Leaf curl disease of almond caused by Taphrina deformans. III. Ultrastructural cytology of the pathogen

Abstract

The formation of ascogenous cells of Taphrina deformans (Berk.) Tul. from vegetative hyphae and their subsequent development have been investigated with the electron microscope. Ascus formation, ascosporogenesis, ascospore budding, and spore discharge are described. Nuclear pairs occur in vegetative and ascogenous cells. Spindle pole bodies of nuclear pairs are often closely associated. Two spindle pole bodies that are associated with each nucleus have been observed in ascogenous cells, ascus initials, and asci. Endoplasmic reticulum cisternae are numerous in vegetative hyphae but are absent in reproductive cells. Networks of smooth membranes are located in ascogenous cells. The ascus wall is unitunicate and splits at the ascus apex to release the ascospores. Ascospores may bud before or after their release.