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Resistance

Expression of Field Resistance in Callus Tissue Inoculated with Phytophthora cinnamomi. J. A. McComb, Department of Environmental and Life Sciences, Murdoch University, Murdoch, W. Australia 6150; J. M. Hinch, and A. E. Clarke. Plant Cell Biology Research Centre, School of Botany, University of Melbourne, Parkville, Victoria, Australia 3052. Phytopathology 77:346-351. Accepted for publication 25 July 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/Phyto-77-346.

Callus cultures initiated from Australian native and horticultural species with varying degrees of field resistance or tolerance to the fungal pathogen Phytophthora cinnamomi were screened for expression of resistance to the pathogen. The extent of hyphal growth on callus correlated with the susceptibility of the plant from which the callus was derived. The optimum temperature for fungal growth on the calli was 30 C. This was the temperature at which the difference was greatest between hyphal growth on callus derived from resistant and susceptible plants. The amount of callose formed in the cultured cells in response to the pathogen correlated with the degree of field resistance.