Les*-U957, isolated from a Mutator screening project, is a dominant lesion mimic mutant whose expression ranges from small necrotic lesions (similar to Les2), arranged in a clonal fashion, to large necrotic sectors. Appearance of lesions begins at the 5 to 7-leaf stage, with lesion formation beginning at the tips of newly emerging leaves and progressing towards the base of the leaf. Lesion formation is characterized by small, watery spots that turn into small necrotic lesions or light green sectors, which will eventually become completely necrotic. Revertant (completely green) sectors are also characteristic of this mutant. Direct exposure of the newly emerging leaf tissue to light appears to be necessary for lesion formation. Depending on genetic background, Les*-U957 can be maintained as a homozygote. In some backgrounds, such as W23, heterozygous plants will senesce before anthesis. We are currently mapping Les*-U957 using waxy translocation stocks and examining several environmental/physiological parameters influencing its expression. 

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