Involvement of cathepsin B in the plant disease resistance hypersensitive response.
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.
Gilroy
Eleanor M
EM
Plant Pathology Programme, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UK.
Hein
Ingo
I
van der Hoorn
Renier
R
Boevink
Petra C
PC
Venter
Eduard
E
McLellan
Hazel
H
Kaffarnik
Florian
F
Hrubikova
Katarina
K
Shaw
Jane
J
Holeva
Maria
M
López
Eduardo C
EC
Borras-Hidalgo
Orlando
O
Pritchard
Leighton
L
Loake
Gary J
GJ
Lacomme
Christophe
C
Birch
Paul R J
PR
D001483:Base Sequence; D002401:Cathepsin B / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D020868:Gene Silencing; D005819:Genetic Markers; D010935:Plant Diseases / Q000382:microbiology* / Q000821:virology; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017931:DNA Primers; D005819:Genetic Markers; D002401:Cathepsin B