INDUCTION OF DEFENSE RELATED ENZYMES AND PHENOLS TED ENZYMES AND PHENOLS IN GERBERA J GERBERA JAMESONII AMESONII AMESONII BY BACILLUS SPP. AGAINST ROOT KNOT NEMATODE, MELOIDOGYNE INCOGNITA

Abstract

Bacillus spp. (BG42, BG37 and B4) isolates were identified as potential bacterial antagonists against Root Knot Nematode, Meloidogyne incognita based on hatching and mortality studies. These three isolates were screened for their ability to induce defense related enzymes like peroxidase, polyphenoloxidase, phenylalanine ammonialyase, super oxide dismutase and phenols against M. incognita in gerbera plants of Valletta variety. Among the bacterial antagonists tested, liquid formulation of B. subtilis BG42 showed the higher activities of PO (2.93 change in OD min-1g-1 compared to control 1.23), PPO activity (1.22 change in OD min-1g-1 compared to control 0.76), PAL (5.49 change in OD min-1g-1 compared to control 3.23) and total phenols (3.43 ìg mg-1 compared to control 1.57) after 7 days of application in gerbera plants inoculated with M. incognita. Native PAGE analysis revealed that liquid formulation of B. subtilis BG42 treated gerbera roots showed three isoforms indicating the higher induction of SOD. The other treatments showed similar trend but the enzyme activities and SOD content were less compared to liquid formulation of B. subtilis BG42. These results indicated that the liquid formulation of B. subtilis BG42 was capable of inducing systemic resistance against M. incognita by accumulation of defence enzymes and phenols.