Host-pathogen Relations in Powdery Mildew of Barley III. Utilization of Respiratory Energy

Abstract

A quantitative comparison was made of the respiratory response, and concurrent changes in the concentrations of nucleic acid and protein, following infection of barley with the powdery mildew fungus (Erysiphe graminis var. hordei). Infection of a susceptible barley variety resulted in increased respiration and increased amounts of ribonucleic acid phosphorus (RNAP) in the host tissue. Infection of etiolated tissue of a susceptible variety was not accompanied by increased respiration or by increased RNAP levels. The increased respiration in resistant barley varieties following infection was not associated with increased RN AP levels. It is suggested that the metabolic responses following infection are different in susceptible and resistant varieties.