Modulation of polyamine metabolism in Arabidopsis thaliana by salicylic acid

ROSSI, FRANCO R.; GÁRRIZ, ANDRÉS; MARINA, MARÍA; PIECKENSTAIN, FERNANDO L.

PHYSIOLOGIA PLANTARUM

WILEY-BLACKWELL PUBLISHING, INC

Año: 2021

0031-9317

Polyamines (PAs) play important roles in plant defense against pathogens, but theregulation of PA metabolism by hormone-mediated defense signaling pathways hasnot been studied in depth. In this study, the modulation of PA metabolism by salicylicacid (SA) was analyzed in Arabidopsis by combining the exogenous application of thishormone with PA biosynthesis and SA synthesis/signaling mutants. SA induced notablemodifications of PA metabolism, mainly consisting in putrescine (Put) accumulationboth in whole-plant extracts and apoplastic fluids. Put was accumulated at theexpense of increased biosynthesis by Arginine Decarboxylase 2 and decreased oxidationby copper amine oxidase. Enhancement of Put levels by SA was independent ofthe regulatory protein Nonexpressor of Pathogenesis-Related Genes 1 (NPR1) andthe signaling kinases MKK4 and MPK3, but depended on MPK6. However, plantinfection by Pseudomonas syringae pv. tomato DC3000 elicited Put accumulation inan SA-dependent way. The present study demonstrates a clear connection betweenSA signaling and plant PA metabolism in Arabidopsis and contributes to understandingthe mechanisms by which SA modulates PA levels during plant-pathogeninteractions.