Farnesol-induced apoptosis in Aspergillus nidulans reveals a possible mechanism for antagonistic interactions between fungi

Authors

Camile P. Semighini, University of Nebraska-Lincoln
Jacob M. Hornby, Lewis-Clark State CollegeFollow
Raluca Dumitru, University of Nebraska-Lincoln
Kenneth W. Nickerson, University of Nebraska-LincolnFollow
Steven D. Harris, University of Nebraska-LincolnFollow

Date of this Version

2-1-2006

Comments

Published in Molecular Microbiology 59:3 (February 2006), pp. 753-764; doi:10.1111/j.1365-2958.2005.04976.x Copyright © 2005 Camile P. Semighini, Jacob M. Hornby, Raluca Dumitru, Kenneth W. Nickerson, and Steven D. Harris; journal compilation copyright © 2005 Blackwell Publishing Ltd. Used by permission. http://www.blackwell-synergy.com

Abstract

The dimorphic fungus Candida albicans secretes farnesol, which acts as a quorum-sensing molecule and prevents the yeast to mycelium conversion. In this study we examined the effect of farnesol in the filamentous fungus Aspergillus nidulans. We show that externally added farnesol has no effect on hyphal morphogenesis; instead, it triggers morphological features characteristic of apoptosis. Additional experiments suggest that mitochondria and reactive oxygen species (ROS) participate in farnesol-induced apoptosis. Moreover, the effects of farnesol appear to be mediated by the FadA heterotrimeric G protein complex. Because A. nidulans does not secrete detectable amounts of farnesol, we propose that it responds to farnesol produced by other fungi. In agreement with this notion, growth and development were impaired in a farnesol- dependent manner when A. nidulans was co-cultivated with C. albicans. Taken together, our data suggest that farnesol, in addition to its quorum-sensing function that regulates morphogenesis, is also employed by C. albicans to reduce competition from other microbes.