Abstract
Efficient nitrogen assimilation is important for sustainable agriculture1, yet its subcellular organization remains unknown. Here we show that plastoglobules (PGs) in the chloroplasts of mesophyll cells function as a metabolic hub that orchestrates nitrogen utilization in maize. Nitrogen-responsive dynamics of PGs represent a conserved feature across plant species. We identify two key enzymes, nitrite reductase 2 (ZmNIR2) and glutamine synthetase 1 (ZmGLN1), specifically targeted to PGs by a chloroplast transit peptide and hydrophobic region. Cryogenic electron microscopy analysis of recombinant ZmGLN1 shows a decameric complex, enabling a metabolon with ZmNIR2 for enhanced efficiency. Among two NIR and six GLN enzymes, ZmNIR2 and ZmGLN1 are the primary PG-localized components that orchestrate sub-organellar nitrogen assimilation and dictate nitrogen use efficiency. Genetic variation in ZmNIR2 splicing in cultivated germplasm generates a PG-targeted isoform (ZmNIR2T1) that boosts NUE. Our work establishes PGs as a central compartment for primary nitrogen assimilation, providing a promising strategy to develop high-NUE crops for global food security. Chloroplast plastoglobules act as nitrogen-assimilation hubs in maize, with key enzymes enhancing nitrogen-use efficiency and offering new strategies for developing high-yield, sustainable crops.
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Claims 6
Claim · model-written summary
Plastoglobules in the chloroplasts of maize mesophyll cells function as a metabolic hub orchestrating nitrogen utilization.
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“maize”
e0“plastoglobules (PGs) in the chloroplasts of mesophyll cells function as a metabolic hub that orchestrates nitrogen utilization in maize”
Claim · model-written summary
Nitrogen-responsive dynamics of plastoglobules are a conserved feature across plant species.
Verbatim
t0“maize”
e0“Nitrogen-responsive dynamics of PGs represent a conserved feature across plant species”
Claim · model-written summary
Two enzymes, ZmNIR2 and ZmGLN1, are specifically targeted to plastoglobules by a chloroplast transit peptide and a hydrophobic region.
- Gene
- nitrite reductase 2 (ZmNIR2) and glutamine synthetase 1 (ZmGLN1)e0
- Outcome
- specifically targeted to PGse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“maize”
e0“We identify two key enzymes, nitrite reductase 2 (ZmNIR2) and glutamine synthetase 1 (ZmGLN1), specifically targeted to PGs by a chloroplast transit peptide and hydrophobic region”
Claim · model-written summary
Cryogenic electron microscopy of recombinant ZmGLN1 shows a decameric complex.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“maize”
e0“Cryogenic electron microscopy analysis of recombinant ZmGLN1 shows a decameric complex”
Claim · model-written summary
ZmNIR2 and ZmGLN1 are the primary plastoglobule-localized components that orchestrate sub-organellar nitrogen assimilation and dictate nitrogen use efficiency.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“maize”
e0“ZmNIR2 and ZmGLN1 are the primary PG-localized components that orchestrate sub-organellar nitrogen assimilation and dictate nitrogen use efficiency”
Claim · model-written summary
Genetic variation in ZmNIR2 splicing in cultivated germplasm generates a plastoglobule-targeted isoform, ZmNIR2T1, that boosts nitrogen use efficiency.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“maize”
e0“Genetic variation in ZmNIR2 splicing in cultivated germplasm generates a PG-targeted isoform (ZmNIR2T1) that boosts NUE”