Molecular Analysis of the Genes Responsible for Catalysing Intracellular Steps of Aurofusarin Biosynthesis in Fusarium culmorum

Abstract

Fusarium culmorum produces polyketide-structured aurofusarin and its precursor metabolites. Aurofusarin biosynthetic pathway is catalysed by the products of eleven genes located in gene cluster. In this study, the effects of the expression levels of Pks12, Gip6, and Gip7, responsible genes for the intracellular steps of the pathway, on pigmentation were investigated in an F. culmorum field isolate. Presence of three genes were determined via PCR and sequencing. Their expressions were investigated by qPCR at 48 th , 72 nd , 120 th and 168 th hours. Aurofusarin and rubrofusarin production were verified by HPLC at the same time periods. Mycelial pigmentation, which was initially white, turned yellow, then carmine red during the sevenday culture. Pks12, Gip6, Gip7 genes with 1282, 449 and 1278 bps had sequence similarities (86,6%, 99,4% and 80,5% respectively) with the genes of reference (FcUK99). The ΣCp values of all genes ranged from 29th to 32nd cycles, whereas the ΣΔΔCt values were calculated between 9,59 E-02 and 1,30 E-02. Relative quantification revealed these genes were controlled by down-regulation compared to the β-tubulin expression. Aurofusarin quantities ranged from 2,355 ppm to 27,350 ppm between the 72 nd and 168 th hours whereas the yield of rubrofusarin decreased from 0,098 ppm to 0,063 ppm. ( 4) Conclusion: This study becomes first report for both investigating the expression levels of the genes responsible for the catalysis of intracellular steps of aurofusarin biosynthesis in F. culmorum, and for examining the relationship between gene expression and mycelium pigmentation. HIGHLIGHTS• Molecular analysis of aurofusarin biosynthesis in F. culmorum.• Mycelial pigmentation depending on gene expression and aurofusarin accumulation.• Pigmentation variations depending on growth phase.

Trichoderma atroviride suppresses Fusarium graminearum by altering primary and secondary metabolite biosynthesis profiling

“…These transcriptomic changes were supported by the Petri dish profiling of the FGvsTA set (Figure 2). It is clear that the lifecycle of F. graminearum was disrupted by T. atroviride because aurofusarin and its precursors are primarily responsible for the pigmentation and antifungal effects of F. graminearum (Frandsen et al, 2006;Gaffoor et al, 2005;Gazdağlı et al, 2023). Additionally, killer toxin genes (FGSG_10551, FGSG_00061, FGSG_00060 and FGSG_00062) exhibited downregulation or no expression in the FGvsTA set in contrast to the previous report including dual culture tests in F. graminearum (Zapparata et al, 2021).…”

“…Overall, at least 15 nonribosomal peptide synthase and polyketide synthase genes were up-regulated, representing a sign of the F. graminearum survival strategy (Table 2). Among these genes, nrps and pks genes could be associated with more than one secondary metabolite production in phytopathogenic fungi (Frandsen et al, 2006;Gaffoor et al, 2005;Gazdağlı et al, 2023;Ma et al, 2013). Even if the majority of these nrps and pks genes were associated with the precise pathways, up-regulated genes (such as FGSG_11026, FGSG_02394, FGSG_09182 and FGSG_04694;…”

“…graminearum survival strategy (Table 2). Among these genes, nrps and pks genes could be associated with more than one secondary metabolite production in phytopathogenic fungi (Frandsen et al, 2006; Gaffoor et al, 2005; Gazdağlı et al, 2023; Ma et al, 2013). Even if the majority of these nrps and pks genes were associated with the precise pathways, up‐regulated genes (such as FGSG_11026, FGSG_02394, FGSG_09182 and FGSG_04694; Table 2) in the FGvsTA experimental set should be used in further studies in evaluating the pathogenomics and pathotranscriptomics in Fusarium .…”

“…atroviride because aurofusarin and its precursors are primarily responsible for the pigmentation and antifungal effects of F . graminearum (Frandsen et al, 2006; Gaffoor et al, 2005; Gazdağlı et al, 2023). Additionally, killer toxin genes (FGSG_10551, FGSG_00061, FGSG_00060 and FGSG_00062) exhibited down‐regulation or no expression in the FGvsTA set in contrast to the previous report including dual culture tests in F .…”