BRAZILIAN ARCHIVES OF BIOLOGY AND TECHNOLOGY, cilt.66, ss.1-10, 2023 (SCI-Expanded)
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 48th, 72nd
,
120th and 168th 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 72nd and 168th 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.