Horizontal Transfer of a Large and Highly Toxic Secondary Metabolic Gene Cluster between Fungi

SummaryGenes involved in intermediary and secondary metabolism in fungi are frequently physically linked or clustered. For example, in Aspergillus nidulans the entire pathway for the production of sterigmatocystin (ST), a highly toxic secondary metabolite and a precursor to the aflatoxins (AF), is located in a ∼54 kb, 23 gene cluster. We discovered that a complete ST gene cluster in Podospora anserina was horizontally transferred from Aspergillus. Phylogenetic analysis shows that most Podospora cluster genes are adjacent to or nested within Aspergillus cluster genes, although the two genera belong to different taxonomic classes. Furthermore, the Podospora cluster is highly conserved in content, sequence, and microsynteny with the Aspergillus ST/AF clusters and its intergenic regions contain 14 putative binding sites for AflR, the transcription factor required for activation of the ST/AF biosynthetic genes. Examination of ∼52,000 Podospora expressed sequence tags identified transcripts for 14 genes in the cluster, with several expressed at multiple life cycle stages. The presence of putative AflR-binding sites and the expression evidence for several cluster genes, coupled with the recent independent discovery of ST production in Podospora [1], suggest that this HGT event probably resulted in a functional cluster. Given the abundance of metabolic gene clusters in fungi, our finding that one of the largest known metabolic gene clusters moved intact between species suggests that such transfers might have significantly contributed to fungal metabolic diversity.PaperFlic

Chemoreceptor Evolution in Hymenoptera and Its Implications for the Evolution of Eusociality.

Eusocial insects, mostly Hymenoptera, have evolved unique colonial lifestyles that rely on the perception of social context mainly through pheromones, and chemoreceptors are hypothesized to have played important adaptive roles in the evolution of sociality. However, because chemoreceptor repertoires have been characterized in few social insects and their solitary relatives, a comprehensive examination of this hypothesis has not been possible. Here, we annotate ∼3,000 odorant and gustatory receptors in recently sequenced Hymenoptera genomes and systematically compare >4,000 chemoreceptors from 13 hymenopterans, representing one solitary lineage (wasps) and three independently evolved eusocial lineages (ants and two bees). We observe a strong general tendency for chemoreceptors to expand in Hymenoptera, whereas the specifics of gene gains/losses are highly diverse between lineages. We also find more frequent positive selection on chemoreceptors in a facultative eusocial bee and in the common ancestor of ants compared with solitary wasps. Our results suggest that the frequent expansions of chemoreceptors have facilitated the transition to eusociality. Divergent expression patterns of odorant receptors between honeybee and ants further indicate differential roles of chemoreceptors in parallel trajectories of social evolution

Draft genome sequence of an onion basal rot isolate of Fusarium proliferatum

Fusarium proliferatum is a component of the onion basal rot disease complex. We present an annotated F. proliferatum draft genome sequence, totaling 45.8 Mb in size, assembled into 597 contigs, with a predicted 15,418 genes. The genome contains 58 secondary metabolite clusters and homologs of the Fusarium oxysporum effector SIX2

Draft genome sequence of the strawberry anthracnose pathogen colletotrichum fructicola

Colletotrichum fructicola is a causal agent of strawberry anthracnose and a major economic pathogen of horticultural and ornamental crops worldwide. Here, we present an annotated draft genome sequence for a C. fructicola isolate previously used for transcriptomic analysis. The assembly totals 58.0 Mb in 477 contigs with 18,143 predicted genes

Current issues on the political representation of middle classes in Chile

In this article, we analyze the impact that the evolution of the middle classes has had on political representation in Chile. Based on a description of the transformations of Chilean social structure in recent decades, we review the conceptual frameworks available on the subject, from modernization theories and the rise of new masses -particularly the one that "emerged" from poverty- to the forming of new critical citizens. We state that the heterogeneity of Chilean middle classes has challenged the discredited representation system. We observe more efficient representation channels developing for medium-high-income, educated, and consolidated sectors in contrast to new social policy demands from emerging and vulnerable sectors, focusing more on consolidating their economic status than on improving representation channels.En este artículo, analizamos el impacto de la evolución de las clases medias en la representación política en Chile. En base a la descripción de la estructura social chilena en las décadas recientes, examinamos los distintos marcos teóricos disponibles, desde las teorías de la modernización y el auge de las nuevas masas -particularmente de los grupos sociales que emergen de la pobreza- hasta la aparición de nuevos ciudadanos críticos. Argumentamos que la heterogeneidad de las clases medias chilenas ha desafiado el sistema de representación, actualmente desprestigiado. Observamos canales de representación más eficientes en el caso de las clases medias de ingresos más altos, más educadas y más consolidadas, en contraste con demandas por nuevas políticas sociales de parte de los sectores emergentes y vulnerables, que se enfocan más en la consolidación de sus status que en la mejora de los canales de representación

The power of discussion : Support for women at the fungal Gordon Research Conference

We would like to thank Abigail LaBella for sharing the pictures taking during the session and Felicia Wu for her suggestions. We are grateful to all the colleagues that helped leading the discussion groups and all the participants of the session.Peer reviewedPostprin

The Awesome Power of Yeast Evolutionary Genetics: New Genome Sequences and Strain Resources for the Saccharomyces sensu stricto Genus

High-quality, well-annotated genome sequences and standardized laboratory strains fuel experimental and evolutionary research. We present improved genome sequences of three species of Saccharomyces sensu stricto yeasts: S. bayanus var. uvarum (CBS 7001), S. kudriavzevii (IFO 1802T and ZP 591), and S. mikatae (IFO 1815T), and describe their comparison to the genomes of S. cerevisiae and S. paradoxus. The new sequences, derived by assembling millions of short DNA sequence reads together with previously published Sanger shotgun reads, have vastly greater long-range continuity and far fewer gaps than the previously available genome sequences. New gene predictions defined a set of 5261 protein-coding orthologs across the five most commonly studied Saccharomyces yeasts, enabling a re-examination of the tempo and mode of yeast gene evolution and improved inferences of species-specific gains and losses. To facilitate experimental investigations, we generated genetically marked, stable haploid strains for all three of these Saccharomyces species. These nearly complete genome sequences and the collection of genetically marked strains provide a valuable toolset for comparative studies of gene function, metabolism, and evolution, and render Saccharomyces sensu stricto the most experimentally tractable model genus. These resources are freely available and accessible through www.SaccharomycesSensuStricto.org