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

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

PLANT SCIENCE

ELSEVIER IRELAND LTD

Lugar: Amsterdam; Año: 2019

0168-9452

Polyamines (PAs) are small aliphatic amines with important regulatory activities in plants. Biotic stress resultsin changes 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 activity generatesH⁠2O⁠2, an important molecule involved in cell signaling, elongation, programmed cell death, and defenseresponses. In this work we analyzed the role of AtPAO genes in the Arabidopsis thaliana-Pseudomonas syringaepathosystem. 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 susceptibility was foundin the double mutant Atpao1-1 x Atpao2-1. These polyamine oxidases mutant lines showed disturbed contents ofROS (H⁠2O⁠2 and O⁠2 ⁠−) and altered activities of RBOH, CAT and SOD enzymes both in infected and control plants.In addition, changes in the expression levels of AtRBOHD, AtRBOHF, AtPRX33, and AtPRX34 genes were also noticed. Our data indicate an important role for polyamine oxidases in plant defense and ROS homeostasis.