[Host-parasite metabolic relationship between puccinia graminis var. tritici and triticum vulgare (Wheat) : II. Uptake of hexoses from the host].

Rust infected leaves of wheat plants were incubated with glucose-(14)C. Uredospores which were formed during the application of the tracer were analyzed. All isolated compounds were labeled with (14)C. When germinating uredospores were incubated directly with (14)C-glucose, the isolated glutamic acid, arginine and lysine had practically no radioactivity. These compounds did, however, contain considerable (14)C-activity when they were isolated from uredospores formed on leaves that had been treated with the tracer. We therefore conclude that these amino acids were synthesized in the host and were taken up by the haustoria of the mycelium.High (14)C-radioactivity was also found in all carbohydrates (chitin, glucomannan, polyols etc.). Hexoses isolated from the spore constituents chitin and glucomannan showed the same distribution of radioactivity as the applied glucose-1-(14)C or glucose-6-(14)C. It follows that the rust mycelium takes up glucose or a similar monosaccharide from the wheat plant. The C-6-skeleton is not degraded to smaller metabolites before it is taken up.