VIEW ARTICLE

Cytology and Histology

Interaction of Phytophthora cinnamomi and a Resistant Host, Acacia pulchella. Joanna Tippett, Research student, Botany Department, Monash University, Clayton, 3168, Victoria, Australia; N. Malajczuk, research scientist, Division of Land Resources Management, CSIRO, Wembley, 6014, Western Australia. Phytopathology 69:764-772. Accepted for publication 6 February 1979. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-764.

On the lateritic soils of Western Australia, the jarrah forest may be managed to encourage an understory of Acacia pulchella as a means of reducing the inoculum potential of Phytophthora cinnamomi. The cytology and ultrastructure of the interaction between P. cinnamomi and the legume A. pulchella were studied to determine whether the acacia is inherently resistant to attack by this root-infecting fungus. Penetration and attempted establishment of P. cinnamomi in the acacia roots suggested that the interaction was incompatible, because the host cells appeared to respond hypersensitively to infection. Darkly staining material, which was autofluorescent and presumably phenolic, accumulated in the necrotic cells, and wall appositions formed close to invading hyphae. This study reports the first resistant host reaction to infection with P. cinnamomi.