Open AccessThe bacterial effector DspA/E is toxic in A rabidopsis thaliana and is required for multiplication and survival of fire blight pathogen
Author(s) -
Degrave Alexandre,
Moreau Ma,
Launay Alban,
Barny MarieAnne,
Brisset MarieNoëlle,
Patrit Oriane,
Taconnat Ludivine,
Vedel Regine,
Fagard Mathilde
Publication year - 2013
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/mpp.12022
Subject(s) - biology , erwinia , arabidopsis thaliana , effector , green fluorescent protein , transgene , mutant , microbiology and biotechnology , gene , genetics
Summary The type III effector DspA/E is an essential pathogenicity factor of the phytopathogenic bacterium E rwinia amylovora . We showed that DspA/E was required for transient bacterial growth in nonhost A rabidopsis thaliana leaves, as an E. amylovora dspA/E mutant was unable to grow. We expressed DspA/E in A . thaliana transgenic plants under the control of an oestradiol‐inducible promoter, and found that DspA/E expressed in planta restored the growth of a dspA/E mutant. DspA/E expression in these transgenic plants led to the modulation by at least two‐fold of the expression of 384 genes, mostly induced (324 genes). Both induced and repressed genes contained high proportions of defence genes. DspA/E expression ultimately resulted in plant cell death without requiring a functional salicylic acid signalling pathway. Analysis of A . thaliana transgenic seedlings expressing a green fluorescent protein ( GFP ): DspA/E fusion indicated that the fusion protein could only be detected in a few cells per seedling, suggesting the degradation or absence of accumulation of DspA/E in plant cells. Consistently, we found that DspA/E repressed plant protein synthesis when injected by E. amylovora or when expressed in transgenic plants. Thus, we conclude that DspA/E is toxic to A . thaliana : it promotes modifications, among which the repression of protein synthesis could be determinant in the facilitation of necrosis and bacterial growth.