TY - JOUR

T1 - Solanimycin

T2 - Biosynthesis and Distribution of a New Antifungal Antibiotic Regulated by Two Quorum-Sensing Systems

AU - Matilla, Miguel A.

AU - Monson, Rita E.

AU - Murphy, Annabel

AU - Schicketanz, Muriel

AU - Rawlinson, Alison

AU - Duncan, Caia

AU - Mata, Juan

AU - Leeper, Finian

AU - Salmond, George P. C.

PY - 2022

Y1 - 2022

N2 - The increasing emergence of drug-resistant fungal infections has necessitated a search for new compounds capable of combating fungal pathogens of plants, animals, and humans. Microorganisms represent the main source of antibiotics with applicability in agriculture and in the clinic, but many aspects of their metabolic potential remain to be explored. This report describes the discovery and characterization of a new antifungal compound, solanimycin, produced by a hybrid polyketide/nonribosomal peptide (PKS/NRPS) system in Dickeya solani, the enterobacterial pathogen of potato. Solanimycin was active against a broad range of plant-pathogenic fungi of global economic concern and the human pathogen Candida albicans. The genomic cluster responsible for solanimycin production was defined and analyzed to identify the corresponding biosynthetic proteins, which include four multimodular PKS/NRPS proteins and several tailoring enzymes. Antifungal production in D. solani was enhanced in response to experimental conditions found in infected potato tubers and high-density fungal cultures. Solanimycin biosynthesis was cell density dependent in D. solani and was controlled by both the ExpIR acyl-homoserine lactone and Vfm quorum-sensing systems of the bacterial phytopathogen. The expression of the solanimycin cluster was also regulated at the post-transcriptional level, with the regulator RsmA playing a major role. The solanimycin biosynthetic cluster was conserved across phylogenetically distant bacterial genera, and multiple pieces of evidence support that the corresponding gene clusters were acquired by horizontal gene transfer. Given its potent broad-range antifungal properties, this study suggests that solanimycin and related molecules may have potential utility for agricultural and clinical exploitation.

AB - The increasing emergence of drug-resistant fungal infections has necessitated a search for new compounds capable of combating fungal pathogens of plants, animals, and humans. Microorganisms represent the main source of antibiotics with applicability in agriculture and in the clinic, but many aspects of their metabolic potential remain to be explored. This report describes the discovery and characterization of a new antifungal compound, solanimycin, produced by a hybrid polyketide/nonribosomal peptide (PKS/NRPS) system in Dickeya solani, the enterobacterial pathogen of potato. Solanimycin was active against a broad range of plant-pathogenic fungi of global economic concern and the human pathogen Candida albicans. The genomic cluster responsible for solanimycin production was defined and analyzed to identify the corresponding biosynthetic proteins, which include four multimodular PKS/NRPS proteins and several tailoring enzymes. Antifungal production in D. solani was enhanced in response to experimental conditions found in infected potato tubers and high-density fungal cultures. Solanimycin biosynthesis was cell density dependent in D. solani and was controlled by both the ExpIR acyl-homoserine lactone and Vfm quorum-sensing systems of the bacterial phytopathogen. The expression of the solanimycin cluster was also regulated at the post-transcriptional level, with the regulator RsmA playing a major role. The solanimycin biosynthetic cluster was conserved across phylogenetically distant bacterial genera, and multiple pieces of evidence support that the corresponding gene clusters were acquired by horizontal gene transfer. Given its potent broad-range antifungal properties, this study suggests that solanimycin and related molecules may have potential utility for agricultural and clinical exploitation.

KW - Dickeya solani

KW - acyl-homoserine lactone

KW - agriculture and global food security

KW - antibiotics

KW - antifungal agents

KW - gene regulation

KW - horizontal gene transfer

KW - hybrid polyketide

KW - nonribosomal peptide

KW - phytopathogens

KW - post-transcriptional control mechanisms

KW - quorum sensing

KW - secondary metabolism

KW - DICKEYA-SOLANI

KW - NATURAL-PRODUCTS

KW - SALMONELLA-TYPHIMURIUM

KW - STRUCTURAL DIVERSITY

KW - ERWINIA-CAROTOVORA

KW - EMERGING FUNGAL

KW - SOFT-ROT

KW - VIRULENCE

KW - PLANT

KW - POTATO

U2 - 10.1128/mbio.02472-22

DO - 10.1128/mbio.02472-22

M3 - Journal article

C2 - 36214559

VL - 13

JO - mBio

JF - mBio

SN - 2161-2129

IS - 6

ER -