Transcriptome changes of fission yeast cells exposed to fumonisin B1 or co-cultured with Fusarium verticillioides.

Fusarium verticillioides poses a high food safety risk worldwide due to its mycotoxin production. Successful control of Fusaria may rely on promising biocontrol agents, including yeasts. Although the fission yeast Schizosaccharomyces pombe tolerated Fusarium mycotoxins well, including zearalenone, T2, deoxynivalenol, and fumonisins (FUMs), it did not significantly inhibit the growth of F. verticillioides. Meanwhile fumonisin B1 (FB1) supplementation did not decrease S. pombe cell density in submerged liquid cultures, the colony-forming capability of the yeast was reduced. RNA sequencing showed that S. pombe genes involved in cell adhesion and flocculation were downregulated after FB1 exposure. In addition, the expression of several hydrolase genes was also altered. In co-cultures with F. verticillioides, genes encoding oxidoreductases and hydrolases and those linked to purine nucleotide metabolisms were downregulated, while the expression of genes involved in membrane and transport processes was increased. The expression of several F. verticillioides genes also changed after co-cultivation. Oxidoreductase, transmembrane transport, and purine metabolism genes were upregulated under co-culturing; meanwhile, hydrolase genes, together with carbon metabolism and polysaccharide catabolism genes, were downregulated. Co-cultivation also decreased fumonisin production via the downregulation of genes FUM19, FUM21, and FvATFA encoding the fumonisin transporter, a local Zn(II)2Cys6-type transcriptional regulator and an important global regulator bZIP-type transcription factor, respectively. Although further experiments should clarify the mechanism of the fission yeast-elicited inhibition of fumonisin production, these results may pave the way for the development and implementation of novel, innovative approaches to control mycotoxin production by F. verticillioides in the feed and food chain. KEY POINTS: • 0.5 ppm FB1 reduced the colony-forming ability of S. pombe and caused transcriptional changes. • Expression of transport and hydrolase genes changed in yeast during co-cultivation with mold. • Two FUM cluster genes and FvATFA were downregulated in Fusarium co-cultured with S. pombe.