Document Type

Dissertation - Open Access

Award Date

1984

Degree Name

Doctor of Philosophy (PhD)

Department / School

Agronomy

Abstract

Puccinia recondita ultrastructure resembles that of other rust species. The urediospore infection was characterized by the formation of a specialized structure, the haustorium, within the leaf cells. The haustorium contains organelles such as nuclei, mitochondria, microbodies, ribosomes, lipid bodies, and vacuoles. A haustorial neck connects the haustorium with the haustorial mother cell, and contains a neck band made up of darkly stained material. The neck band was located at the last one third of its length toward the haustorium. The haustorial mother cell was situated intercellularly, and closely adhering to the cell wall, but contained few organelles, and the nucleus was never evident. The intercellular hyphae were packed with organelles. The hyphal cells were separated by septa which were perforated and nonperforated. Nuclei, and nucleoli.were frequently found in intercellular hyphae. In the septal pore region, mitochondria, microbodies, and glycogen bodies, appear to be bounded by a membrane which separates it from the cytoplasm. Rod and spherical shaped virus-like particles (VLPs) were observed in several haustoria and intercellular hyphae. Most of the VLPs examined were different from the wheat streak mosaic virus, (WSMV), and existed in fungal haustoria, and intercellular hyphae infecting wheat tissues that were either infected or not infected with WSMV. The VLPs detected in one haustorium, were indistinguishable from the virus particles infecting the host cell outside the haustorium. The fungal plasmalemma in the haustoria, haustorial necks, intercellular hyphae and urediospores, were repeatedly folded, and formed conspicuous invaginated membranous structures which occurred either connected to or next to the plasma membrane. It is proposed that those membranous structures be called " Invaginated Fungal PlasmaleJTma" (IFP). Crystalline and noncrystalline containing microbodies were found in haustoria, intercellular hyphae and urediospores. Their number ranged from two to nine per fungal propagule, but generally they were more abundant in haustoria. Crystalline and noncrystalline microbodies appeared together in several haustoria. Attempts to transmjt WSMV by urediospores were unsuccessful, even though VLPs were detected in the fungal propagules.

Library of Congress Subject Headings

Wheat -- Diseases and pests
Wheat streak mosaic disease
Puccinia recondita
Leaf rust of wheat

Number of Pages

129

Publisher

South Dakota State University

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