The Pichia fermentans strain DISAABA 726 is a biofilm-forming yeast that has been proposed as biocontrol agent to control brown rot (Monilia spp.) on apple fruit. However, when inoculated on peach fruit, strain 726 shows yeast-like to pseudohyphal morphological transition coupled to a pathogenic behaviour. To identify the proteins potentially involved in the transition process, P. fermentans 726 proteome was analysed using two-dimensional gel electrophoresis (2-DE) coupled with mass spectrometry analysis.