Pythiogeton zeae sp. nov. Causing Root and Basal Stalk Rot of Corn in Korea

Abstract

In South Korea, a pythiaceous fungus was consistently isolated from the diseased tissues of field corn plants (Zea mays) showing severe rot of the roots and basal stalks. Based on the morphology, it was described as Pythiogeton zeae sp. nov., and a taxonomic key was constructed to differentiate it from the other known species of Pythiogeton. It is characterized by small to extremely large, ovoid, cylindrical, bursiform, ventricose, bilobulate, trilobulate to irregular saccate sporangia, large globose to ellipsoidal oogonium, plerotic oospore with thick wall and mostly single, diclinous or monoclinous antheridium. Its pathogenicity to corn plants was confirmed by artificial inoculation and successful re-isolation. This is the first documented report of a plant-pathogenic species of Pythiogeton, a genus known to be saprophytic usually on plant debris in freshwater.