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A Rapid and Sensitive Plate Assay for the Detection of Cutinase Produced by Plant Pathogenic Fungi. Martin B. Dickman, Department of Plant Pathology, University of Hawaii, Honolulu 96822; Suresh S. Patil, Department of Plant Pathology, University of Hawaii, Honolulu 96822. Phytopathology 76:473-475. Accepted for publication 12 November 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/Phyto-76-473.

A selective procedure for the detection of cutinase production by plant pathogenic fungi has been developed. This procedure involves growing fungi on a modified Czapek-Dox mineral medium containing purified cutin as the sole source of carbon and a basic pH indicator dye. On this medium, the cutinase-producing isolates generate zones of color change in the basic indicator dye in advance of visible mycelial growth. Presumably this is caused by a lowering of the pH in the medium due to the release of a fatty acid monomer into the medium from cutin hydrolysis. This is a convenient, rapid, and sensitive assay for detecting cutinase production by fungi. Although it was originally designed to screen cutinase-deficient mutants of Colletotrichum gloeosporioides, the causal agent of papaya anthracnose, it also can be applied to test other fungi for cutinase production.