Gene organization of the mating type regions in the ectomycorrhizal fungus Laccaria bicolor reveals distinct evolution between the two mating type loci

Seleccionado por: Chris

Niculita-Hirzel H, Labbé J, Kohler A et al. (2008) Gene organization of the mating type regions in the ectomycorrhizal fungus Laccaria bicolor reveals distinct evolution between the two mating type loci. New Phytologist, 180, 329–342.

Abstract
In natural conditions, basidiomycete ectomycorrhizal fungi such as Laccaria bicolor are typically in the dikaryotic state when forming symbioses with trees, meaning that two genetically different individuals have to fuse or 'mate'. Nevertheless, nothing is known about the molecular mechanisms of mating in these ecologically important fungi. Here, advantage was taken of the first sequenced genome of the ectomycorrhizal fungus, Laccaria bicolor, to determine the genes that govern the establishment of cell-type identity and orchestrate mating. The L. bicolor mating type loci were identified through genomic screening. The evolutionary history of the genomic regions that contained them was determined by genome-wide comparison of L. bicolor sequences with those of known tetrapolar and bipolar basidiomycete species, and by phylogenetic reconstruction of gene family history. It is shown that the genes of the two mating type loci, A and B, are conserved across the Agaricales, but they are contained in regions of the genome with different evolutionary histories. The A locus is in a region where the gene order is under strong selection across the Agaricales. By contrast, the B locus is in a region where the gene order is likely under a low selection pressure but where gene duplication, translocation and transposon insertion are frequent.

Los hongos agaricales son sumamente específicos en el momento del apareamiento. Esto ocurre en los suelos con hifas primarias, ósea, monocarióticas. Para poder formar el micelio secundario, dicariótico, es necesario la unión de dos hifas primarias, y para que suceda el mating entre las hifas hay un show genetico tras esto. El articulo trata de los loci encargados del "mating" en Laccaria bicolor. Los autores intentan demostrar la ubicación de dichos loci, haciendo comparaciones con otros genomas de agaricales, expresión de genes y filogenia molecular.