Systemic movement of long non-coding RNA ELENA1 attenuates leaf senescence under nitrogen deficiency.

Nitrogen is an essential macronutrient that is absorbed by roots and stored in leaves, mainly as ribulose-1,5-bisphosphate carboxylase/oxygenase 1,2 . During nitrogen deficiency (-N), plants activate leaf senescence for source-to-sink nitrogen remobilization for adaptative growth 3-6 . However, how -N signals perceived by roots are propagated to shoots remains underexplored. We found that ELF18-INDUCED LONG NONCODING RNA 1 (ELENA1) is -N inducible and attenuates -N-induced leaf senescence in Arabidopsis. Analysis of plants expressing the ELENA1 promoter β-glucuronidase fusion gene showed that ELENA1 is transcribed specifically in roots under -N. Reciprocal grafting of the wild type and elena1 demonstrated that ELENA1 functions systemically. ELENA1 dissociates the MEDIATOR SUBUNIT 19a-ORESARA1 transcriptional complex, thereby calibrating senescence progression. Our observations establish the systemic regulation of leaf senescence by a root-derived long non-coding RNA under -N in Arabidopsis.