Utilization of compost tea for biochemical response assessment associated with resistance to phytopathogen causing leaf spot in Melicope ptelefolia

Abstract

Compost teas were proved to be used as effective biocontrol agent owing to their ability to inhibit plant diseases. In this experiment, aerated compost tea (ACT) and molasses aerated compost tea (MACT) sourced from oil palm compost were assessed to suppress against fungal pathogen namely, Grammothele lineata (KX532185) that causes leaf spot on Melicope ptelefolia leaf. Characterization of both aerated compost teas for physiochemical and microbiological analysis was carried out. All different concentrations (15%, 25%, 30%, and 40% v/v) of ACT and MACT significantly retarded the mycelial growth of Grammothele lineata in the range of 14.5–77.8% and 12.7–75.9%, respectively. The highest inhibition over Grammothele lineata was obtained by both compost teas at concentration of 40% (v/v) resulted with 12% and 14% growth only, respectively. Peroxidase (PO) and polyphenol oxidase (PPO) activities peaked 2–4 days after Grammothele lineata fungal suspension (5 × 105 conidia/mL) challenged on fortified leaf disks. Besides, in Melicope ptelefolia leaf fortified with both compost teas, peroxidase (PO) reached the highest (245.05 IU min−1 g−1 fresh weight) after 7 days, whereas polyphenol oxidase (PPO) recorded the highest at 91.3 IU min−1 g−1 fresh weight after 4 days upon challenged by Grammothele lineata suspension (5 × 105 conidia/mL). Our result showed that the defense enzyme properties play a significant role in contributing disease resistance against phytopathogen attack.