Fungal elicitation of wall modifications in leaves of Phaseolus vulgaris L.cv. Pinto. II. Effects of fungal wall components
1992
Ryerson, D.E. | Heath, M.C.
Cell wall fragments isolated from the rust fungi, Uromyces vignae, a non-pathogen of bean, and Uromyces appendiculatus, a pathogen, were injected into French bean plants. A significant number of fungal wall fragments elicited cell wall autofluorescence and an increase in cell wall refractivity in plant cells with which they came into contact. There was no statistical difference between the two fungal species in the capacity of their wall fragments to elicit the plant responses despite their differences in pathogenicity. Elicitation was also shown to be independent of whether the wall fragments were derived from differentiated or undifferentiated fungal structures. Frequency of elicitation was not altered by treatment of cell wall preparations with periodate, protease, or laminarinase. Furthermore, no evidence could be found for the presence of elicitors released from fungal cell walls via the action of laminarinase. Injection of suspensions or solutions of chitin, chitin tetramer, chitosan, laminarin or laminarin treated with laminarinase were not able to increase either of the plant cell wall responses above control levels. However, these responses were elicited by heat-released components or the cell wall of the bean pathogen Colletrotrichum lindemuthianum. The addition of intercellular washing fluids that prevent these responses when elicited by U vignae did not alter the responses elicited by the wall fragments. Ultrastructural studies suggested that the increased refractivity of the plant cell wall was not the result of silica deposition.
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