Profiling of secondary metabolites produced by Pseudomonas sp. isolate PY-122 and PY-142 as biocontrol agent againts fusarium wilt disease on chili.

Abstract

Fusarium wilt is an important disease on chili plants caused by the fungus Fusarium oxysporum. This study aims to determine the effectiveness of secondary metabolites from 2 Pseudomonad isolates in controlling Fusarium wilt in chili plants and their effect on chili plant growth. This research was conducted in two stages, namely in vitro, which was carried out in the plant health laboratory and greenhouse, Faculty of Agriculture, Universitas Pembangunan Nasional Veteran Jawa Timur, and in vivo which was carried out in chili plantations known to be endemic to Fusarium wilt in Menganti, Gresik. The research design used in this study was Completely Randomized Design for in vitro testing and Randomized Group Design for in vivo testing by testing 9 treatments repeated 3 times. The treatment tested was control, secondary metabolite application of Pseudomonas isolates PY-122 and PY-142 with concentrations of 20% 30%, 40% and 50%. The variables observed were inhibition of secondary metabolites on the growth of Fusarium fungus, disease incubation period, disease severity index, and plant growth. Sequencing results with 16rRNA gene markers for both Pseudomonas isolates showed similarities to Pseudomonas sp. The results showed that the treatment of secondary metabolite PY-142 with a concentration of 50% showed the highest consistent inhibition. In the greenhouse and field tests, the two isolates slowed down the disease incubation period and development compared to controls. In agronomical observations, the average plant height, number of leaves, root length, and appearance of the first flower on the treated plants were higher and more numerous than the control plants.