Arabidopsis thaliana-Pseudomonas syringae interaction is affected in plant polyamine oxidase null mutant lines

RODRIGUEZ-KESSLER M; JASSO-ROBLES FI; GONZALEZ ME; MÉNDEZ-IBERRI A; JIMÉNEZ-BREMONT F; GUERRERO-GONZÁLEZ ML; PIECKENSTAIN FL

Austin

Congreso; Plant Biology; 2016

American Society of Plant Biologists

Polyamines (PAs) are small aliphatic amines with important regulatory activities in plant cells. Changes in PA levels are prevalent under plant stress conditions. Under biotic stress, the accumulation of these amines can be accompanied by polyamine oxidation mediated by FAD-dependent polyamine oxidase enzymes (PAOs). Arabidopsis thaliana has five PAO enzymes with different intracellular localization: in the cytosol (AtPAO1 and AtPAO5) and in the peroxisome (AtPAO2, AtPAO3, and AtPAO4). PAO enzyme compartmentalization could impact in H2O2 production, as a result of polyamine oxidation, thereby controlling important physiological responses such as defense to pathogens. In this work we analyzed the role of AtPAO genes in the Arabidopsis thaliana-Pseudomonas syringae pathosystem. In particular, the AtPAO1 and AtPAO2 genes seem to be important for the interaction since their expression levels are increased in plants infected with Pseudomonas. Furthermore, histochemical analysis of the AtPAO2prom::GUS reporter line infected with P. syringae showed an increment in GUS activity in aerial tissues of the plants. Moreover, Atpao1-1 and Atpao2-1 null mutant lines are affected in their response to Pseudomonas and, the doble mutant Atpao1-1 x Atpao2-1 showed increased susceptibility as reflected by higher bacterial titers than WT plants. Since different phenotypes observed in AtPAO mutant lines-Pseudomonas interaction might be attributed to altered plant H2O2 levels, the role of H2O2 is discussed.