INVESTIGATIONS ON THE ACTIVITY OF CELL WALL-DEGRADING ENZYMES IN YOUNG WHEAT PLANTS AFTER INFECTION WITH PSEUDOCERCOSPORELLA-HERPOTRICHOIDES (FRON) DEIGHTON

In earlier investigations, it has been demonstrated that Pseudocercosp orella herpotrichoides (Fron) Deighton is capable of producing pectoly tic and cellulolytic enzymes as well as hemicellulases in vitro. The i nvestigation of enzyme activity in extracts from wheat plants infected with P. herpotrichoides (isolates 21e and R6) and from non-infected p lants revealed the activity of the following enzymes: pectin methylest erase (PME), polymethylgalacturonase (PMG), pectin lyase (PL), carboxy methyl-cellulase (CMCase), xylanase and arabanase. Compared to non-inf ected plants, the enzyme activity in infected plants was considerably higher; in some experiments, only traces of enzyme activity could be f ound in control plants. The difference in the enzyme activity in infec ted as compared to non-infected plants was, in most cases, statistical ly significant, especially beginning at the end of the second week aft er inoculation. The enzyme activity depended on the temperature during plant cultivation; with the exception of pectin methylesterase (PME), the activity of all investigated enzymes increased with temperature a nd the highest activity was found in plants grown at 20 degrees C. The highest PME activity was measured in plants grown at 10 degrees C; th e activity of this enzyme was generally lower at 15 and 20 degrees C.