Changes in Metabolite Pools in Host and Pathogen during the Uredinio and Teliospore Development of the Bean Rust Fungus Uromyces appendiculatus

Metabolite pool sizes as well as indications for changes in the translocation of metabolites from the host to the parasite were investigated on primary leaves of decapitated bean plants infected with the bean rust fungus Uromyces appendiculatus var. appendiculatus (Pers.) Link with respect to changes in the spore type from uredinioto teliospores. Noninfected control leaves were compared to the directly infltjenced sorus region of infected leaves and the mycelium-free areas of these leaves (ʹleaf-remainderʹ). The data show evidence for an intensive change in the metabolite pools, indicating translocation from the metabolically active leaf-remainder to the sori, expressing characteristic changes according to the spore type produced. The importance of single metabolites and changes in their pool sizes is discussed and correlated to the respective pools within the uredinio- and teliospores. The data indicate that vegetative urediniospores contain mainly preformed metabohtes and precursors, whereas teliospores need to undergo metabolite syntheses before germination