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School of Life Sciences' Friday Seminar

"Adventures in Fungal Evolution from Genotype to Phenotype" - Speaker: Dr. Rachel Brem, Professor, Department of Plant and Microbial Biology, University of California, Berkeley ** Abstract: Understanding trait heterogeneity in the natural world is a fundamental goal of evolutionary genetics. Many phenotypes of biomedical relevance evolved long ago and are now fixed in a given species, distinguishing it from its relatives. Finding the mechanisms by which these ancient traits arose remains a key challenge for the field. Fungi, which despite their small genomes manifest a very diverse range of lifestyles, are a powerful system for studying how evolution builds traits over long timescales. I will describe projects in which my lab has discovered traits unique to fungal lineages from unusual niches, characterized them biologically, and pursued the underlying molecular mechanisms. With quantitative-genetic tools in wild single-celled Saccharomyces yeast, we mapped a suite of genes that govern thermotolerance differences between species. Using genomic analyses of the heat-loving filamentous fungus Thermothelomyces from compost, we dissected a regulatory network enabling exquisite control of germination (spore growth) at high temperature. In Coccidioides, a desert specialist fungus that causes the human disease Valley Fever, we uncovered molecular determinants of a unique spore form triggered by desiccation. And in Botryozyma, a fungus from galleries of tree-boring beetles, we found that it acts as a sexually transmitted disease of nematodes, adhering to the host’s reproductive organs and manipulating its behavior. As I cover these case studies, I will emphasize principles that emerge from them, including insights into heretofore unknown fungal biology, and the apparent paradox by which an evolutionary innovation can arise relatively quickly in fungi and yet require changes at genes all over the genome.

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School of Life Sciences, Mānoa Campus

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