BIOCHEMICAL-STUDIES ON THE CELL-WALL DEGRADATION OF FUSARIUM-OXYSPORUM F SP LYCOPERSICI RACE 2 BY LYTIC ENZYMES FROM MUCORALES FOR ITS BIOCONTROL

The lysis of cell wall, cell wall fractions (F1S-alkali and water soluble, F1I-alkali soluble and water insoluble, and F4-beta-chitin-glucan) and chlamydospores of Fusarium oxysporum f.sp. lycopersici race 2 (Fol2) with crude enzyme preparations from Mucorales (Absidia californica, Mortierella vinacea, Mucor hiemalis, Phycomyces blakesleeanus, Rhizopus stolonifer and Syncephalastrum racemosum) has been studied during an incubation period of 72 h. The lysis of the F1S fraction and chlamydospores was followed by the release of reducing substances. The lysis of the other fractions and cell walls was followed by percentage of decrease in optical density (lysis degree) and release of reducing substances. A correlation between the degradation of cell walls and cell wall fractions was observed. The soluble fraction was the most resistant to lysis by these enzymes, with the highest release of reducing substances at 4% of the material as glucose equivalent using the crude enzyme preparation from Mucor hiemalis. Crude enzyme preparations from Rhizopus stolonifer produced the highest lysis (33.4%) and release of reducing substances (22.1%) from the Fol2 cell wall. The enzymes from M. hiemalis produced the highest degradation of chlamydospores. A possible biological control of Fol2 with lyric enzymes from R. stolonifer or M. hiemalis is indicated.