Decrease of Arabidopsis PAO activity entails increased RBOH activity, ROS content and altered responses to Pseudomonas

PIECKENSTAIN, FL; JIMÉNEZ-BREMONT, JF; JASSO ROBLES, FI; RAMÍREZ-GARCÍA, JM; RODRÍGUEZ-KESSLER, M; GONZALEZ, ME; GUERRERO-GONZÁLEZ, ML

PLANT SCIENCE

ELSEVIER IRELAND LTD

Lugar: Amsterdam; Año: 2020

0168-9452

Polyamines (PAs) are small aliphatic amines with important regulatory activities in plants. Biotic stress results inchanges in PA levels due to de novo synthesis and PA oxidation. In Arabidopsis thaliana five FAD-dependentpolyamine oxidase enzymes (AtPAO1-5) participate in PA back-conversion and degradation. PAO activitygenerates H2O2, an important molecule involved in cell signaling, elongation, programmed cell death, and de-fense responses. In this work we analyzed the role of AtPAO genes in the Arabidopsis thaliana-Pseudomonassyringae pathosystem. AtPAO1 and AtPAO2 genes were transcriptionally up-regulated in infected plants. Atpao1-1 and Atpao2-1 single mutant lines displayed altered responses to Pseudomonas, and an increased susceptibilitywas found in the double mutant Atpao1-1 x Atpao2-1. These polyamine oxidases mutant lines showed disturbedcontents of ROS (H2O2 and O2%−) and altered activities of RBOH, CAT and SOD enzymes both in infected andcontrol plants. In addition, changes in the expression levels of AtRBOHD, AtRBOHF, AtPRX33, and AtPRX34genes were also noticed. Our data indicate an important role for polyamine oxidases in plant defense and ROShomeostasis.