This invention relates to plant Hydroperoxide Lyase or HPO lyase polynucleotides and polypeptides. DNA constructs useful for the expression of a plant HPO lyase in a cell are described. Furthermore, DNA constructs useful for the antisense expression of a plant HPO lyase in a plant cell are described. Such constructs will contain a DNA sequence encoding the plant HPO lyase of interest under the control of regulatory elements capable of preferentially directing the expression of the plant HPO lyase in plant tissue, when such a construct is expressed in a transgenic plant. This invention also relates to methods of using a DNA sequence encoding a plant HPO lyase for the modification of the volatile aldehydes in plant tissues, as well as for methods of increasing disease resistance in a plant.
