Pseudophomins A–D Produced from <i>Pseudomonas</i> sp. HN8-3 Using an OSMAC Approach and Their Roles in Biocontrol of <i>Phytophthora capsici</i> in Cucumbers
Zongwang Ma, Jun Sheng
Abstract
In this study, two new cyclic lipopeptides (CLPs) pseudophomins C ( 3 ) and D ( 4 ) and two known CLPs pseudophomins A ( 1 ) and B ( 2 ) were produced and characterized from the bacterial supernatant of Pseudomonas sp. HN8-3 by an OSMAC (one strain-many compounds) approach. OSMAC is a strategy that involves feeding of a single microorganism with divergent substrates to stimulate the production of new secondary metabolites. These pseudophomins were purified and identified via chromatographic methods, droplet collapse assay, genome mining, spectroscopic and spectrometric analyses, and single-crystal X-ray diffraction (XRD). Moreover, bioactivity tests showed that pseudophomins could lyse the zoospores of Phytophthora capsici in vitro, and coapplication of pseudophomins with zoospores of P. capsici further reduced the incidence of P. capsici on cucumber leaves. Collectively, these results indicated that pseudophomins have the potential to be developed as biopesticides for controlling P. capsici in cucumber.