DISTRIBUTION OF FUMONISINS IN MAIZE EARS INFECTED WITH STRAINS OF FUSARIUM MONILIFORME THAT DIFFER IN FUMONISIN PRODUCTION

Authors: Desjardins, Anne; Plattner, Ronald; LU, M - KANSAS STATE UNIV; CLAFLIN, L - KANSAS STATE UNIV

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Fumonisins are a family of toxins that are produced by a common fungus that is often found on corn. These toxins when present in high levels in grains contaminated with fungus can cause health problems to animals that consume them. Human exposure to the toxins in corn is also a potential concern because the toxins have been linked with cancers in laboratory animals. Although the levels of fumonisins in good commercial corn are generally low, little was known about how fumonisins are distributed in the corn. In this study corn seeds that were planted were infected with strains of fumonisin producing fungi and the ears produced by the plants were analyzed for the presence of fumonisins. Kernels from the harvested ears were separated into good kernels and visibly moldy or damaged kernels. Nearly all the fumonisins were found in the damaged and moldy kernels. These results suggest that it may be possible to lower fumonisin exposure to the humans by using only the highest quality corn for human foods and diverting damaged and moldy kernels into other uses.

Technical Abstract: Strains of Gibberella fujikuroi mating population A that differ in fumonisin production in vitro were previously identified in a Kansas field population. One strain that produced high levels of fumonisins and two strains that produced very low levels of fumonisins were applied to maize kernels at planting at the Rocky Ford Farm near Manhattan, Kansas. The distribution of fumonisins in symptomatic and symptomless kernels from individual harvested ears was determined by high performance liquid chromatography, and the distribution of the three applied strains was determined by vegetative compatibility group analysis. Both symptomatic and symptomless kernels were extensively colonized with G. fujikuroi, but the highest levels of fumonisins were in the symptomatic kernels. All three applied strains were recovered from kernels in 1993, and two of them were recovered from kernels in 1994. However, a high frequency of ear and kernel infection with a fumonisin low-producing strain did not consistently decrease the level of fumonisins. The frequency of infection with fumonisin low-producing strains may have been too low for competitive exclusion of naturally-occurring fumonisin high-producing strains. Also, strains that are low fumonisin producers under laboratory conditions may be high producers in the field.