HCF-1, A HYDROPHOBIN FROM THE TOMATO PATHOGEN CLADOSPORIUM-FULVUM

A hydrophobin, named HCF-1, was isolated from the culture medium of Cl adosporium fulvum, the causal agent of tomato leaf mould. The protein forms insoluble aggregates when the medium is vigorously aerated. Thes e aggregates can be dissociated by trifluoroacetic acid into monomers which migrate as 10-kDa molecules on SDS-PAGE. HCf-1 is encoded by a s ingle gene, HCf-1 1. The gene contains two small introns and is transl ated into a 105-amino acid protein which is then processed to give a m ature 83-amino acid protein. The position of the eight cysteine residu es and the predicted hydrophobicity profile are typical of fungal hydr ophobins. HCf-1 RNA is expressed in growing mycelium and conidia but i ts quantity diminishes transiently after germination; its abundance do es not change when the fungus is grown on nitrogen- or carbon-deficien t medium. This is the first step in evaluating the role of hydrophobin s in establishment of basic compatibility between C. fulvum and tomato . (C) 1997 Elsevier Science B.V.