Author
 |
Muhitch, Michael |
|
Submitted to: Association Official Analytical Chemists Midwest Section Program Abstracts
Publication Type: Abstract Only Publication Acceptance Date: 4/6/2001 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Fusarium verticillioides (formerly moniliforme) is implicated as a causative agent in ear rot in maize. Fusarium verticillioides appears to be frequently found within the pedicel or "tip cap" region of asymptomatic field-grown corn kernels. This suggests that the pedicel serves as both a survival structure for the fungus and as a ready port of entry when the environmental conditions (either in the field or in storage) allow it to invade the embryo and endosperm and produce fumonisins. Targeting of a disease resistance agent to this region of the kernel appears to be a viable strategy for increasing resistance in maize kernels to invasion by F. moniliforme and other cob rotting fungi. Glutamine synthetase (GS) is a key enzyme in plant nitrogen metabolism. In maize, GS is encoded as a single plastid gene and five cytoplasmic genes. One of these, GS1-2, is strongly expressed within the basal maternal tissues of developing seeds and therefore appears as an excellent candidate for developing a pedicel-specific gene expression cassette for producing antifungal proteins within this region of the kernel. Stable expression of a heterologous gene consisting of the GS1-2 5' upstream regulatory region attached to the reporter gene GUS results in the predicted tissue-specific expression in the basal maternal seed tissues, including the surrounding pericarp. The GS1-2 /GUS expression pattern in transgenic demonstrates the suitability of the promoter for expressing antifungal and other disease resistance genes within the basal maternal tissues of the developing kernel. |