VIEW ARTICLE

Biochemistry and Cell Biology

Targeted Secretion of Cutinase in Fusarium solani f. sp. pisi and Colletotrichum gloeosporioides. G. K. Podila, Ohio State Biotechnology Center, Ohio State University, Columbus 43210, Current address: Department of Biological Sciences, Michigan Technological University, Houghton 49931; E. Rosen(2), M. J. D. San Francisco(3), and P. E. Kolattukudy(4). (2)(3)(4)Ohio State Biotechnology Center, Ohio State University, Columbus 43210; (3)Current address: Department of Biological Sciences, Texas Tech University, Lubbock 79409. Phytopathology 85:238-242. Accepted for publication 3 November 1994. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/Phyto-85-238.

Immunofluorescence studies of cutinase secretion by phytopathogenic fungi Fusarium solani f. sp. pisi and Colletotrichum gloeosporioides were made to determine targeting of the enzyme in germinating spores. Our results indicate that the secretion of cutinase was directed towards the region that penetrates the host. In F. s. pisi, which penetrates plant tissue without appressorium formation, cutinase was targeted to the growing tip of germinating spores. In C. gloeosporioides, cutinase secretion was directed to the infection peg that arises from the appressorium. Monensin, the carboxylic ionophore, inhibited secretion of cutinase and caused intracellular accumulation of cutinase in F. s. pisi. Subcellular fractionation of monensin-treated cells indicated involvement of the Golgi in the secretion and targeting of cutinase by germinating spores of F. s. pisi.