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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Mycotoxin Prevention and Applied Microbiology Research » Research » Publications at this Location » Publication #197243
Title: AMYLOPECTIN IN MAIZE KERNEL INDUCES FUMONISIN PRODUCTION BY FUSARIUM VERTICILLIOIDES DURING COLONIZATION.

Author
item WOLOSHUK, C. P. - PURDUE UNIVERSITY
item BLUHM, B.H. - PURDUE UNIVERSITY
item Butchko, Robert

Submitted to: European Seminar in Fusarium Mycotoxins Taxonomy and Pathogenicity
Publication Type: Abstract Only
Publication Acceptance Date: 6/23/2006
Publication Date: 9/22/2006
Citation: Woloshuk, C., Bluhm, B., Butchko, R.A. 2006. Amylopectin in maize kernel induces fumonisin production by fusarium verticillioides during colonization [abstract]. 9th European Fusarium Seminar. p. 101.

Interpretive Summary:

Technical Abstract: Fusarium verticillioides, a fungal pathogen of maize, produces fumonisin mycotoxins. To better understand the interactions between F. verticillioides and maize kernels, we have investigated the impact of kernel composition on the accumulation of fumonisin B1 (FB1). We found that kernels lacking starch due to physiological immaturity do not accumulate FB1, and that kernel development also affects the expression of fungal genes involved in FB1 biosynthesis, starch metabolism, and nitrogen regulation. F. verticillioides produced significantly less FB1 on a high-amylose kernel mutant of maize than high amylopectin maize. When grown on a defined medium with amylose as the sole carbon source, the wild-type strain produced only trace amounts of FB1, but it produced large amounts of toxin when grown on amylopectin or dextrin, a product of amylopectin hydrolysis. A strain of F. verticillioides disrupted in ZFR1, a putative regulatory gene, produces only trace amounts of FB1 when grown on amylopectin and displayed reduced growth on endosperm tissue. The mutant exhibited higher alpha-amylase activity and expression of genes involved in starch saccharification than wild type, which indicated the reduced growth of the strain is not due to inhibition of amylolytic enzymes. Of the 25 putative sugar transporters identified in F. verticillioides, two are expressed at higher levels on endosperm tissue compared to germ tissue in the wild type, and disruption of ZFR1 results in three-fold reductions in their expression. Based on these findings, we hypothesize that during colonization of maize kernels ZFR1 regulates the uptake of breakdown products of amylopectin required for the induction of fumonisin biosynthesis.