Farnesol and Candida albicans: quorum sensing or not quorum sensing?

Quorum sensing (QS) molecules function within communities of single-cell organisms to allow concerted behavior in response to changing conditions, and certain criteria have been established to determine whether a particular molecule is quorum sensing or not. Farnesol has been identified as a secreted molecule responsible for the inoculum size effect in Candida albicans and synthetic farnesol has been used as a QS molecule in different studies. However, farnesol also exhibits growth inhibitory effects, and so a critical evaluation of farnesol is warranted. Here we review the literature to determine whether or not farnesol can indeed be considered a QS molecule in C. albicans.