Isolation and Structure Elucidation of Fujikurins A–D: Products of the PKS19 Gene Cluster in Fusarium fujikuroi

Abstract

Fusarium fujikuroi is a member of the Gibberella fujikuroi species complex and well known for the production of gibberellins and mycotoxins including fusarins and fusaric acid. A recent genome sequencing study revealed that the fungus has the genetic potential to produce many more secondary metabolites than have been reported. This paper describes the structure elucidation of the products of the cryptic and silent PKS19 gene cluster that were recently identified (fujikurins A-D). We present the complete NMR data for the structure elucidation of the main compound fujikurin D, which shows tautomeric 1,3-diketo elements. The different tautomeric structures could be confirmed using quantum chemical calculations. Additionally, the structures of the minor compounds fujikurins A-C were elucidated by high-resolution mass spectrometric fragmentation experiments. It emerged that fujikurin A was identical to the bioactive compound CR377 of the taxonomically unclassified Fusarium strain CR377, while fujikurins B-D have not been reported from other fungi.

Comparative “Omics” of theFusarium fujikuroiSpecies Complex Highlights Differences in Genetic Potential and Metabolite Synthesis

“…Previous functional analyses in F. fujikuroi indicated that PKS19 and five genes flanking it constitute an SM gene cluster responsible for synthesis of fujikurin (Wiemann et al 2013; von Bargen et al 2015). Comparative analyses in the current study indicate that the fujikurin cluster is present in F. fujikuroi and both F. proliferatum strains but absent in F. mangiferae , F. verticillioides , and F. oxysporum (fig.…”

“…Although a majority of the putative SM gene clusters occur in other FFC species, some appear to be unique to a single species or even a single isolate of one species. For example, the NRPS31 cluster which is responsible for apicidin F biosynthesis (Wiemann et al 2013; Niehaus et al 2014a; von Bargen et al 2015) is unique to F. fujikuroi. However, novel F. fujikuroi genome sequences showed that this cluster is not present in all strains of this species (Chiara et al 2015).…”

Lack of the COMPASS Component Ccl1 Reduces H3K4 Trimethylation Levels and Affects Transcription of Secondary Metabolite Genes in Two Plant–Pathogenic Fusarium Species

“…Several additional SMs have been characterized in both fungi over the last years. Those include distinct SMs produced by only one of the two fusaria such as fusaric acid (FSA), fumonisins, fujikurins, or apicidin F produced by F. fujikuroi (von Bargen et al, 2013, 2015; Niehaus et al, 2014a; Rösler et al, 2016), and zearalenone (ZON), fusarielins, culmorin, or butenolide produced by F. graminearum (Hansen et al, 2012; Sørensen et al, 2012). There are also common SMs, such as the fusarins (FUS), a family of structurally related polyketide mycotoxins (Gelderblom et al, 1984; Díaz-Sánchez et al, 2012; Niehaus et al, 2013), and some non-ribosomal peptide synthetase (NRPS)-derived siderophores (Hansen et al, 2015).…”

Establishment of the Inducible Tet-On System for the Activation of the Silent Trichosetin Gene Cluster in Fusarium fujikuroi

“…The chlorosis and hyper-elongation of plant internodes characteristic of this disease occur due to the production of the phytohormone gibberellic acid by F. fujikuroi [4,5]. F. fujikuroi can also synthesize a variety of other secondary metabolites (SMs) including the polyketide synthase (PKS)-derived bikaverin, fusarubins, fujikurins, fumonisins, and gibepyrones [6,7,8,9,10,11]; the non-ribosomal peptide synthetase (NRPS)-derived apicidin F and beauvericin [12,13]; the PKS-NRPS- or PKS and NRPS-derived fusarins and fusaric acid [14,15,16]; as well as the terpene cyclase-derived (+)-eremophilene, (−)-α-acorenol, (−)-guaia-6,10(14)-diene and (+)-koraiol [17,18]. In addition, F. fujikuroi has the genetic potential to synthesize at least 31 more SMs based on the presence of core SM genes and analysis of flanking genes [19].…”