OXR2 increases plant defense against a hemibiotrophic pathogen via the salicylic acid pathway

MENCIA, REGINA; CÉCCOLI, GABRIEL; FABRO, GEORGINA; TORTI, PABLO; COLOMBATTI, FRANCISCO; LUDWIG-MÜLLER, JUTTA; ALVAREZ, MARIA ELENA; WELCHEN, ELINA

PLANT PHYSIOLOGY.

AMER SOC PLANT BIOLOGISTS

Año: 2020

0032-0889

ABSTRACT54 Arabidopsis thaliana OXIDATION RESISTANCE 2 (AtOXR2) is a mitochondrial protein55 belonging to the Oxidation Resistance (OXR) protein family, recently described in plants. We56 analyzed the impact of AtOXR2 in Arabidopsis defense mechanisms against the57 hemibiotrophic bacterial pathogen Pseudomonas syringae. oxr2 mutant plants are more58 susceptible to infection by the pathogen and, conversely, plants over-expressing AtOXR259 (oeOXR2 plants) show enhanced disease resistance. Resistance in these plants is accompanied60 by higher expression of WRKY transcription factors, induction of genes involved in salicylic61 acid (SA) synthesis, accumulation of free SA, and overall activation of the SA-signaling62 pathway. Accordingly, defense phenotypes are dependent on SA-synthesis and SA-perception63 pathways, since they are lost in ics1/sid2 (isochorismate synthase 1/salicylic acid induction64 deficient 2) and npr1 (nonexpressor of pathogenesis-related genes 1) mutant backgrounds.65 Over-expression of AtOXR2 leads to faster and stronger oxidative burst in response to the66 bacterial flagellin peptide flg22. Moreover, AtOXR2 affects the nuclear localization of the67 transcriptional coactivator NPR1, a master regulator of SA signaling. oeOXR2 plants have68 increased levels of total glutathione and a more oxidized cytosolic redox cellular environment69 under normal growth conditions. Therefore, AtOXR2 contributes to establishing plant70 protection against infection by P. syringae acting on the activity of the SA pathway