Induction of systemic resistance by mixtures of fungal and endophytic bacterial isolates against <Emphasis Type="Italic">Pythium aphanidermatum</Emphasis>

The efficacy of eight fungal and ten endophytic bacterial isolates were tested for their ability to inhibit the growth of Pythium aphanidermatum, the causal agent of chilli damping-off. In vitro studies revealed that Trichoderma viride (TVA) and endophytic Pseudomonas fluorescens (EBL 20-PF) showed the highest inhibition of mycelial growth (71.5%; 76.7%) of P. aphanidermatum. Both the antagonists were compatible with each other and they were tested alone and together in vivo for the control of P. aphanidermatum. Besides, the induction of defense-related enzymes such as peroxidase (PO), polyphenoloxidase (PPO), phenylalanine ammonia-lyase (PAL), PR-protein like β-1, 3-glucanase and the accumulation of phenolics in chilli seedlings due to the application of bioagents were also studied. Combined application of talc-based formulation of bio-agents and challenge inoculated with P. aphanidermatum recorded maximum induction of defense-related enzymes, PR-proteins and accumulation of phenolics compared with individual application. This study suggest that the increased induction of defense-related enzymes (four to fivefold) and phenolic content (sixfold) due to the combination treatment of bioagents might have involved in the reduction of damping-off incidence and in turn increased the plant growth and yield of chilli.