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Research Paper
Cryptogein-Induced Anion Effluxes: Electrophysiological Properties and Analysis of the Mechanisms Through Which They Contribute to the Elicitor-Triggered Cell Death
Adrien Gauthier, Olivier Lamotte, David Reboutier, Francois Bouteau, Alain Pugin and David Wendehenne
volume 2 | issue 2
march/april 2007Pages: 86 - 95
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Anion effluxes are amongst the earliest reactions of plant cells to elicitors of defence responses. However, their properties and their role in disease resistance remain almost unknown. We previously demonstrated that cryptogein, an elicitor of tobacco defence responses, induces a nitrate (NO3−) efflux. This efflux is an early prerequisite to the cryptogein-triggered hypersensitive response (HR). Here, we analyzed the electrophysiological properties of the elicitor-mediated NO3−− efflux and clarified the mechanisms through which it contributes to cell death. Application of the discontinuous single electrode voltage-clamp technique in tobacco cells elicited with cryptogein enabled us to record the activation of slow-type deactivating anion channel currents. Cryptogein-induced plasma membrane depolarization and Ca2+ influx, an essential component of elicitor signalling for HR cell death, were prevented by inhibiting the NO3−− efflux. Similarly, pharmacological blocking of the anion efflux suppressed vacuolar collapse, a hallmark of cell death. The role of NO3−− efflux in mediating proteases activation was further assessed. It is shown that cryptogein induced the activation of three proteases with apparent molecular masses of 95, 190 and 240 kDa. Their activation occurred independently on the anion efflux and, together with cell death, was strongly reduced by cycloheximide and the protease inhibitor PMSF. In contrast, the NO3− efflux was shown to promote the accumulation of transcripts encoding vacuolar processing enzymes, a family of proteases previously reported to contribute to the disruption of vacuole integrity observed during the HR. Collectively, our data indicate that anion efflux is an early prerequisite to morphological and biochemical events participating to cell death.
Authors
Adrien Gauthier
Université de Bourgogne; Dijon, France
Olivier Lamotte
Department of Plant Biology, Fribourg, Switzerland
David Reboutier
Université Paris, Paris, France
Francois Bouteau
Université Paris, Paris, France
Alain Pugin
Université de Bourgogne; Dijon, France
David Wendehenne
Université de Bourgogne; Dijon, France
We now provide open access to journal articles published online for one year or more. This article may be downloaded at the following link:
Download PDF If the document does not open, please right-click on the link (control-click on a Macintosh) and select the option to save the file to disk.