Thigmotropism and stretch-activated channels in the pathogenic fungus Candida albicans

1 Department of Molecular & Cell Biology, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZN, UK 2 Plant Laboratory, University of York, PO Box 373, York Y01 5YW, UK ABSTRACT The direction of growth of hyphae of the pathogenic fungus Candida albicans responds thigmotropically to surface contours by following scratches, ridges and grooves and by penetrating pores. Here it is shown that the thigmotropic response to ridges is attenuated by GdCl 3 and verapamil [blockers of stretch-activated (SA) ion channels and L-type calcium channels, respectively]. At low concentrations, both compounds reduced the percentage of hyphae reorienting on contact with a ridge without markedly affecting hyphal extension rate, suggesting a possible role for SA or other calcium channels in the transduction of the thigmotropic response. In addition, patch-clamp recordings demonstrated SA channel activity in the plasma membrane of both yeast and hyphal cells of C. albicans. Two distinct SA channels with conductances of 54 pS and 20-25 pS in 200 mM KCI were observed in protoplasts from yeast cells and one channel of 51 pS was found in protoplasts from hyphal cells. Author for correspondence: N. A. R. Gow. Tel: +44 1224 273179. Fax: +44 1224 273144. e-mail: n.gow@abdn.ac.uk Keywords: Candida albicans, thigmotropism, stretch-activated channels Present address: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.