Compositions and methods for enhancing disease resistance to a pathogen in
a plant are provided. Methods of the invention comprise stably
transforming a plant with an antisense nucleotide sequence for a gene
encoding an enzyme in the C-5 porphyrin metabolic pathway and operably
linking said antisense sequence to a pathogen-inducible promoter, such
that invasion of a cell by a pathogen elicits a hypersensitive-like
response that results in confinement of the pathogen to cells of initial
contact. Transformed plants and seeds are provided. Nucleotide sequences
encoding a wild-type maize urod gene useful in the present invention and
the amino acid sequence for the protein encoded thereby are provided.
These compositions are also useful for regulating cell death in
specifically targeted tissues. A maize lesion mimic, dominant mutant
phenotype, designated Les22, and the molecular basis for its manifestation
are also provided.