Comparative genome structure of Basidiomycetes using Pleurotus ostreatus as a model.

RAMIREZ L., ; OMARINI A.,; PÉREZ G.,; SANTOYO F.,; PISABARRO G.

San Feliu de Guixols

Conferencia; First EMBO Conference on: Comparative Genomics of Eukaryotic Microorganisms.; 2009

EMBO

Basidiomycetes are members of a fungal phylum that include human (Cryptococcus) and plant (Ustilago) pathogens, wood saprophytes (Phanerochaete, Pleurotus, Postia), plant symbionts (Laccaria bicolour), among others. During most of their life cycle, the two nuclei of dikaryotic meiotically competent basidiomycetes remain independent, though coordinated, within the cell. This fact permits studying separately the two haplotypes present in an otherwise diploid organism. Our group has coordinated the production of a high quality assemblage of the whole genome of P. ostreatus. One of the haplotypes has been sequenced using classical technologies complemented with pair end BAC sequencing, and a sequence of 35 Mbp in which the 11 chromosomes of this species are grouped in corresponding scaffolds (N/L50 5/ 3.3) has been produced. The second haplotype is currently being independently assembled using a 454-Titanium produced sequence plus pair and BAC sequencing. The two independent assemblages will permit to analyze for first time the sinteny of the two haplotypes of a mature organism directly. Besides that, we are interested in understanding the ordering of genes on the chromosomes, studying the physical and sequence position of genes coding for enzymes involved in lignocellulose degradation (the main ecological role of P. ostreatus) as a model. We have observed a tendency to the grouping of genes coding for enzymes specific of the way used by this fungus to degrade lignin in the subtelomeric region of a chromosome highly variable in size.