Effects of Different Carbon Sources on Fumonisin Production and FUM Gene Expression by Fusarium proliferatum

Fusarium proliferatumcan infect many crops and then produce fumonisins that are very harmful to humans and animals. Previous study indicates that carbon sources play important roles in regulating the fumonisin biosynthesis. Unfortunately, there is limited information on the effects of carbon starvation in comparison with the carbon sources present in the host of fumonisin production inF. proliferatum. Our results indicated thatF. proliferatumcultivated in the Czapek’s broth (CB) medium in the absence of sucrose could greatly induce production of fumonisin, while an additional supplementation of sucrose to the culture medium significantly reduced the fumonisin production. Furthermore, cellulose and hemicellulose, and polysaccharide extracted from banana peel, which replaced sucrose as the carbon source, can reduce the production of fumonisin byF. proliferatum. Further work showed that these genes related to the synthesis of fumonisin, such asFUM1andFUM8, were significantly up-regulated in the culture medium in the absence of sucrose. Consistent with fumonisin production, the expressions ofFUMgene cluster andZFR1gene decreased after the addition of sucrose. Moreover, these genes were also significantly down-regulated in the presence of cellulose, hemicellulose or polysaccharide extracted from peel. Altogether, our results suggested that fumonisin production was regulated inF. proliferatumin response to different carbon source conditions, and this regulation might be mainly via the transcriptional level. Future work on these expressions of the fumonisin biosynthesis-related genes is needed to further clarify the response under different carbon conditions during the infection ofF. proliferatumon banana fruit hosts. The findings in this study will provide a new clue regarding the biological effect of the fumonisin production in response to environmental stress.Keywords:Fusarium proliferatum;fumonisin biosynthesis;carbon source;environmental stress;gene expressionKey Contribution:F. proliferatumcan produce fumonisins which are harmful to human health. This study aimed to explore the effect in the absence; followed by addition of carbon sources on fumonisin production; which will be beneficial for understanding the infection ofF. proliferatuminto banana fruit.