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- Title
Ultrastructural analysis of responses of host and fungal cells during plant infection.
- Authors
Park, Pyoyun; Ikeda, Ken-ichi
- Abstract
Cellular responses in fungi and in susceptible or resistant hosts during fungus–plant interactions have been studied ultrastructurally to examine their role in pathogenicity. Pathogenicity is determined in some saprophytic fungi by various factors: the production of disease determinants such as the production of host-specific toxins (HSTs) or the extracellular matrix (ECM) by fungal infection structures and H2O2 generation from penetration pegs. Three different target sites for HSTs have been identified in host cells in many ultrastructural studies: plasma membranes, chloroplasts, and mitochondria. The mode of action of HSTs is characterized by the partial destruction of the target structures only in susceptible genotypes of host plants, with the result that the fungus can colonize the host. The infection structures of most fungal pathogen secrete ECM on plant surfaces during fungal differentiation, while the penetration pegs of some pathogens produce reactive oxygen species (ROS) in the cell walls and plasma membranes. The pathological roles of ECM and H2O2 generation are discussed here in light of ultrastructural evidence. Host and fungal characteristics in the incompatible interactions include the rapid formation of lignin in host epidermal cell walls, failure of penetration pegs to invade lignin-fortified pectin layers, the inhibition of subcuticular hyphal proliferation and the collapse of hyphae that have degraded cell walls within pectin layers of the host. Apoptosis-like host resistant mechanism is also discussed.
- Subjects
PLANT diseases; PHYTOPATHOGENIC microorganisms; PLANT parasites; DISEASE resistance of plants; PLANT toxins; EXTRACELLULAR matrix; REACTIVE oxygen species
- Publication
Journal of General Plant Pathology, 2008, Vol 74, Issue 1, p2
- ISSN
1345-2630
- Publication type
Article
- DOI
10.1007/s10327-007-0042-8