Underground AZA-priming against pathogens / Conferencista invitado.

CECCHINI NM; ROYCHOUDHRY S; STEFFES K; TAMBE A; ZODROW K; KONSTANTINOFF K; JUNG HW; GREENBERG JT

Conferencia; Gordon Research Conference - Plant Lipids: Structure, Metabolism & Function.; 2017

Local interactions with diverse microorganisms can lead to whole plant immunity. During this systemic resistance establishment, distal tissues become ?primed? to mount stronger/faster defense responses after the perception of systemic signals generated locally. One such signal is the plastid-produced lipid-derived oxylipin azelaic acid (AZA). The lipid transfer proteins (LTPs) AZI1 and EARLI1 are required for a normal AZA transport and the induction of systemic ?priming?. Because AZA can also be generated in roots, it is possible that AZA signaling and/or transport may play a role in this plant organ. Here we show that AZA treatment inhibits root growth in Arabidopsis WT but not in azi1 and earli1 mutant seedlings. Interestingly, AZA treatment on adult plant roots induces systemic resistance to Pseudomonas syringae in aerial tissues. Moreover, this root-triggered priming is reduced in azi1 and totally missing in earli1. We also observed that AZI1 localizes to root plastids implying that its underground site of action may be similar to those observed in leaves. However, we found that deuterated-AZA applied on the roots does not move to aerial tissues. Taken together, our results suggest that AZA generated in roots its needed for the root-triggered systemic priming through an AZI1/EARLI1-dependent pathway.