PIRIN 2 stabilizes cysteine protease XCP 2 and increases susceptibility to the vascular pathogen Ralstonia solanacearum in Arabidopsis

• Published in: The Plant journal : for cell and molecular biology Vol. 79; no. 6; pp. 1009 - 1019
• Main Authors: Zhang, Bo, Tremousaygue, Dominique, Denancé, Nicolas, van Esse, H. Peter, Hörger, Anja C., Dabos, Patrick, Goffner, Deborah, Thomma, Bart P. H. J., van der Hoorn, Renier A. L., Tuominen, Hannele
• Format: Journal Article
• Language: English
• Published: 01-09-2014
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/tpj.12602

PIRIN
(
PRN
) is a member of the functionally diverse cupin protein superfamily. There are four members of the
Arabidopsis thaliana
PRN
family, but the roles of these proteins are largely unknown. Here we describe a function of the Arabidopsis
PIRIN
2 (
PRN
2) that is related to susceptibility to the bacterial plant pathogen
Ralstonia solanacearum
. Two
prn2
mutant alleles displayed decreased disease development and bacterial growth in response to
R.  solanacearum
infection. We elucidated the underlying molecular mechanism by analyzing
PRN
2 interactions with the papain‐like cysteine proteases (
PLCP
s)
XCP
2,
RD
21A, and
RD
21B, all of which bound to
PRN
2 in yeast two‐hybrid assays and in Arabidopsis protoplast co‐immunoprecipitation assays. We show that
XCP
2 is stabilized by
PRN
2 through inhibition of its autolysis on the basis of
PLCP
activity profiling assays and enzymatic assays with recombinant protein. The stabilization of
XCP
2 by
PRN
2 was also confirmed
in planta
. Like
prn2
mutants, an
xcp2
single knockout mutant and
xcp2 prn2
double knockout mutant displayed decreased susceptibility to
R. solanacearum
, suggesting that stabilization of
XCP
2 by
PRN
2 underlies susceptibility to
R. solanacearum
in Arabidopsis.