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Cutinase A of Botrytis cinerea is Expressed, but not Essential, During Penetration of Gerbera and Tomato

January 1997 , Volume 10 , Number  1
Pages  30 - 38

J. A. L. van Kan , J. W. van 't Klooster , C. A. M. Wagemakers , D. C. T. Dees , C. J. B. van der Vlugt-Bergmans

Department of Phytopathology, Wageningen Agricultural University, P.O. Box 8025, 6700 EE Wageningen, The Netherlands

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Accepted 30 October 1996.

The plant pathogen Botrytis cinerea can infect undamaged plant tissue directly by penetration of the cuticle. This penetration has been suggested to be enzyme-mediated, and an important role for cutinase in the infection process has been proposed. In this study the expression of the cutinase encoding gene cutA of B. cinerea was analyzed using a cutA promoter-GUS reporter gene fusion. Transformants containing the fusion construct were examined for GUS expression on gerbera flowers and tomato fruits. High GUS activity was detected from the onset of conidial germination and during penetration into epidermal cells, indicating that cutA is expressed during the early stages of infection. To determine the biological relevance of cutinase A for successful penetration, cutinase A-deficient mutants were constructed by gene disruption. Pathogenicity of two transformants lacking a functional cutA gene was studied on gerbera flowers and tomato fruits. Their ability to penetrate and cause symptoms was unaltered compared to the wild-type strain. These results exclude an important role for cutinase A during direct penetration of host tissue by B. cinerea.

Additional keywords: gene disruption, grey mold, homologous recombination, pathogenicity gene, reporter gene.

© 1997 The American Phytopathological Society