Temporal and spatial dynamics of appressorium formation inUromyces appendiculatus

摘要: Appressorium development in Uromyces appendiculatus was studied to establish temporal and spatial parameters possibly important signaling mechanisms this fungus. It determined that urediospore germling apices sensed inductive topographies, e.g., precisely shaped ridges 0.5 μm high by 2.0 wide, within 4 minutes after initial contact. The area the senses such topographies located on substrate side of cell 6.0 apex. These conclusions were based observed changes rate growth nuclear migration as well timing apical tip swelling began DNA synthesis during appressorium occurred only first division probably preparation for second mitosis normally occurs substomatal vesicle. Treatments with inhibitors hydroxyurea actinomycin D reduced content individual nuclei division. results indicate germlings already G2 phase when germination began. Formation a septum initiated 45–50 contact ridge completed 60 all cytoplasm had entered into swollen