Salicylic acid induces H2O2 production and endochitinase gene expression but not ethylene biosynthesis in Castanea sativa in vitro model system
Author(s)
Date Issued
2008
Type
Article
Abstract
Salicylic acid (SA), ethylene (ET), and wounding are all known to influence plant
defense response. Experiments attempting to determine SA’s relation to ET
biosynthesis and defense gene expression have shown conflicting results. To confront
this, we developed an in vitro model system to investigate how SA affects ET
biosynthesis, hydrogen peroxide (H2O2) production and endochitinase gene expression
in the European chestnut. ET measurements of in vitro shoots indicated a
critical time point for SA exogenous application, enabling us to study its effects
independent of ET. In addition, ET measurements demonstrated that its own
increased biosynthesis was a response to wounding but not to SA treatment.
Application of the ET biosynthesis inhibitor, aminoethoxyvinylglycine (AVG),
on wounded and SA-treated shoots blocked wounding-induced ET production.
Interestingly, SA inhibited ET production, but to a lesser extent than AVG.
Additionally, SA also induced the accumulation of endochitinase transcript level.
Likewise, a sensitive tissue-print assay showed that SA further increased the level of
H2O2. Yet, SA-induced endochitinase gene expression and SA-enhanced H2O2
production levels were independent of ET. The cumulative results indicate that SA
acts as an inducer of endochitinase PR gene expression and of H2O2 oxidative burst.
This suggests that SA is a component of the signal transduction pathway leading to
defense against pathogens in chestnut. Further, the model system developed for this experiment should facilitate the deciphering of defense signaling pathways and their
cross-talk. Moreover, it should also benefit the study of trees of long generation time
that are known to be recalcitrant to in vitro studies.
Additional information
L'articolo é disponibile sul sito dell'editore: http://www.sciencedirect.com
Citation
Harfouche, A.L. et al. 2008. Salicylic acid induces H2O2 production and endochitinase gene expression but not ethylene biosynthesis in Castanea sativa in vitro model system. "Journal of Plant Physiology" 165(7): 734-744
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