DspA/E, a Type III Effector Essential for Erwinia amylovora Pathogenicity and Growth In Planta, Induces Cell Death in Host Apple and Nonhost Tobacco Plants

Autor: Tristan Boureau, Hayat ElMaarouf-Bouteau, Amélie Garnier, Marie-Noëlle Brisset, Claude Perino, Igor Pucheu, Marie-Anne Barny
Jazyk: angličtina
Rok vydání: 2006
Předmět:
Zdroj: Molecular Plant-Microbe Interactions, Vol 19, Iss 1, Pp 16-24 (2006)
Druh dokumentu: article
ISSN: 1943-7706
0894-0282
DOI: 10.1094/MPMI-19-0016
Popis: 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.
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