Helminthosporium Maydis Race Research Articles

A Comparison of Mitochondria Isolated from Male‐Sterile and Nonserile Cytoplasm Etiolated Corn Seedlings

AbstractToxins from Helminthosporium maydis race T and Phyllosticta maydis have been found to affect the functional processes of corn mitochondria isolated from Texas male‐sterile (T) cytoplasm, but not of mitochondria isolated from nonsterile (N) cytoplasm.The effects of chemicals known to induce responses similar to those of the toxin were compared on mitochondria isolated from T and N cytoplasm inbreds (W64A, Zea mays L.). Valinomycin, gramicidin, and decenylsuccinic acid (DSA) each caused more swelling (measured by transmission changes in %) of N mitochondria than of T mitochondira. The stimulation of exogenous NADH oxidation was the same for N and T mitochondria in the valinomycin, DSA, and Ca2+ plus phosphate treatments, was greater for T mitochondria than for N mitochondria in the gramicidin and DNP treatments, and was greater for N mitochondrai than for T mitochondira in the Ca+2 minus phosphate treatment. Sodium azide inhibited NADH oxidation equally for N and T mitochondria. In addition, N and T mitochondria had similar respiration rates for various substrates and equal efficiencies of oxidative phosphorylation. In contrast to the specificity of toxins for T mitochondria, none of the treatment effects were specific for N or T mitochondria. The results indicate that mitochondria isolated from N and T cytoplasm generally respond similarly to various conditions, but that there can be quantitative differences in the response. The extent to which these differences represent cytoplasmically controlled modification of mitochondrial physiology or structure is not known.

Monogenic Chlorotic‐Lesion Resistance in Corn to Helminthosporium maydis1

Chlorotic‐lesion resistance in corn (Zea mays L.) to Helminthosporium maydis race O was inherited as a single recessive gene. Resistant plants in both normal and cms‐T cytoplasm expressed small chlorotic lesions whereas suceptible plant exhibited large tan to brown, oval to rectangular lesions.

Inhibition of the K +-stimulated ATPase of maize root microsomes by [formula omitted][formula omitted] Race T pathotoxin

The microsomes obtained by centrifugation between 12,000 g and 80,000 g of an homogenate of maize root tips contain K +-stimulated ATPase activity. Pre-incubation of the microsomes from roots of cytoplasmic male sterile (cmsT) plants with partially purified pathotoxin from Helminthosporium maydis Race T strongly inhibits the K + stimulation; the same treatment of microsomes from normal roots has no effect. We suggest this inhibition is closely related to the mode of action of H . maydis Race T pathotoxin.

Leakage from Corn Tissues Induced by Helminthosporium maydis Race T Toxin

Leakage from Corn Tissues Induced by Helminthosporium maydis Race T Toxin

Degradation of Corn Cell Walls by Extracellular Enzymes Produced by Helminthosporium maydis Race T

Degradation of Corn Cell Walls by Extracellular Enzymes Produced by Helminthosporium maydis Race T

Ear-Rotting Potential of Helminthosporium maydis Race T in Corn

Ear-Rotting Potential of Helminthosporium maydis Race T in Corn

Nontoxigenieity to Broiler Chickens of Corn Invaded by a Pure Culture of Helminthosporium Maydis Race T

Corn invaded by a pure culture of Helminthosporium maydis race T was substituted for noninoculated corn in a diet for broiler chickens at the levels of 0, 20, 50, and 80% inoculated corn meal. Five groups of ten birds each were fed at each treatment from hatching until three weeks of age. None of the treatments had a significant (P < 0.05) effect on body weight, hemoglobin, total serum protein, total serum cholesterol, total serum lipid, or total livier lipid. The relative weights of the liver, pancreas, spleen, and bursa of Fabricius also were not affected. Since these parameters are affected by mycotoxins such as anatoxin, ochratoxin, fusariotoxin T-2, and rubratoxin, it was concluded that H. maydis race T is not toxic to chickens. Nevertheless, theoretical considerations suggest a prompt toxicological evaluation of new races of the Southern corn blight pathogen.

Transmission of Helminthosporium maydis Race T by Infected Corn Seed

Transmission of Helminthosporium maydis Race T by Infected Corn Seed