Insights in polyamine transport under biotic stress: roles in local and systemic responses

FLORES HERNÁNDEZ, E; PEÑA-LUCIO, EM; MORQUECHO-ROBLEDO, M; ALVARADO-GUITRON, P; GONZALEZ, ME; PIECKENSTAIN, FL; JASSO ROBLES, FI; DE DIEGO, N; OVANDO-VÁZQUEZ, C; BECERRA-FLORA, A; JIMÉNEZ-BREMONT, JF; RODRÍGUEZ-KESSLER, M

Congreso; XX National Plant Biochemistry and Molecular Biology Congress, 3rd Meeting of the Mexico Section of the American Society of Plant Biologists, 13th Mexico-USA Plant Biology Symposium; 2023

Polyamine transport is the less-understood mechanism involved in plant polyamine homeostasis. Until now, all the characterized plant polyamine uptake transporters (PUTs) import polyamines (mainly spermidine), amino acids (i.e., leucine), and the herbicide paraquat. The Arabidopsis thaliana PUT family (AtPUT) consists of five members with different intracellular localizations,which point to an important role in polyamine mobilization within the cell. Under biotic stress,significant changes in polyamine metabolism occur, like the accumulation of free and conjugated forms at the infection site. Hydrogen peroxide is generated by polyamine catabolism, it signals in plant defense and interconnects polyamines with other important stress-responsive pathways. Herein, we describe for the first time that polyamine transport is essential for plant defense.Arabidopsis thaliana Atput single mutants (Atput1-1 to Atput5-1) were screened in response toPseudomonas syringae pv. tomato DC3000 (Pst) and Botrytis cinerea (Bc) infection. Among the Atput family, two genes were identified to be differentially expressed in response to these pathogens. Under Bc infection, a bigger lesion size was found in the single and double mutant lines, and spermidine supplementation did not alleviate disease symptoms in the mutant lines. Deregulation in ROS levels, polyamine oxidase activity, and the expression of SA and JA/Et marker genes were found, which suggests that polyamine transport impacts ROS homeostasis and hormone signaling. In addition, under Pst infection, local and systemic responses to the pathogen were assessed, observing that one Atput mutant line abolishes systemic acquired resistance to Pst and Bc. RNA-seq data revealing changes in the systemic transcriptome of WT and Atput mutantline will be presented and discussed. Altogether our data suggest an important role for polyamine transport in the plant immune responses to pathogens of different lifestyles and point to the speculation that polyamines are or generate a signal for systemic responses in plants.