| Autor: |
Fonseca A; Millennium Science Initiative Program (ANID), Millennium Institute for Integrative Biology (iBio), Santiago 8331150, Chile.; Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), 75007 Uppsala, Sweden., Urzúa T; Millennium Science Initiative Program (ANID), Millennium Institute for Integrative Biology (iBio), Santiago 8331150, Chile.; Millennium Science Initiative Program (ANID), Millennium Nucleus for the Development of Super Adaptable Plants (MN-SAP), Santiago 8331150, Chile., Jelenska J; Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA., Sbarbaro C; Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370146, Chile., Seguel A; Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile., Duarte Y; Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370146, Chile., Greenberg JT; Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA., Holuigue L; Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile., Blanco-Herrera F; Millennium Science Initiative Program (ANID), Millennium Institute for Integrative Biology (iBio), Santiago 8331150, Chile.; Millennium Science Initiative Program (ANID), Millennium Nucleus for the Development of Super Adaptable Plants (MN-SAP), Santiago 8331150, Chile.; Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370146, Chile.; Center of Applied Ecology and Sustainability (CAPES), Santiago 8320000, Chile., Herrera-Vásquez A; Millennium Science Initiative Program (ANID), Millennium Institute for Integrative Biology (iBio), Santiago 8331150, Chile.; Millennium Science Initiative Program (ANID), Millennium Nucleus for the Development of Super Adaptable Plants (MN-SAP), Santiago 8331150, Chile.; Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370146, Chile. |
| Abstrakt: |
Salicylic acid (SA) is a hormone that modulates plant defenses by inducing changes in gene expression. The mechanisms that control SA accumulation are essential for understanding the defensive process. TGA transcription factors from clade II in Arabidopsis, which include the proteins TGA2, TGA5, and TGA6, are known to be key positive mediators for the transcription of genes such as PR-1 that are induced by SA application. However, unexpectedly, stress conditions that induce SA accumulation, such as infection with the avirulent pathogen P. syringae DC3000/AvrRPM1 and UV-C irradiation, result in enhanced PR-1 induction in plants lacking the clade II TGAs ( tga256 plants). Increased PR-1 induction was accompanied by enhanced isochorismate synthase-dependent SA production as well as the upregulation of several genes involved in the hormone's accumulation. In response to avirulent P. syringae , PR-1 was previously shown to be controlled by both SA-dependent and -independent pathways. Therefore, the enhanced induction of PR-1 (and other defense genes) and accumulation of SA in the tga256 mutant plants is consistent with the clade II TGA factors providing negative feedback regulation of the SA-dependent and/or -independent pathways. Together, our results indicate that the TGA transcription factors from clade II negatively control SA accumulation under stress conditions that induce the hormone production. Our study describes a mechanism involving old actors playing new roles in regulating SA homeostasis under stress. |
