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Extracellular Spermine Triggers a Rapid Intracellular Phosphatidic Acid Response in Arabidopsis, Involving PLDδ Activation and Stimulating Ion Flux
Ist Teil von
Frontiers in plant science, 2019-05, Vol.10, p.601-601
Ort / Verlag
Switzerland: Frontiers Media S.A
Erscheinungsjahr
2019
Link zum Volltext
Quelle
EZB Electronic Journals Library
Beschreibungen/Notizen
Polyamines, such as putrescine (Put), spermidine (Spd), and spermine (Spm), are low-molecular-weight polycationic molecules found in all living organisms. Despite the fact that they have been implicated in various important developmental and adaptative processes, their mode of action is still largely unclear. Here, we report that Put, Spd, and Spm trigger a rapid increase in the signaling lipid, phosphatidic acid (PA) in Arabidopsis seedlings but also mature leaves. Using time-course and dose-response experiments, Spm was found to be the most effective; promoting PA responses at physiological (low μM) concentrations. In seedlings, the increase of PA occurred mainly in the root and partly involved the plasma membrane polyamine-uptake transporter (PUT), RMV1. Using a differential
P
-labeling strategy combined with transphosphatidylation assays and T-DNA insertion mutants, we found that phospholipase D (PLD), and in particular
was the main contributor of the increase in PA. Measuring non-invasive ion fluxes (MIFE) across the root plasma membrane of wild type and
mutant seedlings, revealed that the formation of PA is linked to a gradual- and transient efflux of K
. Potential mechanisms of how
and the increase of PA are involved in polyamine function is discussed.