Education

Ph.D. Biochemistry (1988)
Purdue University

The diversity of fungi is apparent in the many types of specialized cells and forms of multicellular development described for this fascinating group of organisms. My group is interested in understanding how environmental cues are sensed to initiate development and how morphogenesis is regulated. Neurospora crassa is well known for the ease with which it can be genetically manipulated. Our interest in N. crassa is to examine multicellular development in a simple eukaryotic system. N. crassa produces asexual spores, called macroconidia. We have identified a gene of N. crassa, rco-3, that controls glucose-repression and conidiophore development. rco-3 appears to function as a glucose receptor/sensor to signal information about carbon availability into cells to regulate development. Characterization of this signaling pathway is one important objective.

The fluffy gene of N. crassa is required for the switch from filamentous to budding growth during conidiophore morphogenesis. fluffy encodes a Zn-finger transcription factor similar to pathway-specific regulators of primary and secondary metabolism. Characterization of the role of fluffy during conidiophore development is a continuing effort. A related interest is to compare the regulatory genes for conidiation in N. crassa and other fungi, including plant pathogens, to examine the evolution of regulatory pathways governing development. fluffy is a regulator of a number of genes that are induced during conidiation. con-10 is one such gene that we have examined in some detail. con-10 encodes a stress response protein that has homologues in bacteria, other fungi, and plants. con-10 is regulated during macroconidiation, microconidiation (another form of asexual sporulation) and sexual development. In addition, con-10 is subject to cell-type specific repression, and is regulated by carbon, nitrogen, heat shock, light and the circadian clock. As we examine regulators, such as fluffy, we hope to continue to examine the complex promoter structure of con-10.

Another remarkable form of development at the level of a single cell is the formation of the appressorium of the rice blast fungus, Magnaporthe grisea. The appressorium is an infection structure that is required for physical penetration of the plant host. M. grisea has sophisticated mechanisms to sense the presence of a potential host and we have examined the role of a hydrophobin of M. grisea in surface sensing. In our examination of appressorium formation we discovered peptides that inhibit appressorium formation. We are investigating the mechanisms for bioactivity of these peptides.

• Ebbole, D.J. 1998. Carbon catabolite repression of gene expression and conidiation in Neurospora crassa. Fungal Genet. & Biol. 25:15-21.



• Lee, K. and D.J. Ebbole. 1998. Tissue-specific repression of starvation and stress responses of the Neurospora crassa con-10 gene is mediated by RCO1. Fungal Genet. & Biol. 23:259-278.



• Bailey, L.A. and D.J. Ebbole. 1998. The fluffy gene of Neurospora crassa encodes a Gal4p-type C6 zinc cluster protein required for conidial development. Genetics 148: 1813-1820.



• Shen, W-C., J. Wieser, T.H. Adams, and D.J. Ebbole. 1998 The Neurospora rca-1 gene complements an Aspergillus flbD sporulation mutant but has no identifiable role in Neurospora sporulation. Genetics 148:1031-1041.



• Madi, L., S.A. McBride, L.A. Bailey and D.J. Ebbole. 1997. rco-3, a gene involved in glucose transport and conidiation in Neurospora crassa. Genetics 146:499-508.