Research Areas

• Heterotrimeric G Proteins  

Heterotrimeric (αβγ) G proteins control major signal transduction pathways in eukaryotes. Their importance is underscored by the fact that more than 30% of pharmaceutical drugs target G protein signaling pathways. My laboratory discovered heterotrimeric G proteins in filamentous fungi, using the model organism Neurospora crassa. My group has now characterized the myriad functions and physical interactions between three Gα, one Gβ and one Gγ proteins in Neurospora. Since our original discovery, Gα proteins have been implicated in pathogenesis in numerous plant and animal fungal pathogens. Therefore, our work is relevant to development of new infection control practices and identification of targets for chemical agents to combat fungal diseases in plants and animals.

Current research in the laboratory is focused on two projects:

1) The requirement for G Protein Coupled Receptors (GPCRs) and G proteins in sensing and regulation of the plant cell wall. This work is relevant to carbon turnover in the environment, plant pathogenesis and second generation biofuels.

2) Control of asexual development and amino acid metabolism by the Resistance to Inhibitors of Cholinesterase-8 (ric8) gene. RIC8 is a non-receptor Guanine Nucleotide Exchange Factor (GEF) that regulates GDP-GTP exchange and stability of Gα subunits in N. crassa.

• Functional Genomics and Systems Biology of Fungi

Neurospora is the NIH model organism for the filamentous fungi, the group of organisms most closely related to animals and which includes important pathogens of animals and plants. I was heavily involved in the effort to sequence and annotate the Neurospora genome. My laboratory was a major player in the genome-wide targeted gene replacement project that successfully mutated nearly all of the nearly 10,000 genes. We have also completed large-scale analysis of mutants for Neurospora serine/threonine protein phosphatase and kinase genes, transcription factors and G protein coupled receptors. Notably, much of the functional analysis of these large gene families has been performed by undergraduate students in the capstone course for the Microbiology major, Experimental Microbiology (MCBL125).

• Fungal Pathogenesis

Members of the Fusarium oxysporum species complex are root pathogens of numerous crops of economic importance to the United States. Certain subspecies are also opportunistic human pathogens. My group annotated signaling genes in the genome of F. oxysporum f.sp. lycopersici, a fungal pathogen of tomato and animals. Production of small RNAs that target and down-regulate specific genes has been associated with infection by microorganisms in other plants. We have used next generation sequencing to identify small RNAs from F. oxsporum and tomato that are associated with the disease state.  Our results have revealed microRNAs that modulate the plant immune response. We are continuing our studies in F. oxysporum in collaboration with former Postdoc and now Professor Shouqiang Ouyang at Yangzhou University in China.