Skip to main content
ARS Home » Midwest Area » West Lafayette, Indiana » Crop Production and Pest Control Research » Research » Publications at this Location » Publication #214846
Title: Involvement of ZFR1 of Fusarium verticilliodes in kernel colonization and the regulation of FST1, a putative sugar transporter gene required for fumonisin biosynthesis on maize kernels

Author
item Bluhm, Burton
item KIM, H - PURDUE UNIV.
item Butchko, Robert
item WOLOSHUK, C - PURDUE UNIV.

Submitted to: Molecular Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2008
Publication Date: 3/1/2008
Citation: Bluhm, B., Kim, H., Butchko, R.A., Woloshuk, C.P. 2008. Involvement of ZFR1 of Fusarium verticilliodes in kernel colonization and the regulation of FST1, a putative sugar transporter gene required for fumonisin biosynthesis on maize kernels. Molecular Plant Pathology. 9(2):203-211.

Interpretive Summary: The fungus Fusarium verticillioides can cause diseases on corn and in doing so can contaminate the corn kernels with toxic chemicals called mycotoxins. In an effort to reduce or eliminate the contamination of corn kernels with mycotoxins, we are studying the genetics and biology of mycotoxin production while the fungus grows on the corn kernel. Previous efforts have led to the identification of genes involved in regulating the production of mycotoxins in F. verticillioides. Here, we are studying the effects of a mutation in one of these genes. It was observed that this mutant grows poorly on the starch-rich portion of the corn kernel. This indicated that the utilization of starch as a food source for the fungus, via conversion of starch to sugar, might be involved in this phenomenon. Recently developed resources, including DNA microarrays and the availability of the DNA sequence of the entire genome of F. verticillioides, were utilized to characterize a number of genes involved in sugar catabolism. By understanding how the fungus not only colonizes the corn kernel, but also how it produces toxin we hope to be able to develop novel strategies for the elimination of this toxin from food and feed products produced from corn.

Technical Abstract: Fumonisins comprise a class of carcinogenic mycotoxins produced by Fusarium verticillioides during colonization of maize kernels. In previous work, we identified ZFR1, which is predicted to encode a Zn(II)2Cys6 zinc finger transcription factor required for fumonisin B1 (FB1) production during growth on kernels. In this study, we characterized the role of ZFR1 in colonizing maize kernels and inducing FB1 biosynthesis. The ZFR1 deletion strain ('zfr1) grew less than wild type on endosperm tissue and a variety of other carbon sources including glucose and amylopectin. However, the 'zfr1 strain displayed higher alpha-amylase activity and expression of genes involved in starch saccharification than wild type, thus indicating that the reduced growth of the 'zfr1 strain was not due to inhibition of amylolytic enzymes. In the wild-type strain, expression of three genes encoding putative sugar transporters (FST1, FST2, and FST3) was at least two-fold greater on endosperm tissue relative to germ tissue, and their expression was also affected by disruption of ZFR1. Intriguingly, disruption of FST1 had no effect on growth, kernel colonization, or kernel pH but decreased FB1 production by nearly 80% on maize kernels. Based on these findings, we hypothesize that ZFR1 controls FB1 biosynthesis by regulating genes involved in the perception or uptake of carbohydrates.