Integrated Management of Bacterial Wilt and Root-Knot Nematode Diseases in Pepper: Discovery of Phenazine-1-Carboxamide from W-126.

is an important pathogen causing bacterial wilt in pepper ( L.). The concurrent infection of and root-knot nematodes spp.) exacerbates the severity of bacterial wilt in pepper. Utilizing plant endophytic bacteria to control these mixed diseases is a viable strategy. L. (Sterculiaceae) is a traditional medicine plant. A total of 209 endophytic bacteria were isolated from , and W-126 showed an efficient antagonistic effect against . Based on active compound tracking principles, a compound was isolated through silica gel column chromatography and preparative HPLC combined with TLC analysis. It was identified as phenazine-1-carboxamide (PCN) by spectral techniques (ESI-MS, H-NMR, C-NMR). PCN displayed excellent inhibitory activity against , with an EC of 64.16 μg/mL in vitro. In addition, it showed certain nematocide activity, with an LC value of 118.63 μg/mL at 72 h. PCN also showed certain inhibitory activity against five other phytopathogenic bacteria. The structure-activity relationship indicated that the phenazine skeleton and acylamide groups were the key pharmacophores for the activity of phenazine-related compounds against . PCN controlled the complex diseases of and in a pot experiment, with respective 51.41 and 39.80% inhibitory rates. The exploration of secondary metabolites of biocontrol bacteria can provide reference for the development of novel and efficient pesticides.