The Molecular Genetics of Light-Sensing in Fungi

University Of Missouri-Kansas City, Columbia MO

Investigators

Abstract

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Light is a ubiquitous environmental signal that regulates many aspects of the behavior of organisms, including the majority of species of fungi. In the fungal kingdom light can influence the production of sexual or asexual spores, pigmentation, and the setting of a circadian clock, all of which are required for survival and success. Almost all of the estimated 1.5 million fungal species, with some notable exceptions, are thought to sense and respond to light. A conserved set of two proteins, known as White Collar 1 and White Collar 2 (WC-1 and WC-2, encoded by the madA and madB genes), are required for sensing blue and ultraviolet light in evolutionarily diverse fungi. Phycomyces blakesleeanus, a zygomycete filamentous fungus, is remarkable in having at least eight additional genes required for responding to light, in contrast to just the two white collar genes needed in other species. The identity of these eight mad genes is unknown, and in this research they will be sought through map-based cloning. The central hypothesis is that genes altered in mad mutants encode two classes of interacting proteins for the WC-1/WC-2 complex: (a) madC encodes a novel type of blue light photoreceptor and (b) madD-madJ encode regulators of, or targets for direct transcriptional regulation by, madA, madB and madC. A high-resolution genetic map of Phycomyces will be generated based on crosses between two wild type strains whose genomes have been sequenced. The map will be created using conventional markers combined with high-throughput analyses of single nucleotide polymorphism (SNP) markers on microarray chips. This genetic map will serve as the platform for mapping light-insensitive mad mutations and the identification of genes affected in the madC-madJ mutants. A complementary genome-wide screen will be performed for proteins that interact physically with the Phycomyces WC-1 and WC-2 proteins. This approach provides an independent method to identify genes that regulate fungal photobiology. Broader Impacts The PI places an emphasis on the importance of learning basic biology through research. The PI trains undergraduate and graduate students, including individuals from under-represented minority populations, at a campus in a city setting with many non-traditional undergraduate students. Undergraduate and high school students will participate in the proposed research. The research will advance ongoing programs to train students in scientific thinking using genetic and molecular biological approaches in a model organism that occupies an important place in the history of science.