Antibacterial Radicicol Analogs from Pochonia chlamydosporia and Their Biosynthesis Gene Cluster

Chemical investigation of fungus Pochonia chlamydosporia strain 170, derived from rice fermentation sediment samples, afforded seven radicicol analogs, including two new compounds, monocillin Ⅵ (1) and monocillin Ⅶ (2), and five known compounds, monocillin Ⅱ (3), monorden D (4), monocillin Ⅳ (5), monocillin Ⅴ (6) and pochonin M (7). The structures of 1–7 were established primarily by analysis of nuclear magnetic resonance data, and the absolute configurations of the secondary alcohol in 1 and 2 were assigned by the modified Mosher method. All seven compounds have modest antibacterial activities, with a minimal inhibitory concentration (MIC) 25.6 µg/mL for compounds 1 and 3–7 and 51.2 µg/mL for compound 2, on inhibition of the growth of the plant pathogen Xanthomonas campestris (the positive control ampicillin showed a MIC value of 12.8 μg/mL), indicating that the fungus has the potential to control bacterial disease. The biosynthetic gene cluster and putative biosynthetic pathways of these radicicol analo...