Pseudophomins A–D Produced from Pseudomonas sp. HN8-3 Using an OSMAC Approach and Their Roles in Biocontrol of Phytophthora capsici in Cucumbers

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.

WLIP, WLIPβ, and WLIPγ Produced from Pseudomonas canadensis Q3–1 via Precursor-Directed Biosynthesis and Their Roles on Biocontrol of Phytophthora Blight in Peppers

“…HN8−3, while pseudophomins A and B were coproduced in such PDB of this strain. 2 Intriguingly, L-Leu, L-norvaline and L-cyclopropylalanine as precursors were inactive for PDB of the NRPS coding for WLIP in this study. Additionally, L-Leu, L-Val, and L-Ile as precursors were also inactive (Ma Z, unpublished data) for PDB on the NRPS encoding for CLP bananamide from Pseudomons sp.…”

“…PDB for the Production of CLPs. Previous reports have shown that the amendment of protein amino acids L-Leu, 2 L-Ile, 27 and L-Val, 28 and nonprotein amino acids L-2-aminobytyric acid, 29 L-norvaline, 29 and L-cyclopropylalanine 29 in bacterial cultures will lead to the specific incorporation of these amino acids in the final CLPs; thus, this procedure will generate new CLP derivatives possessing of the diversification on peptidic sequences. Hence, we have first used protein amino acids L-Leu, L-Ile, and L-Val (Figure 2A) as precursors in PDB experiments for P. canadensis Q3−1.…”

“…2 In most cases, the biocontrol capacity of these strains against Phytophthora capsici relies on their secondary metabolites secreted extracellularly. 2 CLPs produced by plant-beneficial microbes are among the well-studied secondary metabolites with biocontrol potentials. 3−5 CLPs produced by biocontrol-related Bacillus, Pseudomonas, and Streptomyces species include hundreds of families with varieties of peptidic backbones and the length (or saturation and branches) of the fatty acid tails.…”

“…As an alternative control strategy, the biocontrol capacity of plant-beneficial microbes against Phytophthora capsici has been widely studied during the last decades. To date, the reported biocontrol-related microbes used for the management of Phytophthora blight include Bacillus, Pseudomonas, Streptomyces spp . In most cases, the biocontrol capacity of these strains against Phytophthora capsici relies on their secondary metabolites secreted extracellularly …”

“…To date, the reported biocontrol-related microbes used for the management of Phytophthora blight include Bacillus, Pseudomonas, Streptomyces spp . In most cases, the biocontrol capacity of these strains against Phytophthora capsici relies on their secondary metabolites secreted extracellularly …”