Evaluation of a Chemical Method for Assay of Helminthosporium maydis Race T Toxin.
A chemical test reported by Karr et al. (Plant Physiol. 55:727) to assay for host-specific toxin produced by Helminthosporium maydis race T was evaluated. Preparations from culture filtrates of both race T isolates, containing host-specific toxin, and similar preparations from race O isolates, containing no detectable host-specific toxin, gave positive reactions in the chemical assay. Also, preparations containing active or inactive toxin gave equal responses in this test. The procedure does not provide a reliable method for assaying H. maydis race T toxin.
Yoder
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Departments of Plant Pathology and Plant Breeding, Cornell University, Ithaca, New York 14853.
Gracen
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