Differential growth of<i>Fusarium moniliforme</i>relative to tissues from 'Silver Queen', a sweet maize

Abstract

Vegetative and reproductive tissues of maize, Zea mays L., were inoculated in vitro with Fusarium moniliforme J. Sheld. to determine inherent differences among plant tissue types to support mycelia proliferation. The F. moniliforme isolate used for inoculations was tagged with gusA, a reporter gene, providing evidence that developing mycelia were from the inoculum source and excluding possibilities of an external contaminant or an internal endophytic F. moniliforme. Vegetative tissues were dissected from roots, stems, and leaves; reproductive tissues were dissected from developing male and female inflorescences and fruits. In addition, mycelial development was analyzed on nonwounded and wounded mature kernels. Fusarium moniliforme mycelial accumulation was more rapid and extensive on reproductive than on vegetative plant tissue. Fusarium moniliforme conidia inoculated on immature kernels formed a dense mycelial mat, whereas F. moniliforme conidia inoculated on mature kernels developed sparse hyphae, unless the kernels had been wounded. Thus, the type, maturity, and physical condition of maize plant tissues are factors responsible for in vitro differences in mycelial proliferation.Key words: conidia, mycotoxins, plant pathogen, reproductive tissue, vegetative tissue, Zea mays.