Nitrogen-metabolizing enzymes of Diplodia maydis, a Zea mays L. stalk rot causing fungus.

The nitrogen source available to Diplodia maydis in vivo is reported to affect the severity of stalk rot in maize. Nitrate and (or) ammonium salts were tested for their effect on the type of nitrogen metabolism found in Diplodia maydis in vitro. The level of glutamate dehydrogenase remained essentially constant on either nitrogen salt but nitrate reductase was induced by growth on nitrate salts and was not extractable on ammonium salts. Properties of nitrate reductase reported here are similar to those reported for the higher plant and Neurospora crassa enzymes. Thr relationship of nitrogen metabolism in Diplodia maydis to Zea mays L. stalk rot is discussed.