Polyamine catabolism, hydrogen peroxide production and RBOH oxidases in the Arabidopsis thaliana- Pseudomonas interaction.

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

Puerto Vallarta

Congreso; XVII National Congress on Plant Biochemistry and Molecular Biology. X Joint Mexico - U. S. Symposium; 2017

Polyamines(PA), Put, Spd and Spm are low molecular weight aliphatic amines with important regulatory activities in plant cells. Diamine Oxidases(DAO), which are responsible for Put deamination, and Poliamine Oxidases(PAO) involved in Spd and Spm degradation mediate PA catabolism. In Arabidopsis, PAO enzymes are localized in the cytoplasm and the peroxisome this compartmentalization implies that PA degradation products(i.e. H2O2) are generated at specific sites and could participate in defense, signaling and programmed cell death.Herein, we focused on the regulation of PA catabolism and the relation of their degradation products(H2O2) with other enzymes that produce ROS in the Arabidopsis-Pseudomonas pathosystem. For this purpose, Arabidopsis seedlings were inoculated with P. syringae pv. tomato DC3000. It was found that AtPAO1 and AtPAO2 expression increased at 48 hpi. Interestingly, altered responses to P. syringae were observed in the T-DNA mutant lines Atpao1-1, Atpao2-1 and Atpao1-1 x Atpao2-1, implying that AtPAO1 and AtPAO2 genes are important for plant defense. These mutant lines had altered activities of RBOH, SOD and catalase enzymes, and increased ROS contents(O2.- and H2O2) even in control conditions without stress. The AtRBOHD and AtRBOHF expression levels were also increased in the mutant lines. A change in the spatio-temporal production of O2.- and H2O2 species was observed in the mutant lines infected with P. syringae. Our data suggest that AtPAO genes are important in defense responses against Pseudomonas, and that alteration in PA catabolism affects ROS production and the activities of RBOH, SOD and catalase enzymes.