Cell wall degrading enzymes in Orobanche aegyptiaca and its host Brassica campestris

Activities of the cell-wall degrading enzymes cellulase (EC 3. 2. 1. 4). poly-galacturonase (EC 3. 2. 1. 15) and xylanase (EC 3. 2. 1. 8), and also that of protease (EC 3. 4. 21. 14) have been determined in the parasite Orobanche aegyiptiaca Pers. and in the roots of infected and control host plants of Brassica campestris L. var. rapa Hartm. Shoots, roots and root-freed tubers of Orobanche showed pronounced activities of these enzymes. When expressed in terms of specific activity, protease, cellulase and polygalacturonase activities were higher and xylanase lower in all parts of Orobanche than in the roots of infected or control host plants. Orobanche roots had higher activities of cellulase, polygalacturonase and protease than tuber or shoot. While xylanase activity was higher in the shoot than in roots or tuber. Infection by Orobanche significantly enhanced the cellulase activity of host roots. Cellulase and polygalacturonase in the Orobanche roots appear as the main enzymes involved in establishing haustorial connection with the host root. Protease might be involved in degrading proteins and lipoproteins of the cell walls and membranes of the host tissues.