OsEIL1 protects rice growth under NH₄⁺ nutrition by regulating OsVTC1‐3‐dependent N‐glycosylation and root NH₄⁺ efflux

Abstract

Rice is known for its superior adaptation to ammonium (NH 4 + ) as a nitrogen source. Compared to many other cereals, it displays lower NH 4 + efflux in roots and higher nitrogen-use efficiency on NH 4 + . A critical role for GDP-mannose pyrophosphorylase (VTC1) in controlling root NH 4 + fluxes was previously documented in Arabidopsis, but the molecular pathways involved in regulating VTC1-dependent NH 4 + efflux remain unclear. Here, we report that ETHYLENE-INSENSITIVE3-LIKE1 (OsEIL1) acts as a key transcription factor regulating OsVTC1-3-dependent NH 4 + efflux and protein N-glycosylation in rice grown under NH 4 + nutrition. We show that OsEIL1 in rice plays a contrasting role to Arabidopsis-homologous ETHYLENE-INSENSITIVE3 (AtEIN3) and maintains rice growth under NH 4 + by stabilizing protein N-glycosylation and reducing root NH 4 + efflux. OsEIL1 constrains NH 4 + efflux by activation of OsVTC1-3, but not OsVTC1-1 or OsVTC1-8. OsEIL1 binds directly to the promoter EIN3-binding site (EBS) of OsVTC1-3 in vitro and in vivo and acts to increase the transcription of OsVTC1-3. Our work demonstrates an important link between excessive root NH 4 + efflux and OsVTC1-3-mediated protein N-glycosylation in rice grown under NH 4 + nutrition and identifies OsEIL1 as a direct genetic regulator of OsVTC1-3 expression.

OsEIL1 and OsEIL2, two master regulators of rice ethylene signaling, promote the expression of ROS scavenging genes to facilitate coleoptile elongation and seedling emergence from soil

“…The ein2 and eil1 mutants, VTC1-3 overexpression line, and eil1 / VTC1-3-OX line have been described previously ( Ma et al., 2013a ; 2013b ; Yang et al., 2015 ; Qin et al., 2016a ; Li et al., 2022 ). The eil2 allelic mutants were generated using CRISPR‒Cas9 as described previously ( Xu et al., 2017 ); the target region 5′-ACGTTGATAGCAAGGCCGCC-3′ of OsEIL2 was introduced into the pHUN4c12 vector backbone, and the recombinant vector was transformed into Agrobacterium strain EHA105-pSOUP for rice transformation.…”

The alleviation of ammonium toxicity in plants

“…Transcription factor WRKY46 regulates the contents of GDP‐mannose by directly suppressing the expression of NUDX9 , which negatively regulates GDP‐mannose levels (Di et al, 2021). In rice, transcription factor OsEIL1 directly activates OsVTC1‐3 expression under high‐NH 4 + conditions (Li et al, 2022).…”

Plant nitrogen availability and crosstalk with phytohormones signallings and their biotechnology breeding application in crops

“…ETH, BR, and JA regulate NH 4 + uptake by regulating AMT1 family (Figure 5 ; Table 1 ). ETH signalling key TF OsEIL1 positively regulates NH 4 + efflux by directly regulating OsVTC1‐3 ‐mediated protein N‐glycosylation in rice (Li et al ., 2022 ). Transcriptome analysis suggests that BR up‐regulates AMTs in Arabidopsis and rice (Yu et al ., 2011 ).…”