Infection potential of vegetative incompatible Ganoderma boninense isolates with known ligninolytic enzyme production

Ganoderma boninense produces ligninolytic enzymes namely lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase to degrade the lignin composition in plant cell walls. The present study aimed to evaluate the infection potential of vegetative incompatible isolates of G. boninense in causing Basal Stem Rot (BSR) disease in oil palm through the production of ligninolytic enzymes. Vegetative incompatibility test was carried out to test the antagonistic relationship of G. boninense isolates. G. boninense isolates with strong antagonistic reaction were selected for ligninolytic enzymes analyses. In vitro infection of oil palm seedlings and downstream analyses were then carried out. Control experiment was carried out with GBLS, a known G. boninense isolate. From this study, G. boninense isolates a1 and h2 showed the highest laccase (43.07 and 40.44 Ul-1) and MnP (14.80 and 16.21 Ul-1) enzymes production. Oil palm seedlings infected by isolates a1 and h2 resulted in relatively high percentage of disease severity index (DSI) (42.50 and 56.25% respectively). GBLS had lower laccase and MnP enzyme activities (24.31 and 9.27 Ul-1 respectively) and obtained the lowest DSI value (29.55%). Overall, a direct relationship was observed between the production of ligninolytic enzymes and the infection potential in vegetative incompatible G. boninense isolates.   Key words: Oil palm, Basal Stem Rot (BSR), vegetative incompatible, ligninolytic enzymes, in vitro infection.