EVIDENCE FOR CUTINASE PRODUCTION BY ASPERGILLUS-FLAVUS AND ITS POSSIBLE ROLE IN INFECTION OF CORN KERNELS

Aspergillus flavus can infect nondamaged corn kernels and produce afla toxins before harvest. Experiments were conducted to determine if A. f lavus produces cutinase and, if so, to investigate its possible role i n kernel infection. Plate assays in vitro showed that A. flavus can gr ow on purified cutin as the sole carbon source and that it secretes ex tracellular cutinase. A. flavus grew better in Liquid culture at pH 8 than at pH 6. Most cutinase substrate (p-nitrophenyl butyrate [PNB]) h ydrolysis activity was in the 30% ammonium sulfate fraction. Two prote ins with different PNB hydrolysis activity, designated C-1 and C-2, we re isolated from A, flavus culture filtrates using native polyacrylami de gel electrophoresis.