Modulation of Plant Defenses by Ethylene
Ethylene (ET) plays a critical role in the activation of plant defenses against different biotic stresses through its participation in a complex signaling network that includes jasmonic acid (JA), salicylic acid (SA), and abscisic acid (ABA). Pathogen attack, wounding, and herbivory trigger asymmetric activation of this defense signaling network, thereby affecting the final balance of interactions between its components and establishing a targeted response to the initial threat. Ethylene’s contribution to the modulation of this defense network relies on the complexity of the regulation of multigene families involved in ET biosynthesis, signal transduction, and crosstalk and enables the plant to fine-tune its response. The function of the members of these multigene families is tightly regulated at transcriptional, post-transcriptional, and post-translational levels. It is generally accepted that ET cooperates with JA in the activation of defenses against necrotrophic pathogens and antagonizes SA-dependent resistance against biotrophic pathogens. However, this is likely an oversimplified view, because cooperative interactions between ET and SA pathways have been reported and ET has been implicated in the activation of defenses against some biotrophic and hemibiotrophic pathogens. Therefore, deciphering ET’s place in this hormonal network is essential to understanding how the cell orchestrates an optimal response to a specific biotic stress.
KeywordsEthylene Plant defense Necrotroph Jasmonic acid Salicylic acid Abscisic acid Hormone crosstalk PRs ERFs GCC box
This work was financed by grants to R.S. from the Spanish Ministerio de Ciencia y Tecnología (BIO2001-0567, BIO2004-02502, and GEN2003-20218-C02-02), and from the Comunidad de Madrid (07G/0048/2000, 07B/0044/2002, and GR/SAL/0674/2004).
B.A. has been supported by postdoctoral fellowships from the EU (CRISP project HPRN-CT-2000-00093) and from the Spanish Ministerio de Educación y Ciencia (GEN2003-20218-C02-02).
J-M.C. has been supported by postdoctoral contract associated with BIO2004-02502 funded by Spanish Ministerio de Educación y Ciencia.
I.R-S. has been supported by postdoctoral I3P fellowship funded by Consejo Superior de Investigaciones Cientificas (CSIC).
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