Disease suppression efficacy of Dysoxylum terpenoids against the bacterial sheath light pathogen, Xanthomonas oryzae pv. oryzae (Xoo) on susceptible rice (Oryza sativa L) through induced resistance through biocatalysis

The severe disease Xanthomonas oryzae pv. oryzae (Xoo) causes in rice plants is known as rice bacterial blight.As a result of the risks associated with the indiscriminate use of chemical pesticides, bio elicitors derived from plant sources may be sought after as superior and safer substitutes. Thus, the objective of the current study was to assess the potential of terpenes from Dysoxylum malabaricum (D. Meliaceae) leaf to promote plant defence and provide protection from Xoo. It was observed that D. malabaricum leaves contained eight major terpene compounds (DMT). The application of DMT induced defence enzyme synthesis (peroxidase, PO - polyphenol oxidase, PPO) and accumulation till 120 h post treatment and their levels increased further post infection of Xoo. Direct suppression of Xoo growth in-vitro evidently decreased disease incidence and severity offering effective disease control, consequently enhancing plant growth parameters and biomass. Overall, our study suggests that D. malabaricum terpenes have a significant role in preventing the growth of Xoo in rice plants, providing long-term plant protection.