accessions and exploited these assemblies to identify loci underlying three traits: response to climate, a ‘loss of shattering’ trait that permits mechanical harvest and leaf angle, a predictor of yield in many grass crops. With CRISPR–Cas9 genome editing, we validated Less Shattering1 (SvLes1) as a gene whose product controls seed shattering. In S. italica, this gene was rendered nonfunctional by a retrotransposon insertion in the domesticated loss-of-shattering allele SiLes1-TE (transposable element). This resource will enhance the utility of S. viridis for dissection of complex traits and biotechnological improvement of panicoid crops.
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