Biosynthesis and Antimicrobial Activity of Pseudodesmin and Viscosinamide Cyclic Lipopeptides Produced by Pseudomonads Associated with the Cocoyam Rhizosphere

Abstract

Pseudomonas cyclic lipopeptides (CLPs) are encoded non-ribosomally by biosynthetic gene clusters (BGCs) and possess diverse biological activities. In this study, we conducted chemical structure and BGC analyses with antimicrobial activity assays for two CLPs produced by Pseudomonas strains isolated from the cocoyam rhizosphere in Cameroon and Nigeria. LC-MS and NMR analyses showed that the Pseudomonas sp. COR52 and A2W4.9 produce pseudodesmin and viscosinamide, respectively. These CLPs belong to the Viscosin group characterized by a nonapeptidic moiety with a 7-membered macrocycle. Similar to other Viscosin-group CLPs, the initiatory non-ribosomal peptide synthetase (NRPS) gene of the viscosinamide BGC is situated remotely from the other two NRPS genes. In contrast, the pseudodesmin genes are all clustered in a single genomic locus. Nano- to micromolar levels of pseudodesmin and viscosinamide led to the hyphal distortion and/or disintegration of Rhizoctonia solani AG2-2 and Pythium myriotylum CMR1, whereas similar levels of White Line-Inducing Principle (WLIP), another member of the Viscosin group, resulted in complete lysis of both soil-borne phytopathogens. In addition to the identification of the biosynthetic genes of these two CLPs and the demonstration of their interaction with soil-borne pathogens, this study provides further insights regarding evolutionary divergence within the Viscosin group.

The use of Pseudomonas spp. as bacterial biocontrol agents to control plant diseases

“…They play a role in swarming motility, biofilm formation, environmental adaptation, nutrient availability, root colonization and biocontrol (D'aes et al, 2010;Olorunleke et al, 2015b;Raaijmakers et al, 2010). Omoboye et al, 2019b;Oni et al, 2020a;Thrane et al, 2000;Tran et al, 2007…”

“…Specific strains within the P. fluorescens subgroup are known to produce CLPs that belong to the Viscosin group (viscosin, massetolide, WLIP, viscosinamide) (Oni et al, 2020a). Well-studied strains in this aspect include the massetolide producer P. fluorescens (lactis) SS101 and the viscosin-producer P. fluorescens SBW25.…”

“…Production of CLPs is a common feature and include WLIP (Oni et al, 2020a(Oni et al, , 2019bRokni-Zadeh et al, 2013), xantholysin (Li et al, 2013a,b;Oni et al, 2019b), entolysin (Oni et al, 2020b;Vallet-Gely et al, 2010) and putisolvin (Kuiper et al, 2003;Oni et al, 2020bOni et al, , 2019b. WLIP and entolysin can induce systemic resistance to Pyricularia oryzae in rice (Omoboye et al, 2019b).…”

Structural Revision of Natural Cyclic Depsipeptide MA026 Established by Total Synthesis and Biosynthetic Gene Cluster Analysis

“…Pseudomonas spp. have also been reported to produce many other cyclic lipodepsipeptides with diverse biological activities (Supporting Information, Table S1) [3–7] . Among them, a 14‐mer cyclic depsipeptide, xantholysin A (Figure 1), which is an anti‐microbial product isolated in 2013 from Pseudomonas putida BW11M1 by Li et al [3] .…”

“…have also been reported to produce many other cyclic lipodepsipeptides with diverse biological activities (Supporting Information, Table S1). [3][4][5][6][7] Among them, a 14-mer cyclic depsipeptide, xantholysin A (Figure 1), which is an anti-microbial product Figure 1. Reported (1) [2,9] and revised (2) structures of MA026 and the structure of xantholysin A.…”