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 translocati on of metabolites from the host to the parasite were investigated on primar y leaves of decapitated bean plants infected with the bean rust fungus Ui U romyces appendiculatus var. appendiculatus (Pers.) Link with respect to cha nges in the spore type from uredinioto teliospores. Noninfected control lea ves were compared to the directly influenced sorus region of infected leave s and the mycelium-free areas of these leaves ('leaf-remainder'). The data show evidence for an intensive change in the metabolite pools, indicating t ranslocation from the metabolically active leaf-remainder to the sori, expr essing characteristic changes according to the spore type produced. The imp ortance 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 metabolites and precursors, whereas teliospores need to undergo metabolite syntheses before germination.