Three-dimensional surface reconstruction and in situ site-specific cutting of the teliospores of Puccinia miscanthi causing leaf rust of the biomass plant Miscanthus sinensis

Teliospore mucilage of Puccinia miscanthi revealed through the axial imaging of secondary electrons

Puccinia miscanthi teliospores were observed on the leaf surface of Miscanthus sinensis using a field emission scanning electron microscope. Details of teliospore mucilage could be visualized through the axial imaging of secondary electrons for a better understanding of pathogen behavior in rust diseases.

Ultrastructure of the Rust Fungus Puccinia miscanthi in the Teliospore Stage Interacting with the Biofuel Plant Miscanthus sinensis

Interaction of the the rust fungus Puccinia miscanthi with the biofuel plant Miscanthus sinensis during the teliospore phase was investigated by light and electron microscopy. P. miscanthi telia were oval-shaped and present on both the adaxial and abaxial leaf surfaces. Teliospores were brown, one-septate (two-celled), and had pedicels attached to one end. Transmission electron microscopy revealed numerous electron-translucent lipid globules in the cytoplasm of teliospores. Extensive cell wall dissolution around hyphae was not observed in the host tissues beneath the telia. Hyphae were found between mesophyll cells in the leaf tissues as well as in host cells. Intracellular hyphae, possibly haustoria, possessed electron-dense fungal cell walls encased by an electron-transparent fibrillar extrahaustorial sheath that had an electron-dense extrahaustorial membrane. The infected host cells appeared to maintain their membrane-bound structures such as nuclei and chloroplasts. These results suggest that the rust fungus maintains its biotrophic phase with most mesophyll cells of M. sinensis. Such a nutritional mode would permit the rust fungus to obtain food reserves for transient growth in the course of host alteration.