Open AccessDspA/E, a Type III Effector Essential for Erwinia amylovora Pathogenicity and Growth In Planta, Induces Cell Death in Host Apple and Nonhost Tobacco Plants
Author(s) -
Tristan Boureau,
Hayat ElMaarouf-Bouteau,
Amélie Garnier,
Marie-Noëlle Brisset,
C. Perino,
Igor Pucheu,
MarieAnne Barny
Publication year - 2006
Publication title -
molecular plant-microbe interactions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.565
H-Index - 153
eISSN - 1943-7706
pISSN - 0894-0282
DOI - 10.1094/mpmi-19-0016
Subject(s) - erwinia , biology , hypersensitive response , fire blight , microbiology and biotechnology , virulence , effector , type three secretion system , secretion , callose , necrosis , programmed cell death , cell wall , bacteria , botany , gene , genetics , immunology , apoptosis , biochemistry
Erwinia amylovora is responsible for fire blight, a necrotic disease of apples and pears. E. amylovora relies on a type III secretion system (TTSS) to induce disease on hosts and hypersensitive response (HR) on nonhost plants. The DspA/E protein is essential for E. amylovora pathogenicity and is secreted via the TTSS in vitro. DspA/E belongs to a type III effector family that is conserved in several phytopathogenic bacteria. In E. amylovora, DspA/E has been implicated in the generation of an oxidative stress during disease and the suppression of callose deposition. We investigated the fate of DspA/E in planta. DspA/E delivered artificially to apple or tobacco cells by agroinfection induced necrotic symptoms, indicating that DspA/E was probably injected via the TTSS. We confirmed that DspA/E acts as a major cell-death inducer during disease and HR, because the dspA/E mutant is severely impaired in its ability to induce electrolyte leakage in apple and tobacco leaves. Expression of the defense marker gene PR1 was delayed when dspA/E was transiently expressed in tobacco, suggesting that DspA/E-mediated necrosis may be associated with an alteration of defense responses.