Involvement of cathepsin B in the plant disease resistance hypersensitive response

Eleanor M. Gilroy, Ingo Hein, Renier van der Hoorn, Petra C. Boevink, Eduard Venter, Hazel McLellan, Florian Kaffarnik, Katarina Hrubikova, Jane Shaw, Maria Holeva, Eduardo C. Lopez, Orlando Borras-Hidalgo, Leighton Pritchard, Gary J. Loake, Christophe Lacomme, Paul R. J. Birch

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A diverse range of plant proteases are implicated in pathogen perception and in subsequent signalling and execution of disease resistance. We demonstrate, using protease inhibitors and virus-induced gene silencing (VIGS), that the plant papain cysteine protease cathepsin B is required for the disease resistance hypersensitive response (HR). VIGS of cathepsin B prevented programmed cell death (PCD) and compromised disease resistance induced by two distinct non-host bacterial pathogens. It also suppressed the HR triggered by transient co-expression of potato R3a and Phytophthora infestans Avr3a genes. However, VIGS of cathepsin B did not compromise HR following recognition of Cladosporium fulvum AVR4 by tomato Cf-4, indicating that plant PCD can be independent of cathepsin B. The non-host HR to Erwinia amylovora was accompanied by a transient increase in cathepsin B transcript level and enzymatic activity and induction of the HR marker gene Hsr203. VIGS of cathepsin B significantly reduced the induction of Hsr203 following E. amylovora challenge, further demonstrating a role for this protease in PCD. Whereas cathepsin B is often relocalized from the lysosome to the cytosol during animal PCD, plant cathepsin B is secreted into the apoplast, and is activated upon secretion in the absence of pathogen challenge.

Original languageEnglish
Pages (from-to)113
Number of pages13
JournalThe Plant Journal
Issue number1
Publication statusPublished - Oct 2007

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