Analysis of fluG Mutations That Affect Light-Dependent Conidiation in Aspergillus nidulans

Corresponding author: Lawrence N. Yager, Temple University, Department of Biology, 1900 N. 12th St., Philadelphia, PA 19122-6078., lyager{at}thunder.ocis.temple.edu (E-mail).

Communicating editor: J. J. LOROS

Conidiation in Aspergillus nidulans is induced by exposure to red light but can also be induced by blue light in certain mutant strains. We have isolated a mutation in the fluG gene that abolishes responsiveness to red light but does not affect the response to blue light. It has been shown that the veA1 (velvet) mutation allows conidiation to occur in the absence of light. We have identified three other fluG mutations that suppress the veA1 phenotype; these double mutants do not conidiate in the dark. The mutations described here define two new phenotypic classes of fluG alleles that display abnormal responses to light. We have characterized these mutations with respect to their molecular identity and to their effect on fluG transcription. Although it has been shown that fluG is required for the synthesis of an extracellular factor that directs conidiation, we do not detect this factor under conditions that promote conidiation in the veA1 suppressors. Furthermore, extracellular rescue is not observed in fluG deletion strains containing the wild-type veA allele. We propose that a genetic interaction between fluG and veA influences the production of the extracellular signal and regulates the initiation of conidiation.

This article has been cited by other articles:

				Y. Liu and D. Bell-Pedersen Circadian Rhythms in Neurospora crassa and Other Filamentous Fungi. Eukaryot. Cell, August 1, 2006; 5(8): 1184 - 1193. [Full Text] [PDF]

				A. C. Froehlich, B. Noh, R. D. Vierstra, J. Loros, and J. C. Dunlap Genetic and Molecular Analysis of Phytochromes from the Filamentous Fungus Neurospora crassa Eukaryot. Cell, December 1, 2005; 4(12): 2140 - 2152. [Abstract] [Full Text] [PDF]

				S. Zeilinger, B. Reithner, V. Scala, I. Peissl, M. Lorito, and R. L. Mach Signal Transduction by Tga3, a Novel G Protein {alpha} Subunit of Trichoderma atroviride Appl. Envir. Microbiol., March 1, 2005; 71(3): 1591 - 1597. [Abstract] [Full Text] [PDF]

				N. Kato, W. Brooks, and A. M. Calvo The Expression of Sterigmatocystin and Penicillin Genes in Aspergillus nidulans Is Controlled by veA, a Gene Required for Sexual Development Eukaryot. Cell, December 1, 2003; 2(6): 1178 - 1186. [Abstract] [Full Text] [PDF]

				A. V. Greene, N. Keller, H. Haas, and D. Bell-Pedersen A Circadian Oscillator in Aspergillus spp. Regulates Daily Development and Gene Expression Eukaryot. Cell, April 1, 2003; 2(2): 231 - 237. [Abstract] [Full Text] [PDF]

				J. A. Rollins and M. B. Dickman pH Signaling in Sclerotinia sclerotiorum: Identification of a pacC/RIM1 Homolog Appl. Envir. Microbiol., January 1, 2001; 67(1): 75 - 81. [Abstract] [Full Text]

				A. M. Calvo, L. L. Hinze, H. W. Gardner, and N. P. Keller Sporogenic Effect of Polyunsaturated Fatty Acids on Development of Aspergillus spp. Appl. Envir. Microbiol., August 1, 1999; 65(8): 3668 - 3673. [Abstract] [Full Text]